#include "Renderer.h"
#include "AnimationStrategy.cpp"
#include "AnimationStrategy.h"
#include "TransitionStrategy.cpp"
#include <android/log.h>
#include <algorithm>
#include <cmath>
#include <thread>
#include <chrono>

extern void callNextMediaCallback();

#define LOG_TAG "Renderer"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__)

// ====================================================================
// 생성자, 소멸자 및 설정(Setter) 함수들
// ====================================================================
Renderer::Renderer() {
    randomEngine_.seed(std::chrono::high_resolution_clock::now().time_since_epoch().count());
    setAnimationMode(static_cast<int>(AnimationMode::PAN));
    setTransitionMode(static_cast<int>(TransitionMode::FADE));
}
Renderer::~Renderer() { release(); }
void Renderer::release() { std::lock_guard<std::mutex> lock(renderMutex_); currentMedia_.release(); nextMedia_.release(); }
void Renderer::setNextMedia(int fd) { preloader_.startNextPreload(fd); }
void Renderer::setAnimationSpeed(float speed) { animationSpeed_ = speed > 0 ? speed : 1.0f; }
void Renderer::setFadeDuration(int durationMs) { fadeDurationMs_ = durationMs > 0 ? durationMs : 3000; }
void Renderer::setPageTurnDelay(int delayMs) { pageTurnDelayMs_ = delayMs > 0 ? delayMs : 5000; }

void Renderer::setAnimationMode(int mode) {
    configuredAnimationMode_ = (mode >= 0 && mode <= static_cast<int>(AnimationMode::PAGE_TURN)) ? static_cast<AnimationMode>(mode) : AnimationMode::PAN;
    determineActiveAnimationMode();
}
void Renderer::setTransitionMode(int mode) {
    configuredTransitionMode_ = (mode >= 0 && mode <= static_cast<int>(TransitionMode::MOSAIC)) ? static_cast<TransitionMode>(mode) : TransitionMode::FADE;
}

void Renderer::determineActiveAnimationMode() {
    AnimationMode modeToSetActive;
    if (configuredAnimationMode_ == AnimationMode::RANDOM) {
        static const std::vector<AnimationMode> availableModes = { AnimationMode::PAN, AnimationMode::ZOOM, AnimationMode::NONE, AnimationMode::PAN_ONE_WAY, AnimationMode::PAGE_TURN };
        std::uniform_int_distribution<size_t> dist(0, availableModes.size() - 1);
        modeToSetActive = availableModes[dist(randomEngine_)];
    } else {
        modeToSetActive = configuredAnimationMode_;
    }
    activeAnimationMode_ = modeToSetActive;
    switch (activeAnimationMode_) {
        case AnimationMode::PAN: animationStrategy_ = std::make_unique<PanAnimation>(animationSpeed_); break;
        case AnimationMode::PAN_ONE_WAY: animationStrategy_ = std::make_unique<PanOneWayAnimation>(animationSpeed_); break;
        case AnimationMode::ZOOM: animationStrategy_ = std::make_unique<ZoomAnimation>(animationSpeed_); break;
        case AnimationMode::PAGE_TURN: animationStrategy_ = std::make_unique<PageTurnAnimation>(animationSpeed_, pageTurnDelayMs_); break;
        case AnimationMode::NONE: default: animationStrategy_ = std::make_unique<NoneAnimation>(animationSpeed_); break;
    }
}

// ====================================================================
// 상태 머신(State Machine) 핸들러 함수들
// ====================================================================

void Renderer::handleAnimationState(ANativeWindow_Buffer& buffer, int surfaceWidth, int surfaceHeight) {
    if (!animationStrategy_) return;

    bool isCycleComplete = animationStrategy_->execute(this, buffer, currentMedia_, surfaceWidth, surfaceHeight);

    if (isCycleComplete && nextMedia_.isValid()) {
        lastAnimationState_ = animationStrategy_->getState();
        predictedNextAnimationMode_ = predictNextAnimationMode();
        currentState_ = RenderState::TRANSITIONING;
        transitionStartTime_ = std::chrono::steady_clock::now();

