content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  package org.apache.bifromq.apiserver.http.handler;
  
  import static io.netty.handler.codec.http.HttpResponseStatus.NOT_FOUND;
  import static io.netty.handler.codec.http.HttpResponseStatus.OK;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.node.ObjectNode;
  import io.netty.buffer.Unpooled;
  import io.netty.handler.codec.http.DefaultFullHttpResponse;
  import io.netty.handler.codec.http.FullHttpRequest;
  import io.netty.handler.codec.http.FullHttpResponse;
  import io.swagger.v3.oas.annotations.Operation;
  import io.swagger.v3.oas.annotations.Parameter;
  import io.swagger.v3.oas.annotations.Parameters;
  import io.swagger.v3.oas.annotations.enums.ParameterIn;
  import io.swagger.v3.oas.annotations.media.Content;
  import io.swagger.v3.oas.annotations.media.Schema;
  import io.swagger.v3.oas.annotations.parameters.RequestBody;
  import io.swagger.v3.oas.annotations.responses.ApiResponse;
  import io.swagger.v3.oas.annotations.responses.ApiResponses;
  import jakarta.ws.rs.GET;
  import jakarta.ws.rs.Path;
  import java.util.Map;
  import java.util.concurrent.CompletableFuture;
  import org.apache.bifromq.apiserver.Headers;
  import org.apache.bifromq.apiserver.http.IHTTPRequestHandler;
  import org.apache.bifromq.apiserver.http.handler.utils.HeaderUtils;
  import org.apache.bifromq.apiserver.http.handler.utils.JSONUtils;
  import org.apache.bifromq.baserpc.trafficgovernor.IRPCServiceLandscape;
  import org.apache.bifromq.baserpc.trafficgovernor.IRPCServiceTrafficService;
  
  @Path("/service/traffic")
  final class GetTrafficRulesHandler extends AbstractTrafficRulesHandler implements IHTTPRequestHandler {
      GetTrafficRulesHandler(IRPCServiceTrafficService trafficService) {
          super(trafficService);
      }
  
      @GET
      @Operation(summary = "Get the traffic rules of a service")
      @Parameters({
          @Parameter(name = "req_id", in = ParameterIn.HEADER,
              description = "optional caller provided request id", schema = @Schema(implementation = Long.class)),
          @Parameter(name = "service_name", in = ParameterIn.HEADER, required = true,
              description = "the service name", schema = @Schema(implementation = String.class))
      })
      @RequestBody(required = false)
      @ApiResponses(value = {
          @ApiResponse(responseCode = "200",
              description = "Success",
              content = @Content(mediaType = "application/json")),
          @ApiResponse(responseCode = "404",
              description = "Service not found",
              content = @Content(schema = @Schema(implementation = String.class))),
      })
      @Override
      public CompletableFuture<FullHttpResponse> handle(@Parameter(hidden = true) long reqId,
                                                        @Parameter(hidden = true) FullHttpRequest req) {
          String serviceName = HeaderUtils.getHeader(Headers.HEADER_SERVICE_NAME, req, true);
          if (serviceName == null || !isTrafficGovernable(serviceName)) {
              return CompletableFuture.completedFuture(new DefaultFullHttpResponse(req.protocolVersion(), NOT_FOUND,
                  Unpooled.copiedBuffer(("Service not found: " + serviceName).getBytes())));
          }
          IRPCServiceLandscape landscape = governorMap.get(serviceName);
          if (landscape == null) {
              return CompletableFuture.completedFuture(new DefaultFullHttpResponse(req.protocolVersion(), NOT_FOUND,
                  Unpooled.copiedBuffer(("Service not found: " + serviceName).getBytes())));
          }
          return landscape.trafficRules()
              .firstElement()
              .toCompletionStage()
              .toCompletableFuture()
              .thenApply(trafficDirective -> {
                  DefaultFullHttpResponse
                      resp = new DefaultFullHttpResponse(req.protocolVersion(), OK,
                      Unpooled.wrappedBuffer(toJSON(trafficDirective).getBytes()));
                  resp.headers().set("Content-Type", "application/json");
                  return resp;
              });
      }
  
      private String toJSON(Map<String, Map<String, Integer>> trafficDirective) {
          ObjectMapper mapper = JSONUtils.MAPPER;
          ObjectNode rootObject = mapper.createObjectNode();
          for (String tenantIdPrefix : trafficDirective.keySet()) {
              Map<String, Integer> groupWeights = trafficDirective.get(tenantIdPrefix);
              ObjectNode groupWeightsObject = mapper.createObjectNode();
              for (String group : groupWeights.keySet()) {
                  groupWeightsObject.put(group, groupWeights.get(group));
              }
              rootObject.set(tenantIdPrefix, groupWeightsObject);
          }
          return rootObject.toString();
      }
  }
  