from manim_imports_ext import *

SICKLY_GREEN = "#9BBD37"
COLOR_MAP = {
    "S": BLUE,
    "I": RED,
    "R": GREY_D,
}


def update_time(mob, dt):
    mob.time += dt


class Person(VGroup):
    CONFIG = {
        "status": "S",  # S, I or R
        "height": 0.2,
        "color_map": COLOR_MAP,
        "infection_ring_style": {
            "stroke_color": RED,
            "stroke_opacity": 0.8,
            "stroke_width": 0,
        },
        "infection_radius": 0.5,
        "infection_animation_period": 2,
        "symptomatic": False,
        "p_symptomatic_on_infection": 1,
        "max_speed": 1,
        "dl_bound": [-FRAME_WIDTH / 2, -FRAME_HEIGHT / 2],
        "ur_bound": [FRAME_WIDTH / 2, FRAME_HEIGHT / 2],
        "gravity_well": None,
        "gravity_strength": 1,
        "wall_buffer": 1,
        "wander_step_size": 1,
        "wander_step_duration": 1,
        "social_distance_factor": 0,
        "social_distance_color_threshold": 2,
        "n_repulsion_points": 10,
        "social_distance_color": YELLOW,
        "max_social_distance_stroke_width": 5,
        "asymptomatic_color": YELLOW,
    }

    def __init__(self, **kwargs):
        super().__init__(**kwargs)

        self.time = 0
        self.last_step_change = -1
        self.change_anims = []
        self.velocity = np.zeros(3)
        self.infection_start_time = np.inf
        self.infection_end_time = np.inf
        self.repulsion_points = []
        self.num_infected = 0

        self.center_point = VectorizedPoint()
        self.add(self.center_point)
        self.add_body()
        self.add_infection_ring()
        self.set_status(self.status, run_time=0)

        # Updaters
        self.add_updater(update_time)
        self.add_updater(lambda m, dt: m.update_position(dt))
        self.add_updater(lambda m, dt: m.update_infection_ring(dt))
        self.add_updater(lambda m: m.progress_through_change_anims())

    def add_body(self):
        body = self.get_body()
        body.set_height(self.height)
        body.move_to(self.get_center())
        self.add(body)
        self.body = body

    def get_body(self, status):
        person = SVGMobject(file_name="person")
        person.set_stroke(width=0)
        return person

    def set_status(self, status, run_time=1):
        start_color = self.color_map[self.status]
        end_color = self.color_map[status]

        if status == "I":
            self.infection_start_time = self.time
            self.infection_ring.set_stroke(width=0, opacity=0)
            if random.random() < self.p_symptomatic_on_infection:
                self.symptomatic = True
            else:
                self.infection_ring.set_color(self.asymptomatic_color)
                end_color = self.asymptomatic_color
        if self.status == "I":
            self.infection_end_time = self.time
            self.symptomatic = False

        anims = [
            UpdateFromAlphaFunc(
                self.body,
                lambda m, a: m.set_color(interpolate_color(
                    start_color, end_color, a
                )),
                run_time=run_time,
            )
        ]
        for anim in anims:
            self.push_anim(anim)

        self.status = status

    def push_anim(self, anim):
        anim.suspend_mobject_updating = False
        anim.begin()
        anim.start_time = self.time
        self.change_anims.append(anim)
        return self

    def pop_anim(self, anim):
        anim.update(1)
        anim.finish()
        self.change_anims.remove(anim)

    def add_infection_ring(self):
        self.infection_ring = Circle(
            radius=self.height / 2,
        )
        self.infection_ring.set_style(**self.infection_ring_style)
        self.add(self.infection_ring)
        self.infection_ring.time = 0
        return self

    def update_position(self, dt):
        center = self.get_center()
        total_force = np.zeros(3)

        # Gravity
        if self.wander_step_size != 0:
            if (self.time - self.last_step_change) > self.wander_step_duration:
                vect = rotate_vector(RIGHT, TAU * random.random())
                self.gravity_well = center + self.wander_step_size * vect
                self.last_step_change = self.time

        if self.gravity_well is not None:
            to_well = (self.gravity_well - center)
            dist = get_norm(to_well)
            if dist != 0:
                total_force += self.gravity_strength * to_well / (dist**3)

        # Potentially avoid neighbors
        if self.social_distance_factor > 0:
            repulsion_force = np.zeros(3)
            min_dist = np.inf
            for point in self.repulsion_points:
                to_point = point - center
                dist = get_norm(to_point)
                if 0 < dist < min_dist:
                    min_dist = dist
                if dist > 0:
                    repulsion_force -= self.social_distance_factor * to_point / (dist**3)
            sdct = self.social_distance_color_threshold
            self.body.set_stroke(
                self.social_distance_color,
                width=clip(
                    (sdct / min_dist) - sdct,
                    # 2 * (sdct / min_dist),
                    0,
                    self.max_social_distance_stroke_width
                ),
                background=True,
            )
            total_force += repulsion_force

        # Avoid walls
        wall_force = np.zeros(3)
        for i in range(2):
            to_lower = center[i] - self.dl_bound[i]
            to_upper = self.ur_bound[i] - center[i]

            # Bounce
            if to_lower < 0:
                self.velocity[i] = abs(self.velocity[i])
                self.set_coord(self.dl_bound[i], i)
            if to_upper < 0:
                self.velocity[i] = -abs(self.velocity[i])
                self.set_coord(self.ur_bound[i], i)

            # Repelling force
            wall_force[i] += max((-1 / self.wall_buffer + 1 / to_lower), 0)
            wall_force[i] -= max((-1 / self.wall_buffer + 1 / to_upper), 0)
        total_force += wall_force

        # Apply force
        self.velocity += total_force * dt

        # Limit speed
        speed = get_norm(self.velocity)
        if speed > self.max_speed:
            self.velocity *= self.max_speed / speed

        # Update position
        self.shift(self.velocity * dt)

    def update_infection_ring(self, dt):
        ring = self.infection_ring
        if not (self.infection_start_time <= self.time <= self.infection_end_time + 1):
            return self

        ring_time = self.time - self.infection_start_time
        period = self.infection_animation_period

        alpha = (ring_time % period) / period
        ring.set_height(interpolate(
            self.height,
            self.infection_radius,
            smooth(alpha),
        ))
        ring.set_stroke(
            width=interpolate(
                0, 5,
                there_and_back(alpha),
            ),
            opacity=min([
                min([ring_time, 1]),
                min([self.infection_end_time + 1 - self.time, 1]),
            ]),
        )

        return self

    def progress_through_change_anims(self):
        for anim in self.change_anims:
            if anim.run_time == 0:
                alpha = 1
            else:
                alpha = (self.time - anim.start_time) / anim.run_time
            anim.interpolate(alpha)
            if alpha >= 1:
                self.pop_anim(anim)

    def get_center(self):
        return self.center_point.points[0]


class DotPerson(Person):
    def get_body(self):
        return Dot()


class PiPerson(Person):
    CONFIG = {
        "mode_map": {
            "S": "guilty",
            "I": "sick",
            "R": "tease",
        }
    }

    def get_body(self):
        return Randolph()

    def set_status(self, status, run_time=1):
        super().set_status(status)

        target = self.body.copy()
        target.change(self.mode_map[status])
        target.set_color(self.color_map[status])

        transform = Transform(self.body, target)
        transform.begin()

        def update(body, alpha):
            transform.update(alpha)
            body.move_to(self.center_point)

        anims = [
            UpdateFromAlphaFunc(self.body, update, run_time=run_time),
        ]
        for anim in anims:
            self.push_anim(anim)

        return self


class SIRSimulation(VGroup):
    CONFIG = {
        "n_cities": 1,
        "city_population": 100,
        "box_size": 7,
        "person_type": PiPerson,
        "person_config": {
            "height": 0.2,
            "infection_radius": 0.6,
            "gravity_strength": 1,
            "wander_step_size": 1,
        },
        "p_infection_per_day": 0.2,
        "infection_time": 5,
        "travel_rate": 0,
        "limit_social_distancing_to_infectious": False,
    }

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.time = 0
        self.add_updater(update_time)

        self.add_boxes()
        self.add_people()

        self.add_updater(lambda m, dt: m.update_statusses(dt))

    def add_boxes(self):
        boxes = VGroup()
        for x in range(self.n_cities):
            box = Square()
            box.set_height(self.box_size)
            box.set_stroke(WHITE, 3)
            boxes.add(box)
        boxes.arrange_in_grid(buff=LARGE_BUFF)
        self.add(boxes)
        self.boxes = boxes

    def add_people(self):
        people = VGroup()
        for box in self.boxes:
            dl_bound = box.get_corner(DL)
            ur_bound = box.get_corner(UR)
            box.people = VGroup()
            for x in range(self.city_population):
                person = self.person_type(
                    dl_bound=dl_bound,
                    ur_bound=ur_bound,
                    **self.person_config
                )
                person.move_to([
                    interpolate(lower, upper, random.random())
                    for lower, upper in zip(dl_bound, ur_bound)
                ])
                person.box = box
                box.people.add(person)
                people.add(person)

        # Choose a patient zero
        random.choice(people).set_status("I")
        self.add(people)
        self.people = people

    def update_statusses(self, dt):
        for box in self.boxes:
            s_group, i_group = [
                list(filter(
                    lambda m: m.status == status,
                    box.people
                ))
                for status in ["S", "I"]
            ]

            for s_person in s_group:
                for i_person in i_group:
                    dist = get_norm(i_person.get_center() - s_person.get_center())
                    if dist < s_person.infection_radius and random.random() < self.p_infection_per_day * dt:
                        s_person.set_status("I")
                        i_person.num_infected += 1
            for i_person in i_group:
                if (i_person.time - i_person.infection_start_time) > self.infection_time:
                    i_person.set_status("R")

        # Travel
        if self.travel_rate > 0:
            path_func = path_along_arc(45 * DEGREES)
            for person in self.people:
                if random.random() < self.travel_rate * dt:
                    new_box = random.choice(self.boxes)
                    person.box.people.remove(person)
                    new_box.people.add(person)
                    person.box = new_box
                    person.dl_bound = new_box.get_corner(DL)
                    person.ur_bound = new_box.get_corner(UR)

                    person.old_center = person.get_center()
                    person.new_center = new_box.get_center()
                    anim = UpdateFromAlphaFunc(
                        person,
                        lambda m, a: m.move_to(path_func(
                            m.old_center, m.new_center, a,
                        )),
                        run_time=1,
                    )
                    person.push_anim(anim)

