// 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_CONFIG_HPP
#define INCLUDED_SRC_BUILDTOOL_EXECUTION_API_REMOTE_CONFIG_HPP

#include <cstdint>
#include <exception>
#include <filesystem>
#include <map>
#include <optional>
#include <stdexcept>
#include <string>
#include <utility>
#include <vector>

#include "nlohmann/json.hpp"
#include "src/buildtool/common/remote/remote_common.hpp"

class RemoteExecutionConfig {
  public:
    // Obtain global instance
    [[nodiscard]] static auto Instance() noexcept -> RemoteExecutionConfig& {
        static RemoteExecutionConfig config;
        return config;
    }

    // Set remote execution and cache address, unsets if parsing `address` fails
    [[nodiscard]] static auto SetRemoteAddress(
        std::string const& address) noexcept -> bool {
        auto& inst = Instance();
        return static_cast<bool>(inst.remote_address_ = inst.cache_address_ =
                                     ParseAddress(address));
    }

    // Set remote-execution dispatch property list
    [[nodiscard]] static auto SetRemoteExecutionDispatch(
        const std::filesystem::path& filename) noexcept -> bool;

    // Set specific cache address, unsets if parsing `address` fails
    [[nodiscard]] static auto SetCacheAddress(
        std::string const& address) noexcept -> bool {
        return static_cast<bool>(Instance().cache_address_ =
                                     ParseAddress(address));
    }

    // Add platform property from string of form "key:val"
    [[nodiscard]] static auto AddPlatformProperty(
        std::string const& property) noexcept -> bool {
        if (auto pair = ParseProperty(property)) {
            Instance().platform_properties_[std::move(pair->first)] =
                std::move(pair->second);
            return true;
        }
        return false;
    }

    // Remote execution address, if set
    [[nodiscard]] static auto RemoteAddress() noexcept
        -> std::optional<ServerAddress> {
        return Instance().remote_address_;
    }

    // Cache address, if set
    [[nodiscard]] static auto CacheAddress() noexcept
        -> std::optional<ServerAddress> {
        return Instance().cache_address_;
    }

    // Instance dispatch list
    [[nodiscard]] static auto DispatchList() noexcept
        -> std::vector<DispatchEndpoint> {
        return Instance().dispatch_;
    }

    [[nodiscard]] static auto PlatformProperties() noexcept
        -> ExecutionProperties {
        return Instance().platform_properties_;
    }

    /// \brief String representation of the used execution backend.
    [[nodiscard]] static auto DescribeBackend() noexcept -> std::string {
        auto address = RemoteAddress();
        auto properties = PlatformProperties();
        auto dispatch = DispatchList();
        auto description = nlohmann::json{
            {"remote_address", address ? address->ToJson() : nlohmann::json{}},
            {"platform_properties", properties}};
        if (!dispatch.empty()) {
            try {
                // only add the dispatch list, if not empty, so that keys remain
                // not only more readable, but also backwards compatible with
                // earlier versions.
                auto dispatch_list = nlohmann::json::array();
                for (auto const& [props, endpoint] : dispatch) {
                    auto entry = nlohmann::json::array();
                    entry.push_back(nlohmann::json(props));
                    entry.push_back(endpoint.ToJson());
                    dispatch_list.push_back(entry);
                }
                description["endpoint dispatch list"] = dispatch_list;
            } catch (std::exception const& e) {
                Logger::Log(LogLevel::Error,
                            "Failed to serialize endpoint dispatch list: {}",
                            e.what());
            }
        }
        try {
            // json::dump with json::error_handler_t::replace will not throw an
            // exception if invalid UTF-8 sequences are detected in the input.
            // Instead, it will replace them with the UTF-8 replacement
            // character, but still it needs to be inside a try-catch clause to
            // ensure the noexcept modifier of the enclosing function.
            return description.dump(
                2, ' ', false, nlohmann::json::error_handler_t::replace);
        } catch (...) {
            return "";
        }
    }

  private:
    // Server address of remote execution.
    std::optional<ServerAddress> remote_address_{};

    // Server dispatch data
    std::vector<DispatchEndpoint> dispatch_{};

    // Server address of cache endpoint for rebuild.
    std::optional<ServerAddress> cache_address_{};

    // Platform properties for execution.
    ExecutionProperties platform_properties_{};
};

#endif  // INCLUDED_SRC_BUILDTOOL_EXECUTION_API_REMOTE_CONFIG_HPP