import secrets

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


def generate_api_key():
    """`dbk_` prefix (recognizable as a AgentFeed key) + 40 hex chars."""
    return "dbk_" + secrets.token_hex(20)


class Artifact(models.Model):
    HTML_FRAGMENT = "html_fragment"
    HTML_FULL = "html_full"
    MARKDOWN = "markdown"
    DECK = "deck"
    IMAGE = "image"
    PDF = "pdf"
    BINARY = "binary"
    JSON = "json"
    CSV = "csv"

    AGENT = "agent"
    PERSON = "person"
    SYSTEM = "system"

    KIND_CHOICES = [
        (HTML_FRAGMENT, "HTML fragment"),
        (HTML_FULL, "Full HTML"),
        (MARKDOWN, "Markdown"),
        (DECK, "Deck"),
        (IMAGE, "Image"),
        (PDF, "PDF"),
        (BINARY, "Binary"),
        (JSON, "JSON"),
        (CSV, "CSV"),
    ]

    SOURCE_TYPE_CHOICES = [
        (AGENT, "Agent"),
        (PERSON, "Person"),
        (SYSTEM, "System"),
    ]

    id = models.CharField(max_length=8, primary_key=True)
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="artifacts")
    source = models.CharField(max_length=80, db_index=True)
    title = models.CharField(max_length=200)
    kind = models.CharField(max_length=20, choices=KIND_CHOICES)
    theme = models.CharField(max_length=40, blank=True)
    day = models.DateField(db_index=True)
    created_at = models.DateTimeField(auto_now_add=True)
    path = models.CharField(max_length=500)
    original_kind = models.CharField(max_length=20)
    tags = models.JSONField(default=list, blank=True)
    source_prompt = models.TextField(blank=True)
    source_type = models.CharField(max_length=20, choices=SOURCE_TYPE_CHOICES, default=AGENT)
    source_name = models.CharField(max_length=120, blank=True)
    source_id = models.CharField(max_length=120, blank=True)
    metadata = models.JSONField(default=dict, blank=True)
    read_at = models.DateTimeField(null=True, blank=True)
    is_kept = models.BooleanField(default=False)
    # Soft-delete: non-null = in Trash (hidden from feed/sources, off-quota,
    # recoverable via undelete, purged by Empty Trash). NULL = live.
    deleted_at = models.DateTimeField(null=True, blank=True, db_index=True)
    size_bytes = models.BigIntegerField(default=0)
    # NULL = not shared. Many rows share NULL (SQL treats each NULL as
    # distinct, so `unique=True` still holds); a real value must be unique
    # since it's the sole credential for the unauthenticated /s/<token> route.
    share_token = models.CharField(max_length=64, null=True, blank=True, unique=True, default=None)

    @property
    def is_unread(self):
        return self.read_at is None

    @property
    def is_shared(self):
        return bool(self.share_token)

    @property
    def is_deleted(self):
        return self.deleted_at is not None

    class Meta:
        ordering = ["-created_at"]

    def __str__(self):
        return f"{self.title} ({self.source})"


class TagColor(models.Model):
    name = models.CharField(max_length=40, primary_key=True)
    color = models.CharField(max_length=20)

    def __str__(self):
        return f"{self.name} ({self.color})"


class UserProfile(models.Model):
    DEFAULT_QUOTA_BYTES = 1024 * 1024 * 1024  # 1 GB

    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="profile")
    quota_bytes = models.BigIntegerField(default=DEFAULT_QUOTA_BYTES)

    def __str__(self):
        return f"{self.user} quota={self.quota_bytes}"


class ApiKey(models.Model):
    """A named, per-user API key for ingest. A user can hold several — one per
    agent or script — and revoke them individually. Stored and shown in
    plaintext: this is a self-hosted, single-operator app and keys are
    viewable on demand by design.
    """

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="api_keys"
    )
    name = models.CharField(max_length=100)
    key = models.CharField(max_length=64, unique=True, default=generate_api_key, db_index=True)
    created_at = models.DateTimeField(auto_now_add=True)
    last_used_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ["created_at"]

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


class Asset(models.Model):
    """An image uploaded for embedding inside an artifact's content.

    Uploaded before the artifact exists, so `artifact` is null until the
    artifact referencing its URL is created. Unattached assets are swept
    after ASSET_ORPHAN_GRACE; attached ones die with their artifact.
    """

    id = models.CharField(max_length=12, primary_key=True)
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="assets")
    artifact = models.ForeignKey(
        Artifact, on_delete=models.CASCADE, related_name="assets", null=True, blank=True
    )
    path = models.CharField(max_length=500)
    content_type = models.CharField(max_length=100)
    size_bytes = models.BigIntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["-created_at"]

    def __str__(self):
        return f"{self.id} ({self.content_type})"