import base64
import datetime
import hashlib
import hmac
import html
import re
import struct
import sys
from binascii import hexlify
from hashlib import sha1
from itertools import chain
from random import randint

import dateutil
import feedparser
import lxml.etree
import lxml.html
from django.utils.dateformat import DateFormat
from django.utils.html import strip_tags as strip_tags_django
from lxml.etree import ParserError, SerialisationError, XMLSyntaxError
from lxml.html.clean import Cleaner
from lxml.html.diff import fixup_ins_del_tags, htmldiff_tokens, tokenize

from utils.tornado_escape import linkify as linkify_tornado
from utils.tornado_escape import xhtml_unescape as xhtml_unescape_tornado

# COMMENTS_RE = re.compile('\<![ \r\n\t]*(--([^\-]|[\r\n]|-[^\-])*--[ \r\n\t]*)\>')
COMMENTS_RE = re.compile("\<!--.*?--\>")


def midnight_today(now=None):
    if not now:
        now = datetime.datetime.now()
    return now.replace(hour=0, minute=0, second=0, microsecond=0, tzinfo=None)


def midnight_yesterday(midnight=None):
    if not midnight:
        midnight = midnight_today()
    return midnight - datetime.timedelta(days=1)


def beginning_of_this_month():
    return datetime.datetime.now().replace(day=1, hour=0, minute=0, second=0, microsecond=0)


def format_story_link_date__short(date, now=None):
    if not now:
        now = datetime.datetime.now()
    date = date.replace(tzinfo=None)
    midnight = midnight_today(now)
    if date >= midnight:
        return date.strftime("%I:%M%p").lstrip("0").lower()
    elif date >= midnight_yesterday(midnight):
        return "Yesterday, " + date.strftime("%I:%M%p").lstrip("0").lower()
    else:
        return date.strftime("%d %b %Y, ") + date.strftime("%I:%M%p").lstrip("0").lower()


def format_story_link_date__long(date, now=None):
    if not now:
        now = datetime.datetime.now()
    date = date.replace(tzinfo=None)
    midnight = midnight_today(now)
    parsed_date = DateFormat(date)

    if date >= midnight:
        return "Today, " + parsed_date.format("F jS ") + date.strftime("%I:%M%p").lstrip("0").lower()
    elif date >= midnight_yesterday(midnight):
        return "Yesterday, " + parsed_date.format("F jS g:ia").replace(".", "")
    elif date >= beginning_of_this_month():
        return parsed_date.format("l, F jS g:ia").replace(".", "")
    else:
        return parsed_date.format("l, F jS, Y g:ia").replace(".", "")


def relative_date(d):
    diff = datetime.datetime.utcnow() - d
    s = diff.seconds
    if diff.days == 1:
        return "1 day ago"
    elif diff.days > 1:
        return "{} days ago".format(diff.days)
    elif s < 60:
        return "just now"
    elif s < 120:
        return "1 minute ago"
    elif s < 3600:
        return "{} minutes ago".format(s // 60)
    elif s < 7200:
        return "1 hour ago"
    else:
        return "{} hours ago".format(s // 3600)


def _extract_date_tuples(date):
    parsed_date = DateFormat(date)
    date_tuple = datetime.datetime.timetuple(date)[:3]
    today_tuple = datetime.datetime.timetuple(datetime.datetime.utcnow())[:3]
    today = datetime.datetime.today()
    yesterday_tuple = datetime.datetime.timetuple(today - datetime.timedelta(1))[:3]

    return parsed_date, date_tuple, today_tuple, yesterday_tuple


def pre_process_story(entry, encoding):
    # Do not switch to published_parsed or every story will be dated the fetch time
    publish_date = entry.get("g_parsed") or entry.get("updated_parsed")
    if publish_date:
        publish_date = datetime.datetime(*publish_date[:6])
    if not publish_date and entry.get("published"):
        try:
            publish_date = dateutil.parser.parse(entry.get("published")).replace(tzinfo=None)
        except (ValueError, TypeError, OverflowError):
            pass

    if publish_date:
        entry["published"] = publish_date
    else:
        entry["published"] = datetime.datetime.utcnow() + datetime.timedelta(seconds=randint(0, 59))

    if entry["published"] < datetime.datetime(2000, 1, 1):
        entry["published"] = datetime.datetime.utcnow()

