/*
 * This file is part of vimix - video live mixer
 *
 * **Copyright** (C) 2019-2022 Bruno Herbelin <bruno.herbelin@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
**/

#include <gst/gst.h>

#include <glm/gtc/matrix_access.hpp>
#include <glm/gtc/matrix_transform.hpp>

#include "Log.h"
#include "defines.h"
#include "Resource.h"
#include "Visitor.h"
#include "FrameBuffer.h"
#include "Decorations.h"

#include "CloneSource.h"

const char* CloneSource::cloning_provenance_label[2] = { "Original texture", "Post-processed image" };


CloneSource::CloneSource(Source *origin, uint64_t id) : Source(id), origin_(origin), cloningsurface_(nullptr),
    to_delete_(nullptr), delay_(0.0), paused_(false), provenance_(CLONE_TEXTURE)
{
    // initial name copies the origin name: diplucates are namanged in session
    name_ = origin->name();

    // set symbol
    symbol_ = new Symbol(Symbol::CLONE, glm::vec3(0.75f, 0.75f, 0.01f));
    symbol_->scale_.y = 1.5f;

    // init connecting line
    connection_ = new DotLine;
    connection_->color = glm::vec4(COLOR_DEFAULT_SOURCE, 0.5f);
    connection_->target = origin->groups_[View::MIXING]->translation_;
    groups_[View::MIXING]->attach(connection_);

    // init timer
    timer_ = g_timer_new ();
}

CloneSource::~CloneSource()
{
    if (origin_)
        origin_->clones_.remove(this);

    // delete all frame buffers
    while (!images_.empty()) {
        if (images_.front() != nullptr)
            delete images_.front();
        images_.pop();
    }

    if (cloningsurface_)
        delete cloningsurface_;

    g_free(timer_);
}

CloneSource *CloneSource::clone(uint64_t id)
{
    // do not clone a clone : clone the original instead
    if (origin_)
        return origin_->clone(id);
    else
        return nullptr;
}

void CloneSource::init()
{
    if (origin_ && origin_->mode_ > Source::UNINITIALIZED) {

        // internal surface to draw the original texture
        cloningsurface_ = new Surface;
        cloningsurface_->setTextureIndex( origin()->texture() );

        // frame buffers where to draw frames from the origin source
        glm::vec3 res = origin_->frame()->resolution();
        images_.push( new FrameBuffer( res, origin_->frame()->use_alpha() ) );
        timestamps_.push( origin_->playtime() );
        elapsed_.push( 0.f );

        // activate elapsed-timer
        g_timer_start(timer_);

        // set initial texture surface
        texturesurface_->setTextureIndex( images_.front()->texture() );

        // create render Frame buffer matching size of images
        FrameBuffer *renderbuffer = new FrameBuffer( res, true);

        // set the renderbuffer of the source and attach rendering nodes
        attach(renderbuffer);

        // force update of activation mode
        active_ = true;

        // deep update to reorder
        ++View::need_deep_update_;

        // done init
        Log::Info("Source '%s' cloning source '%s'.", name().c_str(), origin_->name().c_str() );
    }
}

void CloneSource::setActive (bool on)
{
    // request update
    need_update_ |= active_ != on;

    active_ = on;

    groups_[View::RENDERING]->visible_ = active_;
    groups_[View::GEOMETRY]->visible_ = active_;
    groups_[View::LAYER]->visible_ = active_;

    if (origin_) {
        if ( mode_ > Source::UNINITIALIZED)
            origin_->touch();

        // change visibility of active surface (show preview of origin when inactive)
        if (activesurface_) {
            if (active_ || images_.empty())
                activesurface_->setTextureIndex(Resource::getTextureTransparent());
            else
                activesurface_->setTextureIndex(images_.front()->texture());
        }
    }
}

void CloneSource::update(float dt)
{
    Source::update(dt);

    if (origin_) {

        if (!paused_ && cloningsurface_ != nullptr) {

            // if temporary FBO was pending to be deleted, delete it now
            if (to_delete_ != nullptr) {
                delete to_delete_;
                to_delete_ = nullptr;
            }