        # Social distancing
        centers = np.array([person.get_center() for person in self.people])
        if self.limit_social_distancing_to_infectious:
            repelled_centers = np.array([
                person.get_center()
                for person in self.people
                if person.symptomatic
            ])
        else:
            repelled_centers = centers

        if len(repelled_centers) > 0:
            for center, person in zip(centers, self.people):
                if person.social_distance_factor > 0:
                    diffs = np.linalg.norm(repelled_centers - center, axis=1)
                    person.repulsion_points = repelled_centers[np.argsort(diffs)[1:person.n_repulsion_points + 1]]

    def get_status_counts(self):
        return np.array([
            len(list(filter(
                lambda m: m.status == status,
                self.people
            )))
            for status in "SIR"
        ])

    def get_status_proportions(self):
        counts = self.get_status_counts()
        return counts / sum(counts)


class SIRGraph(VGroup):
    CONFIG = {
        "color_map": COLOR_MAP,
        "height": 7,
        "width": 5,
        "update_frequency": 0.5,
        "include_braces": False,
    }

    def __init__(self, simulation, **kwargs):
        super().__init__(**kwargs)
        self.simulation = simulation
        self.data = [simulation.get_status_proportions()] * 2
        self.add_axes()
        self.add_graph()
        self.add_x_labels()

        self.time = 0
        self.last_update_time = 0
        self.add_updater(update_time)
        self.add_updater(lambda m: m.update_graph())
        self.add_updater(lambda m: m.update_x_labels())

    def add_axes(self):
        axes = Axes(
            y_min=0,
            y_max=1,
            y_axis_config={
                "tick_frequency": 0.1,
            },
            x_min=0,
            x_max=1,
            axis_config={
                "include_tip": False,
            },
        )
        origin = axes.c2p(0, 0)
        axes.x_axis.set_width(self.width, about_point=origin, stretch=True)
        axes.y_axis.set_height(self.height, about_point=origin, stretch=True)

        self.add(axes)
        self.axes = axes

    def add_graph(self):
        self.graph = self.get_graph(self.data)
        self.add(self.graph)

    def add_x_labels(self):
        self.x_labels = VGroup()
        self.x_ticks = VGroup()
        self.add(self.x_ticks, self.x_labels)

    def get_graph(self, data):
        axes = self.axes
        i_points = []
        s_points = []
        for x, props in zip(np.linspace(0, 1, len(data)), data):
            i_point = axes.c2p(x, props[1])
            s_point = axes.c2p(x, sum(props[:2]))
            i_points.append(i_point)
            s_points.append(s_point)

        r_points = [
            axes.c2p(0, 1),
            axes.c2p(1, 1),
            *s_points[::-1],
            axes.c2p(0, 1),
        ]
        s_points.extend([
            *i_points[::-1],
            s_points[0],
        ])
        i_points.extend([
            axes.c2p(1, 0),
            axes.c2p(0, 0),
            i_points[0],
        ])

        points_lists = [s_points, i_points, r_points]
        regions = VGroup(VMobject(), VMobject(), VMobject())

        for region, status, points in zip(regions, "SIR", points_lists):
            region.set_points_as_corners(points)
            region.set_stroke(width=0)
            region.set_fill(self.color_map[status], 1)
        regions[0].set_fill(opacity=0.5)

        return regions

    def update_graph(self):
        if (self.time - self.last_update_time) > self.update_frequency:
            self.data.append(self.simulation.get_status_proportions())
            self.graph.become(self.get_graph(self.data))
            self.last_update_time = self.time

    def update_x_labels(self):
        tick_height = 0.03 * self.graph.get_height()
        tick_template = Line(DOWN, UP)
        tick_template.set_height(tick_height)

        def get_tick(x):
            tick = tick_template.copy()
            tick.move_to(self.axes.c2p(x / self.time, 0))
            return tick

        def get_label(x, tick):
            label = Integer(x)
            label.set_height(tick_height)
            label.next_to(tick, DOWN, buff=0.5 * tick_height)
            return label

        self.x_labels.set_submobjects([])
        self.x_ticks.set_submobjects([])

        if self.time < 15:
            tick_range = range(1, int(self.time) + 1)
        elif self.time < 50:
            tick_range = range(5, int(self.time) + 1, 5)
        elif self.time < 100:
            tick_range = range(10, int(self.time) + 1, 10)
        else:
            tick_range = range(20, int(self.time) + 1, 20)

        for x in tick_range:
            tick = get_tick(x)
            label = get_label(x, tick)
            self.x_ticks.add(tick)
            self.x_labels.add(label)

        # TODO, if I care, refactor
        if 10 < self.time < 15:
            alpha = (self.time - 10) / 5
            for tick, label in zip(self.x_ticks, self.x_labels):
                if label.get_value() % 5 != 0:
                    label.set_opacity(1 - alpha)
                    tick.set_opacity(1 - alpha)
        if 45 < self.time < 50:
            alpha = (self.time - 45) / 5
            for tick, label in zip(self.x_ticks, self.x_labels):
                if label.get_value() % 10 == 5:
                    label.set_opacity(1 - alpha)
                    tick.set_opacity(1 - alpha)

    def add_v_line(self, line_time=None, color=YELLOW, stroke_width=3):
        if line_time is None:
            line_time = self.time

        axes = self.axes
        v_line = Line(
            axes.c2p(1, 0), axes.c2p(1, 1),
            stroke_color=color,
            stroke_width=stroke_width,
        )
        v_line.add_updater(
            lambda m: m.move_to(
                axes.c2p(line_time / max(self.time, 1e-6), 0),
                DOWN,
            )
        )

        self.add(v_line)


class GraphBraces(VGroup):
    CONFIG = {
        "update_frequency": 0.5,
    }

    def __init__(self, graph, simulation, **kwargs):
        super().__init__(**kwargs)
        axes = self.axes = graph.axes
        self.simulation = simulation

        ys = np.linspace(0, 1, 4)
        self.lines = VGroup(*[
            Line(axes.c2p(1, y1), axes.c2p(1, y2))
            for y1, y2 in zip(ys, ys[1:])
        ])
        self.braces = VGroup(*[Brace(line, RIGHT) for line in self.lines])
        self.labels = VGroup(
            TextMobject("Susceptible", color=COLOR_MAP["S"]),
            TextMobject("Infectious", color=COLOR_MAP["I"]),
            TextMobject("Removed", color=COLOR_MAP["R"]),
        )

        self.max_label_height = graph.get_height() * 0.05

        self.add(self.braces, self.labels)

        self.time = 0
        self.last_update_time = -1
        self.add_updater(update_time)
        self.add_updater(lambda m: m.update_braces())
        self.update(0)

    def update_braces(self):
        if (self.time - self.last_update_time) <= self.update_frequency:
            return

        self.last_update_time = self.time
        lines = self.lines
        braces = self.braces
        labels = self.labels
        axes = self.axes

        props = self.simulation.get_status_proportions()
        ys = np.cumsum([0, props[1], props[0], props[2]])

        epsilon = 1e-6
        for i, y1, y2 in zip([1, 0, 2], ys, ys[1:]):
            lines[i].set_points_as_corners([
                axes.c2p(1, y1),
                axes.c2p(1, y2),
            ])
            height = lines[i].get_height()

            braces[i].set_height(
                max(height, epsilon),
                stretch=True
            )
            braces[i].next_to(lines[i], RIGHT)
            label_height = clip(height, epsilon, self.max_label_height)
            labels[i].scale(label_height / labels[i][0][0].get_height())
            labels[i].next_to(braces[i], RIGHT)
        return self


class ValueSlider(NumberLine):
    CONFIG = {
        "x_min": 0,
        "x_max": 1,
        "tick_frequency": 0.1,
        "numbers_with_elongated_ticks": [],
        "numbers_to_show": np.linspace(0, 1, 6),
        "decimal_number_config": {
            "num_decimal_places": 1,
        },
        "stroke_width": 5,
        "width": 8,
        "marker_color": BLUE,
    }

    def __init__(self, name, value, **kwargs):
        super().__init__(**kwargs)
        self.set_width(self.width, stretch=True)
        self.add_numbers()

        self.marker = ArrowTip(start_angle=-90 * DEGREES)
        self.marker.move_to(self.n2p(value), DOWN)
        self.marker.set_color(self.marker_color)
        self.add(self.marker)

        # self.label = DecimalNumber(value)
        # self.label.next_to(self.marker, UP)
        # self.add(self.label)

        self.name = TextMobject(name)
        self.name.scale(1.25)
        self.name.next_to(self, DOWN)
        self.name.match_color(self.marker)
        self.add(self.name)

    def get_change_anim(self, new_value, **kwargs):
        start_value = self.p2n(self.marker.get_bottom())
        # m2l = self.label.get_center() - self.marker.get_center()

        def update(mob, alpha):
            interim_value = interpolate(start_value, new_value, alpha)
            mob.marker.move_to(mob.n2p(interim_value), DOWN)
            # mob.label.move_to(mob.marker.get_center() + m2l)
            # mob.label.set_value(interim_value)

        return UpdateFromAlphaFunc(self, update, **kwargs)


# Scenes

class Test(Scene):
    def construct(self):
        path_func = path_along_arc(45 * DEGREES)
        person = PiPerson(height=1, gravity_strength=0.2)
        person.gravity_strength = 0

        person.old_center = person.get_center()
        person.new_center = 4 * RIGHT

        self.add(person)
        self.wait()

        self.play(UpdateFromAlphaFunc(
            person,
            lambda m, a: m.move_to(path_func(
                m.old_center,
                m.new_center,
                a,
            )),
            run_time=3,
            rate_func=there_and_back,
        ))

        self.wait(3)
        self.wait(3)


class RunSimpleSimulation(Scene):
    CONFIG = {
        "simulation_config": {
            "person_type": PiPerson,
            "n_cities": 1,
            "city_population": 100,
            "person_config": {
                "infection_radius": 0.75,
                "social_distance_factor": 0,
                "gravity_strength": 0.2,
                "max_speed": 0.5,
            },
            "travel_rate": 0,
            "infection_time": 5,
        },
        "graph_config": {
            "update_frequency": 1 / 15,
        },
        "graph_height_to_frame_height": 0.5,
        "graph_width_to_frame_height": 0.75,
        "include_graph_braces": True,
    }

    def setup(self):
        self.add_simulation()
        self.position_camera()
        self.add_graph()
        self.add_sliders()
        self.add_R_label()
        self.add_total_cases_label()

    def construct(self):
        self.run_until_zero_infections()

    def wait_until_infection_threshold(self, threshold):
        self.wait_until(lambda: self.simulation.get_status_counts()[1] > threshold)

    def run_until_zero_infections(self):
        while True:
            self.wait(5)
            if self.simulation.get_status_counts()[1] == 0:
                self.wait(5)
                break

    def add_R_label(self):
        label = VGroup(
            TexMobject("R = "),
            DecimalNumber(),
        )
        label.arrange(RIGHT)
        boxes = self.simulation.boxes
        label.set_width(0.25 * boxes.get_width())
        label.next_to(boxes.get_corner(DL), DR)
        self.add(label)

        all_R0_values = []

        def update_label(label):
            if (self.time - label.last_update_time) < label.update_period:
                return
            label.last_update_time = self.time

            values = []
            for person in self.simulation.people:
                if person.status == "I":
                    prop = (person.time - person.infection_start_time) / self.simulation.infection_time
                    if prop > 0.1:
                        values.append(person.num_infected / prop)
            if len(values) > 0:
                all_R0_values.append(np.mean(values))
                average = np.mean(all_R0_values[-20:])
                label[1].set_value(average)

        label.last_update_time = 0
        label.update_period = 1
        label.add_updater(update_label)

    def add_total_cases_label(self):
        label = VGroup(
            TextMobject("\\# Active cases = "),
            Integer(1),
        )
        label.arrange(RIGHT)
        label[1].align_to(label[0][0][1], DOWN)
        label.set_color(RED)
        boxes = self.simulation.boxes
        label.set_width(0.5 * boxes.get_width())
        label.next_to(boxes, UP, buff=0.03 * boxes.get_width())

        label.add_updater(
            lambda m: m[1].set_value(self.simulation.get_status_counts()[1])
        )
        self.total_cases_label = label
        self.add(label)

    def add_simulation(self):
        self.simulation = SIRSimulation(**self.simulation_config)
        self.add(self.simulation)

