from flask import Flask, request, jsonify
from flask_swagger_ui import get_swaggerui_blueprint
from flask_cors import CORS
import pymysql
import jwt
from datetime import datetime
import hashlib
import hmac
import base64
from config import Config

app = Flask(__name__)

# 啟用 CORS 支援
CORS(app, resources={
    r"/api/*": {
        "origins": "*",
        "methods": ["GET", "POST", "PUT", "DELETE", "OPTIONS"],
        "allow_headers": ["Content-Type", "Authorization"]
    }
})

# 使用配置類別
DB_CONFIG = Config.get_db_config()
JWT_SECRET = Config.JWT_SECRET

# Swagger UI 配置
SWAGGER_URL = '/api/docs'  # Swagger UI 的 URL
API_URL = '/api/swagger.json'  # API 文件的 JSON 位置

# 建立 Swagger UI Blueprint
swaggerui_blueprint = get_swaggerui_blueprint(
    SWAGGER_URL,
    API_URL,
    config={
        'app_name': Config.APP_NAME,
        'app_version': Config.APP_VERSION,
        'description': Config.APP_DESCRIPTION
    }
)

# 註冊 Swagger UI Blueprint
app.register_blueprint(swaggerui_blueprint, url_prefix=SWAGGER_URL)

@app.route('/api/swagger.json')
def swagger():
    """
    Swagger API 文件 JSON
    """
    return jsonify({
        "swagger": "2.0",
        "info": {
            "title": Config.APP_NAME,
            "version": Config.APP_VERSION,
            "description": Config.APP_DESCRIPTION,
            "contact": {
                "name": "Panjit IT Department",
                "email": "it@panjit.com.tw"
            }
        },
        "host": f"{Config.API_HOST}:{Config.API_PORT}",
        "basePath": "/api",
        "schemes": ["http", "https"],
        "consumes": ["application/json"],
        "produces": ["application/json"],
        "paths": {
            "/login": {
                "post": {
                    "tags": ["Authentication"],
                    "summary": "用戶登入驗證",
                    "description": "使用帳號和密碼進行登入驗證",
                    "parameters": [
                        {
                            "name": "body",
                            "in": "body",
                            "required": True,
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "account": {
                                        "type": "string",
                                        "description": "用戶帳號（loginid 或 email）",
                                        "example": "92460"
                                    },
                                    "password": {
                                        "type": "string",
                                        "description": "用戶密碼",
                                        "example": "Panjit92460"
                                    }
                                },
                                "required": ["account", "password"]
                            }
                        }
                    ],
                    "responses": {
                        "200": {
                            "description": "登入成功",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "message": {"type": "string"},
                                    "user": {
                                        "type": "object",
                                        "properties": {
                                            "id": {"type": "integer"},
                                            "loginid": {"type": "string"},
                                            "username": {"type": "string"},
                                            "email": {"type": "string"}
                                        }
                                    }
                                }
                            }
                        },
                        "401": {
                            "description": "登入失敗",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "message": {"type": "string"},
                                    "error_code": {"type": "string"}
                                }
                            }
                        }
                    }
                }
            },
            "/change-password": {
                "post": {
                    "tags": ["Password Management"],
                    "summary": "修改用戶密碼",
                    "description": "修改用戶的登入密碼",
                    "parameters": [
                        {
                            "name": "body",
                            "in": "body",
                            "required": True,
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "account": {
                                        "type": "string",
                                        "description": "用戶帳號（loginid 或 email）",
                                        "example": "92460"
                                    },
                                    "old_password": {
                                        "type": "string",
                                        "description": "舊密碼",
                                        "example": "Panjit92460"
                                    },
                                    "new_password": {
                                        "type": "string",
                                        "description": "新密碼（6-50字元，需包含字母和數字）",
                                        "example": "MyNewPassword123"
                                    }
                                },
                                "required": ["account", "old_password", "new_password"]
                            }
                        }
                    ],
                    "responses": {
                        "200": {
                            "description": "密碼修改成功",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "message": {"type": "string"}
                                }
                            }
                        },
                        "400": {
                            "description": "請求錯誤",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "message": {"type": "string"},
                                    "error_code": {"type": "string"}
                                }
                            }
                        },
                        "401": {
                            "description": "舊密碼不正確",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "message": {"type": "string"},
                                    "error_code": {"type": "string"}
                                }
                            }
                        }
                    }
                }
            },
            "/health": {
                "get": {
                    "tags": ["System"],
                    "summary": "系統健康檢查",
                    "description": "檢查 API 服務和資料庫連線狀態",
                    "responses": {
                        "200": {
                            "description": "系統正常",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "message": {"type": "string"},
                                    "database": {"type": "string"},
                                    "timestamp": {"type": "string"}
                                }
                            }
                        }
                    }
                }
            },
            "/user/{account}": {
                "get": {
                    "tags": ["User Management"],
                    "summary": "查詢用戶資訊",
                    "description": "根據帳號查詢用戶基本資訊",
                    "parameters": [
                        {
                            "name": "account",
                            "in": "path",
                            "required": True,
                            "type": "string",
                            "description": "用戶帳號（loginid 或 email）",
                            "example": "92460"
                        }
                    ],
                    "responses": {
                        "200": {
                            "description": "查詢成功",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "user": {
                                        "type": "object",
                                        "properties": {
                                            "id": {"type": "integer"},
                                            "loginid": {"type": "string"},
                                            "username": {"type": "string"},
                                            "email": {"type": "string"}
                                        }
                                    }
                                }
                            }
                        },
                        "404": {
                            "description": "用戶不存在",
                            "schema": {
                                "type": "object",
                                "properties": {
                                    "success": {"type": "boolean"},
                                    "message": {"type": "string"},
                                    "error_code": {"type": "string"}
                                }
                            }
                        }
                    }
                }
            }
        },
        "definitions": {
            "Error": {
                "type": "object",
                "properties": {
                    "success": {"type": "boolean", "example": False},
                    "message": {"type": "string"},
                    "error_code": {"type": "string"}
                }
            },
            "User": {
                "type": "object",
                "properties": {
                    "id": {"type": "integer", "example": 1},
                    "loginid": {"type": "string", "example": "92460"},
                    "username": {"type": "string", "example": "丁于軒"},
                    "email": {"type": "string", "example": "sharnading@panjit.com.tw"}
                }
            }
        }
    })

