#include "InsightWorker.hpp"

#include <QObject>
#include <QTimer>

#include "src/TargetController/TargetControllerState.hpp"

#include "src/Logger/Logger.hpp"

namespace Bloom
{
    using namespace Bloom::Exceptions;

    using Bloom::Targets::TargetState;

    void InsightWorker::queueTask(InsightWorkerTask* task) {
        auto taskQueueLock = this->queuedTasks.acquireLock();
        task->moveToThread(this->thread());
        task->setParent(this);
        this->queuedTasks.getValue().push(task);
        emit this->taskQueued();
    }

    void InsightWorker::startup() {
        Logger::debug("Starting InsightWorker thread");
        EventManager::registerListener(this->eventListener);

        this->eventListener->registerCallbackForEventType<Events::TargetControllerStateChanged>(
            std::bind(&InsightWorker::onTargetControllerStateChangedEvent, this, std::placeholders::_1)
        );

        this->eventListener->registerCallbackForEventType<Events::TargetExecutionStopped>(
            std::bind(&InsightWorker::onTargetStoppedEvent, this, std::placeholders::_1)
        );

        this->eventListener->registerCallbackForEventType<Events::TargetExecutionResumed>(
            std::bind(&InsightWorker::onTargetResumedEvent, this, std::placeholders::_1)
        );

        this->eventListener->registerCallbackForEventType<Events::TargetReset>(
            std::bind(&InsightWorker::onTargetResetEvent, this, std::placeholders::_1)
        );

        this->eventListener->registerCallbackForEventType<Events::RegistersWrittenToTarget>(
            std::bind(&InsightWorker::onTargetRegistersWrittenEvent, this, std::placeholders::_1)
        );

        this->eventDispatchTimer = new QTimer(this);
        QObject::connect(this->eventDispatchTimer, &QTimer::timeout, this, &InsightWorker::dispatchEvents);
        this->eventDispatchTimer->start(5);

        QObject::connect(this, &InsightWorker::taskQueued, this, &InsightWorker::executeTasks);

        EventManager::triggerEvent(
            std::make_shared<Events::InsightThreadStateChanged>(ThreadState::READY)
        );

        emit this->ready();
    }

    std::optional<InsightWorkerTask*> InsightWorker::getQueuedTask() {
        auto task = std::optional<InsightWorkerTask*>();

        auto& queuedTasks = this->queuedTasks.getValue();
        auto taskQueueLock = this->queuedTasks.acquireLock();

        if (!queuedTasks.empty()) {
            task = queuedTasks.front();
            queuedTasks.pop();
        }

        return task;
    }

    void InsightWorker::onTargetStoppedEvent(const Events::TargetExecutionStopped& event) {
        if (this->lastTargetState == TargetState::STOPPED) {
            return;
        }

        /*
         * When we report a target halt to Insight, Insight will immediately seek more data from the target (such as
         * GPIO pin states). This can be problematic for cases where the target had halted due to a conditional
         * breakpoint.
         *
         * For conditional breakpoints, a software breakpoint is employed to halt target execution and give the debug
         * client an opportunity to check the condition. In cases where the condition is not met, the client will
         * immediately request for execution to be resumed. It's important that Insight does not get in the way of this
         * process, as it could end up slowing things down significantly.
         *
         * For the above reason, we don't want to report any target halts to Insight, unless we can be sure that the
         * client isn't going to immediately resume execution upon checking the condition.
         *
         * We do this by providing a time window for the TargetExecutionResumed event. If the event is triggered within
         * that time window, we won't report the target halt to Insight, thus preventing Insight from needlessly
         * seeking data from the target and slowing things down.
         *
         * This isn't the best approach, TBH, as it introduces a delay to Insight's response to the target halting. The
         * problem is, we cannot differentiate a conditional breakpoint with a software breakpoint, so this seems to be
         * the only way. It would be nice if the debug client gave us some form of indication of whether the breakpoint
         * is a conditional one.
         */
        auto resumedEvent = this->eventListener->waitForEvent<Events::TargetExecutionResumed>(
            std::chrono::milliseconds(650)
        );

        if (!resumedEvent.has_value()) {
            this->lastTargetState = TargetState::STOPPED;
            emit this->targetStateUpdated(TargetState::STOPPED);
            emit this->targetProgramCounterUpdated(event.programCounter);
        }
    }

    void InsightWorker::onTargetResumedEvent(const Events::TargetExecutionResumed& event) {
        this->lastTargetState = TargetState::RUNNING;
        emit this->targetStateUpdated(TargetState::RUNNING);
    }

    void InsightWorker::onTargetResetEvent(const Events::TargetReset& event) {
        // TODO: Pull PC from target. This will be done as part of the TC refactor (https://github.com/navnavnav/Bloom/issues/25)
        this->lastTargetState = TargetState::STOPPED;
        emit this->targetStateUpdated(TargetState::STOPPED);
        emit this->targetProgramCounterUpdated(0);
    }

    void InsightWorker::onTargetRegistersWrittenEvent(const Events::RegistersWrittenToTarget& event) {
        emit this->targetRegistersWritten(event.registers, event.createdTimestamp);
    }

    void InsightWorker::onTargetControllerStateChangedEvent(const Events::TargetControllerStateChanged& event) {
        using TargetController::TargetControllerState;

        if (event.state == TargetControllerState::SUSPENDED) {
            emit this->targetControllerSuspended();

        } else if (event.state == TargetControllerState::ACTIVE) {
            try {
                emit this->targetControllerResumed(this->targetControllerConsole.getTargetDescriptor());

            } catch (const Exception& exception) {
                Logger::error("Insight resume failed - " + exception.getMessage());
            }
        }
    }

    void InsightWorker::executeTasks() {
        auto task = std::optional<InsightWorkerTask*>();

        while ((task = this->getQueuedTask()).has_value()) {
            task.value()->execute(this->targetControllerConsole);
        }
    }
}