// Copyright 2024 The Pigweed 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
//
//     https://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.

// Client binary for the cross-language integration test.
//
// Usage:
//  bazel-bin/pw_transfer/integration_test_client 3300 <<< "resource_id: 12
//  file: '/tmp/myfile.txt'"
//
// WORK IN PROGRESS, SEE b/228516801
#include "pw_transfer/client.h"

#include <sys/socket.h>

#include <cstddef>
#include <cstdio>

#include "google/protobuf/text_format.h"
#include "pw_assert/check.h"
#include "pw_log/log.h"
#include "pw_rpc/channel.h"
#include "pw_rpc/integration_testing.h"
#include "pw_status/status.h"
#include "pw_status/try.h"
#include "pw_stream/std_file_stream.h"
#include "pw_sync/binary_semaphore.h"
#include "pw_thread/thread.h"
#include "pw_thread_stl/options.h"
#include "pw_transfer/integration_test/config.pb.h"
#include "pw_transfer/transfer_thread.h"

namespace pw::transfer::integration_test {
namespace {

// This is the maximum size of the socket send buffers. Ideally, this is set
// to the lowest allowed value to minimize buffering between the proxy and
// clients so rate limiting causes the client to block and wait for the
// integration test proxy to drain rather than allowing OS buffers to backlog
// large quantities of data.
//
// Note that the OS may chose to not strictly follow this requested buffer size.
// Still, setting this value to be as small as possible does reduce bufer sizes
// significantly enough to better reflect typical inter-device communication.
//
// For this to be effective, servers should also configure their sockets to a
// smaller receive buffer size.
constexpr int kMaxSocketSendBufferSize = 1;

constexpr size_t kDefaultMaxWindowSizeBytes = 16384;

thread::Options& TransferThreadOptions() {
  static thread::stl::Options options;
  return options;
}

// Transfer status, valid only after semaphore is acquired.
//
// We need to bundle the status and semaphore together because a pw_function
// callback can at most capture the reference to one variable (and we need to
// both set the status and release the semaphore).
struct TransferResult {
  Status status = Status::Unknown();
  sync::BinarySemaphore completed;
};

// Create a pw_transfer client and perform the transfer actions.
pw::Status PerformTransferActions(const pw::transfer::ClientConfig& config) {
  constexpr size_t kMaxPayloadSize = rpc::MaxSafePayloadSize();
  std::byte chunk_buffer[kMaxPayloadSize];
  std::byte encode_buffer[kMaxPayloadSize];
  transfer::Thread<2, 2> transfer_thread(chunk_buffer, encode_buffer);
  thread::Thread system_thread(TransferThreadOptions(), transfer_thread);

  // As much as we don't want to dynamically allocate an array,
  // variable length arrays (VLA) are nonstandard, and a std::vector could cause
  // references to go stale if the vector's underlying buffer is resized. This
  // array of TransferResults needs to outlive the loop that performs the
  // actual transfer actions due to how some references to TransferResult
  // may persist beyond the lifetime of a transfer.
  const int num_actions = config.transfer_actions().size();
  auto transfer_results = std::make_unique<TransferResult[]>(num_actions);

  pw::transfer::Client client(rpc::integration_test::client(),
                              rpc::integration_test::kChannelId,
                              transfer_thread,
                              kDefaultMaxWindowSizeBytes);

  client.set_max_retries(config.max_retries());
  client.set_max_lifetime_retries(config.max_lifetime_retries());

