"""Asset data model.

An Asset represents an uploaded file (sound, image, video, or other)
stored on the server. Assets are referenced by ID from other entities
(e.g. NotificationColorStripSource uses sound assets for alert sounds).
"""

from dataclasses import dataclass, field
from datetime import datetime
from typing import List, Optional


# Map MIME type prefixes to asset_type categories
_MIME_TO_ASSET_TYPE = {
    "audio/": "sound",
    "image/": "image",
    "video/": "video",
}


def asset_type_from_mime(mime_type: str) -> str:
    """Derive asset_type from a MIME type string."""
    for prefix, asset_type in _MIME_TO_ASSET_TYPE.items():
        if mime_type.startswith(prefix):
            return asset_type
    return "other"


@dataclass
class Asset:
    """Persistent metadata for an uploaded file asset."""

    id: str
    name: str
    filename: str                    # original upload filename
    stored_filename: str             # on-disk filename (uuid-based)
    mime_type: str                   # e.g. "audio/wav", "image/png"
    asset_type: str                  # "sound" | "image" | "video" | "other"
    size_bytes: int
    created_at: datetime
    updated_at: datetime
    description: Optional[str] = None
    tags: List[str] = field(default_factory=list)
    prebuilt: bool = False           # True for shipped assets
    deleted: bool = False            # soft-delete for prebuilt assets

    def to_dict(self) -> dict:
        return {
            "id": self.id,
            "name": self.name,
            "filename": self.filename,
            "stored_filename": self.stored_filename,
            "mime_type": self.mime_type,
            "asset_type": self.asset_type,
            "size_bytes": self.size_bytes,
            "description": self.description,
            "tags": self.tags,
            "prebuilt": self.prebuilt,
            "deleted": self.deleted,
            "created_at": self.created_at.isoformat(),
            "updated_at": self.updated_at.isoformat(),
        }

    @staticmethod
    def from_dict(data: dict) -> "Asset":
        return Asset(
            id=data["id"],
            name=data["name"],
            filename=data.get("filename", ""),
            stored_filename=data.get("stored_filename", ""),
            mime_type=data.get("mime_type", "application/octet-stream"),
            asset_type=data.get("asset_type", "other"),
            size_bytes=int(data.get("size_bytes", 0)),
            description=data.get("description"),
            tags=data.get("tags", []),
            prebuilt=bool(data.get("prebuilt", False)),
            deleted=bool(data.get("deleted", False)),
            created_at=datetime.fromisoformat(data["created_at"]),
            updated_at=datetime.fromisoformat(data["updated_at"]),
        )