// Copyright 2016 gRPC authors.
//
// Licensed 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.

#include <string>

#include "absl/types/optional.h"

#include <grpc/grpc.h>
#include <grpc/grpc_security.h>
#include <grpc/slice.h>
#include <grpc/support/log.h>

#include "src/core/lib/config/core_configuration.h"
#include "src/core/lib/experiments/config.h"
#include "src/core/lib/gprpp/env.h"
#include "src/core/lib/iomgr/exec_ctx.h"
#include "test/core/end2end/fuzzers/api_fuzzer.pb.h"
#include "test/core/end2end/fuzzers/fuzzer_input.pb.h"
#include "test/core/end2end/fuzzers/fuzzing_common.h"
#include "test/core/end2end/fuzzers/network_input.h"
#include "test/core/util/fuzz_config_vars.h"

bool squelch = true;
bool leak_check = true;

static void dont_log(gpr_log_func_args* /*args*/) {}

namespace grpc_core {
namespace testing {

class ServerFuzzer final : public BasicFuzzer {
 public:
  explicit ServerFuzzer(
      const fuzzer_input::Msg& msg,
      absl::FunctionRef<void(grpc_server*, int, const ChannelArgs&)>
          server_setup)
      : BasicFuzzer(msg.event_engine_actions()) {
    ExecCtx exec_ctx;
    grpc_server_register_completion_queue(server_, cq(), nullptr);
    // TODO(ctiller): add more registered methods (one for POST, one for PUT)
    grpc_server_register_method(server_, "/reg", nullptr, {}, 0);
    server_setup(
        server_, 1234,
        CoreConfiguration::Get()
            .channel_args_preconditioning()
            .PreconditionChannelArgs(
                CreateChannelArgsFromFuzzingConfiguration(
                    msg.channel_args(), FuzzingEnvironment{resource_quota()})
                    .ToC()
                    .get()));
    grpc_server_start(server_);
    for (const auto& input : msg.network_input()) {
      UpdateMinimumRunTime(ScheduleConnection(
          input, engine(), FuzzingEnvironment{resource_quota()}, 1234));
    }
  }

  ~ServerFuzzer() { GPR_ASSERT(server_ == nullptr); }

 private:
  Result CreateChannel(
      const api_fuzzer::CreateChannel& /* create_channel */) override {
    return Result::kFailed;
  }
  Result CreateServer(
      const api_fuzzer::CreateServer& /* create_server */) override {
    return Result::kFailed;
  }
  void DestroyServer() override {
    grpc_server_destroy(server_);
    server_ = nullptr;
  }
  void DestroyChannel() override {}

  grpc_server* server() override { return server_; }
  grpc_channel* channel() override { return nullptr; }

  grpc_server* server_ = grpc_server_create(nullptr, nullptr);
};

}  // namespace testing

void RunServerFuzzer(
    const fuzzer_input::Msg& msg,
    absl::FunctionRef<void(grpc_server*, int, const ChannelArgs&)>
        server_setup) {
  if (squelch && !GetEnv("GRPC_TRACE_FUZZER").has_value()) {
    gpr_set_log_function(dont_log);
  }
  static const int once = []() {
    ForceEnableExperiment("event_engine_client", true);
    ForceEnableExperiment("event_engine_listener", true);
    return 42;
  }();
  GPR_ASSERT(once == 42);  // avoid unused variable warning
  ApplyFuzzConfigVars(msg.config_vars());
  TestOnlyReloadExperimentsFromConfigVariables();
  testing::ServerFuzzer(msg, server_setup).Run(msg.api_actions());
}

}  // namespace grpc_core