    def position_camera(self):
        frame = self.camera.frame
        boxes = self.simulation.boxes
        min_height = boxes.get_height() + 1
        min_width = 3 * boxes.get_width()
        if frame.get_height() < min_height:
            frame.set_height(min_height)
        if frame.get_width() < min_width:
            frame.set_width(min_width)

        frame.next_to(boxes.get_right(), LEFT, buff=-0.1 * boxes.get_width())

    def add_graph(self):
        frame = self.camera.frame
        frame_height = frame.get_height()
        graph = SIRGraph(
            self.simulation,
            height=self.graph_height_to_frame_height * frame_height,
            width=self.graph_width_to_frame_height * frame_height,
            **self.graph_config,
        )
        graph.move_to(frame, UL)
        graph.shift(0.05 * DR * frame_height)
        self.add(graph)
        self.graph = graph

        if self.include_graph_braces:
            self.graph_braces = GraphBraces(
                graph,
                self.simulation,
                update_frequency=graph.update_frequency
            )
            self.add(self.graph_braces)

    def add_sliders(self):
        pass


class RunSimpleSimulationWithDots(RunSimpleSimulation):
    CONFIG = {
        "simulation_config": {
            "person_type": DotPerson,
        }
    }


class LargerCity(RunSimpleSimulation):
    CONFIG = {
        "simulation_config": {
            "person_type": DotPerson,
            "city_population": 1000,
            "person_config": {
                "infection_radius": 0.25,
                "social_distance_factor": 0,
                "gravity_strength": 0.2,
                "max_speed": 0.25,
                "height": 0.2 / 3,
                "wall_buffer": 1 / 3,
                "social_distance_color_threshold": 2 / 3,
            },
        }
    }


class LargerCity2(LargerCity):
    CONFIG = {
        "random_seed": 1,
    }


class LargeCityHighInfectionRadius(LargerCity):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "infection_radius": 0.5,
            },
        },
        "graph_config": {
            "update_frequency": 1 / 60,
        },
    }


class LargeCityLowerInfectionRate(LargerCity):
    CONFIG = {
        "p_infection_per_day": 0.1,
    }


class SimpleSocialDistancing(RunSimpleSimulation):
    CONFIG = {
        "simulation_config": {
            "person_type": PiPerson,
            "n_cities": 1,
            "city_population": 100,
            "person_config": {
                "infection_radius": 0.75,
                "social_distance_factor": 2,
                "gravity_strength": 0.1,
            },
            "travel_rate": 0,
            "infection_time": 5,
        },
    }


class DelayedSocialDistancing(RunSimpleSimulation):
    CONFIG = {
        "delay_time": 8,
        "target_sd_factor": 2,
        "sd_probability": 1,
        "random_seed": 1,
    }

    def construct(self):
        self.wait(self.delay_time)
        self.change_social_distance_factor(
            self.target_sd_factor,
            self.sd_probability,
        )
        self.graph.add_v_line()
        self.play(self.sd_slider.get_change_anim(self.target_sd_factor))

        self.run_until_zero_infections()

    def change_social_distance_factor(self, new_factor, prob):
        for person in self.simulation.people:
            if random.random() < prob:
                person.social_distance_factor = new_factor

    def add_sliders(self):
        slider = ValueSlider(
            self.get_sd_slider_name(),
            value=0,
            x_min=0,
            x_max=2,
            tick_frequency=0.5,
            numbers_with_elongated_ticks=[],
            numbers_to_show=range(3),
            decimal_number_config={
                "num_decimal_places": 0,
            }
        )
        slider.match_width(self.graph)
        slider.next_to(self.graph, DOWN, buff=0.2 * self.graph.get_height())
        self.add(slider)
        self.sd_slider = slider

    def get_sd_slider_name(self):
        return f"Social Distance Factor\\\\({int(100 * self.sd_probability)}$\\%$ of population)"


class DelayedSocialDistancingDot(DelayedSocialDistancing):
    CONFIG = {
        "simulation_config": {
            "person_type": DotPerson,
        }
    }


class DelayedSocialDistancingLargeCity(DelayedSocialDistancing, LargerCity):
    CONFIG = {
        "trigger_infection_count": 50,
        "simulation_config": {
            'city_population': 900,
        }
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.change_social_distance_factor(
            self.target_sd_factor,
            self.sd_probability,
        )
        self.graph.add_v_line()
        self.play(self.sd_slider.get_change_anim(self.target_sd_factor))

        self.run_until_zero_infections()


class DelayedSocialDistancingLargeCity90p(DelayedSocialDistancingLargeCity):
    CONFIG = {
        "sd_probability": 0.9,
    }


class DelayedSocialDistancingLargeCity90pAlt(DelayedSocialDistancingLargeCity):
    CONFIG = {
        "sd_probability": 0.9,
        "random_seed": 5,
    }


class DelayedSocialDistancingLargeCity70p(DelayedSocialDistancingLargeCity):
    CONFIG = {
        "sd_probability": 0.7,
    }


class DelayedSocialDistancingLargeCity50p(DelayedSocialDistancingLargeCity):
    CONFIG = {
        "sd_probability": 0.5,
    }


class DelayedSocialDistancingWithDots(DelayedSocialDistancing):
    CONFIG = {
        "person_type": DotPerson,
    }


class DelayedSocialDistancingProbHalf(DelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.5,
    }


class ReduceInfectionDuration(LargerCity):
    CONFIG = {
        "trigger_infection_count": 50,
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.play(self.slider.get_change_anim(1))
        self.simulation.infection_time = 1
        self.graph.add_v_line()
        self.run_until_zero_infections()

    def add_sliders(self):
        slider = ValueSlider(
            "Infection duration",
            value=5,
            x_min=0,
            x_max=5,
            tick_frequency=1,
            numbers_with_elongated_ticks=[],
            numbers_to_show=range(6),
            decimal_number_config={
                "num_decimal_places": 0,
            },
            marker_color=RED,
        )
        slider.match_width(self.graph)
        slider.next_to(self.graph, DOWN, buff=0.2 * self.graph.get_height())
        self.add(slider)
        self.slider = slider


class SimpleTravel(RunSimpleSimulation):
    CONFIG = {
        "simulation_config": {
            "person_type": DotPerson,
            "n_cities": 12,
            "city_population": 100,
            "person_config": {
                "infection_radius": 0.75,
                "social_distance_factor": 0,
                "gravity_strength": 0.5,
            },
            "travel_rate": 0.02,
            "infection_time": 5,
        },
    }

    def add_sliders(self):
        slider = ValueSlider(
            "Travel rate",
            self.simulation.travel_rate,
            x_min=0,
            x_max=0.02,
            tick_frequency=0.005,
            numbers_with_elongated_ticks=[],
            numbers_to_show=np.arange(0, 0.03, 0.01),
            decimal_number_config={
                "num_decimal_places": 2,
            }
        )
        slider.match_width(self.graph)
        slider.next_to(self.graph, DOWN, buff=0.2 * self.graph.get_height())
        self.add(slider)
        self.tr_slider = slider


class SimpleTravel2(SimpleTravel):
    CONFIG = {
        "random_seed": 1,
    }


class SimpleTravelLongInfectionPeriod(SimpleTravel):
    CONFIG = {
        "simulation_config": {
            "infection_time": 10,
        }
    }


class SimpleTravelDelayedSocialDistancing(DelayedSocialDistancing, SimpleTravel):
    CONFIG = {
        "target_sd_factor": 2,
        "sd_probability": 0.7,
        "delay_time": 15,
        "trigger_infection_count": 50,
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.change_social_distance_factor(
            self.target_sd_factor,
            self.sd_probability,
        )
        self.graph.add_v_line()
        self.play(self.sd_slider.get_change_anim(self.target_sd_factor))

        self.run_until_zero_infections()

    def add_sliders(self):
        SimpleTravel.add_sliders(self)
        DelayedSocialDistancing.add_sliders(self)

        buff = 0.1 * self.graph.get_height()

        self.tr_slider.scale(0.8, about_edge=UP)
        self.tr_slider.next_to(self.graph, DOWN, buff=buff)

        self.sd_slider.scale(0.8)
        self.sd_slider.marker.set_color(YELLOW)
        self.sd_slider.name.set_color(YELLOW)
        self.sd_slider.next_to(self.tr_slider, DOWN, buff=buff)


class SimpleTravelDelayedSocialDistancing70p(SimpleTravelDelayedSocialDistancing):
    pass


class SimpleTravelDelayedSocialDistancing99p(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.99,
    }


class SimpleTravelDelayedSocialDistancing20p(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.20,
    }


class SimpleTravelDelayedSocialDistancing50p(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.50,
        "random_seed": 1,
    }


class SimpleTravelDelayedSocialDistancing50pThreshold100(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.50,
        "trigger_infection_count": 100,
        "random_seed": 5,
    }


class SimpleTravelDelayedSocialDistancing70pThreshold100(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.70,
        "trigger_infection_count": 100,
    }


class SimpleTravelSocialDistancePlusZeroTravel(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 1,
        "target_travel_rate": 0,
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.change_social_distance_factor(
            self.target_sd_factor,
            self.sd_probability,
        )
        self.simulation.travel_rate = self.target_travel_rate
        self.graph.add_v_line()
        self.play(
            self.tr_slider.get_change_anim(self.simulation.travel_rate),
            self.sd_slider.get_change_anim(self.target_sd_factor),
        )

        self.run_until_zero_infections()


class SecondWave(SimpleTravelSocialDistancePlusZeroTravel):
    def run_until_zero_infections(self):
        self.wait_until(lambda: self.simulation.get_status_counts()[1] < 10)
        self.change_social_distance_factor(0, 1)
        self.simulation.travel_rate = 0.02
        self.graph.add_v_line()
        self.play(
            self.tr_slider.get_change_anim(0.02),
            self.sd_slider.get_change_anim(0),
        )
        super().run_until_zero_infections()


class SimpleTravelSocialDistancePlusZeroTravel99p(SimpleTravelSocialDistancePlusZeroTravel):
    CONFIG = {
        "sd_probability": 0.99,
    }


class SimpleTravelDelayedTravelReduction(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "trigger_infection_count": 50,
        "target_travel_rate": 0.002,
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.simulation.travel_rate = self.target_travel_rate
        self.graph.add_v_line()
        self.play(self.tr_slider.get_change_anim(self.simulation.travel_rate))
        self.run_until_zero_infections()


class SimpleTravelDelayedTravelReductionThreshold100(SimpleTravelDelayedTravelReduction):
    CONFIG = {
        "random_seed": 2,
        "trigger_infection_count": 100,
    }


class SimpleTravelDelayedTravelReductionThreshold100TargetHalfPercent(SimpleTravelDelayedTravelReduction):
    CONFIG = {
        "random_seed": 2,
        "trigger_infection_count": 100,
        "target_travel_rate": 0.005,
    }


class SimpleTravelDelayedTravelReductionThreshold100TargetHalfPercent2(SimpleTravelDelayedTravelReductionThreshold100TargetHalfPercent):
    CONFIG = {
        "random_seed": 1,
        "sd_probability": 0.5,
    }

    def setup(self):
        super().setup()
        for x in range(2):
            random.choice(self.simulation.people).set_status("I")


class SimpleTravelLargeCity(SimpleTravel, LargerCity):
    CONFIG = {
        "simulation_config": {
            "n_cities": 12,
            "travel_rate": 0.02,
        }
    }


class SimpleTravelLongerDelayedSocialDistancing(SimpleTravelDelayedSocialDistancing):
    CONFIG = {
        "trigger_infection_count": 100,
    }


