package com.iflytop.gd.common.handler;

import com.iflytop.gd.common.exception.AppException;
import com.iflytop.gd.common.result.Result;
import com.iflytop.gd.common.result.ResultCode;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.validation.ConstraintViolationException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.validation.BindException;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.util.stream.Collectors;

@Slf4j
@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(HttpRequestMethodNotSupportedException.class)
    public Result<?> handleMethodNotSupported(HttpRequestMethodNotSupportedException ex, HttpServletRequest request) {
        String method = request.getMethod();
        String uri = request.getRequestURI();
        String allowed = ex.getSupportedHttpMethods() != null
                ? ex.getSupportedHttpMethods().toString()
                : "[]";
        String msg = String.format(
                "请求方法 '%s' 不支持 (URL: %s)。支持的方法有：%s",
                method, uri, allowed);
        log.error(msg, ex);
        return Result.failed(ResultCode.METHOD_NOT_ALLOWED.getCode(), msg);
    }

    // 1) JSON Body 校验失败
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public Result<?> handleBodyValid(MethodArgumentNotValidException ex) {
        String msg = ex.getBindingResult().getFieldErrors().stream()
                .map(f -> f.getField() + ": " + f.getDefaultMessage())
                .collect(Collectors.joining("; "));
        return Result.failed(ResultCode.INVALID_PARAMETER.getCode(), msg);
    }

    // 2) 方法级参数校验失败（PathVariable/RequestParam）
    @ExceptionHandler(ConstraintViolationException.class)
    public Result<?> handleParamValid(ConstraintViolationException ex) {
        String msg = ex.getConstraintViolations().stream()
                .map(v -> {
                    String path = v.getPropertyPath().toString();
                    String field = path.substring(path.lastIndexOf('.') + 1);
                    return field + ": " + v.getMessage();
                })
                .collect(Collectors.joining("; "));
        return Result.failed(ResultCode.INVALID_PARAMETER.getCode(), msg);
    }

    // 3) 表单绑定失败
    @ExceptionHandler(BindException.class)
    public Result<?> handleBind(BindException ex) {
        String msg = ex.getFieldErrors().stream()
                .map(f -> f.getField() + ": " + f.getDefaultMessage())
                .collect(Collectors.joining("; "));
        return Result.failed(ResultCode.INVALID_PARAMETER.getCode(), msg);
    }

    @ExceptionHandler(Exception.class)
    public Result<?> handleException(Exception ex) {
        if (ex instanceof AppException ae) {
            log.warn("AppException:", ae);
            return Result.failed(ae.getResultCode());
        }
        log.error("Unhandled exception:", ex);
        return Result.failed(ResultCode.SYSTEM_ERROR.getCode(), ex.getMessage());
    }

}