package com.gitee.cashzhang27.ftf.gateway.filter;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR;
import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.URI_TEMPLATE_VARIABLES_ATTRIBUTE;
import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.addOriginalRequestUrl;

import cn.hutool.json.JSONUtil;
import com.gitee.cashzhang27.ftf.common.core.entity.Response;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Map;
import java.util.stream.Collectors;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.util.pattern.PathPattern;
import reactor.core.publisher.Mono;

/**
 * @author Cash Zhang
 * @version v1.0
 * @since 2019/03/10 17:16
 */
@Component
public class RequestGlobalFilter implements GlobalFilter, Ordered {

  @Value("${spring.profiles.active}")
  private String active;

  private final static String SEGMENT = "-";

  /**
   * Process the Web request and (optionally) delegate to the next {@code WebFilter} through the
   * given {@link GatewayFilterChain}.
   *
   * @param exchange the current server exchange
   * @param chain provides a way to delegate to the next filter
   * @return {@code Mono<Void>} to indicate when request processing is complete
   */
  @Override
  public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
    ServerHttpRequest request = exchange.getRequest();
    ServerHttpResponse response = exchange.getResponse();
    // 获取请求路径前缀（api-dev/api-prod）
    PathPattern.PathMatchInfo pathMatchInfo = exchange
        .getAttribute(URI_TEMPLATE_VARIABLES_ATTRIBUTE);
    if (pathMatchInfo != null) {
      Map<String, String> uriVariables = pathMatchInfo.getUriVariables();
      String api = uriVariables.get("api");
      // 判断请求路径是否符合当前环境
      if (!api.split(SEGMENT)[1].equals(active)) {
        byte[] responseBytes = JSONUtil
            .toJsonStr(Response
                .failed(HttpStatus.FORBIDDEN.value(), HttpStatus.FORBIDDEN.getReasonPhrase()))
            .getBytes(StandardCharsets.UTF_8);
        DataBuffer buffer = response.bufferFactory().wrap(responseBytes);
        response.setStatusCode(HttpStatus.FORBIDDEN);
        response.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
        return response.writeWith(Mono.just(buffer));
      }
    }

    // 将StripPrefixGatewayFilter加入全局过滤器中
    addOriginalRequestUrl(exchange, request.getURI());
    String rawPath = request.getURI().getRawPath();
    String newPath = "/" + Arrays.stream(StringUtils.tokenizeToStringArray(rawPath, "/"))
        .skip(2L).collect(Collectors.joining("/"));
    ServerHttpRequest newRequest = request.mutate()
        .path(newPath)
        .build();
    exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, newRequest.getURI());

    return chain.filter(exchange.mutate()
        .request(newRequest).build());
  }

  @Override
  public int getOrder() {
    return -1000;
  }
}