"""Supplier <-> Material catalog links (v2.5).

GET/POST /suppliers/{id}/materials — manage a supplier's catalog.
DELETE /suppliers/{id}/materials/{material_id} — unlink.
GET /materials/{id}/suppliers — price-comparison data source.
"""
from fastapi import APIRouter, Depends, Query
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.auth import require_procurement_writer, require_role
from app.db.engine import get_db
from app.models.catalog import Material, MaterialCategory
from app.models.procurement import Supplier, SupplierMaterial
from app.schemas.procurement import SupplierMaterialCreate
from app.services.supplier_material_service import link_supplier_material, unlink_supplier_material
from app.utils.errors import NotFoundError
from app.utils.pagination import paginate
from app.utils.serialization import to_iso

router = APIRouter(tags=["supplier-materials"])
_procurement_writer = require_procurement_writer()


def link_to_dict(link: SupplierMaterial, material: Material | None = None,
                 category: MaterialCategory | None = None,
                 supplier: Supplier | None = None) -> dict:
    return {
        "id": str(link.id),
        "supplier_id": str(link.supplier_id),
        "material_id": str(link.material_id),
        "is_active": link.is_active,
        "last_quoted_price": float(link.last_quoted_price) if link.last_quoted_price is not None else None,
        "last_quoted_at": to_iso(link.last_quoted_at) if link.last_quoted_at else None,
        "created_at": to_iso(link.created_at),
        "material": {
            "id": str(material.id),
            "name": material.name,
            "category": {"id": str(category.id), "name": category.name} if category else None,
        } if material else None,
        "supplier": {"id": str(supplier.id), "name": supplier.name} if supplier else None,
    }


@router.get("/suppliers/{supplier_id}/materials")
async def list_supplier_materials(
    supplier_id,
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    db: AsyncSession = Depends(get_db),
):
    supplier = await db.get(Supplier, supplier_id)
    if supplier is None:
        raise NotFoundError("تأمین‌کننده یافت نشد")
    stmt = (
        select(SupplierMaterial)
        .where(SupplierMaterial.supplier_id == supplier_id)
        .order_by(SupplierMaterial.created_at)
    )
    items, meta = await paginate(stmt, page, page_size, db)
    mat_ids = {l.material_id for l in items}
    materials = {m.id: m for m in (await db.execute(select(Material).where(Material.id.in_(mat_ids)))).scalars()}
    return {"data": [link_to_dict(l, materials.get(l.material_id), None) for l in items], "meta": meta}


@router.post("/suppliers/{supplier_id}/materials", status_code=201)
async def create_supplier_material(
    supplier_id,
    payload: SupplierMaterialCreate,
    db: AsyncSession = Depends(get_db),
    _auth=Depends(_procurement_writer),
):
    async with db.begin():
        link = await link_supplier_material(db, supplier_id, payload.material_id)
        material = await db.get(Material, payload.material_id)
    return {"data": link_to_dict(link, material, None)}


@router.delete("/suppliers/{supplier_id}/materials/{material_id}")
async def delete_supplier_material(
    supplier_id,
    material_id,
    db: AsyncSession = Depends(get_db),
    _auth=Depends(_procurement_writer),
):
    async with db.begin():
        await unlink_supplier_material(db, supplier_id, material_id)
    return {"data": {"supplier_id": str(supplier_id), "material_id": str(material_id), "deleted": True}}


@router.get("/materials/{material_id}/suppliers")
async def list_material_suppliers(
    material_id,
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    db: AsyncSession = Depends(get_db),
):
    material = await db.get(Material, material_id)
    if material is None:
        raise NotFoundError("متریال یافت نشد")
    stmt = (
        select(SupplierMaterial)
        .where(SupplierMaterial.material_id == material_id)
        .order_by(SupplierMaterial.last_quoted_at.desc().nulls_last())
    )
    items, meta = await paginate(stmt, page, page_size, db)
    sup_ids = {l.supplier_id for l in items}
    suppliers = {s.id: s for s in (await db.execute(select(Supplier).where(Supplier.id.in_(sup_ids)))).scalars()}
    return {"data": [link_to_dict(l, supplier=suppliers.get(l.supplier_id)) for l in items], "meta": meta}