/**
 * @file
 * @brief Source file for QtImageReader class
 * @author Jonathan Thomas <jonathan@openshot.org>
 *
 * @ref License
 */

// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later

#include "QtImageReader.h"

#include "Clip.h"
#include "CacheMemory.h"
#include "Exceptions.h"
#include "Timeline.h"
#include "effects/CropHelpers.h"

#include <algorithm>
#include <QString>
#include <QImage>
#include <QPainter>
#include <QIcon>
#include <QImageReader>
#if USE_RESVG != 1
#include <QSvgRenderer>
#endif

using namespace openshot;

QtImageReader::QtImageReader(std::string path, bool inspect_reader) : path{QString::fromStdString(path)}, is_open(false)
{
    // Open and Close the reader, to populate its attributes (such as height, width, etc...)
    if (inspect_reader) {
        Open();
        Close();
    }
}

QtImageReader::~QtImageReader()
{
    Close();
}

// Open image file
void QtImageReader::Open()
{
    // Open reader if not already open
    if (!is_open)
    {
        bool loaded = false;
        QSize default_svg_size;

        // Check for SVG files and rasterizing them to QImages
        if (path.toLower().endsWith(".svg") || path.toLower().endsWith(".svgz")) {
            #if RESVG_VERSION_MIN(0, 11)
                // Initialize the Resvg options
                resvg_options.loadSystemFonts();
            #endif
            
            // Parse SVG file
            default_svg_size = load_svg_path(path);
            if (!default_svg_size.isEmpty()) {
                loaded = true;
            }
        }

        if (!loaded) {
            // Attempt to open file using Qt's build in image processing capabilities
            // AutoTransform enables exif data to be parsed and auto transform the image
            // to the correct orientation
            image = std::make_shared<QImage>();
            QImageReader imgReader( path );
            imgReader.setAutoTransform( true );
            imgReader.setDecideFormatFromContent( true );
            loaded = imgReader.read(image.get());
        }

        if (!loaded) {
            // raise exception
            throw InvalidFile("QtImageReader could not open image file.", path.toStdString());
        }

        // Update image properties
        info.has_audio = false;
        info.has_video = true;
        info.has_single_image = true;
        #if QT_VERSION >= QT_VERSION_CHECK(5, 10, 0)
            // byteCount() is deprecated from Qt 5.10
            info.file_size = image->sizeInBytes();
        #else
            info.file_size = image->byteCount();
        #endif
        info.vcodec = "QImage";
        if (!default_svg_size.isEmpty()) {
            // Use default SVG size (if detected)
            info.width = default_svg_size.width();
            info.height = default_svg_size.height();
        } else {
            // Use Qt Image size as a fallback
            info.width = image->width();
            info.height = image->height();
        }
        info.pixel_ratio.num = 1;
        info.pixel_ratio.den = 1;
        info.fps.num = 30;
        info.fps.den = 1;
        info.video_timebase.num = 1;
        info.video_timebase.den = 30;
        // Default still-image duration: 1 hour, aligned to fps
        info.video_length = 60 * 60 * info.fps.num; // 3600 seconds * 30 fps
        info.duration = static_cast<float>(info.video_length / info.fps.ToDouble());

        // Calculate the DAR (display aspect ratio)
        Fraction size(info.width * info.pixel_ratio.num, info.height * info.pixel_ratio.den);

        // Reduce size fraction
        size.Reduce();

        // Set the ratio based on the reduced fraction
        info.display_ratio.num = size.num;
        info.display_ratio.den = size.den;

        // Set current max size
        max_size.setWidth(info.width);
        max_size.setHeight(info.height);

        // Mark as "open"
        is_open = true;
    }
}

// Close image file
void QtImageReader::Close()
{
    // Close all objects, if reader is 'open'
    if (is_open)
    {
        // Mark as "closed"
        is_open = false;

        // Delete the image
        image.reset();
        cached_image.reset();

        info.vcodec = "";
        info.acodec = "";
    }
}

// Get an openshot::Frame object for a specific frame number of this reader.
std::shared_ptr<Frame> QtImageReader::GetFrame(int64_t requested_frame)
{
    // Check for open reader (or throw exception)
    if (!is_open)
        throw ReaderClosed("The Image is closed.  Call Open() before calling this method.", path.toStdString());

	// Create a scoped lock, allowing only a single thread to run the following code at one time
	const std::lock_guard<std::recursive_mutex> lock(getFrameMutex);

    // Calculate max image size
    QSize current_max_size = calculate_max_size();

