"""
員工身份管理 API
"""
from typing import List, Optional
from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy.orm import Session

from app.db.session import get_db
from app.models.employee import Employee
from app.models.employee_identity import EmployeeIdentity
from app.models.business_unit import BusinessUnit
from app.models.department import Department
from app.schemas.employee_identity import (
    EmployeeIdentityCreate,
    EmployeeIdentityUpdate,
    EmployeeIdentityResponse,
    EmployeeIdentityListItem,
)
from app.schemas.response import MessageResponse

router = APIRouter()


@router.get("/", response_model=List[EmployeeIdentityListItem])
def get_identities(
    db: Session = Depends(get_db),
    employee_id: Optional[int] = Query(None, description="員工 ID 篩選"),
    business_unit_id: Optional[int] = Query(None, description="事業部 ID 篩選"),
    department_id: Optional[int] = Query(None, description="部門 ID 篩選"),
    is_active: Optional[bool] = Query(None, description="是否活躍"),
):
    """
    獲取員工身份列表

    支援多種篩選條件
    """
    query = db.query(EmployeeIdentity)

    if employee_id:
        query = query.filter(EmployeeIdentity.employee_id == employee_id)

    if business_unit_id:
        query = query.filter(EmployeeIdentity.business_unit_id == business_unit_id)

    if department_id:
        query = query.filter(EmployeeIdentity.department_id == department_id)

    if is_active is not None:
        query = query.filter(EmployeeIdentity.is_active == is_active)

    identities = query.order_by(
        EmployeeIdentity.employee_id,
        EmployeeIdentity.is_primary.desc()
    ).all()

    return [EmployeeIdentityListItem.model_validate(identity) for identity in identities]


@router.get("/{identity_id}", response_model=EmployeeIdentityResponse)
def get_identity(
    identity_id: int,
    db: Session = Depends(get_db),
):
    """
    獲取員工身份詳情
    """
    identity = db.query(EmployeeIdentity).filter(
        EmployeeIdentity.id == identity_id
    ).first()

    if not identity:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Identity with id {identity_id} not found"
        )

    response = EmployeeIdentityResponse.model_validate(identity)
    response.employee_name = identity.employee.legal_name
    response.business_unit_name = identity.business_unit.name
    response.email_domain = identity.business_unit.email_domain
    if identity.department:
        response.department_name = identity.department.name

    return response


@router.post("/", response_model=EmployeeIdentityResponse, status_code=status.HTTP_201_CREATED)
def create_identity(
    identity_data: EmployeeIdentityCreate,
    db: Session = Depends(get_db),
):
    """
    創建員工身份

    自動生成 SSO 帳號:
    - 格式: {username_base}@{email_domain}
    - 需要生成 Keycloak UUID (TODO)

    檢查:
    - 員工是否存在
    - 事業部是否存在
    - 部門是否存在 (如果指定)
    - 同一員工在同一事業部只能有一個身份
    """
    # 檢查員工是否存在
    employee = db.query(Employee).filter(
        Employee.id == identity_data.employee_id
    ).first()

    if not employee:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Employee with id {identity_data.employee_id} not found"
        )

    # 檢查事業部是否存在
    business_unit = db.query(BusinessUnit).filter(
        BusinessUnit.id == identity_data.business_unit_id
    ).first()

    if not business_unit:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Business unit with id {identity_data.business_unit_id} not found"
        )

    # 檢查部門是否存在 (如果指定)
    if identity_data.department_id:
        department = db.query(Department).filter(
            Department.id == identity_data.department_id,
            Department.business_unit_id == identity_data.business_unit_id
        ).first()

        if not department:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Department with id {identity_data.department_id} not found in this business unit"
            )

    # 檢查同一員工在同一事業部是否已有身份
    existing = db.query(EmployeeIdentity).filter(
        EmployeeIdentity.employee_id == identity_data.employee_id,
        EmployeeIdentity.business_unit_id == identity_data.business_unit_id
    ).first()

    if existing:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Employee already has an identity in this business unit"
        )

    # 生成 SSO 帳號
    username = f"{employee.username_base}@{business_unit.email_domain}"

    # 檢查 SSO 帳號是否已存在
    existing_username = db.query(EmployeeIdentity).filter(
        EmployeeIdentity.username == username
    ).first()

    if existing_username:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Username '{username}' already exists"
        )

    # TODO: 從 Keycloak 創建帳號並獲取 UUID
    keycloak_id = f"temp-uuid-{employee.id}-{business_unit.id}"

    # 創建身份
    identity = EmployeeIdentity(
        employee_id=identity_data.employee_id,
        username=username,
        keycloak_id=keycloak_id,
        business_unit_id=identity_data.business_unit_id,
        department_id=identity_data.department_id,
        job_title=identity_data.job_title,
        job_level=identity_data.job_level,
        is_primary=identity_data.is_primary,
        email_quota_mb=identity_data.email_quota_mb,
        started_at=identity_data.started_at,
    )