    # Future dated stories get forced to current date
    # if entry['published'] > datetime.datetime.now() + datetime.timedelta(days=1):
    if entry["published"] > datetime.datetime.now():
        entry["published"] = datetime.datetime.now() + datetime.timedelta(seconds=randint(0, 59))

    # entry_link = entry.get('link') or ''
    # protocol_index = entry_link.find("://")
    # if protocol_index != -1:
    #     entry['link'] = (entry_link[:protocol_index+3]
    #                     + urlquote(entry_link[protocol_index+3:]))
    # else:
    #     entry['link'] = urlquote(entry_link)
    if isinstance(entry.get("guid"), dict):
        entry["guid"] = str(entry["guid"])

    # Normalize story content/summary
    summary = entry.get("summary") or ""
    content = ""
    if not summary and "summary_detail" in entry:
        summary = entry["summary_detail"].get("value", "")
    if entry.get("content"):
        content = entry["content"][0].get("value", "")
    if len(content) > len(summary):
        entry["story_content"] = content.strip()
    else:
        entry["story_content"] = summary.strip()
    if not entry["story_content"] and entry.get("subtitle"):
        entry["story_content"] = entry.get("subtitle")

    if "summary_detail" in entry and entry["summary_detail"].get("type", None) == "text/plain":
        try:
            entry["story_content"] = feedparser.sanitizer._sanitize_html(
                entry["story_content"], encoding, "text/plain"
            )
            if encoding and not isinstance(entry["story_content"], str):
                entry["story_content"] = entry["story_content"].decode(encoding, "ignore")
        except UnicodeEncodeError:
            pass

    # Add each media enclosure as a Download link
    for media_content in chain(entry.get("media_content", [])[:15], entry.get("links", [])[:15]):
        media_url = media_content.get("url", media_content.get("href", ""))
        media_type = media_content.get("type", media_content.get("medium", ""))
        if media_url and media_type and media_url not in entry["story_content"]:
            media_type_name = media_type.split("/")[0]
            if "audio" in media_type and media_url:
                entry[
                    "story_content"
                ] += """<br><br>
                    <audio controls="controls" preload="none">
                        <source src="%(media_url)s" type="%(media_type)s" />
                    </audio>""" % {
                    "media_url": media_url,
                    "media_type": media_type,
                }
            elif "video" in media_type and media_url:
                entry[
                    "story_content"
                ] += """<br><br>
                    <video controls="controls" preload="none">
                        <source src="%(media_url)s" type="%(media_type)s" />
                    </video>""" % {
                    "media_url": media_url,
                    "media_type": media_type,
                }
            elif "image" in media_type and media_url and media_url not in entry["story_content"]:
                entry["story_content"] += """<br><br><img src="%s" />""" % media_url
                continue
            elif media_content.get("rel", "") == "alternative" or "text" in media_content.get("type", ""):
                continue
            elif media_type_name in ["application"]:
                continue
            entry[
                "story_content"
            ] += """<br><br>
                Download %(media_type)s: <a href="%(media_url)s">%(media_url)s</a>""" % {
                "media_type": media_type_name,
                "media_url": media_url,
            }

    entry["guid"] = entry.get("guid") or entry.get("id") or entry.get("link") or str(entry.get("published"))

    if not entry.get("title"):
        entry["title"] = ""

    entry["title"] = strip_tags(entry.get("title"))
    entry["author"] = strip_tags(entry.get("author"))
    if not entry["author"]:
        entry["author"] = strip_tags(entry.get("credit"))

    entry["story_content"] = attach_media_scripts(entry["story_content"])

    return entry


def attach_media_scripts(content):
    if "instagram-media" in content and "<script" not in content:
        content += '<script async defer src="https://platform.instagram.com/en_US/embeds.js"></script><script>(function(){if(window.instgrm)window.instgrm.Embeds.process()})()</script>'
    if "twitter-tweet" in content and "<script" not in content:
        content += '<script id="twitter-wjs" type="text/javascript" async defer src="https://platform.twitter.com/widgets.js"></script>'
    if "imgur-embed-pub" in content and "<script" not in content:
        content += '<script async src="https://s.imgur.com/min/embed.js" charset="utf-8"></script>'
    return content


