import json
import re
import urllib.parse as urlparse

import requests
from django.http import QueryDict
from django.template.loader import render_to_string
from django.utils.functional import cached_property
from django.utils.module_loading import import_string
from django.utils.safestring import mark_safe

from embed_video.settings import (
    EMBED_VIDEO_BACKENDS,
    EMBED_VIDEO_TIMEOUT,
    EMBED_VIDEO_YOUTUBE_DEFAULT_QUERY,
)


class EmbedVideoException(Exception):
    """ Parental class for all embed_video exceptions """

    pass


class VideoDoesntExistException(EmbedVideoException):
    """ Exception thrown if video doesn't exist """

    pass


class UnknownBackendException(EmbedVideoException):
    """ Exception thrown if video backend is not recognized. """

    pass


class UnknownIdException(VideoDoesntExistException):
    """
    Exception thrown if backend is detected, but video ID cannot be parsed.
    """

    pass


def detect_backend(url):
    """
    Detect the right backend for given URL.

    Goes over backends in ``settings.EMBED_VIDEO_BACKENDS``,
    calls :py:func:`~VideoBackend.is_valid` and returns backend instance.

    :param url: URL which is passed to `is_valid` methods of VideoBackends.
    :type url: str

    :return: Returns recognized VideoBackend
    :rtype: VideoBackend
    """

    for backend_name in EMBED_VIDEO_BACKENDS:
        backend = import_string(backend_name)
        if backend.is_valid(url):
            return backend(url)

    raise UnknownBackendException


class VideoBackend:
    """
    Base class used as parental class for backends.


    Backend variables:

    .. autosummary::

        url
        code
        thumbnail
        query
        info
        is_secure
        protocol
        template_name


    .. code-block:: python

        class MyBackend(VideoBackend):
            ...

    """

    re_code = None
    """
    Compiled regex (:py:func:`re.compile`) to search code in URL.

    Example: ``re.compile(r'myvideo\.com/\?code=(?P<code>\w+)')``
    """

    re_detect = None
    """
    Compilede regec (:py:func:`re.compile`) to detect, if input URL is valid
    for current backend.

    Example: ``re.compile(r'^http://myvideo\.com/.*')``
    """

    pattern_url = None
    """
    Pattern in which the code is inserted.

    Example: ``http://myvideo.com?code=%s``

    :type: str
    """

    pattern_thumbnail_url = None
    """
    Pattern in which the code is inserted to get thumbnail url.

    Example: ``http://static.myvideo.com/thumbs/%s``

    :type: str
    """

    allow_https = True
    """
    Sets if HTTPS version allowed for specific backend.

    :type: bool
    """

    template_name = "embed_video/embed_code.html"
    """
    Name of embed code template used by :py:meth:`get_embed_code`.

    Passed template variables: ``{{ backend }}`` (instance of VideoBackend),
    ``{{ width }}``, ``{{ height }}``

    :type: str
    """

    default_query = ""
    """
    Default query string or `QueryDict` appended to url

    :type: str
    """

    is_secure = False
    """
    Decides if secured protocol (HTTPS) is used.

    :type: bool
    """

    def __init__(self, url):
        """
        First it tries to load data from cache and if it don't succeed, run
        :py:meth:`init` and then save it to cache.

        :type url: str
        """
        self.backend = self.__class__.__name__
        self._url = url
        self.query = QueryDict(self.default_query, mutable=True)

    @property
    def code(self):
        """
        Code of video.
        """
        return self.get_code()

    @property
    def url(self):
        """
        URL of video.
        """
        return self.get_url()

    @property
    def protocol(self):
        """
        Protocol used to generate URL.
        """
        return "https" if self.allow_https and self.is_secure else "http"

    @property
    def thumbnail(self):
        """
        URL of video thumbnail.
        """
        return self.get_thumbnail_url()

    @property
    def info(self):
        """
        Additional information about video. Not implemented in all backends.
        """
        return self.get_info()

    @property
    def query(self):
        """
        String transformed to QueryDict appended to url.
        """
        return self._query

    @query.setter
    def query(self, value):
        """
        :type value: QueryDict | str
        """
        self._query = (
            value if isinstance(value, QueryDict) else QueryDict(value, mutable=True)
        )

    @classmethod
    def is_valid(cls, url):
        """
        Class method to control if passed url is valid for current backend. By
        default it is done by :py:data:`re_detect` regex.

        :type url: str
        """
        return True if cls.re_detect.match(url) else False

    def get_code(self):
        """
        Returns video code matched from given url by :py:data:`re_code`.

        :rtype: str
        """
        match = self.re_code.search(self._url)
        if match:
            return match.group("code")

    def get_url(self):
        """
        Returns URL folded from :py:data:`pattern_url` and parsed code.
        """
        url = self.pattern_url.format(code=self.code, protocol=self.protocol)
        url += "?" + self.query.urlencode() if self.query else ""
        return mark_safe(url)

    def get_thumbnail_url(self):
        """
        Returns thumbnail URL folded from :py:data:`pattern_thumbnail_url` and
        parsed code.

        :rtype: str
        """
        return self.pattern_thumbnail_url.format(code=self.code, protocol=self.protocol)

    def get_embed_code(self, width, height):
        """
        Returns embed code rendered from template :py:data:`template_name`.

