from django.db import models, transaction
from django.urls import reverse
from django.conf import settings

from aliyun_video.core import get_video_play_info
from aliyun_video.core.utils import (
    get_path_from_cdn_url,
    get_play_id_from_web_m3u8,
    build_m3u8_index
)


class AliyunVideo(models.Model):

    STATUS_PROCESSING = 0
    STATUS_NORMAL = 1
    STATUS_CHOICES = (
        (STATUS_PROCESSING, 'processing'),
        (STATUS_NORMAL, 'normal')
    )

    lesson_id = models.IntegerField()
    video_id = models.CharField(max_length=64, primary_key=True, unique=True)
    title = models.CharField(max_length=128)
    cover_image_url = models.URLField(blank=True, null=True)
    duration = models.FloatField(blank=True, null=True, default=0)
    status = models.SmallIntegerField(choices=STATUS_CHOICES, default=STATUS_PROCESSING)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = 'aliyun_video'

    @property
    def log_url(self):
        return reverse(
            'lecture:play-log',
            kwargs={
                'lesson_id': self.lesson_id,
                'video_id': self.video_id
            })


class AliyunVideoPlayDetail(models.Model):

    video = models.ForeignKey(
        AliyunVideo,
        on_delete=models.CASCADE,
        related_name="video_play_details"
    )
    play_id = models.CharField(max_length=128, unique=True)
    bit_rate = models.FloatField()
    definition = models.CharField(max_length=8)
    duration = models.FloatField(blank=True, null=True, default=0)
    width = models.IntegerField()
    height = models.IntegerField()

    class Meta:
        db_table = 'aliyun_video_play_details'

    @property
    def m3u8_index_content(self):
        return build_m3u8_index(
            self.video.lesson_id,
            self.video_id,
            self.play_id,
            self.duration,
            10
        )

    @property
    def play_url(self):
        return reverse(
            'lecture:play-m3u8',
            kwargs={
                'lesson_id': self.video.lesson_id,
                'video_id': self.video_id,
                'play_id': self.play_id
            })


def aliyun_transcode_event_callback(video_id):
    """
    Update video infos: cover image, title, status
    Get and save all the transcoded videos.
    """
    try:
        video = AliyunVideo.objects.get(video_id=video_id)
        # TODO: get_or_create
    except AliyunVideo.DoesNotExist:
        return

    video_info = get_video_play_info(video_id)

    with transaction.atomic():
        video.cover_image_url = get_path_from_cdn_url(video_info['VideoBase']['CoverURL'])
        video.duration = video_info['VideoBase']['Duration']
        video.title = video_info['VideoBase']['Title']
        video.status = AliyunVideo.STATUS_NORMAL
        video.save()
        video.video_play_details.all().delete()

        for play_info in video_info['PlayInfoList']['PlayInfo']:
            if play_info['Format'].lower() != 'm3u8':
                continue
            play_id = get_play_id_from_web_m3u8(play_info['PlayURL'])
            AliyunVideoPlayDetail.objects.create(
                video=video,
                play_id=play_id,
                bit_rate=play_info['Bitrate'],
                definition=play_info['Definition'],
                duration=play_info['Duration'],
                width=play_info['Width'],
                height=play_info['Height']
            )


class AliyunVideoHistory(models.Model):

    video = models.ForeignKey(
        AliyunVideo,
        on_delete=models.DO_NOTHING)
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.DO_NOTHING)
    first_visited_at = models.DateTimeField(auto_now_add=True)
    last_visited_at = models.DateTimeField(auto_now=True)
    total_visited_count = models.IntegerField(default=0)
    played_at = models.FloatField(default=0)
    last_definition = models.CharField(max_length=16, blank=True, null=True)

    class Meta:
        db_table = 'aliyun_video_history'
        unique_together = ('video', 'user')