#include "workspace/Timestep.h"

#include <algorithm>

#include <QFile>
#include <QTextStream>

#include "workspace/WorkSpace.h"

#include "common/RecourceHelper.h"
#include "common/SpdLogger.h"

Timestep::Timestep(const std::vector<double>& steps, const QString& path, WorkSpace* parent /*= nullptr*/) noexcept
    : QObject((QObject*)parent)
    , steps_(steps)
    , path_(path)
    , workSpace_(parent) {
    maxTime_ = *steps_.rbegin();
    // 初始化为 1.0x，如果列表中没有 1.0，则取最接近中间的默认索引
    auto it = std::find(speedLevels_.begin(), speedLevels_.end(), 1.0);
    speedIndex_ = it != speedLevels_.end() ? int(std::distance(speedLevels_.begin(), it)) : speedIndex_;
    currentStep_ = speedLevels_[speedIndex_];
}

Timestep* Timestep::Load(const QString& path, WorkSpace* workSpace) {
    const QString filePath = QString("%1/%2").arg(workSpace->GetDir()).arg(path);
    LOG_INFO("Load timestep: {}", filePath.toStdString());

    QFile file(filePath);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        LOG_WARN("Cannot open file for reading: {}", file.errorString().toLocal8Bit().constData());
        return nullptr;
    }

    QTextStream in(&file);
    std::vector<double> numbers;

    while (!in.atEnd()) {
        QString line = in.readLine();
        bool ok;
        double value = line.toDouble(&ok);
        if (ok) {
            numbers.push_back(value); 
        } else {
            LOG_WARN("Cannot open file for reading: {}", line.toStdString());
        }
    }

    file.close();

    Timestep* timestep = new Timestep(numbers, path, workSpace);
    return timestep;
}

void Timestep::GetRange(double& minTime, double& maxTime, double& step) {
    minTime = *steps_.begin();
    maxTime = maxTime_;
    step = currentStep_;
}

void Timestep::Update(double dt) {
    if (playStatus_ != PlayStatus::PS_Started) {
        return;
    }

    if (nullptr == workSpace_) {
        LOG_WARN("workSpace_ is nullptr");
        return;
    }

    double deltaTime = dt * currentStep_;
    current_ += deltaTime;
    workSpace_->OnFrame(deltaTime);

    if (current_ >= maxTime_ && playStatus_ != PlayStatus::PS_Stoped) {
        current_ = maxTime_;
        Stop();
    }
    emit TimeChanged(current_);
}

bool Timestep::IsPause() {
    return playStatus_ == PlayStatus::PS_Suspended && playStatus_ != PlayStatus::PS_Started;
}

bool Timestep::IsStoped() {
    return playStatus_ == PlayStatus::PS_Stoped;
}

void Timestep::Start() {
    LOG_INFO("enter");
    playStatus_ = PlayStatus::PS_Started;
    current_ = 0.0;

    if (nullptr == workSpace_) {
        LOG_WARN("workSpace_ is nullptr");
        return;
    }
    workSpace_->Begin();
    // 重置速度为 1x 并通知 UI
    auto it = std::find(speedLevels_.begin(), speedLevels_.end(), 1.0);
    speedIndex_ = it != speedLevels_.end() ? int(std::distance(speedLevels_.begin(), it)) : speedIndex_;
    currentStep_ = speedLevels_[speedIndex_];
    emit StepChanged(currentStep_);
    emit StatusChanged((int)playStatus_);
}

void Timestep::Resume() {
    LOG_INFO("enter");
    if (PlayStatus::PS_Suspended != playStatus_) {
        LOG_WARN("play status is not suspended");
        return;
    }
    playStatus_ = PlayStatus::PS_Started;
    emit StatusChanged((int)playStatus_);
}

void Timestep::Pause() {
    LOG_INFO("enter");
    if (PlayStatus::PS_Started == playStatus_) {
        playStatus_ = PlayStatus::PS_Suspended;
    } else if (PlayStatus::PS_Suspended == playStatus_) {
        playStatus_ = PlayStatus::PS_Started;
    }
    emit StatusChanged((int)playStatus_);
}

void Timestep::Stop() {
    LOG_INFO("enter");
    current_ = maxTime_;
    playStatus_ = PlayStatus::PS_Stoped;
    if (nullptr == workSpace_) {
        LOG_WARN("workSpace_ is nullptr");
        return;
    }
    workSpace_->End();
    // 停止时也恢复为 1x，避免停后再次播放仍是异常倍率
    auto it = std::find(speedLevels_.begin(), speedLevels_.end(), 1.0);
    speedIndex_ = it != speedLevels_.end() ? int(std::distance(speedLevels_.begin(), it)) : speedIndex_;
    currentStep_ = speedLevels_[speedIndex_];
    emit StepChanged(currentStep_);
    emit StatusChanged((int)playStatus_);
}

void Timestep::Up() {
    // 提升到下一个倍率（封顶）
    if (speedIndex_ < int(speedLevels_.size()) - 1) {
        ++speedIndex_;
    }
    currentStep_ = speedLevels_[speedIndex_];
    emit StepChanged(currentStep_);
}

void Timestep::Down() {
    // 降到上一个倍率（保底）
    if (speedIndex_ > 0) {
        --speedIndex_;
    }
    currentStep_ = speedLevels_[speedIndex_];
    emit StepChanged(currentStep_);
}