        TransitionMode transModeToUse = configuredTransitionMode_;
        if (transModeToUse == TransitionMode::RANDOM) {
            std::uniform_int_distribution<int> dist(0, 2);
            transModeToUse = static_cast<TransitionMode>(dist(randomEngine_));
        }
        if (transModeToUse == TransitionMode::SLIDE) {
            transitionStrategy_ = std::make_unique<SlideTransition>(fadeDurationMs_, surfaceWidth);
        } else if (transModeToUse == TransitionMode::MOSAIC) {
            transitionStrategy_ = std::make_unique<MosaicTransition>(fadeDurationMs_, 20, 32, randomEngine_);
        } else {
            transitionStrategy_ = std::make_unique<FadeTransition>(fadeDurationMs_);
        }
        if(transitionStrategy_) transitionStrategy_->reset();
    }
}
/**
 * @brief 다음에 실행될 애니메이션 모드를 미리 예측하여 반환합니다.
 */
Renderer::AnimationMode Renderer::predictNextAnimationMode() {
    if (configuredAnimationMode_ == AnimationMode::RANDOM) {
        static const std::vector<AnimationMode> availableModes = {
                AnimationMode::PAN, AnimationMode::ZOOM, AnimationMode::NONE,
                AnimationMode::PAN_ONE_WAY, AnimationMode::PAGE_TURN
        };
        std::uniform_int_distribution<size_t> dist(0, availableModes.size() - 1);
        return availableModes[dist(randomEngine_)];
    } else {
        return configuredAnimationMode_;
    }
}

/**
 * @brief 주어진 애니메이션 모드의 시작 상태(좌표, 스케일)를 계산하여 반환합니다.
 */
AnimationState Renderer::getStartStateForMode(AnimationMode mode, int surfaceWidth, int surfaceHeight) {
    AnimationState startState;
    if (mode == AnimationMode::PAN || mode == AnimationMode::PAN_ONE_WAY) {
        // Pan 계열은 가장자리(0,0)에서 시작
        startState.offsetX = 0.0f;
        startState.offsetY = 0.0f;

        // Pan 계열의 기본 스케일 계산
        float scale;
        if ((static_cast<float>(nextMedia_.getWidth()) / nextMedia_.getHeight()) > ((float)surfaceWidth / surfaceHeight)) {
            scale = (float)surfaceHeight / nextMedia_.getHeight();
        } else {
            scale = (float)surfaceWidth / nextMedia_.getWidth();
        }
        startState.scale = scale;

    } else {
        // Zoom, None, PageTurn 등은 중앙 정렬에서 시작
        float baseScale, baseOffsetX, baseOffsetY;
        calculateFitScaleAndOffset(nextMedia_, surfaceWidth, surfaceHeight, baseScale, baseOffsetX, baseOffsetY);
        startState.offsetX = baseOffsetX;
        startState.offsetY = baseOffsetY;
        startState.scale = baseScale;
    }
    return startState;
}

void Renderer::handleTransitionState(ANativeWindow_Buffer& buffer, int surfaceWidth, int surfaceHeight) {

    if (!transitionStrategy_ || !nextMedia_.isValid()) {
        currentState_ = RenderState::ANIMATING;
        if(animationStrategy_) animationStrategy_->reset();
        return;
    }



    // 2. 해당 모드의 전문가를 "임시로" 고용하여 시작 상태가 어떨지 물어봅니다.
    std::unique_ptr<AnimationStrategy> tempNextStrategy;
    switch (predictedNextAnimationMode_) {
        case AnimationMode::PAN:
            tempNextStrategy = std::make_unique<PanAnimation>(animationSpeed_);
            break;
        case AnimationMode::PAN_ONE_WAY:
            tempNextStrategy = std::make_unique<PanOneWayAnimation>(animationSpeed_);
            break;
        case AnimationMode::ZOOM:
            tempNextStrategy = std::make_unique<ZoomAnimation>(animationSpeed_);
            break;
        case AnimationMode::PAGE_TURN:
            tempNextStrategy = std::make_unique<PageTurnAnimation>(animationSpeed_, pageTurnDelayMs_);
            break;
        case AnimationMode::NONE:
        default:
            tempNextStrategy = std::make_unique<NoneAnimation>(animationSpeed_);
            break;
    }

    AnimationState destStartState;
    if (tempNextStrategy) {
        destStartState = tempNextStrategy->getStartState(this, nextMedia_, surfaceWidth, surfaceHeight);
    }

    // 3. 전환 전문가에게 모든 정보를 (이전 상태의 끝, 다음 상태의 시작) 넘겨주고 그리기를 위임
    auto now = std::chrono::steady_clock::now();
    long long elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - transitionStartTime_).count();
    bool isComplete = transitionStrategy_->execute(this, buffer, currentMedia_, lastAnimationState_, nextMedia_, destStartState, elapsed);