    # 如果設為主要身份,取消其他主要身份
    if identity_data.is_primary:
        db.query(EmployeeIdentity).filter(
            EmployeeIdentity.employee_id == identity_data.employee_id
        ).update({"is_primary": False})

    db.add(identity)
    db.commit()
    db.refresh(identity)

    # TODO: 創建審計日誌
    # TODO: 創建 Keycloak 帳號
    # TODO: 創建郵件帳號

    response = EmployeeIdentityResponse.model_validate(identity)
    response.employee_name = employee.legal_name
    response.business_unit_name = business_unit.name
    response.email_domain = business_unit.email_domain
    if identity.department:
        response.department_name = identity.department.name

    return response


@router.put("/{identity_id}", response_model=EmployeeIdentityResponse)
def update_identity(
    identity_id: int,
    identity_data: EmployeeIdentityUpdate,
    db: Session = Depends(get_db),
):
    """
    更新員工身份
    """
    identity = db.query(EmployeeIdentity).filter(
        EmployeeIdentity.id == identity_id
    ).first()

    if not identity:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Identity with id {identity_id} not found"
        )

    # 檢查部門是否屬於同一事業部 (如果更新部門)
    if identity_data.department_id:
        department = db.query(Department).filter(
            Department.id == identity_data.department_id,
            Department.business_unit_id == identity.business_unit_id
        ).first()

        if not department:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail=f"Department does not belong to this business unit"
            )

    # 更新欄位
    update_data = identity_data.model_dump(exclude_unset=True)

    # 如果設為主要身份,取消其他主要身份
    if update_data.get("is_primary"):
        db.query(EmployeeIdentity).filter(
            EmployeeIdentity.employee_id == identity.employee_id,
            EmployeeIdentity.id != identity_id
        ).update({"is_primary": False})

    for field, value in update_data.items():
        setattr(identity, field, value)

    db.commit()
    db.refresh(identity)

    # TODO: 創建審計日誌
    # TODO: 更新 NAS 配額 (如果職級變更)

    response = EmployeeIdentityResponse.model_validate(identity)
    response.employee_name = identity.employee.legal_name
    response.business_unit_name = identity.business_unit.name
    response.email_domain = identity.business_unit.email_domain
    if identity.department:
        response.department_name = identity.department.name

    return response


@router.delete("/{identity_id}", response_model=MessageResponse)
def delete_identity(
    identity_id: int,
    db: Session = Depends(get_db),
):
    """
    刪除員工身份

    注意:
    - 如果是員工的最後一個身份,無法刪除
    - 刪除後會停用對應的 Keycloak 和郵件帳號
    """
    identity = db.query(EmployeeIdentity).filter(
        EmployeeIdentity.id == identity_id
    ).first()

    if not identity:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Identity with id {identity_id} not found"
        )

    # 檢查是否為員工的最後一個身份
    total_identities = db.query(EmployeeIdentity).filter(
        EmployeeIdentity.employee_id == identity.employee_id
    ).count()

    if total_identities == 1:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Cannot delete employee's last identity. Please terminate the employee instead."
        )

    # 軟刪除 (停用)
    identity.is_active = False
    identity.ended_at = db.func.current_date()

    db.commit()

    # TODO: 創建審計日誌
    # TODO: 停用 Keycloak 帳號
    # TODO: 停用郵件帳號

    return MessageResponse(
        message=f"Identity '{identity.username}' has been deactivated"
    )


@router.post("/{identity_id}/set-primary", response_model=EmployeeIdentityResponse)
def set_primary_identity(
    identity_id: int,
    db: Session = Depends(get_db),
):
    """
    設定為主要身份

    將指定的身份設為員工的主要身份,並取消其他身份的主要狀態
    """
    identity = db.query(EmployeeIdentity).filter(
        EmployeeIdentity.id == identity_id
    ).first()

    if not identity:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Identity with id {identity_id} not found"
        )

    # 檢查身份是否已停用
    if not identity.is_active:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Cannot set inactive identity as primary"
        )

    # 取消同一員工的其他主要身份
    db.query(EmployeeIdentity).filter(
        EmployeeIdentity.employee_id == identity.employee_id,
        EmployeeIdentity.id != identity_id
    ).update({"is_primary": False})

    # 設為主要身份
    identity.is_primary = True

    db.commit()
    db.refresh(identity)

    # TODO: 創建審計日誌

    response = EmployeeIdentityResponse.model_validate(identity)
    response.employee_name = identity.employee.legal_name
    response.business_unit_name = identity.business_unit.name
    response.email_domain = identity.business_unit.email_domain
    if identity.department:
        response.department_name = identity.department.name

    return response