class SimpleTravelLongerDelayedTravelReduction(SimpleTravelDelayedTravelReduction):
    CONFIG = {
        "trigger_infection_count": 100,
    }


class SocialDistanceAfterFiveDays(DelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.7,
        "delay_time": 5,
        "simulation_config": {
            "travel_rate": 0
        },
    }


class QuarantineInfectious(RunSimpleSimulation):
    CONFIG = {
        "trigger_infection_count": 10,
        "target_sd_factor": 3,
        "infection_time_before_quarantine": 1,
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.add_quarantine_box()
        self.set_quarantine_updaters()
        self.run_until_zero_infections()

    def add_quarantine_box(self):
        boxes = self.simulation.boxes
        q_box = boxes[0].copy()
        q_box.set_color(RED_E)
        q_box.set_width(boxes.get_width() / 3)
        q_box.next_to(
            boxes, LEFT,
            aligned_edge=DOWN,
            buff=0.25 * q_box.get_width()
        )

        label = TextMobject("Quarantine zone")
        label.set_color(RED)
        label.match_width(q_box)
        label.next_to(q_box, DOWN, buff=0.1 * q_box.get_width())

        self.add(q_box)
        self.add(label)
        self.q_box = q_box

    def set_quarantine_updaters(self):
        def quarantine_if_ready(simulation):
            for person in simulation.people:
                send_to_q_box = all([
                    not person.is_quarantined,
                    person.symptomatic,
                    (person.time - person.infection_start_time) > self.infection_time_before_quarantine,
                ])
                if send_to_q_box:
                    person.box = self.q_box
                    person.dl_bound = self.q_box.get_corner(DL)
                    person.ur_bound = self.q_box.get_corner(UR)
                    person.old_center = person.get_center()
                    person.new_center = self.q_box.get_center()
                    point = VectorizedPoint(person.get_center())
                    person.push_anim(ApplyMethod(point.move_to, self.q_box.get_center(), run_time=0.5))
                    person.push_anim(MaintainPositionRelativeTo(person, point))
                    person.move_to(self.q_box.get_center())
                    person.is_quarantined = True

        for person in self.simulation.people:
            person.is_quarantined = False
            # person.add_updater(quarantine_if_ready)
        self.simulation.add_updater(quarantine_if_ready)


class QuarantineInfectiousLarger(QuarantineInfectious, LargerCity):
    CONFIG = {
        "trigger_infection_count": 50,
    }


class QuarantineInfectiousLargerWithTail(QuarantineInfectiousLarger):
    def construct(self):
        super().construct()
        self.simulation.clear_updaters()
        self.wait(25)


class QuarantineInfectiousTravel(QuarantineInfectious, SimpleTravel):
    CONFIG = {
        "trigger_infection_count": 50,
    }

    def add_sliders(self):
        pass


class QuarantineInfectious80p(QuarantineInfectious):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "p_symptomatic_on_infection": 0.8,
            }
        }
    }


class QuarantineInfectiousLarger80p(QuarantineInfectiousLarger):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "p_symptomatic_on_infection": 0.8,
            }
        }
    }


class QuarantineInfectiousTravel80p(QuarantineInfectiousTravel):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "p_symptomatic_on_infection": 0.8,
            }
        }
    }


class QuarantineInfectious50p(QuarantineInfectious):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "p_symptomatic_on_infection": 0.5,
            }
        }
    }


class QuarantineInfectiousLarger50p(QuarantineInfectiousLarger):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "p_symptomatic_on_infection": 0.5,
            }
        }
    }


class QuarantineInfectiousTravel50p(QuarantineInfectiousTravel):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "p_symptomatic_on_infection": 0.5,
            }
        }
    }


class CentralMarket(DelayedSocialDistancing):
    CONFIG = {
        "sd_probability": 0.7,
        "delay_time": 5,
        "simulation_config": {
            "person_type": DotPerson,
            "travel_rate": 0
        },
        "shopping_frequency": 0.05,
        "shopping_time": 1,
    }

    def setup(self):
        super().setup()
        for person in self.simulation.people:
            person.last_shopping_trip = -3
            person.is_shopping = False

        square = Square()
        square.set_height(0.2)
        square.set_color(WHITE)
        square.move_to(self.simulation.boxes[0].get_center())
        self.add(square)

        self.simulation.add_updater(
            lambda m, dt: self.add_travel_anims(m, dt)
        )

    def construct(self):
        self.run_until_zero_infections()

    def add_travel_anims(self, simulation, dt):
        shopping_time = self.shopping_time
        for person in simulation.people:
            time_since_trip = person.time - person.last_shopping_trip
            if time_since_trip > shopping_time:
                if random.random() < dt * self.shopping_frequency:
                    person.last_shopping_trip = person.time

                    point = VectorizedPoint(person.get_center())
                    anim1 = ApplyMethod(
                        point.move_to, person.box.get_center(),
                        path_arc=45 * DEGREES,
                        run_time=shopping_time,
                        rate_func=there_and_back_with_pause,
                    )
                    anim2 = MaintainPositionRelativeTo(person, point, run_time=shopping_time)

                    person.push_anim(anim1)
                    person.push_anim(anim2)

    def add_sliders(self):
        pass


class CentralMarketLargePopulation(CentralMarket, LargerCity):
    pass


class CentralMarketLowerInfection(CentralMarketLargePopulation):
    CONFIG = {
        "simulation_config": {
            "p_infection_per_day": 0.1,
        }
    }


class CentralMarketVeryFrequentLargePopulationDelayedSocialDistancing(CentralMarketLowerInfection):
    CONFIG = {
        "sd_probability": 0.7,
        "trigger_infection_count": 25,
        "simulation_config": {
            "person_type": DotPerson,
        },
        "target_sd_factor": 2,
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.graph.add_v_line()
        for person in self.simulation.people:
            person.social_distance_factor = self.target_sd_factor
        self.run_until_zero_infections()


class CentralMarketLessFrequent(CentralMarketVeryFrequentLargePopulationDelayedSocialDistancing):
    CONFIG = {
        "target_shopping_frequency": 0.01,
        "trigger_infection_count": 100,
        "random_seed": 1,
        "simulation_config": {
            'city_population': 900,
        },
    }

    def construct(self):
        self.wait_until(lambda: self.simulation.get_status_counts()[1] > self.trigger_infection_count)
        for person in self.simulation.people:
            person.social_distance_factor = 2
        # Decrease shopping rate
        self.graph.add_v_line()
        self.change_slider()
        self.run_until_zero_infections()

    def change_slider(self):
        self.play(self.shopping_slider.get_change_anim(self.target_shopping_frequency))
        self.shopping_frequency = self.target_shopping_frequency

    def add_sliders(self):
        slider = ValueSlider(
            "Shopping frequency",
            value=self.shopping_frequency,
            x_min=0,
            x_max=0.05,
            tick_frequency=0.01,
            numbers_with_elongated_ticks=[],
            numbers_to_show=np.arange(0, 0.06, 0.01),
            decimal_number_config={
                "num_decimal_places": 2,
            }
        )
        slider.match_width(self.graph)
        slider.next_to(self.graph, DOWN, buff=0.2 * self.graph.get_height())
        self.add(slider)
        self.shopping_slider = slider


class CentralMarketDownToZeroFrequency(CentralMarketLessFrequent):
    CONFIG = {
        "target_shopping_frequency": 0,
    }


class CentralMarketQuarantine(QuarantineInfectiousLarger, CentralMarketLowerInfection):
    CONFIG = {
        "random_seed": 1,
    }

    def construct(self):
        self.wait_until_infection_threshold(self.trigger_infection_count)
        self.graph.add_v_line()
        self.add_quarantine_box()
        self.set_quarantine_updaters()
        self.run_until_zero_infections()


class CentralMarketQuarantine80p(CentralMarketQuarantine):
    CONFIG = {
        "simulation_config": {
            "person_config": {
                "p_symptomatic_on_infection": 0.8,
            }
        }
    }


class CentralMarketTransitionToLowerInfection(CentralMarketLessFrequent):
    CONFIG = {
        "target_p_infection_per_day": 0.05,  # From 0.1
        "trigger_infection_count": 100,
        "random_seed": 1,
        "simulation_config": {
            'city_population': 900,
        },
    }

    def change_slider(self):
        self.play(self.infection_slider.get_change_anim(self.target_p_infection_per_day))
        self.simulation.p_infection_per_day = self.target_p_infection_per_day

    def add_sliders(self):
        slider = ValueSlider(
            "Infection rate",
            value=self.simulation.p_infection_per_day,
            x_min=0,
            x_max=0.2,
            tick_frequency=0.05,
            numbers_with_elongated_ticks=[],
            numbers_to_show=np.arange(0, 0.25, 0.05),
            decimal_number_config={
                "num_decimal_places": 2,
            },
            marker_color=RED,
        )
        slider.match_width(self.graph)
        slider.next_to(self.graph, DOWN, buff=0.2 * self.graph.get_height())
        self.add(slider)
        self.infection_slider = slider


class CentralMarketTransitionToLowerInfectionAndLowerFrequency(CentralMarketTransitionToLowerInfection):
    CONFIG = {
        "random_seed": 2,
    }

    def change_slider(self):
        super().change_slider()
        self.shopping_frequency = self.target_shopping_frequency


# Filler animations

class TableOfContents(Scene):
    def construct(self):
        chapters = VGroup(
            TextMobject("Basic setup"),
            TextMobject("Identify and isolate"),
            TextMobject("Social distancing"),
            TextMobject("Travel restrictions"),
            TextMobject("$R$"),
            TextMobject("Central hubs"),
        )
        chapters.arrange(DOWN, buff=MED_LARGE_BUFF, aligned_edge=LEFT)
        chapters.set_height(FRAME_HEIGHT - 1)
        chapters.to_edge(LEFT, buff=LARGE_BUFF)

        for chapter in chapters:
            dot = Dot()
            dot.next_to(chapter, LEFT, SMALL_BUFF)
            chapter.add(dot)
            chapter.save_state()

        self.add(chapters)

        for chapter in chapters:
            non_chapter = [c for c in chapters if c is not chapter]
            chapter.target = chapter.saved_state.copy()
            chapter.target.scale(1.5, about_edge=LEFT)
            chapter.target.set_fill(YELLOW, 1)
            for nc in non_chapter:
                nc.target = nc.saved_state.copy()
                nc.target.scale(0.8, about_edge=LEFT)
                nc.target.set_fill(WHITE, 0.5)
            self.play(*map(MoveToTarget, chapters))
            self.wait()
        self.play(*map(Restore, chapters))
        self.wait()


class DescribeModel(Scene):
    def construct(self):
        # Setup words
        words = TextMobject(
            "Susceptible",
            "Infectious",
            "Recovered",
        )
        words.scale(0.8 / words[0][0].get_height())

        colors = [
            COLOR_MAP["S"],
            COLOR_MAP["I"],
            interpolate_color(COLOR_MAP["R"], WHITE, 0.5),
        ]

        initials = VGroup()
        for i, word, color in zip(it.count(), words, colors):
            initials.add(word[0][0])
            word.set_color(color)
            word.move_to(2 * i * DOWN)
            word.to_edge(LEFT)
        words.to_corner(UL)