def verify_password(input_password, hashed_password):
    """
    驗證密碼是否正確
    """
    try:
        # 解碼 JWT token
        decoded = jwt.decode(hashed_password, JWT_SECRET, algorithms=['HS256'])
        
        # 檢查 token 類型
        if decoded.get('type') != 'password_hash':
            return False
            
        # 比較密碼
        stored_password = decoded.get('password', '')
        return input_password == stored_password
        
    except jwt.ExpiredSignatureError:
        print("JWT token 已過期")
        return False
    except jwt.InvalidTokenError:
        print("無效的 JWT token")
        return False
    except Exception as e:
        print(f"密碼驗證錯誤: {e}")
        return False

def hash_password_with_jwt(password):
    """
    使用 JWT 將密碼進行雜湊處理
    """
    try:
        # 建立 JWT payload，包含密碼和時間戳
        payload = {
            'password': password,
            'timestamp': datetime.now().isoformat(),
            'type': 'password_hash'
        }
        
        # 使用 JWT 編碼密碼
        token = jwt.encode(payload, JWT_SECRET, algorithm='HS256')
        return token
    except Exception as e:
        print(f"密碼雜湊錯誤: {e}")
        return None

def validate_password_strength(password):
    """
    驗證密碼強度
    """
    if len(password) < 6:
        return False, "密碼長度至少需要 6 個字元"
    
    if len(password) > 50:
        return False, "密碼長度不能超過 50 個字元"
    
    # 檢查是否包含至少一個字母和一個數字
    has_letter = any(c.isalpha() for c in password)
    has_digit = any(c.isdigit() for c in password)
    
    if not has_letter:
        return False, "密碼必須包含至少一個字母"
    
    if not has_digit:
        return False, "密碼必須包含至少一個數字"
    
    return True, "密碼強度符合要求"

def update_user_password(loginid_or_email, old_password, new_password):
    """
    更新用戶密碼
    """
    try:
        connection = pymysql.connect(**DB_CONFIG)
        cursor = connection.cursor(pymysql.cursors.DictCursor)
        
        # 先查詢用戶資料
        query = """
        SELECT id, loginid, username, email, hashed_password 
        FROM user_accounts 
        WHERE loginid = %s OR email = %s
        """
        
        cursor.execute(query, (loginid_or_email, loginid_or_email))
        user = cursor.fetchone()
        
        if not user:
            return False, "用戶不存在"
        
