//
// ResourceImageItem.cpp
//
// Created by David Kelly and Howard Stearns on 2017/06/08
// Copyright 2017 High Fidelity, Inc.

// Distributed under the Apache License, Version 2.0
// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

#include "ResourceImageItem.h"

#include <QOpenGLFramebufferObjectFormat>
#include <QOpenGLFunctions>
#include <QOpenGLExtraFunctions>
#include <QOpenGLContext>

#include <plugins/DisplayPlugin.h>

ResourceImageItem::ResourceImageItem() : QQuickFramebufferObject() {
    auto textureCache = DependencyManager::get<TextureCache>();
    connect(textureCache.data(), SIGNAL(spectatorCameraFramebufferReset()), this, SLOT(update()));
}

void ResourceImageItem::setUrl(const QString& url) {
    if (url != m_url) {
        m_url = url;
        update();
    }
}

void ResourceImageItem::setReady(bool ready) {
    if (ready != m_ready) {
        m_ready = ready;
        update();
    }
}

void ResourceImageItemRenderer::onUpdateTimer() {
    if (_ready) {
        if (_networkTexture && _networkTexture->isLoaded()) {
            if(_fboMutex.tryLock()) {
                invalidateFramebufferObject();
                qApp->getActiveDisplayPlugin()->copyTextureToQuickFramebuffer(_networkTexture, _copyFbo, &_fenceSync);
                _fboMutex.unlock();
            } else {
                qDebug() << "couldn't get a lock, using last frame";
            }
        } else {
            _networkTexture = DependencyManager::get<TextureCache>()->getTexture(_url);
        }
    }
    update();
}

ResourceImageItemRenderer::ResourceImageItemRenderer() : QQuickFramebufferObject::Renderer() {
    connect(&_updateTimer, SIGNAL(timeout()), this, SLOT(onUpdateTimer()));
    auto textureCache = DependencyManager::get<TextureCache>();
}

void ResourceImageItemRenderer::synchronize(QQuickFramebufferObject* item) {
    ResourceImageItem* resourceImageItem = static_cast<ResourceImageItem*>(item);

    resourceImageItem->setFlag(QQuickItem::ItemHasContents);

    _url = resourceImageItem->getUrl();
    _ready = resourceImageItem->getReady();
    _visible = resourceImageItem->isVisible();
    _window = resourceImageItem->window();

    _networkTexture = DependencyManager::get<TextureCache>()->getTexture(_url);
    static const int UPDATE_TIMER_DELAY_IN_MS = 100; // 100 ms = 10 hz for now
    if (_ready && _visible && !_updateTimer.isActive()) {
        _updateTimer.start(UPDATE_TIMER_DELAY_IN_MS);
    } else if (!(_ready && _visible) && _updateTimer.isActive()) {
        _updateTimer.stop();
    }
}

QOpenGLFramebufferObject* ResourceImageItemRenderer::createFramebufferObject(const QSize& size) {
    if (_copyFbo) {
        delete _copyFbo;
    }
    QOpenGLFramebufferObjectFormat format;
    format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
    _copyFbo = new QOpenGLFramebufferObject(size, format);
    _copyFbo->bind();
    return new QOpenGLFramebufferObject(size, format);
}

void ResourceImageItemRenderer::render() {
    auto f = QOpenGLContext::currentContext()->extraFunctions();

    if (_fenceSync) {
        f->glWaitSync(_fenceSync, 0, GL_TIMEOUT_IGNORED);
        f->glDeleteSync(_fenceSync);
        _fenceSync = 0;
    }
    if (_ready) {
        _fboMutex.lock();
        _copyFbo->bind();
        QOpenGLFramebufferObject::blitFramebuffer(framebufferObject(), _copyFbo, GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT, GL_NEAREST);

        // this clears the copyFbo texture
        // so next frame starts fresh - helps
        // when aspect ratio changes
        _copyFbo->takeTexture();
        _copyFbo->bind();
        _copyFbo->release();

        _fboMutex.unlock();
    }
    glFlush();
    _window->resetOpenGLState();
}