        # Rearrange initials
        initials.save_state()
        initials.arrange(RIGHT, buff=SMALL_BUFF)
        initials.set_color(WHITE)

        title = VGroup(initials, TextMobject("Model"))
        title[1].match_height(title[0])
        title.arrange(RIGHT, buff=MED_LARGE_BUFF)
        title.center()
        title.to_edge(UP)

        self.play(FadeInFromDown(title))
        self.wait()
        self.play(
            Restore(
                initials,
                path_arc=-90 * DEGREES,
            ),
            FadeOut(title[1])
        )
        self.wait()

        # Show each category
        pi = PiPerson(
            height=3,
            max_speed=0,
            infection_radius=5,
        )
        pi.color_map["R"] = words[2].get_color()
        pi.center()
        pi.body.change("pondering", initials[0])

        word_anims = []
        for word in words:
            word_anims.append(LaggedStartMap(
                FadeInFrom, word[1:],
                lambda m: (m, 0.2 * LEFT),
            ))

        self.play(
            Succession(
                FadeInFromDown(pi),
                ApplyMethod(pi.body.change, "guilty"),
            ),
            word_anims[0],
            run_time=2,
        )
        words[0].pi = pi.copy()
        self.play(
            words[0].pi.set_height, 1,
            words[0].pi.next_to, words[0], RIGHT,
        )
        self.play(Blink(pi.body))

        pi.set_status("I")
        point = VectorizedPoint(pi.get_center())
        self.play(
            point.shift, 3 * RIGHT,
            MaintainPositionRelativeTo(pi, point),
            word_anims[1],
            run_time=2,
        )
        words[1].pi = pi.copy()
        self.play(
            words[1].pi.set_height, 1,
            words[1].pi.next_to, words[1], RIGHT,
        )
        self.wait(3)

        pi.set_status("R")
        self.play(
            word_anims[2],
            Animation(pi, suspend_mobject_updating=False)
        )
        words[2].pi = pi.copy()
        self.play(
            words[2].pi.set_height, 1,
            words[2].pi.next_to, words[2], RIGHT,
        )
        self.wait()

        # Show rules
        i_pi = PiPerson(
            height=1.5,
            max_speed=0,
            infection_radius=6,
            status="S",
        )
        i_pi.set_status("I")
        s_pis = VGroup()
        for vect in [RIGHT, UP, LEFT, DOWN]:
            s_pi = PiPerson(
                height=1.5,
                max_speed=0,
                infection_radius=6,
                status="S",
            )
            s_pi.next_to(i_pi, vect, MED_LARGE_BUFF)
            s_pis.add(s_pi)

        VGroup(i_pi, s_pis).to_edge(RIGHT)

        circle = Circle(radius=3)
        circle.move_to(i_pi)
        dashed_circle = DashedVMobject(circle, num_dashes=30)
        dashed_circle.set_color(RED)

        self.play(
            FadeOut(pi),
            FadeIn(s_pis),
            FadeIn(i_pi),
        )
        anims = []
        for s_pi in s_pis:
            anims.append(ApplyMethod(s_pi.body.look_at, i_pi.body.eyes))
        self.play(*anims)
        self.add(VGroup(i_pi, *s_pis))
        self.wait()
        self.play(ShowCreation(dashed_circle))
        self.wait()
        shuffled = list(s_pis)
        random.shuffle(shuffled)
        for s_pi in shuffled:
            s_pi.set_status("I")
            self.wait(3 * random.random())
        self.wait(2)
        self.play(FadeOut(s_pis), FadeOut(dashed_circle))

        # Let time pass
        clock = Clock()
        clock.next_to(i_pi.body, UP, buff=LARGE_BUFF)

        self.play(
            VFadeIn(clock),
            ClockPassesTime(
                clock,
                run_time=5,
                hours_passed=5,
            ),
        )
        i_pi.set_status("R")
        self.wait(1)
        self.play(Blink(i_pi.body))
        self.play(FadeOut(clock))

        # Removed
        removed = TextMobject("Removed")
        removed.match_color(words[2])
        removed.match_height(words[2])
        removed.move_to(words[2], DL)

        self.play(
            FadeOut(words[2], UP),
            FadeIn(removed, DOWN),
        )
        self.play(
            i_pi.body.change, 'pleading', removed,
        )
        self.play(Blink(i_pi.body))
        self.wait()


class SubtlePangolin(Scene):
    def construct(self):
        pangolin = SVGMobject(file_name="pangolin")
        pangolin.set_height(0.5)
        pangolin.set_fill(GREY_BROWN, opacity=0)
        pangolin.set_stroke(GREY_BROWN, width=1)
        self.play(ShowCreationThenFadeOut(pangolin))
        self.play(FadeOut(pangolin))

        self.embed()


class DoubleRadiusInGroup(Scene):
    def construct(self):
        radius = 1

        pis = VGroup(*[
            PiPerson(
                height=0.5,
                max_speed=0,
                wander_step_size=0,
                infection_radius=4 * radius,
            )
            for x in range(49)
        ])
        pis.arrange_in_grid()
        pis.set_height(FRAME_HEIGHT - 1)
        sicky = pis[24]
        sicky.set_status("I")

        circle = Circle(radius=radius)
        circle.move_to(sicky)
        dashed_circle = DashedVMobject(circle, num_dashes=30)
        dashed_circle2 = dashed_circle.copy()
        dashed_circle2.scale(2)

        self.add(pis)
        self.play(ShowCreation(dashed_circle, lag_ratio=0))
        self.play(ShowCreation(dashed_circle2, lag_ratio=0))
        anims = []
        for pi in pis:
            if pi.status == "S":
                anims.append(ApplyMethod(
                    pi.body.change, "pleading", sicky.body.eyes
                ))
        random.shuffle(anims)
        self.play(LaggedStart(*anims))
        self.wait(10)


class CutPInfectionInHalf(Scene):
    def construct(self):
        # Add people
        sicky = PiPerson(
            height=1,
            infection_radius=4,
            max_speed=0,
            wander_step_size=0,
        )
        normy = sicky.deepcopy()
        normy.next_to(sicky, RIGHT)
        normy.body.look_at(sicky.body.eyes)

        circ = Circle(radius=4)
        d_circ = DashedVMobject(circ, num_dashes=30)
        d_circ.set_color(RED)
        d_circ.move_to(sicky)

        sicky.set_status("I")
        self.add(sicky, normy)
        self.add(d_circ)
        self.play(d_circ.scale, 0.5)
        self.wait()

        # Prob label
        eq = VGroup(
            TexMobject("P(\\text{Infection}) = "),
            DecimalNumber(0.2),
        )
        eq.arrange(RIGHT, buff=0.2)
        eq.to_edge(UP)

        arrow = Vector(0.5 * RIGHT)
        arrow.next_to(eq, RIGHT)
        new_rhs = eq[1].copy()
        new_rhs.next_to(arrow, RIGHT)
        new_rhs.set_color(YELLOW)

        self.play(FadeIn(eq))
        self.play(
            TransformFromCopy(eq[1], new_rhs),
            GrowArrow(arrow)
        )
        self.play(ChangeDecimalToValue(new_rhs, 0.1))
        self.wait(2)

        # Each day
        clock = Clock()
        clock.set_height(1)
        clock.next_to(normy, UR, buff=0.7)

        def get_clock_run(clock):
            return ClockPassesTime(
                clock,
                hours_passed=1,
                run_time=1,
            )

        self.play(
            VFadeIn(clock),
            get_clock_run(clock),
        )

        # Random choice
        choices = VGroup()
        for x in range(9):
            choices.add(Checkmark())
        for x in range(1):
            choices.add(Exmark())
        choices.arrange(DOWN)
        choices.set_height(3)
        choices.next_to(clock, DOWN)

        rect = SurroundingRectangle(choices[0])
        self.add(choices, rect)

        def show_random_choice(scene, rect, choices):
            for x in range(10):
                rect.move_to(random.choice(choices[:-1]))
                scene.wait(0.1)

        show_random_choice(self, rect, choices)

        for x in range(6):
            self.play(get_clock_run(clock))
            show_random_choice(self, rect, choices)
        rect.move_to(choices[-1])
        normy.set_status("I")
        self.add(normy)
        self.play(
            FadeOut(clock),
            FadeOut(choices),
            FadeOut(rect),
        )
        self.wait(4)


class KeyTakeaways(Scene):
    def construct(self):
        takeaways = VGroup(*[
            TextMobject(
                text,
                alignment="",
            )
            for text in [
                """
                    Changes in how many people slip through the tests\\\\
                    cause disproportionately large changes to the total\\\\
                    number of people infected.
                """,
                """
                    Social distancing slows the spread, but\\\\
                    even small imperfections prolong it.
                """,
                """
                    Reducing transit between communities, late in the game,\\\\
                    has a very limited effect.
                """,
                """
                    Shared central locations dramatically speed up\\\\
                    the spread.
                """,
            ]
        ])
        takeaway = TextMobject(
            "The growth rate is very sensitive to:\\\\",
            "- \\# Daily interactions\\\\",
            "- Probability of infection\\\\",
            "- Duration of illness\\\\",
            alignment="",
        )
        takeaway[1].set_color(GREEN_D)
        takeaway[2].set_color(GREEN_C)
        takeaway[3].set_color(GREEN_B)
        takeaway.arrange(DOWN, buff=MED_LARGE_BUFF, aligned_edge=LEFT)
        takeaways.add_to_back(takeaway)

        takeaways.scale(1.25)

        titles = VGroup()
        for i in range(len(takeaways)):
            title = TextMobject("Key takeaway \\#")
            num = Integer(i + 1)
            num.next_to(title, RIGHT, buff=SMALL_BUFF)
            title.add(num)
            titles.add(title)

        titles.arrange(DOWN, buff=LARGE_BUFF, aligned_edge=LEFT)
        titles.to_edge(LEFT)
        titles.set_color(GREY_D)

        h_line = Line(LEFT, RIGHT)
        h_line.set_width(FRAME_WIDTH - 1)
        h_line.to_edge(UP, buff=1.5)

        for takeaway in takeaways:
            takeaway.next_to(h_line, DOWN, buff=0.75)
            max_width = FRAME_WIDTH - 2
            if takeaway.get_width() > max_width:
                takeaway.set_width(max_width)

        takeaways[3].shift(0.25 * UP)

        self.add(titles)
        self.wait()

        for title, takeaway in zip(titles, takeaways):
            other_titles = VGroup(*titles)
            other_titles.remove(title)
            self.play(title.set_color, WHITE, run_time=0.5)
            title.save_state()
            temp_h_line = h_line.copy()
            self.play(
                title.scale, 1.5,
                title.to_edge, UP,
                title.set_x, 0,
                title.set_color, YELLOW,
                FadeOut(other_titles),
                ShowCreation(temp_h_line),
            )

            self.play(FadeIn(takeaway, lag_ratio=0.1, run_time=2, rate_func=linear))
            self.wait(2)
            temp_h_line.rotate(PI)
            self.play(
                Restore(title),
                FadeIn(other_titles),
                Uncreate(temp_h_line),
                FadeOut(takeaway, DOWN, lag_ratio=0.25 / len(takeaway.family_members_with_points()))
            )
            self.wait()

        self.embed()


class AsymptomaticCases(Scene):
    def construct(self):
        pis = VGroup(*[
            PiPerson(
                height=1,
                infection_radius=2,
                wander_step_size=0,
                max_speed=0,
            )
            for x in range(5)
        ])
        pis.arrange(RIGHT, buff=2)
        pis.to_edge(DOWN, buff=2)

        sneaky = pis[1]
        sneaky.p_symptomatic_on_infection = 0

        self.add(pis)

