from fastapi import HTTPException, Request
from fastapi.responses import JSONResponse
from fastapi.exceptions import RequestValidationError
import logging
from app.schemas.response import ErrorResponse

# 创建日志记录器
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)

class BusinessError(Exception):
    """业务错误异常，使用标准响应格式"""
    def __init__(self, message: str, code: int = 500):
        self.message = message
        self.code = code
        super().__init__(self.message)

# 业务异常处理器
async def business_exception_handler(request: Request, exc: BusinessError):
    """将业务异常转换为标准响应格式"""
    logger.debug(f"处理业务异常: code={exc.code}, message={exc.message}")
    
    error_response = ErrorResponse(
        code=exc.code,
        message=exc.message
    )
    
    return JSONResponse(
        status_code=200,  # 始终返回200状态码，业务错误码在响应内容中
        content=error_response.model_dump()
    )

# 请求验证错误处理器
async def validation_exception_handler(request: Request, exc: RequestValidationError):
    """将请求验证错误转换为标准错误响应"""
    error_messages = []
    for error in exc.errors():
        loc = error.get("loc", [])
        loc_str = " -> ".join(str(l) for l in loc)
        error_messages.append(f"{loc_str}: {error.get('msg')}")
    
    error_message = ", ".join(error_messages)
    logger.debug(f"处理请求验证错误: {error_message}")
    
    error_response = ErrorResponse(
        code=422,
        message=f"请求参数验证错误: {error_message}"
    )
    
    return JSONResponse(
        status_code=200,  # 与业务异常一致，返回200状态码
        content=error_response.model_dump()
    )

# HTTP异常处理器
async def http_exception_handler(request: Request, exc: HTTPException):
    """将HTTP异常转换为标准错误响应"""
    logger.debug(f"处理HTTP异常: status_code={exc.status_code}, detail={exc.detail}")
    
    error_response = ErrorResponse(
        code=exc.status_code,
        message=str(exc.detail)
    )
    
    return JSONResponse(
        status_code=exc.status_code,  
        content=exc.detail
    )

def add_exception_handlers(app):
    """添加异常处理器到FastAPI应用"""
    app.add_exception_handler(BusinessError, business_exception_handler)
    app.add_exception_handler(RequestValidationError, validation_exception_handler)
    app.add_exception_handler(HTTPException, http_exception_handler)