/*******************************************************************************
 * Copyright (c) 2005, 2014 springside.github.io
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 *******************************************************************************/
package com.cjs.site.util.net;

import java.util.Iterator;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.validation.ConstraintViolationException;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;

import com.cjs.site.util.lang.JsonUtil;
import com.cjs.site.util.web.ActionUtil;

/**
 * 自定义ExceptionHandler，专门处理Restful异常.
 * 
 * @author calvin
 */
// 会被Spring-MVC自动扫描，但又不属于Controller的annotation。
//@ControllerAdvice
public class RestExceptionHandler extends ResponseEntityExceptionHandler {

    private Logger logger = LogManager.getLogger(RestExceptionHandler.class);

    /**
     * 处理所有的RuntimeException.
     * 原本只是处理RestException，但是这样就需要在所有的Control方法中try-catch。所以这里直接
     * 处理所有的RuntimeException，精简代码。
     */
    @ExceptionHandler(value = { RuntimeException.class })
    public final ResponseEntity<?> handleException(RuntimeException ex, WebRequest request) {
        HttpHeaders headers = new HttpHeaders();
        HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
        if (ex instanceof RestException) {
            status = ((RestException) ex).status;
            logger.error(ex.getMessage());
        } else {
            //注意：只在开发时打印异常堆栈信息
            logger.error(getErrorMessage(ex, request), ex);
        }
        headers.setContentType(MediaType.parseMediaType(MediaTypes.TEXT_PLAIN_UTF_8));
        return handleExceptionInternal(ex, ex.getMessage(), headers, status, request);
    }

    /**获取发生错误时的请求信息*/
    private String getErrorMessage(RuntimeException ex, WebRequest request) {
        StringBuilder sb = new StringBuilder("\n请求参数：{");
        Map<String, String[]> params = request.getParameterMap();
        Iterator<String> headers = request.getHeaderNames();
        HttpServletRequest httpServletRequest = ActionUtil.getRequest();

        for (String param : params.keySet()) {
            sb.append("\n\t").append(param).append(":").append(request.getParameter(param));
        }
        sb.append("\n}");
        sb.append("\nIP:" + ActionUtil.getIP());
        sb.append("\nURL：");
        if (httpServletRequest != null) {
            sb.append(httpServletRequest.getMethod() + " ");
        }
        sb.append(request.getDescription(true));
        sb.append("\n头信息：{");
        while (headers.hasNext()) {
            String header = headers.next();
            sb.append("\n\t").append(header).append(":").append(request.getHeader(header));
        }
        sb.append("\n}");
        return sb.toString();
    }

    /**
     * 处理RestException.(停用)
     */
    //@ExceptionHandler(value = { RestException.class })
    @Deprecated
    public final ResponseEntity<?> handleRestException(RestException ex, WebRequest request) {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.parseMediaType(MediaTypes.TEXT_PLAIN_UTF_8));
        return handleExceptionInternal(ex, ex.getMessage(), headers, ex.status, request);
    }

    /**
     * 处理JSR311 Validation异常.
     */
    @ExceptionHandler(value = { ConstraintViolationException.class })
    public final ResponseEntity<?> handleException(ConstraintViolationException ex,
                                                   WebRequest request) {
        Map<String, String> errors = BeanValidators.extractPropertyAndMessage(ex
            .getConstraintViolations());
        String body = JsonUtil.toJson(errors);
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.parseMediaType(MediaTypes.TEXT_PLAIN_UTF_8));
        return handleExceptionInternal(ex, body, headers, HttpStatus.BAD_REQUEST, request);
    }
}