        for pi in pis:
            if pi is sneaky:
                pi.color_map["I"] = YELLOW
                pi.mode_map["I"] = "coin_flip_1"
            else:
                pi.color_map["I"] = RED
                pi.mode_map["I"] = "sick"
            pi.unlock_triangulation()
            pi.set_status("I")
            self.wait(0.1)
        self.wait(2)

        label = TextMobject("Never isolated")
        label.set_height(0.8)
        label.to_edge(UP)
        label.set_color(YELLOW)

        arrow = Arrow(
            label.get_bottom(),
            sneaky.body.get_top(),
            buff=0.5,
            max_tip_length_to_length_ratio=0.5,
            stroke_width=6,
            max_stroke_width_to_length_ratio=10,
        )

        self.play(
            FadeInFromDown(label),
            GrowArrow(arrow),
        )
        self.wait(13)


class WeDontHaveThat(TeacherStudentsScene):
    def construct(self):
        self.student_says(
            "But we don't\\\\have that!",
            target_mode="angry",
            added_anims=[self.teacher.change, "guilty"]
        )
        self.change_all_student_modes(
            "angry",
            look_at_arg=self.teacher.eyes
        )
        self.wait(5)


class IntroduceSocialDistancing(Scene):
    def construct(self):
        pis = VGroup(*[
            PiPerson(
                height=2,
                wander_step_size=0,
                gravity_well=None,
                social_distance_color_threshold=5,
                max_social_distance_stroke_width=10,
                dl_bound=[-FRAME_WIDTH / 2 + 1, -2],
                ur_bound=[FRAME_WIDTH / 2 - 1, 2],
            )
            for x in range(3)
        ])
        pis.arrange(RIGHT, buff=0.25)
        pis.move_to(DOWN)
        pi1, pi2, pi3 = pis

        slider = ValueSlider(
            "Social distance factor",
            0,
            x_min=0,
            x_max=5,
            tick_frequency=1,
            numbers_to_show=range(6),
            marker_color=YELLOW,
        )
        slider.center()
        slider.to_edge(UP)
        self.add(slider)

        def update_pi(pi):
            pi.social_distance_factor = 4 * slider.p2n(slider.marker.get_center())

        for pi in pis:
            pi.add_updater(update_pi)
            pi.repulsion_points = [
                pi2.get_center()
                for pi2 in pis
                if pi2 is not pi
            ]

        self.add(pis)
        self.play(
            FadeIn(slider),
            *[
                ApplyMethod(pi1.body.look_at, pi2.body.eyes)
                for pi1, pi2 in zip(pis, [*pis[1:], pis[0]])
            ]
        )
        self.add(*pis)
        self.wait()
        self.play(slider.get_change_anim(3))
        self.wait(4)

        for i, vect in (0, RIGHT), (2, LEFT):
            pis.suspend_updating()
            pis[1].generate_target()
            pis[1].target.next_to(pis[i], vect, SMALL_BUFF)
            pis[1].target.body.look_at(pis[i].body.eyes)
            self.play(
                MoveToTarget(pis[1]),
                path_arc=PI,
            )
            pis.resume_updating()
            self.wait(5)
        self.wait(5)

        self.embed()


class FastForwardBy2(Scene):
    CONFIG = {
        "n": 2,
    }

    def construct(self):
        n = self.n
        triangles = VGroup(*[
            ArrowTip(start_angle=0)
            for x in range(n)
        ])
        triangles.arrange(RIGHT, buff=0.01)

        label = VGroup(TexMobject("\\times"), Integer(n))
        label.set_height(0.4)
        label.arrange(RIGHT, buff=SMALL_BUFF)
        label.next_to(triangles, RIGHT, buff=SMALL_BUFF)

        for mob in triangles, label:
            mob.set_color(GREY_A)
            mob.set_stroke(BLACK, 4, background=True)

        self.play(
            LaggedStartMap(
                FadeInFrom, triangles,
                lambda m: (m, 0.4 * LEFT),
            ),
            FadeIn(label, 0.2 * LEFT),
            run_time=1,
        )
        self.play(
            FadeOut(label),
            FadeOut(triangles),
        )


class FastForwardBy4(FastForwardBy2):
    CONFIG = {
        "n": 4,
    }


class DontLetThisHappen(Scene):
    def construct(self):
        text = TextMobject("Don't let\\\\this happen!")
        text.scale(1.5)
        text.set_stroke(BLACK, 5, background=True)
        arrow = Arrow(
            text.get_top(),
            text.get_top() + 2 * UR + 0.5 * RIGHT,
            path_arc=-120 * DEGREES,
        )

        self.add(text)
        self.play(
            Write(text, run_time=1),
            ShowCreation(arrow),
        )
        self.wait()


class ThatsNotHowIBehave(TeacherStudentsScene):
    def construct(self):
        self.student_says(
            "That's...not\\\\how I behave.",
            target_mode="sassy",
            look_at_arg=self.screen,
        )
        self.play(
            self.teacher.change, "guilty",
            self.get_student_changes("erm", "erm", "sassy")
        )
        self.look_at(self.screen)
        self.wait(20)


class BetweenNothingAndQuarantineWrapper(Scene):
    def construct(self):
        self.add(FullScreenFadeRectangle(
            fill_color=GREY_E,
            fill_opacity=1,
        ))
        rects = VGroup(*[
            ScreenRectangle()
            for x in range(3)
        ])
        rects.arrange(RIGHT)
        rects.set_width(FRAME_WIDTH - 1)
        self.add(rects)

        rects.set_fill(BLACK, 1)
        rects.set_stroke(WHITE, 2)

        titles = VGroup(
            TextMobject("Do nothing"),
            TextMobject("Quarantine\\\\", "80$\\%$ of cases"),
            TextMobject("Quarantine\\\\", "all cases"),
        )
        for title, rect in zip(titles, rects):
            title.next_to(rect, UP)

        q_marks = TexMobject("???")
        q_marks.scale(2)
        q_marks.move_to(rects[1])

        self.add(rects)
        self.play(LaggedStartMap(
            FadeInFromDown,
            VGroup(titles[0], titles[2], titles[1]),
            lag_ratio=0.3,
        ))
        self.play(Write(q_marks))
        self.wait()


class DarkerInterpretation(Scene):
    def construct(self):
        qz = TextMobject("Quarantine zone")
        qz.set_color(RED)
        qz.set_width(2)
        line = Line(qz.get_left(), qz.get_right())

        new_words = TextMobject("Deceased")
        new_words.replace(qz, dim_to_match=1)
        new_words.set_color(RED)

        self.add(qz)
        self.wait()
        self.play(ShowCreation(line))
        self.play(
            FadeOut(qz),
            FadeOut(line),
            FadeIn(new_words)
        )
        self.wait()


class SARS2002(TeacherStudentsScene):
    def construct(self):
        image = ImageMobject("sars_icon")
        image.set_height(3.5)
        image.move_to(self.hold_up_spot, DR)
        image.shift(RIGHT)

        name = TextMobject("2002 SARS Outbreak")
        name.next_to(image, LEFT, MED_LARGE_BUFF, aligned_edge=UP)

        n_cases = VGroup(
            Integer(0, edge_to_fix=UR),
            TextMobject("total cases")
        )
        n_cases.arrange(RIGHT)
        n_cases.scale(1.25)
        n_cases.next_to(name, DOWN, buff=2)

        arrow = Arrow(name.get_bottom(), n_cases.get_top())

        n_cases.shift(MED_SMALL_BUFF * RIGHT)

        self.play(
            self.teacher.change, "raise_right_hand",
            FadeIn(image, DOWN, run_time=2),
            self.get_student_changes(
                "pondering", "thinking", "pondering",
                look_at_arg=image,
            )
        )
        self.play(
            FadeIn(name, RIGHT),
        )
        self.play(
            GrowArrow(arrow),
            UpdateFromAlphaFunc(
                n_cases,
                lambda m, a: m.set_opacity(a),
            ),
            ChangeDecimalToValue(n_cases[0], 8098),
            self.get_student_changes(look_at_arg=n_cases),
        )
        self.wait()
        self.change_all_student_modes(
            "thinking", look_at_arg=n_cases,
        )
        self.play(self.teacher.change, "tease")
        self.wait(6)

        self.embed()


class QuarteringLines(Scene):
    def construct(self):
        lines = VGroup(
            Line(UP, DOWN),
            Line(LEFT, RIGHT),
        )
        lines.set_width(FRAME_WIDTH)
        lines.set_height(FRAME_HEIGHT, stretch=True)
        lines.set_stroke(WHITE, 3)
        self.play(ShowCreation(lines))
        self.wait()


class Eradicated(Scene):
    def construct(self):
        word = TextMobject("Eradicated")
        word.set_color(GREEN)
        self.add(word)


class LeftArrow(Scene):
    def construct(self):
        arrow = Vector(2 * LEFT)
        self.play(GrowArrow(arrow))
        self.wait()
        self.play(FadeOut(arrow))


class IndicationArrow(Scene):
    def construct(self):
        vect = Vector(
            0.5 * DR,
            max_tip_length_to_length_ratio=0.4,
            max_stroke_width_to_length_ratio=10,
            stroke_width=5,
        )
        vect.set_color(YELLOW)
        self.play(GrowArrow(vect))
        self.play(FadeOut(vect))


class REq(Scene):
    def construct(self):
        mob = TexMobject("R_0 = ")[0]
        mob[1].set_color(BLACK)
        mob[2].shift(mob[1].get_width() * LEFT * 0.7)
        self.add(mob)


class IntroduceR0(Scene):
    def construct(self):
        # Infect
        pis = VGroup(*[
            PiPerson(
                height=0.5,
                infection_radius=1.5,
                wander_step_size=0,
                max_speed=0,
            )
            for x in range(5)
        ])

        pis[:4].arrange(RIGHT, buff=2)
        pis[:4].to_edge(DOWN, buff=2)
        sicky = pis[4]
        sicky.move_to(2 * UP)
        sicky.set_status("I")

        pis[1].set_status("R")
        for anim in pis[1].change_anims:
            pis[1].pop_anim(anim)

        count = VGroup(
            TextMobject("Infection count: "),
            Integer(0)
        )
        count.arrange(RIGHT, aligned_edge=DOWN)
        count.to_corner(UL)

        self.add(pis)
        self.add(count)
        self.wait(2)

        for pi in pis[:4]:
            point = VectorizedPoint(sicky.get_center())
            self.play(
                point.move_to, pi.get_right() + 0.25 * RIGHT,
                MaintainPositionRelativeTo(sicky, point),
                run_time=0.5,
            )
            if pi.status == "S":
                count[1].increment_value()
                count[1].set_color(WHITE)
                pi.set_status("I")
            self.play(
                Flash(
                    sicky.get_center(),
                    color=RED,
                    line_length=0.3,
                    flash_radius=0.7,
                ),
                count[1].set_color, RED,
            )
        self.wait()

        # Attach count to sicky
        self.play(
            point.move_to, 2 * UP,
            MaintainPositionRelativeTo(sicky, point),
        )
        count_copy = count[1].copy()
        self.play(
            count_copy.next_to, sicky.body, UR,
            count_copy.set_color, WHITE,
        )
        self.wait()

        # Zeros
        zeros = VGroup()
        for pi in pis[:4]:
            if pi.status == "I":
                zero = Integer(0)
                zero.next_to(pi.body, UR)
                zeros.add(zero)

