#include "tristate_obj.h"
#include "core/global_defs.h"
#include "utility/coro_signal2.hpp"
#include "utility/debug_utility.hpp"
#include "utility/name_translator.hpp"

#include <spdlog/spdlog.h>

#include <boost/asio/experimental/awaitable_operators.hpp>

#include "utility/assert_utility.h"

namespace sophiar {

    name_translator<uint8_t> *state_name_translator;

    using boost::asio::awaitable;

    using namespace boost::asio::experimental::awaitable_operators;

    struct tristate_obj::impl {

        tristate_obj *q_this = nullptr;

        state_type state = state_type::INITIAL;
        coro_signal2 init_cancel_signal;
        coro_signal2 start_cancel_signal;
        coro_signal2 init_finished_signal;
        coro_signal2 start_finished_signal;
        coro_signal2 stop_finished_signal;
        coro_signal2 reset_finished_signal;

        static void initialize_translator() {
            RUN_ONCE
            state_name_translator = new name_translator<uint8_t>;
            state_name_translator->register_item("Initial", (uint8_t) tristate_obj::state_type::INITIAL);
            state_name_translator->register_item("Initializing", (uint8_t) tristate_obj::state_type::INITIALIZING);
            state_name_translator->register_item("Resetting", (uint8_t) tristate_obj::state_type::RESETTING);
            state_name_translator->register_item("Pending", (uint8_t) tristate_obj::state_type::PENDING);
            state_name_translator->register_item("Starting", (uint8_t) tristate_obj::state_type::STARTING);
            state_name_translator->register_item("Stopping", (uint8_t) tristate_obj::state_type::STOPPING);
            state_name_translator->register_item("Running", (uint8_t) tristate_obj::state_type::RUNNING);
            state_name_translator->register_item("Unknown", (uint8_t) tristate_obj::state_type::UNKNOWN);
        }

        void log_state_change(state_type old_state, state_type new_state) const {
            SPDLOG_INFO("Object [name = {}], State: {} => {}.",
                         QUERY_OBJECT_NAME(q_this),
                         state_name_translator->translate((uint8_t) old_state),
                         state_name_translator->translate((uint8_t) new_state));
        }

        awaitable<bool> init(const nlohmann::json &config) {
            if (state == state_type::INITIALIZING) {
                auto init_finished_watcher = init_finished_signal.new_watcher();
                auto reset_finished_watcher = reset_finished_signal.new_watcher();
                auto result = co_await (init_finished_watcher.coro_wait() ||
                                        reset_finished_watcher.coro_wait());
                co_return result.index() == 0;
            }
            if (state == state_type::RESETTING) {
                auto reset_finished_watcher = reset_finished_signal.new_watcher();
                co_await reset_finished_watcher.coro_wait();
                co_return false;
            }
            if (state != state_type::INITIAL) co_return true; // >= PENDING
            state = state_type::INITIALIZING;
            log_state_change(state_type::INITIAL, state_type::INITIALIZING);
            SPDLOG_TRACE("Initializing object [name = {}] with config {}.",
                         QUERY_OBJECT_NAME(q_this), config.dump());
            auto init_cancel_watcher = init_cancel_signal.new_watcher();
            auto result = co_await (q_this->on_init(config) || init_cancel_watcher.coro_wait());
            if (result.index() == 0 && std::get<0>(result) == true) { // succeeded
                state = state_type::PENDING;
                log_state_change(state_type::INITIALIZING, state_type::PENDING);
                SPDLOG_DEBUG("Initialize object [name = {}] succeeded.", QUERY_OBJECT_NAME(q_this));
                init_finished_signal.try_notify_all();
                co_return true;
            } else { // failed
                co_await q_this->on_reset();
                state = state_type::INITIAL;
                log_state_change(state_type::INITIALIZING, state_type::INITIAL);
                SPDLOG_WARN("Initialize object [name = {}] failed.", QUERY_OBJECT_NAME(q_this));
                reset_finished_signal.try_notify_all();
                co_return false;
            }
        }