    // Scale image smaller (or use a previous scaled image)
    if (!cached_image || max_size != current_max_size) {
        // Check for SVG files and rasterize them to QImages
        if (path.toLower().endsWith(".svg") || path.toLower().endsWith(".svgz")) {
            load_svg_path(path);
        }

        // We need to resize the original image to a smaller image (for performance reasons)
        // Only do this once, to prevent tons of unneeded scaling operations
        cached_image = std::make_shared<QImage>(image->scaled(
                       current_max_size,
                       Qt::KeepAspectRatio, Qt::SmoothTransformation));

        // Set max size (to later determine if max_size is changed)
        max_size = current_max_size;
    }

    auto sample_count = Frame::GetSamplesPerFrame(
        requested_frame, info.fps, info.sample_rate, info.channels);
    auto sz = cached_image->size();

    // Create frame object
    auto image_frame = std::make_shared<Frame>(
            requested_frame, sz.width(), sz.height(), "#000000",
            sample_count, info.channels);
    image_frame->AddImage(cached_image);

    // return frame object
    return image_frame;
}

// Calculate the max_size QSize, based on parent timeline and parent clip settings
QSize QtImageReader::calculate_max_size() {
    // Get max project size
    int max_width = info.width;
    int max_height = info.height;
    if (max_width == 0 || max_height == 0) {
        // If no size determined yet
        max_width = 1920;
        max_height = 1080;
    }

    Clip* parent = (Clip*) ParentClip();
    if (parent) {
        if (parent->ParentTimeline()) {
            // Set max width/height based on parent clip's timeline (if attached to a timeline)
            max_width = parent->ParentTimeline()->preview_width;
            max_height = parent->ParentTimeline()->preview_height;
        }
        if (parent->scale == SCALE_FIT || parent->scale == SCALE_STRETCH) {
            // Best fit or Stretch scaling (based on max timeline size * scaling keyframes)
            float max_scale_x = parent->scale_x.GetMaxPoint().co.Y;
            float max_scale_y = parent->scale_y.GetMaxPoint().co.Y;
            max_width = std::max(float(max_width), max_width * max_scale_x);
            max_height = std::max(float(max_height), max_height * max_scale_y);

        } else if (parent->scale == SCALE_CROP) {
            // Cropping scale mode (based on max timeline size * cropped size * scaling keyframes)
            float max_scale_x = parent->scale_x.GetMaxPoint().co.Y;
            float max_scale_y = parent->scale_y.GetMaxPoint().co.Y;
            QSize width_size(max_width * max_scale_x,
                             round(max_width / (float(info.width) / float(info.height))));
            QSize height_size(round(max_height / (float(info.height) / float(info.width))),
                              max_height * max_scale_y);
            // respect aspect ratio
            if (width_size.width() >= max_width && width_size.height() >= max_height) {
                max_width = std::max(max_width, width_size.width());
                max_height = std::max(max_height, width_size.height());
            } else {
                max_width = std::max(max_width, height_size.width());
                max_height = std::max(max_height, height_size.height());
            }
        } else if (parent->scale == SCALE_NONE) {
            // Scale images to equivalent unscaled size
            // Since the preview window can change sizes, we want to always
            // scale against the ratio of original image size to timeline size
            float preview_ratio = 1.0;
            if (parent->ParentTimeline()) {
                Timeline *t = (Timeline *) parent->ParentTimeline();
                preview_ratio = t->preview_width / float(t->info.width);
            }
            float max_scale_x = parent->scale_x.GetMaxPoint().co.Y;
            float max_scale_y = parent->scale_y.GetMaxPoint().co.Y;
            max_width = info.width * max_scale_x * preview_ratio;
            max_height = info.height * max_scale_y * preview_ratio;
        }

        // If a crop effect is resizing the image, request enough pixels to preserve detail
        ApplyCropResizeScale(parent, info.width, info.height, max_width, max_height);
    }

    if (HasMaxDecodeSize()) {
        QSize bounded_size(max_width, max_height);
        const QSize max_decode_size(MaxDecodeWidth(), MaxDecodeHeight());
        const QString lower_path = path.toLower();
        const bool is_svg = lower_path.endsWith(".svg") || lower_path.endsWith(".svgz");

        if (is_svg && !parent) {
            // Vector images have no fixed source pixel limit. With no parent
            // Timeline/Clip to provide a render size, use MaxDecodeSize as the
            // rasterization target instead of preserving the tiny document size.
            bounded_size.scale(max_decode_size, Qt::KeepAspectRatio);
            max_width = bounded_size.width();
            max_height = bounded_size.height();
        } else if (bounded_size.width() > max_decode_size.width() ||
            bounded_size.height() > max_decode_size.height()) {
            bounded_size.scale(max_decode_size, Qt::KeepAspectRatio);
            max_width = bounded_size.width();
            max_height = bounded_size.height();
        }
    }