        # R label
        R_label = TextMobject("Average :=", " $R$")
        R_label.set_color_by_tex("R", YELLOW)
        R_label.next_to(count, DOWN, buff=1.5)

        arrow = Arrow(R_label[0].get_top(), count.get_bottom())

        self.play(
            LaggedStartMap(FadeInFromDown, zeros),
            GrowArrow(arrow),
            FadeIn(R_label),
        )

        brace = Brace(R_label[1], DOWN)
        name = TextMobject("``Effective reproductive number''")
        name.set_color(YELLOW)
        name.next_to(brace, DOWN)
        name.to_edge(LEFT)
        self.play(
            GrowFromCenter(brace),
            FadeIn(name, 0.5 * UP),
        )
        self.wait(5)

        # R0
        brr = TextMobject("``Basic reproductive number''")
        brr.set_color(TEAL)
        brr.move_to(name, LEFT)
        R0 = TexMobject("R_0")
        R0.move_to(R_label[1], UL)
        R0.set_color(TEAL)

        for pi in pis[:4]:
            pi.set_status("S")

        self.play(
            FadeOut(R_label[1], UP),
            FadeOut(name, UP),
            FadeIn(R0, DOWN),
            FadeIn(brr, DOWN),
            FadeOut(zeros),
            FadeOut(count_copy),
            brace.match_width, R0, {"stretch": True},
            brace.match_x, R0,
        )
        self.wait()

        # Copied from above
        count[1].set_value(0)

        for pi in pis[:4]:
            point = VectorizedPoint(sicky.get_center())
            self.play(
                point.move_to, pi.body.get_right() + 0.25 * RIGHT,
                MaintainPositionRelativeTo(sicky, point),
                run_time=0.5,
            )
            count[1].increment_value()
            count[1].set_color(WHITE)
            pi.set_status("I")
            self.play(
                Flash(
                    sicky.get_center(),
                    color=RED,
                    line_length=0.3,
                    flash_radius=0.7,
                ),
                count[1].set_color, RED,
            )
        self.play(
            point.move_to, 2 * UP,
            MaintainPositionRelativeTo(sicky, point),
        )
        self.wait(4)


class HowR0IsCalculatedHere(Scene):
    def construct(self):
        words = VGroup(
            TextMobject("Count ", "\\# transfers"),
            TextMobject("for every infectious case")
        )
        words.arrange(DOWN)
        words[1].set_color(RED)
        words.to_edge(UP)

        estimate = TextMobject("Estimate")
        estimate.move_to(words[0][0], RIGHT)

        lp, rp = parens = TexMobject("(", ")")
        parens.match_height(words)
        lp.next_to(words, LEFT, SMALL_BUFF)
        rp.next_to(words, RIGHT, SMALL_BUFF)
        average = TextMobject("Average")
        average.scale(1.5)
        average.next_to(parens, LEFT, SMALL_BUFF)

        words.save_state()
        words[1].move_to(words[0])
        words[0].set_opacity(0)

        self.add(FullScreenFadeRectangle(fill_color=GREY_E, fill_opacity=1).scale(2))
        self.wait()
        self.play(Write(words[1], run_time=1))
        self.wait()
        self.add(words)
        self.play(Restore(words))
        self.wait()
        self.play(
            FadeOut(words[0][0], UP),
            FadeIn(estimate, DOWN),
        )
        self.wait()

        self.play(
            Write(parens),
            FadeIn(average, 0.5 * RIGHT),
            self.camera.frame.shift, LEFT,
        )
        self.wait()

        self.embed()


class R0Rect(Scene):
    def construct(self):
        rect = SurroundingRectangle(TextMobject("R0 = 2.20"))
        rect.set_stroke(YELLOW, 4)
        self.play(ShowCreation(rect))
        self.play(FadeOut(rect))


class DoubleInfectionRadius(Scene):
    CONFIG = {
        "random_seed": 1,
    }

    def construct(self):
        c1 = Circle(radius=0.25, color=RED)
        c2 = Circle(radius=0.5, color=RED)
        arrow = Vector(RIGHT)
        c1.next_to(arrow, LEFT)
        c2.next_to(arrow, RIGHT)

        title = TextMobject("Double the\\\\infection radius")
        title.next_to(VGroup(c1, c2), UP)

        self.add(c1, title)
        self.wait()
        self.play(
            GrowArrow(arrow),
            TransformFromCopy(c1, c2),
        )
        self.wait()

        c2.label = TextMobject("4x area")
        c2.label.scale(0.5)
        c2.label.next_to(c2, DOWN)

        for circ, count in (c1, 4), (c2, 16):
            dots = VGroup()
            for x in range(count):
                dot = Dot(color=BLUE)
                dot.set_stroke(BLACK, 2, background=True)
                dot.set_height(0.05)
                vect = rotate_vector(RIGHT, TAU * random.random())
                vect *= 0.9 * random.random() * circ.get_height() / 2
                dot.move_to(circ.get_center() + vect)
                dots.add(dot)
            circ.dot = dots
            anims = [ShowIncreasingSubsets(dots)]
            if hasattr(circ, "label"):
                anims.append(FadeIn(circ.label, 0.5 * UP))
            self.play(*anims)
            self.wait()


class PInfectionSlider(Scene):
    def construct(self):
        slider = ValueSlider(
            "Probability of infection",
            0.2,
            x_min=0,
            x_max=0.2,
            numbers_to_show=np.arange(0.05, 0.25, 0.05),
            decimal_number_config={
                "num_decimal_places": 2,
            },
            tick_frequency=0.05,
        )
        self.add(slider)
        self.wait()
        self.play(slider.get_change_anim(0.1))
        self.wait()
        self.play(slider.get_change_anim(0.05))
        self.wait()


class R0Categories(Scene):
    def construct(self):
        # Titles
        titles = VGroup(
            TexMobject("R > 1", color=RED),
            TexMobject("R = 1", color=YELLOW),
            TexMobject("R < 1", color=GREEN),
        )
        titles.scale(1.25)
        titles.arrange(RIGHT, buff=2.7)
        titles.to_edge(UP)

        v_lines = VGroup()
        for t1, t2 in zip(titles, titles[1:]):
            v_line = Line(UP, DOWN)
            v_line.set_height(FRAME_HEIGHT)
            v_line.set_x(midpoint(t1.get_right(), t2.get_left())[0])
            v_lines.add(v_line)

        self.add(titles)
        self.add(v_lines)

        # Names
        names = VGroup(
            TextMobject("Epidemic", color=RED),
            TextMobject("Endemic", color=YELLOW),
            TextMobject("...Hypodemic?", color=GREEN),
        )
        for name, title in zip(names, titles):
            name.next_to(title, DOWN, MED_LARGE_BUFF)

        # Doubling dots
        dot = Dot(color=RED)
        dot.next_to(names[0], DOWN, LARGE_BUFF)
        rows = VGroup(VGroup(dot))
        lines = VGroup()
        for x in range(4):
            new_row = VGroup()
            new_lines = VGroup()
            for dot in rows[-1]:
                dot.children = [dot.copy(), dot.copy()]
                new_row.add(*dot.children)
            new_row.arrange(RIGHT)
            max_width = 4
            if new_row.get_width() > max_width:
                new_row.set_width(max_width)
            new_row.next_to(rows[-1], DOWN, LARGE_BUFF)
            for dot in rows[-1]:
                for child in dot.children:
                    new_lines.add(Line(
                        dot.get_center(),
                        child.get_center(),
                        buff=0.2,
                    ))
            rows.add(new_row)
            lines.add(new_lines)

        for row, line_row in zip(rows[:-1], lines):
            self.add(row)
            anims = []
            for dot in row:
                for child in dot.children:
                    anims.append(TransformFromCopy(dot, child))
            for line in line_row:
                anims.append(ShowCreation(line))
            self.play(*anims)
        self.play(FadeIn(names[0], UP))
        self.wait()

        exp_tree = VGroup(rows, lines)

        # Singleton dots
        mid_rows = VGroup()
        mid_lines = VGroup()

        for row in rows:
            dot = Dot(color=RED)
            dot.match_y(row)
            mid_rows.add(dot)

        for d1, d2 in zip(mid_rows[:-1], mid_rows[1:]):
            d1.child = d2
            mid_lines.add(Line(
                d1.get_center(),
                d2.get_center(),
                buff=0.2,
            ))

        for dot, line in zip(mid_rows[:-1], mid_lines):
            self.add(dot)
            self.play(
                TransformFromCopy(dot, dot.child),
                ShowCreation(line)
            )
        self.play(FadeIn(names[1], UP))
        self.wait()

        # Inverted tree
        exp_tree_copy = exp_tree.copy()
        exp_tree_copy.rotate(PI)
        exp_tree_copy.match_x(titles[2])

        self.play(TransformFromCopy(exp_tree, exp_tree_copy))
        self.play(FadeIn(names[2], UP))
        self.wait()


class RealR0Estimates(Scene):
    def construct(self):
        labels = VGroup(
            TextMobject("COVID-19\\\\", "$R_0 \\approx 2$"),
            TextMobject("1918 Spanish flu\\\\", "$R_0 \\approx 2$"),
            TextMobject("Usual seasonal flu\\\\", "$R_0 \\approx 1.3$"),
        )
        images = Group(
            ImageMobject("COVID-19_Map"),
            ImageMobject("spanish_flu"),
            ImageMobject("Influenza"),
        )
        for image in images:
            image.set_height(3)

        images.arrange(RIGHT, buff=0.5)
        images.to_edge(UP, buff=2)

        for label, image in zip(labels, images):
            label.next_to(image, DOWN)

        for label, image in zip(labels, images):
            self.play(
                FadeIn(image, DOWN),
                FadeIn(label, UP),
            )
            self.wait()

        self.embed()


class WhyChooseJustOne(TeacherStudentsScene):
    def construct(self):
        self.student_says(
            "Why choose\\\\just one?",
            target_mode="sassy",
            added_anims=[self.teacher.change, "thinking"],
            run_time=1,
        )
        self.play(
            self.get_student_changes(
                "confused", "confused", "sassy",
            ),
        )
        self.wait(2)
        self.teacher_says(
            "For science!", target_mode="hooray",
            look_at_arg=self.students[2].eyes,
        )
        self.change_student_modes("hesitant", "hesitant", "hesitant")
        self.wait(3)

        self.embed()


class NickyCaseMention(Scene):
    def construct(self):
        words = TextMobject(
            "Artwork by Nicky Case\\\\",
            "...who is awesome."
        )
        words.scale(1)
        words.to_edge(LEFT)
        arrow = Arrow(
            words.get_top(),
            words.get_top() + 2 * UR + RIGHT,
            path_arc=-90 * DEGREES,
        )
        self.play(
            Write(words[0]),
            ShowCreation(arrow),
            run_time=1,
        )
        self.wait(2)
        self.play(Write(words[1]), run_time=1)
        self.wait()


class PonderingRandy(Scene):
    def construct(self):
        randy = Randolph()
        self.play(FadeIn(randy))
        self.play(randy.change, "pondering")
        for x in range(3):
            self.play(Blink(randy))
            self.wait(2)


class WideSpreadTesting(Scene):
    def construct(self):
        # Add dots
        dots = VGroup(*[
            DotPerson(
                height=0.2,
                infection_radius=0.6,
                max_speed=0,
                wander_step_size=0,
                p_symptomatic_on_infection=0.8,
            )
            for x in range(600)
        ])
        dots.arrange_in_grid(20, 30)
        dots.set_height(FRAME_HEIGHT - 1)

        self.add(dots)
        sick_dots = VGroup()
        for x in range(36):
            sicky = random.choice(dots)
            sicky.set_status("I")
            sick_dots.add(sicky)
            self.wait(0.1)
        self.wait(2)

        healthy_dots = VGroup()
        for dot in dots:
            if dot.status != "I":
                healthy_dots.add(dot)

