from django.conf import settings
from django.db import models

from apps.core.models import Audience, TimeStampedModel


def library_upload_path(instance, filename):
    return f"library/{instance.owner_id}/originals/{filename}"


def rendition_upload_path(instance, filename):
    return f"library/{instance.library_item.owner_id}/renditions/{instance.kind}/{filename}"


class LibraryItem(TimeStampedModel):
    """A single photo or video backed up to a user's private library.
    Nothing here is visible to anyone but the owner until it is attached to
    a Moment or a shared Album."""

    class MediaType(models.TextChoices):
        PHOTO = "photo", "Photo"
        VIDEO = "video", "Video"

    class ProcessingStatus(models.TextChoices):
        PENDING = "pending", "Pending"
        PROCESSING = "processing", "Processing"
        READY = "ready", "Ready"
        FAILED = "failed", "Failed"

    owner = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="library_items", on_delete=models.CASCADE)
    file = models.FileField(upload_to=library_upload_path)
    media_type = models.CharField(max_length=10, choices=MediaType.choices)
    original_filename = models.CharField(max_length=255)
    file_size = models.PositiveBigIntegerField(default=0)
    width = models.PositiveIntegerField(null=True, blank=True)
    height = models.PositiveIntegerField(null=True, blank=True)
    duration_seconds = models.FloatField(null=True, blank=True)

    captured_at = models.DateTimeField(null=True, blank=True)
    latitude = models.DecimalField(max_digits=9, decimal_places=6, null=True, blank=True)
    longitude = models.DecimalField(max_digits=9, decimal_places=6, null=True, blank=True)
    camera_make = models.CharField(max_length=100, blank=True)
    camera_model = models.CharField(max_length=100, blank=True)

    checksum = models.CharField(max_length=64, db_index=True, help_text="sha256 of the original file, used for dedup")
    processing_status = models.CharField(
        max_length=12, choices=ProcessingStatus.choices, default=ProcessingStatus.PENDING
    )

    class Meta:
        unique_together = ("owner", "checksum")
        ordering = ["-captured_at", "-created_at"]

    def __str__(self):
        return f"{self.original_filename} ({self.owner})"


class MediaRendition(models.Model):
    """A derived, smaller version of a LibraryItem (thumbnail/feed/large),
    generated asynchronously so the original never has to be served to the
    browser just to render a grid."""

    class Kind(models.TextChoices):
        THUMBNAIL = "thumbnail", "Thumbnail"
        FEED = "feed", "Feed"
        LARGE = "large", "Large / Fullscreen"

    library_item = models.ForeignKey(LibraryItem, related_name="renditions", on_delete=models.CASCADE)
    kind = models.CharField(max_length=10, choices=Kind.choices)
    file = models.FileField(upload_to=rendition_upload_path)
    width = models.PositiveIntegerField()
    height = models.PositiveIntegerField()
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ("library_item", "kind")

    def __str__(self):
        return f"{self.library_item_id} - {self.kind}"


class Album(TimeStampedModel):
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="albums", on_delete=models.CASCADE)
    name = models.CharField(max_length=150)
    description = models.TextField(blank=True)
    cover_item = models.ForeignKey(
        LibraryItem, related_name="+", on_delete=models.SET_NULL, null=True, blank=True
    )
    audience = models.CharField(max_length=10, choices=Audience.choices, default=Audience.ONLY_ME)

    def __str__(self):
        return self.name


class AlbumItem(models.Model):
    album = models.ForeignKey(Album, related_name="items", on_delete=models.CASCADE)
    library_item = models.ForeignKey(LibraryItem, related_name="album_items", on_delete=models.CASCADE)
    added_by = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="+", on_delete=models.CASCADE)
    added_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ("album", "library_item")
        ordering = ["-added_at"]


class AlbumCollaborator(models.Model):
    class Role(models.TextChoices):
        VIEWER = "viewer", "Viewer"
        CONTRIBUTOR = "contributor", "Contributor"
        ADMIN = "admin", "Admin"

    class Status(models.TextChoices):
        PENDING = "pending", "Pending"
        ACCEPTED = "accepted", "Accepted"

    album = models.ForeignKey(Album, related_name="collaborators", on_delete=models.CASCADE)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="album_invites", on_delete=models.CASCADE)
    role = models.CharField(max_length=11, choices=Role.choices, default=Role.VIEWER)
    invited_by = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="+", on_delete=models.CASCADE)
    status = models.CharField(max_length=8, choices=Status.choices, default=Status.PENDING)

    class Meta:
        unique_together = ("album", "user")