package com.xly.exception;

import com.xly.constant.ErrorCode;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.validation.ConstraintViolationException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.http.ResponseEntity;
import org.springframework.http.converter.HttpMessageConversionException;
import org.springframework.jdbc.BadSqlGrammarException;
import org.springframework.web.server.ResponseStatusException;
import org.springframework.web.HttpMediaTypeNotSupportedException;
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 org.springframework.web.servlet.NoHandlerFoundException;

import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

@Slf4j
@RestControllerAdvice
public class GlobalExceptionHandler {

    private Map<String, Object> error(Integer code, String message) {
        Map<String, Object> body = new LinkedHashMap<>();
        body.put("code", code);
        body.put("message", message);
        body.put("timestamp", System.currentTimeMillis());
        return body;
    }

    /**
     * 鉴权类异常按**真实 HTTP 状态**返回（401/403），不被下面的兜底包装成 200。
     * 否则客户端/网关/日志都看不出这是一次被拒绝的越权访问。
     */
    @ExceptionHandler(ResponseStatusException.class)
    public ResponseEntity<Map<String, Object>> handleResponseStatus(ResponseStatusException e) {
        log.warn("拒绝访问 {}: {}", e.getStatusCode(), e.getReason());
        return ResponseEntity.status(e.getStatusCode())
                .body(error(e.getStatusCode().value(), e.getReason() == null ? "拒绝访问" : e.getReason()));
    }

    @ExceptionHandler(Exception.class)
    public Map<String, Object> handleException(HttpServletRequest request, Exception e) {
        log.error("请求地址: {}, 全局异常: ", request.getRequestURI(), e);
        return error(ErrorCode.SYSTEM_ERROR.getCode(), "系统异常: " + e.getMessage());
    }

    @ExceptionHandler(MethodArgumentNotValidException.class)
    public Map<String, Object> handleMethodArgumentNotValidException(MethodArgumentNotValidException e) {
        List<String> errors = e.getBindingResult().getFieldErrors()
                .stream()
                .map(err -> err.getField() + ": " + err.getDefaultMessage())
                .collect(Collectors.toList());
        String message = String.join("; ", errors);
        log.warn("参数校验失败: {}", message);
        return error(ErrorCode.PARAM_ERROR.getCode(), message);
    }

    @ExceptionHandler(ConstraintViolationException.class)
    public Map<String, Object> handleConstraintViolationException(ConstraintViolationException e) {
        List<String> errors = e.getConstraintViolations()
                .stream()
                .map(violation -> violation.getPropertyPath() + ": " + violation.getMessage())
                .collect(Collectors.toList());
        String message = String.join("; ", errors);
        log.warn("参数约束违反: {}", message);
        return error(ErrorCode.PARAM_ERROR.getCode(), message);
    }

    @ExceptionHandler(HttpRequestMethodNotSupportedException.class)
    public Map<String, Object> handleHttpRequestMethodNotSupportedException(HttpRequestMethodNotSupportedException e) {
        log.warn("HTTP方法不支持: {} {}", e.getMethod(), e.getSupportedHttpMethods());
        return error(ErrorCode.BAD_REQUEST.getCode(), "请求方法 '" + e.getMethod() + "' 不支持");
    }

    @ExceptionHandler(HttpMediaTypeNotSupportedException.class)
    public Map<String, Object> handleHttpMediaTypeNotSupportedException(HttpMediaTypeNotSupportedException e) {
        log.warn("媒体类型不支持: {}", e.getContentType());
        return error(ErrorCode.BAD_REQUEST.getCode(), "媒体类型不支持: " + e.getContentType());
    }

    @ExceptionHandler(NoHandlerFoundException.class)
    public Map<String, Object> handleNoHandlerFoundException(NoHandlerFoundException e) {
        log.warn("接口不存在: {} {}", e.getHttpMethod(), e.getRequestURL());
        return error(ErrorCode.NOT_FOUND.getCode(), "接口不存在: " + e.getRequestURL());
    }

    @ExceptionHandler(HttpMessageConversionException.class)
    public Map<String, Object> handleHttpMessageConversionException(HttpMessageConversionException e) {
        log.warn("HTTP消息转换异常: {}", e.getMessage());
        return error(ErrorCode.PARAM_ERROR.getCode(), "参数格式错误");
    }

    @ExceptionHandler(DataAccessException.class)
    public Map<String, Object> handleDataAccessException(DataAccessException e) {
        log.error("数据库异常: {}", e.getMessage(), e);
        if (e instanceof DuplicateKeyException) {
            return error(ErrorCode.DATA_EXISTS.getCode(), "数据已存在");
        } else if (e instanceof DataIntegrityViolationException) {
            return error(ErrorCode.DATA_ERROR.getCode(), "数据完整性违反");
        } else if (e instanceof BadSqlGrammarException) {
            return error(ErrorCode.DB_ERROR.getCode(), "SQL语法错误");
        }
        return error(ErrorCode.DB_ERROR.getCode(), ErrorCode.DB_ERROR.getMessage());
    }
}