        # 驗證舊密碼
        if not verify_password(old_password, user['hashed_password']):
            return False, "舊密碼不正確"
        
        # 驗證新密碼強度
        is_valid, message = validate_password_strength(new_password)
        if not is_valid:
            return False, message
        
        # 生成新密碼的雜湊
        new_hashed_password = hash_password_with_jwt(new_password)
        if not new_hashed_password:
            return False, "密碼雜湊失敗"
        
        # 更新密碼
        update_query = """
        UPDATE user_accounts 
        SET hashed_password = %s, updated_at = CURRENT_TIMESTAMP 
        WHERE id = %s
        """
        
        cursor.execute(update_query, (new_hashed_password, user['id']))
        connection.commit()
        
        return True, "密碼修改成功"
        
    except Exception as e:
        print(f"更新密碼錯誤: {e}")
        return False, f"系統錯誤: {str(e)}"
    finally:
        if 'connection' in locals():
            connection.close()

def get_user_by_loginid_or_email(loginid_or_email):
    """
    根據 loginid 或 email 查詢用戶資料
    """
    try:
        connection = pymysql.connect(**DB_CONFIG)
        cursor = connection.cursor(pymysql.cursors.DictCursor)
        
        # 查詢用戶資料
        query = """
        SELECT id, loginid, username, email, hashed_password 
        FROM user_accounts 
        WHERE loginid = %s OR email = %s
        """
        
        cursor.execute(query, (loginid_or_email, loginid_or_email))
        user = cursor.fetchone()
        
        return user
        
    except Exception as e:
        print(f"資料庫查詢錯誤: {e}")
        return None
    finally:
        if 'connection' in locals():
            connection.close()

@app.route('/api/login', methods=['POST'])
def login():
    """
    登入 API
    接收 JSON 格式: {"account": "帳號或email", "password": "密碼"}
    """
    try:
        # 取得請求資料
        data = request.get_json()
        
        if not data:
            return jsonify({
                'success': False,
                'message': '請提供 JSON 格式的資料',
                'error_code': 'INVALID_REQUEST'
            }), 400
        
        account = data.get('account', '').strip()
        password = data.get('password', '').strip()
        
        # 檢查必要欄位
        if not account or not password:
            return jsonify({
                'success': False,
                'message': '請提供帳號和密碼',
                'error_code': 'MISSING_FIELDS'
            }), 400
        
        # 查詢用戶資料
        user = get_user_by_loginid_or_email(account)
        
        if not user:
            return jsonify({
                'success': False,
                'message': '無權限，請詢問資訊部同仁',
                'error_code': 'USER_NOT_FOUND'
            }), 401
        
        # 驗證密碼
        if not verify_password(password, user['hashed_password']):
            return jsonify({
                'success': False,
                'message': '無權限，請詢問資訊部同仁',
                'error_code': 'INVALID_PASSWORD'
            }), 401
        
        # 登入成功
        return jsonify({
            'success': True,
            'message': '登入成功',
            'user': {
                'id': user['id'],
                'loginid': user['loginid'],
                'username': user['username'],
                'email': user['email']
            }
        }), 200
        
    except Exception as e:
        print(f"登入 API 錯誤: {e}")
        return jsonify({
            'success': False,
            'message': '系統錯誤，請稍後再試',
            'error_code': 'SYSTEM_ERROR'
        }), 500

@app.route('/api/health', methods=['GET'])
def health_check():
    """
    健康檢查 API
    """
    try:
        # 測試資料庫連線
        connection = pymysql.connect(**DB_CONFIG)
        cursor = connection.cursor()
        cursor.execute("SELECT 1")
        cursor.fetchone()
        connection.close()
        
        return jsonify({
            'success': True,
            'message': 'API 服務正常',
            'database': '連線正常',
            'timestamp': datetime.now().isoformat()
        }), 200
        
    except Exception as e:
        return jsonify({
            'success': False,
            'message': 'API 服務異常',
            'database': '連線失敗',
            'error': str(e),
            'timestamp': datetime.now().isoformat()
        }), 500

@app.route('/api/user/<account>', methods=['GET'])
def get_user_info(account):
    """
    查詢用戶資訊 API（不包含密碼）
    """
    try:
        user = get_user_by_loginid_or_email(account)
        
        if not user:
            return jsonify({
                'success': False,
                'message': '用戶不存在',
                'error_code': 'USER_NOT_FOUND'
            }), 404
        