        awaitable<bool> start(const nlohmann::json &config) {
            if (state == state_type::STARTING) {
                auto start_finished_watcher = start_finished_signal.new_watcher();
                auto stop_finished_watcher = stop_finished_signal.new_watcher();
                auto result = co_await (start_finished_watcher.coro_wait() ||
                                        stop_finished_watcher.coro_wait());
                co_return result.index() == 0;
            }
            if (state == state_type::STOPPING) {
                auto stop_finished_watcher = stop_finished_signal.new_watcher();
                co_await stop_finished_watcher.coro_wait();
                co_return false;
            }
            if (state == state_type::RUNNING) co_return true;
            if (state != state_type::PENDING) co_return false; // INITIAL, INITIALIZING, RESETTING
            state = state_type::STARTING;
            log_state_change(state_type::PENDING, state_type::STARTING);
            SPDLOG_TRACE("Starting object [name = {}] with config {}.",
                         QUERY_OBJECT_NAME(q_this), config.dump());
            auto start_cancel_watcher = start_cancel_signal.new_watcher();
            auto result = co_await (q_this->on_start(config) || start_cancel_watcher.coro_wait());
            if (result.index() == 0 && std::get<0>(result) == true) { // succeeded
                state = state_type::RUNNING;
                log_state_change(state_type::STARTING, state_type::RUNNING);
                SPDLOG_DEBUG("Start object [name = {}] succeeded.", QUERY_OBJECT_NAME(q_this));
                start_finished_signal.try_notify_all();
                co_return true;
            } else { // failed
                co_await q_this->on_stop();
                state = state_type::PENDING;
                log_state_change(state_type::STARTING, state_type::PENDING);
                SPDLOG_WARN("Start object [name = {}] failed.", QUERY_OBJECT_NAME(q_this));
                stop_finished_signal.try_notify_all();
                co_return false;
            }
        }

        awaitable<void> stop() {
            if (state == state_type::RUNNING) {
                state = state_type::STOPPING;
                log_state_change(state_type::RUNNING, state_type::STOPPING);
                co_await q_this->on_stop();
                state = state_type::PENDING;
                log_state_change(state_type::STOPPING, state_type::PENDING);
                SPDLOG_DEBUG("Stopped object [name = {}].", QUERY_OBJECT_NAME(q_this));
                stop_finished_signal.try_notify_all();
                global_sophiar_manager->notify_object_stop(q_this);
            } else if (state == state_type::STOPPING) {
                auto stop_finished_watcher = stop_finished_signal.new_watcher();
                co_await stop_finished_watcher.coro_wait();
            } else if (state == state_type::STARTING) {
                start_cancel_signal.try_notify_all();
                auto stop_finished_watcher = stop_finished_signal.new_watcher();
                co_await stop_finished_watcher.coro_wait();
            }
            co_return;
        }

        awaitable<void> reset() {
            // force reset
            if (state == state_type::RUNNING ||
                state == state_type::STOPPING ||
                state == state_type::STARTING) {
                co_await stop();
                assert(state == state_type::PENDING);
            }

            if (state == state_type::PENDING) {
                state = state_type::RESETTING;
                log_state_change(state_type::PENDING, state_type::RESETTING);
                co_await q_this->on_reset();
                state = state_type::INITIAL;
                log_state_change(state_type::RESETTING, state_type::INITIAL);
                SPDLOG_DEBUG("Reset object [name = {}].", QUERY_OBJECT_NAME(q_this));
                reset_finished_signal.try_notify_all();
            } else if (state == state_type::RESETTING) {
                auto reset_finished_watcher = reset_finished_signal.new_watcher();
                co_await reset_finished_watcher.coro_wait();
            } else if (state == state_type::INITIALIZING) {
                init_cancel_signal.try_notify_all();
                auto reset_finished_watcher = reset_finished_signal.new_watcher();
                co_await reset_finished_watcher.coro_wait();
            }
            co_return;
        }

        impl() {
            initialize_translator();
        }

    };

    tristate_obj::state_type tristate_obj::get_state() const {
        return pimpl->state;
    }

    awaitable<bool> tristate_obj::init(const nlohmann::json &config) noexcept {
        return pimpl->init(config);
    }

    awaitable<bool> tristate_obj::start(const nlohmann::json &config) noexcept {
        return pimpl->start(config);
    }

    awaitable<void> tristate_obj::stop() noexcept {
        return pimpl->stop();
    }

    awaitable<void> tristate_obj::reset() noexcept {
        return pimpl->reset();
    }

    tristate_obj::tristate_obj()
            : pimpl(std::make_unique<impl>()) {
        pimpl->q_this = this;
    }

    tristate_obj::~tristate_obj() = default;

}