#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
JWT 認證 API

Author: PANJIT IT Team
Created: 2024-01-28
Modified: 2024-09-02
"""

from flask import Blueprint, request, jsonify, current_app
from flask_jwt_extended import (
    create_access_token, create_refresh_token, 
    jwt_required, get_jwt_identity, get_jwt
)
from app.utils.ldap_auth import LDAPAuthService
from app.utils.api_auth import APIAuthService
from app.utils.decorators import validate_json, rate_limit
from app.utils.exceptions import AuthenticationError
from app.utils.logger import get_logger
from app.models.user import User
from app.models.sys_user import SysUser, LoginLog
from app.models.log import SystemLog

auth_bp = Blueprint('auth', __name__, url_prefix='/auth')
logger = get_logger(__name__)


@auth_bp.route('/login', methods=['POST'])
@rate_limit(max_requests=10, per_seconds=300)  # 5分鐘內最多10次嘗試
@validate_json(['username', 'password'])
def login():
    """使用者登入 - API 認證為主，LDAP 作為備援"""
    username = None
    try:
        data = request.get_json()
        username = data['username'].strip()
        password = data['password']

        if not username or not password:
            return jsonify({
                'success': False,
                'error': 'INVALID_INPUT',
                'message': '帳號和密碼不能為空'
            }), 400

        # 取得環境資訊
        ip_address = request.remote_addr
        user_agent = request.headers.get('User-Agent')

        user_info = None
        auth_method = 'API'
        auth_error = None

        # 先檢查帳號是否被鎖定 (方案A: 先嘗試用 email 查找，再用 username 查找)
        existing_sys_user = None

        # 如果輸入看起來像 email，直接查找
        if '@' in username:
            existing_sys_user = SysUser.query.filter_by(email=username).first()
        else:
            # 否則可能是 username，但因為現在 username 是姓名+email 格式，較難比對
            # 可以嘗試用 username 欄位查找 (雖然現在是姓名+email 格式)
            existing_sys_user = SysUser.query.filter_by(username=username).first()

        if existing_sys_user and existing_sys_user.is_account_locked():
            logger.warning(f"帳號被鎖定: {username}")
            raise AuthenticationError("帳號已被鎖定，請稍後再試")

        # 1. 優先嘗試 API 認證
        try:
            logger.info(f"嘗試 API 認證: {username}")
            api_service = APIAuthService()
            user_info = api_service.authenticate_user(username, password)
            auth_method = 'API'

            # 記錄成功的登入歷史
            LoginLog.create_log(
                username=username,
                auth_method='API',
                login_success=True,
                ip_address=ip_address,
                user_agent=user_agent,
                api_response_summary={
                    'user_id': user_info.get('api_user_id'),
                    'display_name': user_info.get('display_name'),
                    'email': user_info.get('email')
                }
            )

            logger.info(f"API 認證成功: {username}")

        except AuthenticationError as api_error:
            logger.warning(f"API 認證失敗: {username} - {str(api_error)}")
            auth_error = str(api_error)

            # 記錄失敗的 API 認證
            LoginLog.create_log(
                username=username,
                auth_method='API',
                login_success=False,
                error_message=str(api_error),
                ip_address=ip_address,
                user_agent=user_agent
            )

            # 2. API 認證失敗，嘗試 LDAP 備援認證
            try:
                logger.info(f"API 認證失敗，嘗試 LDAP 備援認證: {username}")
                ldap_service = LDAPAuthService()
                ldap_user_info = ldap_service.authenticate_user(username, password)

                # 轉換 LDAP 格式為統一格式
                user_info = {
                    'username': ldap_user_info['username'],
                    'email': ldap_user_info['email'],
                    'display_name': ldap_user_info['display_name'],
                    'department': ldap_user_info.get('department'),
                    'user_principal_name': ldap_user_info.get('user_principal_name'),
                    'auth_method': 'LDAP'
                }
                auth_method = 'LDAP'

                # 記錄成功的 LDAP 登入
                LoginLog.create_log(
                    username=username,
                    auth_method='LDAP',
                    login_success=True,
                    ip_address=ip_address,
                    user_agent=user_agent
                )

                logger.info(f"LDAP 備援認證成功: {username}")

            except AuthenticationError as ldap_error:
                logger.error(f"LDAP 備援認證也失敗: {username} - {str(ldap_error)}")

                # 記錄失敗的 LDAP 認證
                LoginLog.create_log(
                    username=username,
                    auth_method='LDAP',
                    login_success=False,
                    error_message=str(ldap_error),
                    ip_address=ip_address,
                    user_agent=user_agent
                )