    // 4. 상태 전환 체크
    if (isComplete) {
        currentMedia_ = std::move(nextMedia_);
        currentState_ = RenderState::ANIMATING;
        // 예측했던 모드를 실제로 적용
        activeAnimationMode_ = predictedNextAnimationMode_;
        switch (activeAnimationMode_) { // 해당 전략 객체 생성
            case AnimationMode::PAN: animationStrategy_ = std::make_unique<PanAnimation>(animationSpeed_); break;
            case AnimationMode::PAN_ONE_WAY: animationStrategy_ = std::make_unique<PanOneWayAnimation>(animationSpeed_); break;
            case AnimationMode::ZOOM: animationStrategy_ = std::make_unique<ZoomAnimation>(animationSpeed_); break;
            case AnimationMode::PAGE_TURN: animationStrategy_ = std::make_unique<PageTurnAnimation>(animationSpeed_, pageTurnDelayMs_); break;
            case AnimationMode::NONE:
            default: animationStrategy_ = std::make_unique<NoneAnimation>(animationSpeed_);
                break;
        }
        if(animationStrategy_) animationStrategy_->reset();
    }
}

// ====================================================================
// 메인 렌더링 루프 (교통정리 담당)
// ====================================================================
void Renderer::renderFrame(ANativeWindow* window) {
    if (!window) return;
    std::lock_guard<std::mutex> lock(renderMutex_);

    if (!currentMedia_.isValid() && preloader_.isPreloadedDataReady()) {
        currentMedia_ = preloader_.swapAndRelease();
        if (currentMedia_.isValid()) {
            currentState_ = RenderState::ANIMATING;
            determineActiveAnimationMode();
            if(animationStrategy_) animationStrategy_->reset();
            callNextMediaCallback();
        }
    }
    if (!currentMedia_.isValid()) {
        ANativeWindow_Buffer buffer;
        if (ANativeWindow_lock(window, &buffer, nullptr) == 0) {
            memset(buffer.bits, 0, buffer.stride * buffer.height * sizeof(uint32_t));
            ANativeWindow_unlockAndPost(window);
        }
        return;
    }
    if (!nextMedia_.isValid() && preloader_.isPreloadedDataReady()) {
        nextMedia_ = preloader_.swapAndRelease();
        if(nextMedia_.isValid()) { callNextMediaCallback(); }
    }

    ANativeWindow_Buffer buffer;
    if (ANativeWindow_lock(window, &buffer, nullptr) != 0) return;
    int surfaceWidth = ANativeWindow_getWidth(window);
    int surfaceHeight = ANativeWindow_getHeight(window);

    switch (currentState_) {
        case RenderState::ANIMATING:
            handleAnimationState(buffer, surfaceWidth, surfaceHeight);
            break;
        case RenderState::TRANSITIONING:
            handleTransitionState(buffer, surfaceWidth, surfaceHeight);
            break;
    }

    ANativeWindow_unlockAndPost(window);
}

// ====================================================================
// 하위 그리기 함수 및 헬퍼 함수들
// ====================================================================
void Renderer::drawMedia(ANativeWindow_Buffer& buffer, MediaAsset& media, float alpha, float finalOffsetX, float finalOffsetY, float finalScale) {
    if (!media.isValid() || alpha <= 0.0f) return;
    if (media.getType() == MediaAsset::Type::IMAGE) {
        renderImageFrame(media, buffer, finalScale, finalOffsetX, finalOffsetY, alpha);
    } else {
        renderVideoFrame(media, buffer, finalScale, finalOffsetX, finalOffsetY, alpha);
    }
}

void Renderer::renderImageFrame(const MediaAsset& media, ANativeWindow_Buffer& buffer, float scale, float offsetX, float offsetY, float alpha) {
    uint32_t* dstPixels = (uint32_t*)buffer.bits;
    int dstStride = buffer.stride;
    const uint8_t* pixelData = media.getType() == MediaAsset::Type::IMAGE ? media.getImageData() : media.getRgbBuffer().data();
    if (!pixelData) return;

    int imgW = media.getWidth();
    int imgH = media.getHeight();
    uint8_t alphaByte = static_cast<uint8_t>(alpha * 255.0f);

    for (int y = 0; y < buffer.height; ++y) {
        int srcY = static_cast<int>((y - offsetY) / scale);
        if (srcY < 0 || srcY >= imgH) continue;
        uint32_t* dstRow = dstPixels + y * dstStride;
        for (int x = 0; x < buffer.width; ++x) {
            int srcX = static_cast<int>((x - offsetX) / scale);
            if (srcX < 0 || srcX >= imgW) continue;
            const uint8_t* srcPixel = &pixelData[(srcY * imgW + srcX) * 4];
            uint32_t dstPixelValue = dstRow[x];
            uint8_t dstB = (dstPixelValue >> 0) & 0xFF;
            uint8_t dstG = (dstPixelValue >> 8) & 0xFF;
            uint8_t dstR = (dstPixelValue >> 16) & 0xFF;
            uint8_t finalR = (srcPixel[0] * alphaByte + dstR * (255 - alphaByte)) / 255;
            uint8_t finalG = (srcPixel[1] * alphaByte + dstG * (255 - alphaByte)) / 255;
            uint8_t finalB = (srcPixel[2] * alphaByte + dstB * (255 - alphaByte)) / 255;
            dstRow[x] = (0xFF << 24) | (finalR << 16) | (finalG << 8) | finalB;
        }
    }
}

