"""GoodDrive's logical folders and delegated user spaces.

A DriveSpace is a numbered physical directory. DriveItems remain DB-managed,
so renaming a space never renames its physical path.
"""
import uuid
from django.conf import settings
from django.db import models
from django.core.exceptions import ValidationError


class DriveSpace(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='drive_space', null=True, blank=True)
    managed_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, null=True, blank=True, related_name='managed_drive_spaces')
    private_owner = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='private_drive_space', null=True, blank=True)
    parent = models.ForeignKey('self', null=True, blank=True, on_delete=models.PROTECT, related_name='children')
    directory_name = models.CharField(max_length=24, unique=True, null=True, blank=True)
    relative_path = models.CharField(max_length=700, unique=True)
    display_name = models.CharField(max_length=120)
    can_view_parent = models.BooleanField(default=True)
    can_write_parent = models.BooleanField(default=False)
    can_invite = models.BooleanField(default=False)
    quota_bytes = models.BigIntegerField(null=True, blank=True, default=None)
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f'{self.display_name} ({self.relative_path})'


class SpaceGrant(models.Model):
    """Grant access to an EXISTING account, without changing its hierarchy."""
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='granted_spaces')
    space = models.ForeignKey(DriveSpace, on_delete=models.CASCADE, related_name='access_grants')
    can_write = models.BooleanField(default=False)
    can_invite = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        constraints = [models.UniqueConstraint(fields=['user', 'space'], name='drive_unique_space_grant')]


class SpaceInvitation(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    token_hash = models.CharField(max_length=64, unique=True)
    parent_space = models.ForeignKey(DriveSpace, on_delete=models.CASCADE, related_name='invitations')
    created_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT)
    can_view_parent = models.BooleanField(default=True)
    can_write_parent = models.BooleanField(default=False)
    can_invite = models.BooleanField(default=False)
    quota_bytes = models.BigIntegerField(null=True, blank=True, default=None)
    expires_at = models.DateTimeField()
    used_by = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, blank=True, on_delete=models.SET_NULL, related_name='redeemed_invitations')
    used_at = models.DateTimeField(null=True, blank=True)
    revoked_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)


class DriveItem(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='drive_items')
    space = models.ForeignKey(DriveSpace, on_delete=models.PROTECT, related_name='items')
    parent = models.ForeignKey('self', null=True, blank=True, on_delete=models.CASCADE, related_name='children')
    name = models.CharField(max_length=255)
    is_folder = models.BooleanField(default=False)
    storage_key = models.CharField(max_length=120, blank=True)
    # Existing files keep a blank storage_location (legacy /files/ab/<uuid>).
    # New files go under /files/root/0001/.../ab/<uuid>.
    storage_location = models.CharField(max_length=1200, blank=True)
    size = models.BigIntegerField(default=0)
    mime_type = models.CharField(max_length=180, default='application/octet-stream')
    is_shared = models.BooleanField(default=False)  # legacy; no global sharing in hierarchical mode
    is_starred = models.BooleanField(default=False)
    trashed_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-is_folder', 'name', 'id']
        indexes = [models.Index(fields=['owner','parent']), models.Index(fields=['space','trashed_at'])]

    def clean(self):
        if not self.name or self.name in {'.', '..'} or any(c in self.name for c in '/\\\x00\r\n'):
            raise ValidationError('Nom de fichier ou dossier invalide.')
        if len(self.name) > 255:
            raise ValidationError('Nom trop long.')
        if self.parent_id and not self.parent.is_folder:
            raise ValidationError('Le parent doit être un dossier.')
        if self.parent_id and self.parent.space_id != self.space_id:
            raise ValidationError('Le dossier de destination appartient à un autre espace.')

    def __str__(self):
        return self.name


class UploadSession(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    space = models.ForeignKey(DriveSpace, on_delete=models.CASCADE)
    parent = models.ForeignKey(DriveItem, null=True, blank=True, on_delete=models.SET_NULL)
    name = models.CharField(max_length=255)
    total_size = models.BigIntegerField()
    received = models.BigIntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)