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


class Document(models.Model):
    """A digital document (ebook, PDF, etc.) uploaded by a user."""

    class FileType(models.TextChoices):
        PDF = "pdf", "PDF"
        EPUB = "epub", "EPUB"
        MOBI = "mobi", "MOBI"
        TXT = "txt", "Plain Text"
        DOCX = "docx", "Word Document"

    title = models.CharField(max_length=500)
    author = models.CharField(max_length=300, blank=True, null=True)
    description = models.TextField(blank=True, default="")
    cover = models.ImageField(upload_to="covers/", blank=True, null=True)
    file = models.FileField(upload_to="documents/")
    file_type = models.CharField(max_length=10, choices=FileType.choices)
    file_size = models.PositiveIntegerField(help_text="File size in bytes")
    page_count = models.PositiveIntegerField(blank=True, null=True)
    tags = models.JSONField(default=list, blank=True)
    is_public = models.BooleanField(default=False)
    owner = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="documents",
    )
    uploaded_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "documents_document"
        ordering = ["-uploaded_at"]
        indexes = [
            models.Index(fields=["owner", "-uploaded_at"]),
            models.Index(fields=["file_type"]),
        ]

    def __str__(self) -> str:
        return self.title

    @property
    def cover_url(self) -> str | None:
        if self.cover:
            return self.cover.url
        return None