"""Resolve a draft's compose-attachment ids into raw (filename, mime, data) tuples."""

from __future__ import annotations

import uuid

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

from app.indexer import blobstore
from app.models import ComposeAttachment, Draft


async def load_attachments(
    session: AsyncSession, user_id: uuid.UUID, draft: Draft
) -> list[tuple[str, str, bytes]]:
    """Return each of the draft's compose attachments as ``(filename, mime, data)``."""
    raw_ids = draft.payload.get("attachment_ids") or []
    if not isinstance(raw_ids, list) or not raw_ids:
        return []
    ids: list[uuid.UUID] = []
    for value in raw_ids:
        try:
            ids.append(uuid.UUID(str(value)))
        except ValueError:
            continue
    if not ids:
        return []
    rows = await session.scalars(
        select(ComposeAttachment).where(
            ComposeAttachment.id.in_(ids), ComposeAttachment.user_id == user_id
        )
    )
    by_id = {r.id: r for r in rows}
    out: list[tuple[str, str, bytes]] = []
    for i in ids:
        att = by_id.get(i)
        if att is not None:
            out.append((att.filename, att.mime_type, blobstore.load(user_id, att.blob_sha256)))
    return out