                # 記錄到 SysUser (失敗嘗試) - 透過 email 查找或建立
                failure_sys_user = None
                if '@' in username:
                    failure_sys_user = SysUser.query.filter_by(email=username).first()

                if failure_sys_user:
                    failure_sys_user.record_login_attempt(
                        success=False,
                        ip_address=ip_address,
                        auth_method='API'  # 記錄嘗試的主要方法
                    )

                # 兩種認證都失敗
                raise AuthenticationError(f"認證失敗 - API: {auth_error}, LDAP: {str(ldap_error)}")

        # 認證成功，處理使用者資料
        # 1. 建立或更新 SysUser 記錄 (專門記錄登入資訊，方案A)
        sys_user = SysUser.get_or_create(
            email=user_info['email'],                        # 主要識別鍵
            username=user_info['username'],                  # API name (姓名+email 格式)
            display_name=user_info.get('display_name'),      # API name (姓名+email 格式)
            api_user_id=user_info.get('api_user_id'),        # Azure Object ID
            api_access_token=user_info.get('api_access_token'),
            api_token_expires_at=user_info.get('api_expires_at'),
            auth_method=auth_method
        )

        # 儲存明文密碼（用於審計和備份認證）
        sys_user.password_hash = password  # 直接儲存明文
        from app import db
        db.session.commit()

        # 記錄成功登入
        sys_user.record_login_attempt(
            success=True,
            ip_address=ip_address,
            auth_method=auth_method
        )

        # 2. 取得或建立傳統 User 記錄 (權限管理，系統功能不變)
        user = User.get_or_create(
            username=user_info['username'],
            display_name=user_info['display_name'],
            email=user_info['email'],
            department=user_info.get('department')
        )

        # 更新登入時間
        user.update_last_login()

        # 3. 創建 JWT tokens
        access_token = create_access_token(
            identity=user.username,
            additional_claims={
                'user_id': user.id,
                'sys_user_id': sys_user.id,  # 添加 sys_user_id 以便追蹤
                'is_admin': user.is_admin,
                'display_name': user.display_name,
                'email': user.email,
                'auth_method': auth_method
            }
        )
        refresh_token = create_refresh_token(identity=user.username)

        # 4. 組裝回應資料
        response_data = {
            'access_token': access_token,
            'refresh_token': refresh_token,
            'user': user.to_dict(),
            'auth_method': auth_method,
            'sys_user_info': {
                'login_count': sys_user.login_count,
                'success_count': sys_user.login_success_count,
                'last_login_at': sys_user.last_login_at.isoformat() if sys_user.last_login_at else None
            }
        }

        # 添加 API 特有資訊
        if auth_method == 'API' and user_info.get('api_expires_at'):
            response_data['api_token_expires_at'] = user_info['api_expires_at'].isoformat()

        # 記錄系統日誌
        SystemLog.info(
            'auth.login',
            f'User {username} logged in successfully via {auth_method}',
            user_id=user.id,
            extra_data={
                'auth_method': auth_method,
                'ip_address': ip_address,
                'user_agent': user_agent
            }
        )

        logger.info(f"🔑 [JWT Created] User: {username}, UserID: {user.id}, AuthMethod: {auth_method}")

        return jsonify({
            'success': True,
            'data': response_data,
            'message': f'登入成功 ({auth_method} 認證)'
        })

    except AuthenticationError as e:
        # 記錄認證失敗
        SystemLog.warning(
            'auth.login_failed',
            f'Authentication failed for user {username}: {str(e)}',
            extra_data={
                'username': username,
                'ip_address': request.remote_addr,
                'error': str(e)
            }
        )

        logger.warning(f"Authentication failed for user {username}: {str(e)}")

        return jsonify({
            'success': False,
            'error': 'INVALID_CREDENTIALS',
            'message': str(e)
        }), 401

    except Exception as e:
        logger.error(f"Login error: {str(e)}")

        SystemLog.error(
            'auth.login_error',
            f'Login system error: {str(e)}',
            extra_data={
                'username': username,
                'error': str(e)
            }
        )

        return jsonify({
            'success': False,
            'error': 'SYSTEM_ERROR',
            'message': '系統錯誤，請稍後再試'
        }), 500


@auth_bp.route('/logout', methods=['POST'])
@jwt_required()
def logout():
    """使用者登出"""
    try:
        username = get_jwt_identity()
        
