from typing import List, Optional

from fastapi import APIRouter, Depends, HTTPException, status
from pydantic import BaseModel, Field
from sqlalchemy.orm import Session

from app.api.bx.export_common import (
    ExportColumn,
    ExportValidationError,
    BxExportBodyBase,
    dump_export_row,
    respond_xlsx,
    status_label,
)
from app.core.bx_auth import BxUserContext, get_bx_current_user
from app.core.database import get_db
from app.core.tenant_context import get_tenant_no
from app.schemas.bx.common import ApiResponse
from app.schemas.bx.expense_item import ExpenseItemCreate, ExpenseItemOut, ExpenseItemUpdate
from app.services.bx.expense_item import ExpenseItemService

router = APIRouter(prefix="/expense-items", tags=["费用项目管理"])


@router.get("/tree", response_model=ApiResponse[List[ExpenseItemOut]])
def get_expense_item_tree(
    db: Session = Depends(get_db),
    user: BxUserContext = Depends(get_bx_current_user),
):
    tenant_no = get_tenant_no(db, user.to_tenant_user_dict())
    tree = ExpenseItemService.get_item_tree(db, tenant_no, user=user)
    return ApiResponse(data=[ExpenseItemOut.model_validate(i) for i in tree])



EXPENSE_ITEM_EXPORT_COLUMNS = [
    ExportColumn(title="项目名称", field="itemName"),
    ExportColumn(title="项目编码", field="itemCode"),
    ExportColumn(title="层级", field="level"),
    ExportColumn(title="子项数", field="childCount"),
    ExportColumn(title="排序", field="sortOrder"),
    ExportColumn(title="状态", field="status"),
]


class ExpenseItemExportBody(BxExportBodyBase):
    name: Optional[str] = None
    status: Optional[str] = None


def _flatten_expense_tree(nodes: list, out: list) -> None:
    for n in nodes:
        out.append(n)
        children = getattr(n, "children", None) or (n.get("children") if isinstance(n, dict) else None) or []
        if children:
            _flatten_expense_tree(list(children), out)


@router.post("/export")
def export_expense_items(
    body: ExpenseItemExportBody,
    db: Session = Depends(get_db),
    user: BxUserContext = Depends(get_bx_current_user),
):
    try:
        tenant_no = get_tenant_no(db, user.to_tenant_user_dict())
        tree = ExpenseItemService.get_item_tree(db, tenant_no, user=user)
        flat: list = []
        _flatten_expense_tree(list(tree), flat)
        outs = [ExpenseItemOut.model_validate(i) for i in flat]
        if body.ids:
            id_set = {str(i) for i in body.ids}
            outs = [o for o in outs if str(o.id) in id_set]
        if body.name:
            kw = body.name.strip()
            outs = [o for o in outs if kw in (o.item_name or "")]
        if body.status not in (None, ""):
            outs = [o for o in outs if str(o.status) == str(body.status)]
        rows = []
        for o in outs:
            data = dump_export_row(o, status_fields=())
            data["status"] = status_label(data.get("status"))
            # childCount may be computed
            if "childCount" not in data:
                data["childCount"] = len(getattr(o, "children", None) or [])
            rows.append(data)
        return respond_xlsx(
            db, tenant_no=tenant_no, sheet_title="费用科目", columns=EXPENSE_ITEM_EXPORT_COLUMNS,
            rows=rows, filename_stem="费用科目", requested_columns=body.columns,
        )
    except ExportValidationError as e:
        raise HTTPException(status_code=400, detail=str(e)) from e


@router.get("/{item_id}", response_model=ApiResponse[ExpenseItemOut])
def get_expense_item(
    item_id: str,
    db: Session = Depends(get_db),
    user: BxUserContext = Depends(get_bx_current_user),
):
    tenant_no = get_tenant_no(db, user.to_tenant_user_dict())
    item = ExpenseItemService.get_by_id(db, item_id, tenant_no, user=user)
    if not item:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="费用项目不存在")
    return ApiResponse(data=ExpenseItemOut.model_validate(item))


@router.post("/", response_model=ApiResponse[ExpenseItemOut])
def create_expense_item(
    body: ExpenseItemCreate,
    db: Session = Depends(get_db),
    user: BxUserContext = Depends(get_bx_current_user),
):
    try:
        item = ExpenseItemService.create(db, body.model_dump(exclude_unset=True), user=user)
        db.commit()
        db.refresh(item)
    except ValueError as exc:
        db.rollback()
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
    return ApiResponse(data=ExpenseItemOut.model_validate(item))


@router.put("/{item_id}", response_model=ApiResponse[ExpenseItemOut])
def update_expense_item(
    item_id: str,
    body: ExpenseItemUpdate,
    db: Session = Depends(get_db),
    user: BxUserContext = Depends(get_bx_current_user),
):
    try:
        item = ExpenseItemService.update(
            db, item_id, body.model_dump(exclude_unset=True), user=user
        )
        if not item:
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="费用项目不存在")
        db.commit()
        db.refresh(item)
    except ValueError as exc:
        db.rollback()
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
    return ApiResponse(data=ExpenseItemOut.model_validate(item))


@router.delete("/{item_id}", response_model=ApiResponse[None])
def delete_expense_item(
    item_id: str,
    db: Session = Depends(get_db),
    user: BxUserContext = Depends(get_bx_current_user),
):
    tenant_no = get_tenant_no(db, user.to_tenant_user_dict())
    item = ExpenseItemService.get_by_id(db, item_id, tenant_no, user=user)
    if not item:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="费用项目不存在")
    ExpenseItemService.soft_delete(db, item_id, user=user)
    db.commit()
    return ApiResponse(data=None)