from __future__ import annotations

import hashlib

from fastapi import APIRouter, Depends, File, Form, HTTPException, UploadFile

from sqlalchemy import select

from sqlalchemy.orm import Session

from app.api.deps import Perm, get_db, require

from app.core.config import settings

from app.core.storage import get_storage

from app.models import AuditLog, Import, User

router = APIRouter(prefix="/imports", tags=["imports"])

@router.post("", status_code=201)

async def create_import(

    file: UploadFile = File(...),

    source_id: str | None = Form(default=None),

    process_now: bool = Form(default=True),

    db: Session = Depends(get_db),

    user: User = Depends(require(Perm.INGEST)),

):

    data = await file.read()

    if not data:

        raise HTTPException(400, "empty file")

    if len(data) > settings.max_upload_bytes:

        raise HTTPException(413, f"file exceeds {settings.max_upload_bytes} bytes")

    sha = hashlib.sha256(data).hexdigest()

    existing = db.scalar(select(Import).where(Import.sha256 == sha))

    if existing:

        return {"import_id": existing.id, "status": existing.status, "deduplicated": True,

                "row_count": existing.row_count}

    blob_ref = get_storage().put(f"imports/{sha[:16]}_{file.filename}", data)

    imp = Import(source_id=source_id, filename=file.filename, content_type=file.content_type,

                 sha256=sha, raw_blob_ref=blob_ref, status="received", created_by=user.id)

    db.add(imp)

    db.flush()

    db.add(AuditLog(actor_user_id=user.id, action="import.upload",

                    entity_type="import", entity_id=imp.id, meta={"filename": file.filename}))

    db.commit()

    db.refresh(imp)

    if process_now:

        from app.services.ingest import process_import

        summary = process_import(db, imp.id)

        return {"import_id": imp.id, **summary}

    else:

        from app.workers.tasks import process_import_task

        process_import_task.delay(imp.id)

        return {"import_id": imp.id, "status": "queued"}

@router.get("/{import_id}")

def get_import(import_id: str, db: Session = Depends(get_db), _: User = Depends(require(Perm.READ))):

    imp = db.get(Import, import_id)

    if not imp:

        raise HTTPException(404, "import not found")

    return {"id": imp.id, "filename": imp.filename, "status": imp.status,

            "row_count": imp.row_count, "error": imp.error, "sha256": imp.sha256,

            "created_at": imp.created_at}

@router.get("")

def list_imports(db: Session = Depends(get_db), _: User = Depends(require(Perm.READ))):

    rows = db.scalars(select(Import).order_by(Import.created_at.desc()).limit(100)).all()

    return [{"id": i.id, "filename": i.filename, "status": i.status,

             "row_count": i.row_count, "created_at": i.created_at} for i in rows]