        # 回傳用戶資訊（不包含密碼）
        return jsonify({
            'success': True,
            'user': {
                'id': user['id'],
                'loginid': user['loginid'],
                'username': user['username'],
                'email': user['email']
            }
        }), 200
        
    except Exception as e:
        print(f"查詢用戶資訊錯誤: {e}")
        return jsonify({
            'success': False,
            'message': '系統錯誤，請稍後再試',
            'error_code': 'SYSTEM_ERROR'
        }), 500

@app.route('/api/change-password', methods=['POST'])
def change_password():
    """
    修改密碼 API
    接收 JSON 格式: {"account": "帳號或email", "old_password": "舊密碼", "new_password": "新密碼"}
    """
    try:
        # 取得請求資料
        data = request.get_json()
        
        if not data:
            return jsonify({
                'success': False,
                'message': '請提供 JSON 格式的資料',
                'error_code': 'INVALID_REQUEST'
            }), 400
        
        account = data.get('account', '').strip()
        old_password = data.get('old_password', '').strip()
        new_password = data.get('new_password', '').strip()
        
        # 檢查必要欄位
        if not account or not old_password or not new_password:
            return jsonify({
                'success': False,
                'message': '請提供帳號、舊密碼和新密碼',
                'error_code': 'MISSING_FIELDS'
            }), 400
        
        # 檢查新密碼不能與舊密碼相同
        if old_password == new_password:
            return jsonify({
                'success': False,
                'message': '新密碼不能與舊密碼相同',
                'error_code': 'SAME_PASSWORD'
            }), 400
        
        # 更新密碼
        success, message = update_user_password(account, old_password, new_password)
        
        if success:
            return jsonify({
                'success': True,
                'message': message
            }), 200
        else:
            # 根據錯誤類型返回不同的狀態碼
            if "用戶不存在" in message:
                return jsonify({
                    'success': False,
                    'message': message,
                    'error_code': 'USER_NOT_FOUND'
                }), 404
            elif "舊密碼不正確" in message:
                return jsonify({
                    'success': False,
                    'message': message,
                    'error_code': 'INVALID_OLD_PASSWORD'
                }), 401
            elif "密碼長度" in message or "密碼必須" in message:
                return jsonify({
                    'success': False,
                    'message': message,
                    'error_code': 'WEAK_PASSWORD'
                }), 400
            else:
                return jsonify({
                    'success': False,
                    'message': message,
                    'error_code': 'UPDATE_FAILED'
                }), 500
        
    except Exception as e:
        print(f"修改密碼 API 錯誤: {e}")
        return jsonify({
            'success': False,
            'message': '系統錯誤，請稍後再試',
            'error_code': 'SYSTEM_ERROR'
        }), 500

@app.errorhandler(404)
def not_found(error):
    return jsonify({
        'success': False,
        'message': 'API 端點不存在',
        'error_code': 'NOT_FOUND'
    }), 404

@app.errorhandler(405)
def method_not_allowed(error):
    return jsonify({
        'success': False,
        'message': '不支援的 HTTP 方法',
        'error_code': 'METHOD_NOT_ALLOWED'
    }), 405

if __name__ == '__main__':
    print(f"啟動 {Config.APP_NAME} v{Config.APP_VERSION}...")
    print("API 端點:")
    print("  POST /api/login - 登入驗證")
    print("  POST /api/change-password - 修改密碼")
    print("  GET  /api/health - 健康檢查")
    print("  GET  /api/user/<account> - 查詢用戶資訊")
    print(f"  GET  {SWAGGER_URL} - Swagger API 文件")
    print(f"\n服務地址: http://{Config.API_HOST}:{Config.API_PORT}")
    print(f"Swagger 文件: http://{Config.API_HOST}:{Config.API_PORT}{SWAGGER_URL}")
    print("\n範例請求:")
    print("登入驗證:")
    print(f'curl -X POST http://{Config.API_HOST}:{Config.API_PORT}/api/login \\')
    print('  -H "Content-Type: application/json" \\')
    print('  -d \'{"account": "92460", "password": "Panjit92460"}\'')
    print("\n修改密碼:")
    print(f'curl -X POST http://{Config.API_HOST}:{Config.API_PORT}/api/change-password \\')
    print('  -H "Content-Type: application/json" \\')
    print('  -d \'{"account": "92460", "old_password": "Panjit92460", "new_password": "MyNewPassword123"}\'')
    print("\n服務啟動中...")
    
    app.run(host=Config.API_HOST, port=Config.API_PORT, debug=Config.API_DEBUG)