        # Show Flash
        rings = self.get_rings(ORIGIN, FRAME_WIDTH + FRAME_HEIGHT, 0.1)
        rings.shift(7 * LEFT)
        for i, ring in enumerate(rings):
            ring.shift(0.05 * i**1.2 * RIGHT)

        self.play(LaggedStartMap(
            FadeIn, rings,
            lag_ratio=3 / len(rings),
            run_time=2.5,
            rate_func=there_and_back,
        ))

        # Quarantine
        box = Square()
        box.set_height(2)
        box.to_corner(DL)
        box.shift(LEFT)

        anims = []
        points = VGroup()
        points_target = VGroup()
        for dot in sick_dots:
            point = VectorizedPoint(dot.get_center())
            point.generate_target()
            points.add(point)
            points_target.add(point.target)

            dot.push_anim(MaintainPositionRelativeTo(dot, point, run_time=3))
            anims.append(MoveToTarget(point))

        points_target.arrange_in_grid()
        points_target.set_width(box.get_width() - 1)
        points_target.move_to(box)

        self.play(
            ShowCreation(box),
            LaggedStartMap(MoveToTarget, points, lag_ratio=0.05),
            self.camera.frame.shift, LEFT,
            run_time=3,
        )
        self.wait(9)

    def get_rings(self, center, max_radius, delta_r):
        radii = np.arange(0, max_radius, delta_r)
        rings = VGroup(*[
            Circle(
                radius=r,
                stroke_opacity=0.75 * (1 - fdiv(r, max_radius)),
                stroke_color=TEAL,
                stroke_width=100 * delta_r,
            )
            for r in radii
        ])
        rings.move_to(center)
        return rings


class VirusSpreading(Scene):
    def construct(self):
        virus = SVGMobject(file_name="virus")
        virus.lock_triangulation()
        virus.set_fill(RED_E, 1)
        virus.set_stroke([RED, WHITE], width=0)
        height = 3
        virus.set_height(height)

        self.play(DrawBorderThenFill(virus))

        viruses = VGroup(virus)

        for x in range(8):
            height *= 0.8
            anims = []
            new_viruses = VGroup()
            for virus in viruses:
                children = [virus.copy(), virus.copy()]
                for child in children:
                    child.set_height(height)
                    child.set_color(interpolate_color(
                        RED_E,
                        GREY_D,
                        0.7 * random.random(),
                    ))
                    child.shift([
                        (random.random() - 0.5) * 3,
                        (random.random() - 0.5) * 3,
                        0,
                    ])
                    anims.append(TransformFromCopy(virus, child))
                    new_viruses.add(child)
            new_viruses.center()
            self.remove(viruses)
            self.play(*anims, run_time=0.5)
            viruses.set_submobjects(list(new_viruses))
        self.wait()

        # Eliminate
        for virus in viruses:
            virus.generate_target()
            virus.target.scale(3)
            virus.target.set_color(WHITE)
            virus.target.set_opacity(0)

        self.play(LaggedStartMap(
            MoveToTarget, viruses,
            run_time=8,
            lag_ratio=3 / len(viruses)
        ))


class GraciousPi(Scene):
    def construct(self):
        morty = Mortimer()
        morty.flip()
        self.play(FadeIn(morty))
        self.play(morty.change, "hesitant")
        self.play(Blink(morty))
        self.wait()
        self.play(morty.change, "gracious", morty.get_bottom())
        self.play(Blink(morty))
        self.wait(2)
        self.play(Blink(morty))
        self.wait(2)


class SIREndScreen(PatreonEndScreen):
    CONFIG = {
        "specific_patrons": [
            "1stViewMaths",
            "Adam Dřínek",
            "Aidan Shenkman",
            "Alan Stein",
            "Alex Mijalis",
            "Alexis Olson",
            "Ali Yahya",
            "Andrew Busey",
            "Andrew Cary",
            "Andrew R. Whalley",
            "Aravind C V",
            "Arjun Chakroborty",
            "Arthur Zey",
            "Ashwin Siddarth",
            "Austin Goodman",
            "Avi Finkel",
            "Awoo",
            "Axel Ericsson",
            "Ayan Doss",
            "AZsorcerer",
            "Barry Fam",
            "Ben Delo",
            "Bernd Sing",
            "Boris Veselinovich",
            "Bradley Pirtle",
            "Brandon Huang",
            "Brian Staroselsky",
            "Britt Selvitelle",
            "Britton Finley",
            "Burt Humburg",
            "Calvin Lin",
            "Charles Southerland",
            "Charlie N",
            "Chenna Kautilya",
            "Chris Connett",
            "Christian Kaiser",
            "cinterloper",
            "Clark Gaebel",
            "Colwyn Fritze-Moor",
            "Cooper Jones",
            "Corey Ogburn",
            "D. Sivakumar",
            "Dan Herbatschek",
            "Daniel Herrera C",
            "Dave B",
            "Dave Kester",
            "dave nicponski",
            "David B. Hill",
            "David Clark",
            "David Gow",
            "Delton Ding",
            "Dominik Wagner",
            "Eddie Landesberg",
            "emptymachine",
            "Eric Younge",
            "Eryq Ouithaqueue",
            "Farzaneh Sarafraz",
            "Federico Lebron",
            "Frank R. Brown, Jr.",
            "Giovanni Filippi",
            "Goodwine Carlos",
            "Hal Hildebrand",
            "Hitoshi Yamauchi",
            "Ivan Sorokin",
            "Jacob Baxter",
            "Jacob Harmon",
            "Jacob Hartmann",
            "Jacob Magnuson",
            "Jake Vartuli - Schonberg",
            "Jalex Stark",
            "Jameel Syed",
            "Jason Hise",
            "Jayne Gabriele",
            "Jean-Manuel Izaret",
            "Jeff Linse",
            "Jeff Straathof",
            "Jimmy Yang",
            "John C. Vesey",
            "John Camp",
            "John Haley",
            "John Le",
            "John Rizzo",
            "John V Wertheim",
            "Jonathan Heckerman",
            "Jonathan Wilson",
            "Joseph John Cox",
            "Joseph Kelly",
            "Josh Kinnear",
            "Joshua Claeys",
            "Juan Benet",
            "Kai-Siang Ang",
            "Kanan Gill",
            "Karl Niu",
            "Kartik Cating-Subramanian",
            "Kaustuv DeBiswas",
            "Killian McGuinness",
            "Kros Dai",
            "L0j1k",
            "Lael S Costa",
            "LAI Oscar",
            "Lambda GPU Workstations",
            "Lee Redden",
            "Linh Tran",
            "lol I totally forgot I had a patreon",
            "Luc Ritchie",
            "Ludwig Schubert",
            "Lukas Biewald",
            "Magister Mugit",
            "Magnus Dahlström",
            "Manoj Rewatkar - RITEK SOLUTIONS",
            "Mark B Bahu",
            "Mark Heising",
            "Mark Mann",
            "Martin Price",
            "Mathias Jansson",
            "Matt Godbolt",
            "Matt Langford",
            "Matt Roveto",
            "Matt Russell",
            "Matteo Delabre",
            "Matthew Bouchard",
            "Matthew Cocke",
            "Maxim Nitsche",
            "Mia Parent",
            "Michael Hardel",
            "Michael W White",
            "Mirik Gogri",
            "Mustafa Mahdi",
            "Márton Vaitkus",
            "Nate Heckmann",
            "Nicholas Cahill",
            "Nikita Lesnikov",
            "Oleg Leonov",
            "Oliver Steele",
            "Omar Zrien",
            "Owen Campbell-Moore",
            "Patrick Lucas",
            "Pavel Dubov",
            "Petar Veličković",
            "Peter Ehrnstrom",
            "Peter Mcinerney",
            "Pierre Lancien",
            "Pradeep Gollakota",
            "Quantopian",
            "Rafael Bove Barrios",
            "Randy C. Will",
            "rehmi post",
            "Rex Godby",
            "Ripta Pasay",
            "Rish Kundalia",
            "Roman Sergeychik",
            "Roobie",
            "Ryan Atallah",
            "Samuel Judge",
            "SansWord Huang",
            "Scott Gray",
            "Scott Walter, Ph.D.",
            "soekul",
            "Solara570",
            "Steve Huynh",
            "Steve Sperandeo",
            "Steven Siddals",
            "Stevie Metke",
            "Still working on an upcoming skeptical humanist SciFi novels- Elux Luc",
            "supershabam",
            "Suteerth Vishnu",
            "Suthen Thomas",
            "Tal Einav",
            "Taras Bobrovytsky",
            "Tauba Auerbach",
            "Ted Suzman",
            "Thomas J Sargent",
            "Thomas Tarler",
            "Tianyu Ge",
            "Tihan Seale",
            "Tyler VanValkenburg",
            "Vassili Philippov",
            "Veritasium",
            "Vignesh Ganapathi Subramanian",
            "Vinicius Reis",
            "Xuanji Li",
            "Yana Chernobilsky",
            "Yavor Ivanov",
            "YinYangBalance.Asia",
            "Yu Jun",
            "Yurii Monastyrshyn",
        ],
    }


# For assembling script
# SCENES_IN_ORDER = [
WILL_BE_SCENES_IN_ORDER = [
    # Quarantining
    QuarantineInfectious,
    QuarantineInfectiousLarger,
    QuarantineInfectiousLarger80p,
    QuarantineInfectiousTravel,
    QuarantineInfectiousTravel80p,
    QuarantineInfectiousTravel50p,
    # Social distancing
    SimpleSocialDistancing,
    DelayedSocialDistancing,  # Maybe remove?
    DelayedSocialDistancingLargeCity,  # Probably don't use
    SimpleTravelSocialDistancePlusZeroTravel,
    SimpleTravelDelayedSocialDistancing99p,
    SimpleTravelDelayedTravelReductionThreshold100TargetHalfPercent,
    SimpleTravelDelayedSocialDistancing50pThreshold100,
    SimpleTravelDelayedTravelReductionThreshold100,  # Maybe don't use
    # Describing R0
    LargerCity2,
    LargeCityHighInfectionRadius,
    LargeCityLowerInfectionRate,
    SimpleTravelDelayedSocialDistancing99p,  # Need to re-render
    # Market
    CentralMarketLargePopulation,
    CentralMarketLowerInfection,
    CentralMarketVeryFrequentLargePopulationDelayedSocialDistancing,
    CentralMarketLessFrequent,
    CentralMarketTransitionToLowerInfection,
    CentralMarketTransitionToLowerInfectionAndLowerFrequency,
    CentralMarketQuarantine,
    CentralMarketQuarantine80p,
]


to_run_later = [
    CentralMarketTransitionToLowerInfectionAndLowerFrequency,
    SimpleTravelDelayedTravelReduction,
    CentralMarketLargePopulation,
    CentralMarketLowerInfection,
    CentralMarketVeryFrequentLargePopulationDelayedSocialDistancing,
    CentralMarketLessFrequent,
    CentralMarketTransitionToLowerInfection,
    CentralMarketTransitionToLowerInfectionAndLowerFrequency,
    CentralMarketQuarantine,
    CentralMarketQuarantine80p,
    SecondWave,
]