def strip_tags(html):
    if not html:
        return ""
    return strip_tags_django(html)


def strip_comments(html_string):
    return COMMENTS_RE.sub("", html_string)


def strip_comments__lxml2(html_string=""):
    if not html_string:
        return html_string
    tree = lxml.html.fromstring(html_string)
    comments = tree.xpath("//comment()")

    for c in comments:
        p = c.getparent()
        p.remove(c)

    return lxml.etree.tostring(tree)


def strip_comments__lxml(html_string=""):
    if not html_string:
        return html_string

    params = {
        "comments": True,
        "scripts": False,
        "javascript": False,
        "style": False,
        "links": False,
        "meta": False,
        "page_structure": False,
        "processing_instructions": False,
        "embedded": False,
        "frames": False,
        "forms": False,
        "annoying_tags": False,
        "remove_tags": None,
        "allow_tags": None,
        "remove_unknown_tags": True,
        "safe_attrs_only": False,
    }
    try:
        cleaner = Cleaner(**params)
        html = lxml.html.fromstring(html_string)
        clean_html = cleaner.clean_html(html)

        return lxml.etree.tostring(clean_html).decode()
    except (XMLSyntaxError, ParserError, SerialisationError):
        return html_string


def prep_for_search(html):
    html = strip_tags_django(html)
    html = html.lower()
    html = xhtml_unescape_tornado(html)

    return html[:100000]


def linkify(*args, **kwargs):
    return xhtml_unescape_tornado(linkify_tornado(*args, **kwargs))


def truncate_chars(value, max_length):
    try:
        value = value.encode("utf-8")
    except UnicodeDecodeError:
        pass
    if len(value) <= max_length:
        return value.decode("utf-8", "ignore")

    truncd_val = value[:max_length]
    if value[max_length] != b" ":
        rightmost_space = truncd_val.rfind(b" ")
        if rightmost_space != -1:
            truncd_val = truncd_val[:rightmost_space]

    return truncd_val.decode("utf-8", "ignore") + "..."


def htmldiff(old_html, new_html):
    try:
        old_html_tokens = tokenize(old_html, include_hrefs=False)
        new_html_tokens = tokenize(new_html, include_hrefs=False)
    except (KeyError, ParserError):
        return new_html

    result = htmldiff_tokens(old_html_tokens, new_html_tokens)
    result = "".join(result).strip()

    return fixup_ins_del_tags(result)


def create_camo_signed_url(base_url, hmac_key, url):
    """Create a camo signed URL for the specified image URL
    Args:
        base_url: Base URL of the camo installation
        hmac_key: HMAC shared key to be used for signing
        url: URL of the destination image
    Returns:
        str: A full url that can be used to serve the proxied image
    """

    base_url = base_url.rstrip("/")
    signature = hmac.HMAC(hmac_key, url.encode(), digestmod=sha1).hexdigest()
    hex_url = hexlify(url.encode()).decode()

    return "{base}/{signature}/{hex_url}".format(base=base_url, signature=signature, hex_url=hex_url)


def create_imageproxy_signed_url(base_url, hmac_key, url, options=None):
    """Create a imageproxy signed URL for the specified image URL
    Args:
        base_url: Base URL of the imageproxy installation
        hmac_key: HMAC shared key to be used for signing
        url: URL of the destination image
    Returns:
        str: A full url that can be used to serve the proxied image
    """
    if not options:
        options = []
    if isinstance(options, int):
        options = [str(options)]
    if not isinstance(options, list):
        options = [options]
    if sys.getdefaultencoding() == "ascii":
        url = url.encode("utf-8")

    if url.startswith("data:"):
        return url

    base_url = base_url.rstrip("/")
    signature = base64.urlsafe_b64encode(
        hmac.new(hmac_key.encode(), msg=url.encode(), digestmod=hashlib.sha256).digest()
    )
    options.append("sc")
    options.append("s" + signature.decode())

    return "{base}/{options}/{url}".format(base=base_url, options=",".join(options), url=url)