"""Invoice / proforma attachments — metadata in `quote_attachments`, bytes in MinIO.

Multi-file contract: a quote may hold any number of attachments per kind
(invoice / proforma). Every upload creates a new DB row and a new object
(object key `{quote_id}/{kind}/{attachment_id}` inside the MinIO bucket).
"""
import uuid

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.files import QuoteAttachment
from app.services import storage
from app.utils.errors import NotFoundError


def _object_key(quote_id: uuid.UUID, kind: str, attachment_id: uuid.UUID) -> str:
    return f"{quote_id}/{kind}/{attachment_id}"


async def create(
    db: AsyncSession,
    quote_id: uuid.UUID,
    kind: str,
    file_name: str,
    content: bytes,
    mime_type: str,
) -> QuoteAttachment:
    """Upload the bytes to MinIO, then persist the metadata row."""
    attachment_id = uuid.uuid4()
    object_key = _object_key(quote_id, kind, attachment_id)
    await storage.put_object(object_key, content, mime_type)
    attachment = QuoteAttachment(
        id=attachment_id,
        quote_id=quote_id,
        kind=kind,
        file_name=file_name,
        mime_type=mime_type,
        size_bytes=len(content),
        object_key=object_key,
    )
    db.add(attachment)
    try:
        await db.flush()
    except Exception:
        # Metadata insert failed — best-effort cleanup of the orphan object.
        await storage.remove_object(object_key)
        raise
    return attachment


async def list_for(db: AsyncSession, quote_id: uuid.UUID, kind: str) -> list[QuoteAttachment]:
    result = await db.execute(
        select(QuoteAttachment)
        .where(QuoteAttachment.quote_id == quote_id, QuoteAttachment.kind == kind)
        .order_by(QuoteAttachment.uploaded_at)
    )
    return list(result.scalars().all())


async def get(db: AsyncSession, attachment_id: uuid.UUID) -> QuoteAttachment:
    attachment = await db.get(QuoteAttachment, attachment_id)
    if attachment is None:
        raise NotFoundError("فایل پیوست یافت نشد")
    return attachment


async def read_bytes(attachment: QuoteAttachment) -> bytes:
    """Stream the object bytes from MinIO."""
    return await storage.get_object_bytes(attachment.object_key)


async def remove(db: AsyncSession, attachment: QuoteAttachment) -> None:
    """Delete the object from MinIO (best-effort) and the metadata row."""
    await storage.remove_object(attachment.object_key)
    await db.delete(attachment)