    // Return new QSize of the current max size
    return QSize(max_width, max_height);
}

// Load an SVG file with Resvg or fallback with Qt
QSize QtImageReader::load_svg_path(QString) {
    bool loaded = false;
    QSize default_size(0,0);

    // Calculate max image size
    QSize current_max_size = calculate_max_size();

// Try to use libresvg for parsing/rasterizing SVG, if available
#if RESVG_VERSION_MIN(0, 11)
    ResvgRenderer renderer(path, resvg_options);
    if (renderer.isValid()) {
        default_size = renderer.defaultSize();
        // Scale SVG size to keep aspect ratio, and fill max_size as much as possible
        QSize svg_size = default_size.scaled(current_max_size, Qt::KeepAspectRatio);
        auto qimage = renderer.renderToImage(svg_size);
        image = std::make_shared<QImage>(
                qimage.convertToFormat(QImage::Format_RGBA8888_Premultiplied));
        loaded = true;
    }
#elif RESVG_VERSION_MIN(0, 0)
    ResvgRenderer renderer(path);
    if (renderer.isValid()) {
        default_size = renderer.defaultSize();
        // Scale SVG size to keep aspect ratio, and fill max_size as much as possible
        QSize svg_size = default_size.scaled(current_max_size, Qt::KeepAspectRatio);
        // Load SVG at max size
        image = std::make_shared<QImage>(svg_size,
                QImage::Format_RGBA8888_Premultiplied);
        image->fill(Qt::transparent);
        QPainter p(image.get());
        renderer.render(&p);
        p.end();
        loaded = true;
    }
#endif  // Resvg

    if (!loaded) {
        // Use Qt for parsing/rasterizing SVG
        image = std::make_shared<QImage>();
        loaded = image->load(path);

        if (loaded) {
            // Set default SVG size
            default_size.setWidth(image->width());
            default_size.setHeight(image->height());

            if (image->width() < current_max_size.width() || image->height() < current_max_size.height()) {
                // Load SVG into larger/project size (so image is not blurry)
                QSize svg_size = image->size().scaled(
                                 current_max_size, Qt::KeepAspectRatio);
                if (QCoreApplication::instance()) {
#if USE_RESVG != 1
                    // Re-rasterize SVG directly into a QImage at the target size,
                    // instead of routing through QIcon/QPixmap which can apply
                    // device-pixel-ratio behavior we do not want in timeline frames.
                    QSvgRenderer renderer(path);
                    if (renderer.isValid()) {
                        image = std::make_shared<QImage>(
                            svg_size, QImage::Format_RGBA8888_Premultiplied);
                        image->fill(Qt::transparent);
                        QPainter p(image.get());
                        renderer.render(&p);
                        p.end();
                    } else {
                        image = std::make_shared<QImage>(image->scaled(
                                svg_size, Qt::KeepAspectRatio, Qt::SmoothTransformation));
                    }
#else
                    image = std::make_shared<QImage>(image->scaled(
                            svg_size, Qt::KeepAspectRatio, Qt::SmoothTransformation));
#endif
                } else {
                    // Scale image without re-rasterizing it (due to lack of QApplication)
                    image = std::make_shared<QImage>(image->scaled(
                            svg_size, Qt::KeepAspectRatio, Qt::SmoothTransformation));
                }
            }
        }
    }

    return default_size;
}

// Generate JSON string of this object
std::string QtImageReader::Json() const {

    // Return formatted string
    return JsonValue().toStyledString();
}

// Generate Json::Value for this object
Json::Value QtImageReader::JsonValue() const {

    // Create root json object
    Json::Value root = ReaderBase::JsonValue(); // get parent properties
    root["type"] = "QtImageReader";
    root["path"] = path.toStdString();

    // return JsonValue
    return root;
}

// Load JSON string into this object
void QtImageReader::SetJson(const std::string value) {

    // Parse JSON string into JSON objects
    try
    {
        const Json::Value root = openshot::stringToJson(value);
        // Set all values that match
        SetJsonValue(root);
    }
    catch (const std::exception& e)
    {
        // Error parsing JSON (or missing keys)
        throw InvalidJSON("JSON is invalid (missing keys or invalid data types)");
    }
}

// Load Json::Value into this object
void QtImageReader::SetJsonValue(const Json::Value root) {

    // Set parent data
    ReaderBase::SetJsonValue(root);

    // Set data from Json (if key is found)
    if (!root["path"].isNull())
        path = QString::fromStdString(root["path"].asString());
}
