from __future__ import annotations

from manimlib.mobject.svg.string_mobject import StringMobject
from manimlib.utils.tex_file_writing import display_during_execution
from manimlib.utils.tex_file_writing import tex_content_to_svg_file

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from colour import Color
    import re
    from typing import Iterable, Union

    from manimlib.mobject.types.vectorized_mobject import VGroup

    ManimColor = Union[str, Color]
    Span = tuple[int, int]
    Selector = Union[
        str,
        re.Pattern,
        tuple[Union[int, None], Union[int, None]],
        Iterable[Union[
            str,
            re.Pattern,
            tuple[Union[int, None], Union[int, None]]
        ]]
    ]


SCALE_FACTOR_PER_FONT_POINT = 0.001


class MTex(StringMobject):
    CONFIG = {
        "font_size": 48,
        "alignment": "\\centering",
        "tex_environment": "align*",
        "tex_to_color_map": {},
        "template": "",
        "additional_preamble": "",
    }

    #CMD_PATTERN = r"\\(?:[a-zA-Z]+|.)|[_^{}]"
    #FLAG_DICT = {
    #    r"{": 1,
    #    r"}": -1
    #}
    #CONTENT_REPL = {}
    #MATCH_REPL = {
    #    r"[_^{}]": ""
    #}

    def __init__(self, tex_string: str, **kwargs):
        # Prevent from passing an empty string.
        if not tex_string.strip():
            tex_string = "\\\\"
        self.tex_string = tex_string
        super().__init__(tex_string, **kwargs)

        self.set_color_by_tex_to_color_map(self.tex_to_color_map)
        self.scale(SCALE_FACTOR_PER_FONT_POINT * self.font_size)

    @property
    def hash_seed(self) -> tuple:
        return (
            self.__class__.__name__,
            self.svg_default,
            self.path_string_config,
            self.base_color,
            self.isolate,
            self.tex_string,
            self.alignment,
            self.tex_environment,
            self.tex_to_color_map,
            self.template,
            self.additional_preamble
        )

    def get_file_path_by_content(self, content: str) -> str:
        with display_during_execution(f"Writing \"{self.tex_string}\""):
            file_path = tex_content_to_svg_file(
                content, self.template, self.additional_preamble
            )
        return file_path

    # Parsing

    @staticmethod
    def get_cmd_pattern() -> str | None:
        return r"(\\(?:[a-zA-Z]+|.))|([_^])|([{}])"

    @staticmethod
    def get_matched_flag(match_obj: re.Match) -> int:
        substr = match_obj.group()
        if match_obj.group(3):
            if substr == "{":
                return 1
            if substr == "}":
                return -1
        return 0

    @staticmethod
    def replace_for_content(match_obj: re.Match) -> str:
        return match_obj.group()

    @staticmethod
    def replace_for_matching(match_obj: re.Match) -> str:
        if not match_obj.group(1):
            return ""
        return match_obj.group()

    @staticmethod
    def get_internal_specified_items(
        cmd_match_pairs: list[tuple[re.Match, re.Match]]
    ) -> list[tuple[Span, dict[str, str]]]:
        cmd_content_spans = [
            (begin_match.end(), end_match.start())
            for begin_match, end_match in cmd_match_pairs
        ]
        #print(MTex.get_neighbouring_pairs(cmd_content_spans))
        return [
            (span, {})
            for span, next_span
            in MTex.get_neighbouring_pairs(cmd_content_spans)
            if span[0] == next_span[0] + 1 and span[1] == next_span[1] - 1
        ]
        #return [
        #    (cmd_content_spans[range_begin], {})
        #    for _, (range_begin, range_end) in self.group_neighbours([
        #        (span_begin + index, span_end - index)
        #        for index, (span_begin, span_end) in enumerate(
        #            cmd_content_spans
        #        )
        #    ])
        #    if range_end - range_begin >= 2
        #]

    def get_external_specified_items(
        self
    ) -> list[tuple[Span, dict[str, str]]]:
        return [
            (span, {})
            for selector in self.tex_to_color_map
            for span in self.find_spans_by_selector(selector)
        ]

    @staticmethod
    def get_color_cmd_str(rgb_hex: str) -> str:
        rgb = MTex.hex_to_int(rgb_hex)
        rg, b = divmod(rgb, 256)
        r, g = divmod(rg, 256)
        return f"\\color[RGB]{{{r}, {g}, {b}}}"

    @staticmethod
    def get_cmd_str_pair(
        attr_dict: dict[str, str], label_hex: str | None
    ) -> tuple[str, str]:
        if label_hex is None:
            return "", ""
        return "{{" + MTex.get_color_cmd_str(label_hex), "}}"

    def get_content_prefix_and_suffix(
        self, is_labelled: bool
    ) -> tuple[str, str]:
        prefix_lines = []
        suffix_lines = []
        if not is_labelled:
            prefix_lines.append(self.get_color_cmd_str(self.base_color_hex))
        if self.alignment:
            prefix_lines.append(self.alignment)
        if self.tex_environment:
            if isinstance(self.tex_environment, str):
                env_prefix = f"\\begin{{{self.tex_environment}}}"
                env_suffix = f"\\end{{{self.tex_environment}}}"
            else:
                env_prefix, env_suffix = self.tex_environment
            prefix_lines.append(env_prefix)
            suffix_lines.append(env_suffix)
        return (
            "".join([line + "\n" for line in prefix_lines]),
            "".join(["\n" + line for line in suffix_lines])
        )

    # Method alias

    def get_parts_by_tex(self, selector: Selector) -> VGroup:
        return self.select_parts(selector)

    def get_part_by_tex(self, selector: Selector, **kwargs) -> VGroup:
        return self.select_part(selector, **kwargs)

    def set_color_by_tex(self, selector: Selector, color: ManimColor):
        return self.set_parts_color(selector, color)

    def set_color_by_tex_to_color_map(
        self, color_map: dict[Selector, ManimColor]
    ):
        return self.set_parts_color_by_dict(color_map)

    def get_tex(self) -> str:
        return self.get_string()


class MTexText(MTex):
    CONFIG = {
        "tex_environment": None,
    }