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


class EBook(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='ebooks')
    meta_ct = models.TextField()          # base64 AES-GCM ciphertext of {title, author, filename}
    meta_iv = models.CharField(max_length=32)  # hex IV for metadata
    data_ct = models.TextField()          # base64 AES-GCM ciphertext of raw EPUB bytes
    data_iv = models.CharField(max_length=32)  # hex IV for EPUB data
    uploaded_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['uploaded_at']

    def __str__(self):
        return f"EBook #{self.pk} (user={self.user_id})"


class EBookProgress(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='ebook_progress')
    book = models.ForeignKey(EBook, on_delete=models.CASCADE, related_name='progress')
    scroll_fraction = models.FloatField(default=0.0)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        unique_together = ('user', 'book')

    def __str__(self):
        return f"Progress book={self.book_id} user={self.user_id} {self.scroll_fraction:.2f}"


class EBookHighlights(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='ebook_highlights')
    book = models.ForeignKey(EBook, on_delete=models.CASCADE, related_name='highlights')
    ct   = models.TextField()                # base64 AES-GCM ciphertext of JSON array
    iv   = models.CharField(max_length=32)   # hex IV
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        unique_together = ('user', 'book')

    def __str__(self):
        return f"Highlights book={self.book_id} user={self.user_id}"


class EBookBookmarks(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='ebook_bookmarks')
    book = models.ForeignKey(EBook, on_delete=models.CASCADE, related_name='bookmarks')
    ct   = models.TextField()
    iv   = models.CharField(max_length=32)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        unique_together = ('user', 'book')

    def __str__(self):
        return f"Bookmarks book={self.book_id} user={self.user_id}"