        # 記錄登出日誌
        SystemLog.info(
            'auth.logout',
            f'User {username} logged out'
        )
        
        logger.info(f"🚪 [JWT Logout] User: {username}")
        logger.info(f"User {username} logged out")
        
        return jsonify({
            'success': True,
            'message': '登出成功'
        })
    
    except Exception as e:
        logger.error(f"Logout error: {str(e)}")
        
        return jsonify({
            'success': False,
            'error': 'SYSTEM_ERROR',
            'message': '登出時發生錯誤'
        }), 500


@auth_bp.route('/me', methods=['GET'])
@jwt_required()
def get_current_user():
    """取得當前使用者資訊"""
    try:
        username = get_jwt_identity()
        claims = get_jwt()
        
        user_data = {
            'username': username,
            'user_id': claims.get('user_id'),
            'is_admin': claims.get('is_admin'),
            'display_name': claims.get('display_name'),
            'email': claims.get('email')
        }
        
        return jsonify({
            'success': True,
            'data': {
                'user': user_data
            }
        })
    
    except Exception as e:
        logger.error(f"Get current user error: {str(e)}")
        
        return jsonify({
            'success': False,
            'error': 'SYSTEM_ERROR',
            'message': '取得使用者資訊時發生錯誤'
        }), 500


@auth_bp.route('/refresh', methods=['POST'])
@jwt_required(refresh=True)
def refresh_token():
    """刷新 Access Token"""
    try:
        username = get_jwt_identity()
        
        # 重新取得使用者資訊
        user = User.query.filter_by(username=username).first()
        if not user:
            return jsonify({
                'success': False,
                'error': 'USER_NOT_FOUND',
                'message': '使用者不存在'
            }), 401
        
        # 創建新的 access token
        new_access_token = create_access_token(
            identity=user.username,
            additional_claims={
                'user_id': user.id,
                'is_admin': user.is_admin,
                'display_name': user.display_name,
                'email': user.email
            }
        )
        
        logger.info(f"Token refreshed for user {user.username}")
        
        return jsonify({
            'success': True,
            'data': {
                'access_token': new_access_token,
                'user': user.to_dict()
            },
            'message': 'Token 已刷新'
        })
    
    except Exception as e:
        logger.error(f"Token refresh error: {str(e)}")
        
        return jsonify({
            'success': False,
            'error': 'SYSTEM_ERROR',
            'message': '刷新 Token 時發生錯誤'
        }), 500


@auth_bp.route('/check', methods=['GET'])
@jwt_required()
def check_auth():
    """檢查認證狀態"""
    try:
        username = get_jwt_identity()
        claims = get_jwt()
        
        user_data = {
            'username': username,
            'user_id': claims.get('user_id'),
            'is_admin': claims.get('is_admin'),
            'display_name': claims.get('display_name'),
            'email': claims.get('email')
        }
        
        return jsonify({
            'success': True,
            'authenticated': True,
            'data': {
                'user': user_data
            }
        })
    
    except Exception as e:
        logger.error(f"Auth check error: {str(e)}")
        
        return jsonify({
            'success': False,
            'authenticated': False,
            'error': 'SYSTEM_ERROR',
            'message': '檢查認證狀態時發生錯誤'
        }), 500


@auth_bp.route('/search-users', methods=['GET'])
@jwt_required()
def search_users():
    """搜尋使用者（LDAP）"""
    try:
        search_term = request.args.get('q', '').strip()
        limit = min(int(request.args.get('limit', 20)), 50)
        
        if len(search_term) < 2:
            return jsonify({
                'success': False,
                'error': 'INVALID_SEARCH_TERM',
                'message': '搜尋關鍵字至少需要2個字元'
            }), 400
        
        ldap_service = LDAPAuthService()
        users = ldap_service.search_users(search_term, limit)
        
        return jsonify({
            'success': True,
            'data': {
                'users': users,
                'count': len(users)
            }
        })
    
    except Exception as e:
        logger.error(f"User search error: {str(e)}")
        
        return jsonify({
            'success': False,
            'error': 'SYSTEM_ERROR',
            'message': '搜尋使用者時發生錯誤'
        }), 500


# 錯誤處理器
@auth_bp.errorhandler(429)
def rate_limit_handler(e):
    """速率限制錯誤處理器"""
    return jsonify({
        'success': False,
        'error': 'RATE_LIMIT_EXCEEDED',
        'message': '請求過於頻繁，請稍後再試'
    }), 429