from datetime import datetime
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException, status

from app.core.deps import require_org, require_client_roles, require_write_access, Principal
from app.models import Batch, Product
from app.models.enums import ClientRole, QRType
from app.schemas.common import BatchCreate

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


def _parse(d):
    if not d:
        return None
    try:
        return datetime.fromisoformat(d)
    except ValueError:
        return None


def _out(b: Batch) -> dict:
    return {"id": str(b.id), "product_id": b.product_id, "batch_number": b.batch_number,
            "mfg_date": b.mfg_date, "expiry_date": b.expiry_date,
            "quantity": b.quantity, "qr_type": b.qr_type, "notes": b.notes,
            "created_at": b.created_at}


@router.get("")
async def list_batches(p: Principal = Depends(require_org), product_id: Optional[str] = None):
    q = Batch.find(Batch.org_id == str(p.org.id))
    batches = await q.to_list()
    if product_id:
        batches = [b for b in batches if b.product_id == product_id]
    return [_out(b) for b in batches]


@router.post("", status_code=201)
async def create_batch(body: BatchCreate,
                       p: Principal = Depends(require_client_roles(ClientRole.admin, ClientRole.user))):
    require_write_access(p)
    product = await Product.get(body.product_id)
    if not product or product.org_id != str(p.org.id):
        raise HTTPException(status.HTTP_404_NOT_FOUND, "Product not found")
    bn = body.batch_number or f"{(product.sku or 'B')}{datetime.utcnow():%y%m%d%H%M}"
    batch = Batch(org_id=str(p.org.id), product_id=body.product_id, batch_number=bn,
                  mfg_date=_parse(body.mfg_date), expiry_date=_parse(body.expiry_date),
                  quantity=max(1, body.quantity), qr_type=body.qr_type, notes=body.notes)
    await batch.insert()
    product.batch_count += 1
    await product.save()
    return _out(batch)


@router.get("/{batch_id}")
async def get_batch(batch_id: str, p: Principal = Depends(require_org)):
    batch = await Batch.get(batch_id)
    if not batch or batch.org_id != str(p.org.id):
        raise HTTPException(status.HTTP_404_NOT_FOUND, "Batch not found")
    return _out(batch)