void Renderer::renderVideoFrame(MediaAsset& media, ANativeWindow_Buffer& buffer, float scale, float offsetX, float offsetY, float alpha) {
    AVFormatContext* fmt_ctx = media.getFormatContext();
    AVCodecContext* codec_ctx = media.getCodecContext();
    AVFrame* frame = media.getFrame();
    AVPacket* pkt = media.getPacket();
    SwsContext* sws_ctx = media.getSwsContext();
    int video_stream_idx = media.getVideoStreamIndex();

    if (!fmt_ctx || !codec_ctx || !frame || !pkt || !sws_ctx) return;

    int ret = av_read_frame(fmt_ctx, pkt);
    if (ret >= 0) {
        if (pkt->stream_index == video_stream_idx) {
            if (avcodec_send_packet(codec_ctx, pkt) >= 0) {
                if (avcodec_receive_frame(codec_ctx, frame) == 0) {
                    std::vector<uint8_t>& rgbBuf = media.getRgbBuffer();
                    uint8_t* dst[4] = { rgbBuf.data(), nullptr, nullptr, nullptr };
                    int dstStride_arr[4] = { media.getWidth() * 4, 0, 0, 0 };
                    sws_scale(sws_ctx, frame->data, frame->linesize, 0, media.getHeight(), dst, dstStride_arr);
                }
            }
        }
        av_packet_unref(pkt);
    } else if (ret == AVERROR_EOF) {
        av_seek_frame(fmt_ctx, video_stream_idx, 0, AVSEEK_FLAG_BACKWARD);
    }

    renderImageFrame(media, buffer, scale, offsetX, offsetY, alpha);
}

void Renderer::calculateFitScaleAndOffset(const MediaAsset& media, int surfaceWidth, int surfaceHeight, float& outScale, float& outOffsetX, float& outOffsetY) const {
    if (!media.isValid() || media.getWidth() == 0 || media.getHeight() == 0) {
        outScale = 1.0f; outOffsetX = 0.0f; outOffsetY = 0.0f;
        return;
    }
    float mediaAspect = static_cast<float>(media.getWidth()) / media.getHeight();
    float surfaceAspect = static_cast<float>(surfaceWidth) / surfaceHeight;
    if (mediaAspect > surfaceAspect) {
        outScale = static_cast<float>(surfaceHeight) / media.getHeight();
        outOffsetX = (static_cast<float>(surfaceWidth) - (media.getWidth() * outScale)) / 2.0f;
        outOffsetY = 0.0f;
    } else {
        outScale = static_cast<float>(surfaceWidth) / media.getWidth();
        outOffsetX = 0.0f;
        outOffsetY = (static_cast<float>(surfaceHeight) - (media.getHeight() * outScale)) / 2.0f;
    }
}

/**
 * @brief 현재 렌더러의 내부 상태를 문자열로 반환합니다. (디버깅용)
 */
std::string Renderer::getDebugInfo() const {
    std::stringstream ss;
    ss << "========== Native State ==========\n";
    ss << " Configured Anim: " << static_cast<int>(configuredAnimationMode_) << "\n";
    ss << " Active Anim    : " << static_cast<int>(activeAnimationMode_) << "\n";
    ss << " Configured Trans: " << static_cast<int>(configuredTransitionMode_) << "\n";
    ss << " In CurrentState: " << static_cast<int>(currentState_) << "\n";

    if (currentMedia_.isValid()) {
        ss << " Current Media: VALID ["
           << (currentMedia_.getType() == MediaAsset::Type::IMAGE ? "Image" : "Video")
           << " " << currentMedia_.getWidth() << "x" << currentMedia_.getHeight() << "]\n";
    } else {
        ss << " Current Media: INVALID\n";
    }

    if (nextMedia_.isValid()) {
        ss << " Next Media   : VALID ["
           << (nextMedia_.getType() == MediaAsset::Type::IMAGE ? "Image" : "Video")
           << " " << nextMedia_.getWidth() << "x" << nextMedia_.getHeight() << "]";
    } else {
        ss << " Next Media   : INVALID";
    }
    return ss.str();
}