// Copyright 2022 Huawei Cloud Computing Technology Co., Ltd.
//
// 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.

#ifndef INCLUDED_SRC_BUILDTOOL_EXECUTION_API_REMOTE_BAZEL_BAZEL_EXECUTION_CLIENT_HPP
#define INCLUDED_SRC_BUILDTOOL_EXECUTION_API_REMOTE_BAZEL_BAZEL_EXECUTION_CLIENT_HPP

#include <cstdint>
#include <functional>
#include <memory>
#include <optional>
#include <string>
#include <unordered_map>

#include <grpcpp/grpcpp.h>

#include "build/bazel/remote/execution/v2/remote_execution.grpc.pb.h"
#include "google/longrunning/operations.pb.h"
#include "gsl/gsl"
#include "src/buildtool/auth/authentication.hpp"
#include "src/buildtool/common/bazel_types.hpp"
#include "src/buildtool/common/remote/port.hpp"
#include "src/buildtool/common/remote/retry_config.hpp"
#include "src/buildtool/execution_api/bazel_msg/execution_config.hpp"
#include "src/buildtool/logging/logger.hpp"

/// Implements client side for service defined here:
/// https://github.com/bazelbuild/remote-apis/blob/e1fe21be4c9ae76269a5a63215bb3c72ed9ab3f0/build/bazel/remote/execution/v2/remote_execution.proto#L44
class BazelExecutionClient {
  public:
    struct ExecutionOutput {
        bazel_re::ActionResult action_result;
        bool cached_result{};
        double duration{};
        grpc::Status status{};
        std::unordered_map<std::string, bazel_re::Digest> server_logs{};
        std::string message{};
    };

    struct ExecutionResponse {
        enum class State : std::uint8_t {
            Failed,
            Ongoing,
            Finished,
            Unknown,
            Retry
        };

        std::string execution_handle;
        State state{State::Unknown};
        std::optional<ExecutionOutput> output{std::nullopt};

        static auto MakeEmptyFailed() -> ExecutionResponse {
            return ExecutionResponse{.execution_handle = {},
                                     .state = ExecutionResponse::State::Failed,
                                     .output = std::nullopt};
        }
    };

    explicit BazelExecutionClient(
        std::string const& server,
        Port port,
        gsl::not_null<Auth const*> const& auth,
        gsl::not_null<RetryConfig const*> const& retry_config) noexcept;

    [[nodiscard]] auto Execute(std::string const& instance_name,
                               bazel_re::Digest const& action_digest,
                               ExecutionConfiguration const& config,
                               bool wait) -> ExecutionResponse;

    [[nodiscard]] auto WaitExecution(std::string const& execution_handle)
        -> ExecutionResponse;

  private:
    RetryConfig const& retry_config_;
    std::unique_ptr<bazel_re::Execution::Stub> stub_;
    Logger logger_{"RemoteExecutionClient"};
    struct RetryReadOperation {
        std::optional<google::longrunning::Operation> operation{std::nullopt};
        bool exit_retry_loop{false};
        std::optional<std::string> error_msg{std::nullopt};
    };

    struct RetryExtractContents {
        ExecutionResponse response;
        std::optional<std::string> error_msg{std::nullopt};
    };

    [[nodiscard]] auto ReadExecution(
        grpc::ClientReader<google::longrunning::Operation>* reader,
        bool wait) -> RetryReadOperation;

    [[nodiscard]] auto ExtractContents(
        std::optional<google::longrunning::Operation>&& operation)
        -> RetryExtractContents;
};

#endif  // INCLUDED_SRC_BUILDTOOL_EXECUTION_API_REMOTE_BAZEL_BAZEL_EXECUTION_CLIENT_HPP