"""EquipmentGroup (Bundle) CRUD endpoints."""

from fastapi import APIRouter, Depends, HTTPException, status, Query
from sqlalchemy import select, func
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import joinedload, selectinload

from app.api.deps import require_permission
from app.db.session import get_async_session
from app.models import User, EquipmentGroup, Equipment
from app.models.equipment_group import equipment_group_items
from app.schemas.equipment_group import (
    EquipmentGroupCreateRequest,
    EquipmentGroupUpdateRequest,
    EquipmentGroupResponse,
    EquipmentGroupListResponse,
)

router = APIRouter(prefix="/equipment-groups", tags=["equipment-groups"])


def _load_items(group: EquipmentGroup) -> list[dict]:
    """Build items list from M2M relationship."""
    # The items relationship loads Equipment objects; we need quantity from the association
    # We'll use a separate query approach in the endpoints.
    return []


@router.get("", response_model=EquipmentGroupListResponse)
async def list_equipment_groups(
    page: int = Query(1, ge=1),
    size: int = Query(20, ge=1, le=100),
    search: str | None = Query(None, description="Search in name"),
    current_user: User = Depends(require_permission("equipment:read")),
    session: AsyncSession = Depends(get_async_session),
):
    """List equipment groups with search and pagination."""
    account_id = current_user.account_id
    base_q = select(EquipmentGroup).where(EquipmentGroup.account_id == account_id)

    if search:
        pattern = f"%{search}%"
        base_q = base_q.where(EquipmentGroup.name.ilike(pattern))

    count_q = select(func.count()).select_from(base_q.subquery())
    total = (await session.execute(count_q)).scalar() or 0

    q = (
        base_q.options(
            joinedload(EquipmentGroup.default_location),
            selectinload(EquipmentGroup.items),
        )
        .order_by(EquipmentGroup.name)
        .offset((page - 1) * size)
        .limit(size)
    )
    result = await session.execute(q)
    groups = result.unique().scalars().all()

    return EquipmentGroupListResponse(
        items=[EquipmentGroupResponse.model_validate(g) for g in groups],
        total=total,
        page=page,
        size=size,
    )


@router.post(
    "", response_model=EquipmentGroupResponse, status_code=status.HTTP_201_CREATED
)
async def create_equipment_group(
    body: EquipmentGroupCreateRequest,
    current_user: User = Depends(require_permission("equipment:write")),
    session: AsyncSession = Depends(get_async_session),
):
    """Create a new equipment group (bundle)."""
    account_id = current_user.account_id

    group = EquipmentGroup(
        account_id=account_id,
        name=body.name,
        description=body.description,
        daily_rate=body.daily_rate,
        default_location_id=body.default_location_id,
    )

    if body.items:
        equipment_ids = [i.equipment_id for i in body.items]
        eq_result = await session.execute(
            select(Equipment).where(
                Equipment.id.in_(equipment_ids),
                Equipment.account_id == account_id,
            )
        )
        items = eq_result.scalars().all()
        group.items = items
        # Store quantities via the association table directly
        for item_schema in body.items:
            await session.execute(
                equipment_group_items.update()
                .where(
                    equipment_group_items.c.group_id == group.id,
                    equipment_group_items.c.equipment_id == item_schema.equipment_id,
                )
                .values(quantity=item_schema.quantity)
            )

    session.add(group)
    await session.commit()
    await session.refresh(group)

    # Reload with relationships
    await session.execute(
        select(EquipmentGroup)
        .options(
            joinedload(EquipmentGroup.default_location),
            selectinload(EquipmentGroup.items),
        )
        .where(EquipmentGroup.id == group.id)
    )
    await session.refresh(group)

    return EquipmentGroupResponse.model_validate(group)


@router.get("/{group_id}", response_model=EquipmentGroupResponse)
async def get_equipment_group(
    group_id: str,
    current_user: User = Depends(require_permission("equipment:read")),
    session: AsyncSession = Depends(get_async_session),
):
    """Get a specific equipment group with items."""
    account_id = current_user.account_id
    result = await session.execute(
        select(EquipmentGroup)
        .options(
            joinedload(EquipmentGroup.default_location),
            selectinload(EquipmentGroup.items),
        )
        .where(EquipmentGroup.id == group_id, EquipmentGroup.account_id == account_id)
    )
    group = result.unique().scalars().first()
    if not group:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, detail="Equipment group not found"
        )
    return EquipmentGroupResponse.model_validate(group)


@router.put("/{group_id}", response_model=EquipmentGroupResponse)
async def update_equipment_group(
    group_id: str,
    body: EquipmentGroupUpdateRequest,
    current_user: User = Depends(require_permission("equipment:write")),
    session: AsyncSession = Depends(get_async_session),
):
    """Update an equipment group."""
    account_id = current_user.account_id
    result = await session.execute(
        select(EquipmentGroup)
        .options(
            joinedload(EquipmentGroup.default_location),
            selectinload(EquipmentGroup.items),
        )
        .where(EquipmentGroup.id == group_id, EquipmentGroup.account_id == account_id)
    )
    group = result.unique().scalars().first()
    if not group:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, detail="Equipment group not found"
        )

    update_data = body.model_dump(exclude_unset=True, exclude={"items"})
    for field, value in update_data.items():
        setattr(group, field, value)

    # Handle items replacement
    if body.items is not None:
        equipment_ids = [i.equipment_id for i in body.items]
        eq_result = await session.execute(
            select(Equipment).where(
                Equipment.id.in_(equipment_ids),
                Equipment.account_id == account_id,
            )
        )
        group.items = eq_result.scalars().all()
        # Update quantities
        for item_schema in body.items:
            await session.execute(
                equipment_group_items.update()
                .where(
                    equipment_group_items.c.group_id == group.id,
                    equipment_group_items.c.equipment_id == item_schema.equipment_id,
                )
                .values(quantity=item_schema.quantity)
            )

    await session.commit()
    await session.refresh(group)
    return EquipmentGroupResponse.model_validate(group)


@router.delete("/{group_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_equipment_group(
    group_id: str,
    current_user: User = Depends(require_permission("equipment:delete")),
    session: AsyncSession = Depends(get_async_session),
):
    """Delete an equipment group."""
    account_id = current_user.account_id
    result = await session.execute(
        select(EquipmentGroup).where(
            EquipmentGroup.id == group_id,
            EquipmentGroup.account_id == account_id,
        )
    )
    group = result.scalars().first()
    if not group:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND, detail="Equipment group not found"
        )

    await session.delete(group)
    await session.commit()
    return None