from django.conf import settings
from django.db import models
from django.db.models.signals import post_delete
from django.dispatch import receiver
from pathlib import Path


class ReadingStatus(models.TextChoices):
    WANT_TO_READ = "want_to_read", "Want to Read"
    READING = "reading", "Reading"
    FINISHED = "finished", "Finished"
    DNF = "dnf", "Did Not Finish"


class FontStyle(models.TextChoices):
    SANS_SERIF = "sans-serif", "Sans Serif"
    SERIF = "serif", "Serif"
    MONOSPACE = "monospace", "Monospace"


class BackgroundColor(models.TextChoices):
    WHITE = "#ffffff", "White"
    SEPIA = "#f4e4c1", "Sepia"
    DARK = "#1a1a2e", "Dark"
    GREEN = "#c7edcc", "Green"


class Book(models.Model):
    title = models.CharField(max_length=512, db_index=True)
    author = models.CharField(max_length=256, blank=True, default="", db_index=True)
    genre = models.CharField(max_length=128, blank=True, default="", db_index=True)
    description = models.TextField(blank=True, default="")
    reading_status = models.CharField(max_length=20, choices=ReadingStatus.choices, default=ReadingStatus.WANT_TO_READ, db_index=True)
    total_pages = models.PositiveIntegerField(default=0)
    cover_image = models.URLField(blank=True, default="")
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "books_book"
        verbose_name = "Book"
        verbose_name_plural = "Books"
        ordering = ["title"]
        indexes = [models.Index(fields=["title", "author", "genre"])]

    def __str__(self):
        return self.title


class EBook(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="ebooks")
    title = models.CharField(max_length=512)
    author = models.CharField(max_length=256, blank=True, default="")
    file = models.FileField(upload_to="ebooks/%Y/%m/%d/")
    cover_image = models.ImageField(upload_to="ebook_covers/%Y/%m/%d/", blank=True, null=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "books_ebook"
        verbose_name = "E-Book"
        verbose_name_plural = "E-Books"
        ordering = ["-created_at"]
        indexes = [models.Index(fields=["user", "-created_at"])]

    def __str__(self):
        return self.title

    def filename(self):
        return Path(self.file.name).name if self.file else ""


@receiver(post_delete, sender=EBook)
def _auto_delete_ebook_file(sender, instance, **kwargs):
    if instance.file:
        instance.file.delete(save=False)
    if instance.cover_image:
        instance.cover_image.delete(save=False)


class ReadingProgress(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="reading_progress")
    ebook = models.OneToOneField(EBook, on_delete=models.CASCADE, related_name="reading_progress")
    current_position = models.FloatField(default=0.0)
    last_page = models.IntegerField(default=0)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "books_reading_progress"
        verbose_name_plural = "reading progress"
        unique_together = [("user", "ebook")]

    def __str__(self):
        return f"{self.ebook.title} - {self.current_position:.1f}%"


class ReadingSettings(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="reading_settings")
    font_size = models.IntegerField(default=18)
    font_style = models.CharField(max_length=20, choices=FontStyle.choices, default=FontStyle.SANS_SERIF.value)
    background_color = models.CharField(max_length=7, choices=BackgroundColor.choices, default=BackgroundColor.WHITE.value)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "books_reading_settings"
        verbose_name_plural = "reading settings"

    def __str__(self):
        return f"Settings for {self.user}"