from django.contrib.auth.models import User
from django.db import models


class PodcastFeed(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='podcast_feeds')
    rss_url = models.URLField(max_length=1000)
    title = models.CharField(max_length=300)
    description = models.TextField(blank=True)
    artwork_url = models.URLField(max_length=1000, blank=True)
    author = models.CharField(max_length=300, blank=True)
    link = models.URLField(max_length=1000, blank=True)
    last_refreshed_at = models.DateTimeField(null=True, blank=True)
    added_at = models.DateTimeField(auto_now_add=True)
    auto_queue = models.BooleanField(default=False)

    class Meta:
        unique_together = ('user', 'rss_url')
        ordering = ['title']

    def __str__(self):
        return self.title


class PodcastEpisode(models.Model):
    feed = models.ForeignKey(PodcastFeed, on_delete=models.CASCADE, related_name='episodes')
    guid = models.CharField(max_length=1000)
    title = models.CharField(max_length=500)
    description = models.TextField(blank=True)
    audio_url = models.URLField(max_length=1000)
    duration_seconds = models.IntegerField(default=0)
    pub_date = models.DateTimeField(null=True, blank=True)
    episode_number = models.IntegerField(null=True, blank=True)
    season_number = models.IntegerField(null=True, blank=True)
    artwork_url = models.URLField(max_length=1000, blank=True)
    discovered_at = models.DateTimeField(auto_now_add=True)
    # Podcasting 2.0 <podcast:chapters url=…>: a JSON file, loaded on demand.
    chapters_url = models.URLField(max_length=1000, blank=True)
    # [{start: seconds, title, url?, img?}], from Podlove Simple Chapters in
    # the feed, or once fetched: the JSON at chapters_url, else (or if that
    # has none) the CHAP frames of the audio file's ID3v2 tag.
    chapters = models.JSONField(default=list, blank=True)
    # When chapters were fetched into `chapters` (from chapters_url or the
    # audio file); null = not yet.
    chapters_fetched_at = models.DateTimeField(null=True, blank=True)
    # [{url, type, language}] from <podcast:transcript>.
    transcripts = models.JSONField(default=list, blank=True)

    class Meta:
        unique_together = ('feed', 'guid')
        ordering = ['-pub_date']

    def __str__(self):
        return self.title


class EpisodeTranscript(models.Model):
    """An episode's transcript, fetched and parsed once (transcripts.py).

    A table of its own rather than fields on PodcastEpisode: a parsed
    transcript runs to hundreds of KB, and episode lists load whole rows.
    """
    episode = models.OneToOneField(PodcastEpisode, on_delete=models.CASCADE, related_name='transcript_cache')
    # URLs of the transcripts it was made from, best first. When the feed
    # offers different ones, the cache is stale.
    sources = models.JSONField(default=list)
    # {"segments": [...], "source": {...}}, or null with an error.
    data = models.JSONField(null=True, blank=True)
    # '' when data is there; else why there's none for good: 'unsupported'
    # (no format with timing), 'invalid' (missing, broken, too large).
    error = models.CharField(max_length=20, blank=True)
    fetched_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return f'Transcript of {self.episode}'


# An episode counts as played this close to its end (AntennaPod's default),
# the same rule as the apps' "als gehört zählen".
PLAYED_BEFORE_END_SECONDS = 30


def counts_as_played(position_seconds, duration_seconds):
    return bool(duration_seconds) and duration_seconds > 0 and \
        position_seconds >= max(duration_seconds - PLAYED_BEFORE_END_SECONDS, 1)


class EpisodeProgress(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='episode_progress')
    episode = models.ForeignKey(PodcastEpisode, on_delete=models.CASCADE, related_name='progress')
    position_seconds = models.IntegerField(default=0)
    played = models.BooleanField(default=False)
    dismissed = models.BooleanField(default=False)
    favorite = models.BooleanField(default=False)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        unique_together = ('user', 'episode')
        ordering = ['-updated_at']

    def __str__(self):
        return f'{self.user} - {self.episode}'


class PodcastQueue(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='podcast_queue')
    episode = models.ForeignKey(PodcastEpisode, on_delete=models.CASCADE, related_name='queued_by')
    position = models.PositiveIntegerField(default=0)
    added_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ('user', 'episode')
        ordering = ['position']

    def __str__(self):
        return f'{self.user} queue pos {self.position}: {self.episode}'

class PodcastSettings(models.Model):
    """A user's podcast preferences. Where episodes go in the queue: when added
    by hand (also when played from outside the queue), and when a feed with
    auto_queue brings new ones."""
    BACK = 'back'
    FRONT = 'front'
    AFTER_CURRENT = 'after_current'
    POSITIONS = [
        (BACK, 'Ans Ende'),
        (FRONT, 'An den Anfang'),
        (AFTER_CURRENT, 'Nach der laufenden Folge'),
    ]

    user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='podcast_settings')
    enqueue_position = models.CharField(max_length=20, choices=POSITIONS, default=BACK)
    # front = how auto-queue always worked before this setting existed
    auto_queue_position = models.CharField(max_length=20, choices=POSITIONS, default=FRONT)

    @classmethod
    def for_user(cls, user):
        obj, _ = cls.objects.get_or_create(user=user)
        return obj

    def __str__(self):
        return f'Podcast settings of {self.user}'