        :type width: int | str
        :type height: int | str
        :rtype: str
        """
        return render_to_string(
            self.template_name, {"backend": self, "width": width, "height": height}
        )

    def get_info(self):
        """
        :rtype: dict
        """
        raise NotImplementedError

    def set_options(self, options):
        """
        :type options: dict
        """
        for key in options:
            setattr(self, key, options[key])


class YoutubeBackend(VideoBackend):
    """
    Backend for YouTube URLs.
    """

    re_detect = re.compile(r"^(http(s)?://)?(www\.|m\.)?youtu(\.?)be(\.com)?/.*", re.I)

    re_code = re.compile(
        r"""youtu(\.?)be(\.com)?/  # match youtube's domains
            (\#/)? # for mobile urls
            (embed/)?  # match the embed url syntax
            (v/)?
            (watch\?v=)?  # match the youtube page url
            (ytscreeningroom\?v=)?
            (feeds/api/videos/)?
            (user\S*[^\w\-\s])?
            (?P<code>[\w\-]{11})[a-z0-9;:@?&%=+/\$_.-]*  # match and extract
        """,
        re.I | re.X,
    )

    pattern_url = "{protocol}://www.youtube.com/embed/{code}"
    pattern_thumbnail_url = "{protocol}://img.youtube.com/vi/{code}/{resolution}"
    default_query = EMBED_VIDEO_YOUTUBE_DEFAULT_QUERY
    resolutions = [
        "maxresdefault.jpg",
        "sddefault.jpg",
        "hqdefault.jpg",
        "mqdefault.jpg",
    ]

    is_secure = True
    """
    Decides if secured protocol (HTTPS) is used.

    :type: bool
    """

    def get_code(self):
        code = super().get_code()

        if not code:
            parsed_url = urlparse.urlparse(self._url)
            parsed_qs = urlparse.parse_qs(parsed_url.query)

            if "v" in parsed_qs:
                code = parsed_qs["v"][0]
            elif "video_id" in parsed_qs:
                code = parsed_qs["video_id"][0]
            else:
                raise UnknownIdException("Cannot get ID from `{0}`".format(self._url))

        return code

    def get_thumbnail_url(self):
        """
        Returns thumbnail URL folded from :py:data:`pattern_thumbnail_url` and
        parsed code.

        :rtype: str
        """
        for resolution in self.resolutions:
            temp_thumbnail_url = self.pattern_thumbnail_url.format(
                code=self.code, protocol=self.protocol, resolution=resolution
            )
            if int(requests.head(temp_thumbnail_url).status_code) < 400:
                return temp_thumbnail_url
        return None


class VimeoBackend(VideoBackend):
    """
    Backend for Vimeo URLs.
    """

    re_detect = re.compile(r"^((http(s)?:)?//)?(www\.)?(player\.)?vimeo\.com/.*", re.I)
    re_code = re.compile(
        r"""vimeo\.com/(video/)?(channels/(.*/)?)?((.+)/review/)?(manage/)?(?P<code>[0-9]+)""",
        re.I,
    )
    pattern_url = "{protocol}://player.vimeo.com/video/{code}"
    pattern_info = "{protocol}://vimeo.com/api/v2/video/{code}.json"

    is_secure = True
    """
    Decides if secured protocol (HTTPS) is used.

    :type: bool
    """

    def get_info(self):
        try:
            response = requests.get(
                self.pattern_info.format(code=self.code, protocol=self.protocol),
                timeout=EMBED_VIDEO_TIMEOUT,
            )
            return json.loads(response.text)[0]
        except ValueError:
            raise VideoDoesntExistException()

    def get_thumbnail_url(self):
        return self.info.get("thumbnail_large")


class SoundCloudBackend(VideoBackend):
    """
    Backend for SoundCloud URLs.
    """

    base_url = "{protocol}://soundcloud.com/oembed"

    re_detect = re.compile(r"^(http(s)?://(www\.|m\.)?)?soundcloud\.com/.*", re.I)
    re_code = re.compile(r'src=".*%2F(?P<code>\d+)&show_artwork.*"', re.I)
    re_url = re.compile(r'src="(?P<url>.*?)"', re.I)

    is_secure = True
    """
    Decides if secured protocol (HTTPS) is used.

    :type: bool
    """

    @cached_property
    def width(self):
        """
        :rtype: str
        """
        return self.info.get("width")

    @cached_property
    def height(self):
        """
        :rtype: str
        """
        return self.info.get("height")

    def get_info(self):
        params = {"format": "json", "url": self._url}
        r = requests.get(
            self.base_url.format(protocol=self.protocol),
            params=params,
            timeout=EMBED_VIDEO_TIMEOUT,
        )

        if r.status_code != 200:
            raise VideoDoesntExistException(
                "SoundCloud returned status code `{0}`.".format(r.status_code)
            )

        return json.loads(r.text)

    def get_thumbnail_url(self):
        return self.info.get("thumbnail_url")

    def get_url(self):
        match = self.re_url.search(self.info.get("html"))
        return match.group("url")

    def get_code(self):
        match = self.re_code.search(self.info.get("html"))
        return match.group("code")

    def get_embed_code(self, width, height):
        return super().get_embed_code(width=width, height=height)