  Status status = pw::OkStatus();
  for (int i = 0; i < num_actions; i++) {
    const pw::transfer::TransferAction& action = config.transfer_actions()[i];
    TransferResult& result = transfer_results[i];
    // If no protocol version is specified, default to the latest version.
    pw::transfer::ProtocolVersion protocol_version =
        action.protocol_version() ==
                pw::transfer::TransferAction::ProtocolVersion::
                    TransferAction_ProtocolVersion_UNKNOWN_VERSION
            ? pw::transfer::ProtocolVersion::kLatest
            : static_cast<pw::transfer::ProtocolVersion>(
                  action.protocol_version());
    if (action.transfer_type() ==
        pw::transfer::TransferAction::TransferType::
            TransferAction_TransferType_WRITE_TO_SERVER) {
      pw::stream::StdFileReader input(action.file_path().c_str());
      pw::Result<pw::transfer::Client::Handle> handle = client.Write(
          action.resource_id(),
          input,
          [&result](Status status) {
            result.status = status;
            result.completed.release();
          },
          protocol_version,
          pw::transfer::cfg::kDefaultClientTimeout,
          pw::transfer::cfg::kDefaultInitialChunkTimeout,
          action.initial_offset());
      if (handle.ok()) {
        // Wait for the transfer to complete. We need to do this here so that
        // the StdFileReader doesn't go out of scope.
        result.completed.acquire();
      } else {
        result.status = handle.status();
      }

      input.Close();

    } else if (action.transfer_type() ==
               pw::transfer::TransferAction::TransferType::
                   TransferAction_TransferType_READ_FROM_SERVER) {
      pw::stream::StdFileWriter output(action.file_path().c_str());
      pw::Result<pw::transfer::Client::Handle> handle = client.Read(
          action.resource_id(),
          output,
          [&result](Status status) {
            result.status = status;
            result.completed.release();
          },
          protocol_version,
          pw::transfer::cfg::kDefaultClientTimeout,
          pw::transfer::cfg::kDefaultInitialChunkTimeout,
          action.initial_offset());
      if (handle.ok()) {
        // Wait for the transfer to complete.
        result.completed.acquire();
      } else {
        result.status = handle.status();
      }

      output.Close();
    } else {
      PW_LOG_ERROR("Unrecognized transfer action type %d",
                   action.transfer_type());
      status = pw::Status::InvalidArgument();
      break;
    }

    if (int(result.status.code()) != int(action.expected_status())) {
      PW_LOG_ERROR("Failed to perform action:\n%s",
                   action.DebugString().c_str());
      status = result.status.ok() ? Status::Unknown() : result.status;
      break;
    }
  }

  transfer_thread.Terminate();

  system_thread.join();

  // The RPC thread must join before destroying transfer objects as the transfer
  // service may still reference the transfer thread or transfer client objects.
  pw::rpc::integration_test::TerminateClient();
  return status;
}

}  // namespace
}  // namespace pw::transfer::integration_test

int main(int argc, char* argv[]) {
  if (argc < 2) {
    PW_LOG_INFO("Usage: %s PORT <<< config textproto", argv[0]);
    return 1;
  }

  const int port = std::atoi(argv[1]);

  std::string config_string;
  std::string line;
  while (std::getline(std::cin, line)) {
    config_string = config_string + line + '\n';
  }
  pw::transfer::ClientConfig config;

  bool ok =
      google::protobuf::TextFormat::ParseFromString(config_string, &config);
  if (!ok) {
    PW_LOG_INFO("Failed to parse config: %s", config_string.c_str());
    PW_LOG_INFO("Usage: %s PORT <<< config textproto", argv[0]);
    return 1;
  } else {
    PW_LOG_INFO("Client loaded config:\n%s", config.DebugString().c_str());
  }

  if (!pw::rpc::integration_test::InitializeClient(port).ok()) {
    return 1;
  }

  int retval = pw::rpc::integration_test::SetClientSockOpt(
      SOL_SOCKET,
      SO_SNDBUF,
      &pw::transfer::integration_test::kMaxSocketSendBufferSize,
      sizeof(pw::transfer::integration_test::kMaxSocketSendBufferSize));
  PW_CHECK_INT_EQ(retval,
                  0,
                  "Failed to configure socket send buffer size with errno=%d",
                  errno);

  if (!pw::transfer::integration_test::PerformTransferActions(config).ok()) {
    PW_LOG_INFO("Failed to transfer!");
    return 1;
  }
  return 0;
}