package com.cdzy.gateway;

import com.cdzy.common.enums.Code;
import com.cdzy.common.model.response.JsonResult;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.jetbrains.annotations.NotNull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.web.reactive.error.ErrorWebExceptionHandler;
import org.springframework.cloud.gateway.support.NotFoundException;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ResponseStatusException;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.util.Objects;

/**
 * 网关统一异常处理
 *
 * @author ruoyi
 */
@Order(-1)
@Configuration
public class GatewayExceptionHandler implements ErrorWebExceptionHandler {
    private static final Logger log = LoggerFactory.getLogger(GatewayExceptionHandler.class);

    @NotNull
    @Override
    public Mono<Void> handle(ServerWebExchange exchange, Throwable ex) {
        ServerHttpResponse response = exchange.getResponse();

        if (exchange.getResponse().isCommitted()) {
            return Mono.error(ex);
        }

        String msg;

        if (ex instanceof NotFoundException) {
            msg = "服务未找到";
        } else if (ex instanceof ResponseStatusException responseStatusException) {
            msg = responseStatusException.getMessage();
        }else {
            msg = "内部服务器错误";
        }

        log.error("[网关异常处理]请求路径:{},异常信息:{}", exchange.getRequest().getPath(), ex.getMessage());

        return webFluxResponseWriter(response, msg,null);
    }

    /**
     * 设置webflux模型响应
     *
     * @param response ServerHttpResponse
     * @param value    响应内容
     * @param code    响应码
     * @return Mono<Void>
     */
    public static Mono<Void> webFluxResponseWriter(ServerHttpResponse response, Object value,Integer code) {
        return webFluxResponseWriter(response, HttpStatus.OK, value, Objects.requireNonNullElse(code, Code.FAILED));
    }

    /**
     * 设置webflux模型响应
     *
     * @param response ServerHttpResponse
     * @param code     响应状态码
     * @param value    响应内容
     * @return Mono<Void>
     */
    public static Mono<Void> webFluxResponseWriter(ServerHttpResponse response, Object value, int code) {
        return webFluxResponseWriter(response, HttpStatus.OK, value, code);
    }

    /**
     * 设置webflux模型响应
     *
     * @param response ServerHttpResponse
     * @param status   http状态码
     * @param code     响应状态码
     * @param value    响应内容
     * @return Mono<Void>
     */
    public static Mono<Void> webFluxResponseWriter(ServerHttpResponse response, HttpStatus status, Object value, int code) {
        return webFluxResponseWriter(response, MediaType.APPLICATION_JSON_VALUE, status, value, code);
    }

    /**
     * 设置webflux模型响应
     *
     * @param response    ServerHttpResponse
     * @param contentType content-type
     * @param status      http状态码
     * @param code        响应状态码
     * @param value       响应内容
     * @return Mono<Void>
     */
    public static Mono<Void> webFluxResponseWriter(ServerHttpResponse response, String contentType, HttpStatus status, Object value, int code) {
        response.setStatusCode(status);
        response.getHeaders().add(HttpHeaders.CONTENT_TYPE, contentType);
        JsonResult<String> result = JsonResult.failed(value.toString());
        ObjectMapper objectMapper = new ObjectMapper();
        DataBuffer dataBuffer = null;
        try {
            dataBuffer = response.bufferFactory().wrap(objectMapper.writeValueAsBytes(result));
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }
        return response.writeWith(Mono.just(dataBuffer));
    }
}