            // What time is it?
            double now = g_timer_elapsed (timer_, NULL);

            // is the total buffer of images longer than delay ?
            if ( !images_.empty() && now - elapsed_.front() > delay_ ) {
                // remember FBO to be reused if needed (see below) or deleted later
                to_delete_ = images_.front();
                // remove element from queue (front)
                images_.pop();
                elapsed_.pop();
                timestamps_.pop();
            }

            // add image to queue to accumulate buffer images until delay reached
            if ( images_.empty() || now - elapsed_.front() < delay_ + (dt * 0.001) ) {
                // create a FBO if none can be reused (from above)
                if (to_delete_ == nullptr)
                    to_delete_ = new FrameBuffer( origin_->frame()->resolution(), origin_->frame()->use_alpha() );
                // add element to queue (back)
                images_.push( to_delete_ );
                elapsed_.push( now );
                timestamps_.push( origin_->playtime() );
                // to_delete_ FBO is now used, should not be deleted
                to_delete_ = nullptr;
            }

            // CLONE_RENDER : blit rendered framebuffer in the newest image (back)
            if (provenance_ == CLONE_RENDER)
                origin_->frame()->blit(images_.back());
            // CLONE_TEXTURE : render origin texture in the the newest image (back)
            else {
                images_.back()->begin();
                cloningsurface_->draw(glm::identity<glm::mat4>(), images_.back()->projection());
                images_.back()->end();
            }

            // update the source surface to be rendered with the oldest image (front)
            texturesurface_->setTextureIndex( images_.front()->texture() );
        }

        // update connection line target to position of origin source
        connection_->target = glm::inverse( GlmToolkit::transform(groups_[View::MIXING]->translation_, glm::vec3(0), groups_[View::MIXING]->scale_) ) *
                glm::vec4(origin_->groups_[View::MIXING]->translation_, 1.f);
    }
}


void CloneSource::setDelay(double second)
{
    delay_ = CLAMP(second, 0.0, 2.0);
}

void CloneSource::play (bool on)
{
    // if a different state is asked
    if (paused_ == on) {

        // restart clean if was paused
        if (paused_)
            replay();
        // toggle state
        paused_ = !on;
    }
}

bool CloneSource::playable () const
{
    if (origin_)
        return origin_->playable();
    return true;
}

void CloneSource::replay()
{
    // clear to_delete_ FBO if pending
    if (to_delete_ != nullptr) {
        delete to_delete_;
        to_delete_ = nullptr;
    }

    // remove all images except the one in the back (newest)
    while (images_.size() > 1) {
        // do not delete immediately the (oldest) front image (the FBO is currently displayed)
        if (to_delete_ == nullptr)
            to_delete_ = images_.front();
        // delete other FBO (unused)
        else if (images_.front() != nullptr)
            delete images_.front();
        images_.pop();
    }

    // remove all timing
    while (!elapsed_.empty())
        elapsed_.pop();
    // reset elapsed timer to 0
    g_timer_reset(timer_);
    elapsed_.push(0.);

    // remove all timestamps
    while (!timestamps_.empty())
        timestamps_.pop();
    timestamps_.push(0);
}

guint64 CloneSource::playtime () const
{
    return timestamps_.front();
}


uint CloneSource::texture() const
{
    if (cloningsurface_ != nullptr && !images_.empty())
        return images_.front()->texture();
    else
        return Resource::getTextureTransparent();
}

void CloneSource::accept(Visitor& v)
{
    Source::accept(v);
    if (!failed())
        v.visit(*this);
}

glm::ivec2 CloneSource::icon() const
{
    return glm::ivec2(ICON_SOURCE_CLONE);
}

std::string CloneSource::info() const
{
    return "Clone";
}