/*
 * Copyright (c) 2020-2022, Andreas Kling <andreas@ladybird.org>
 * Copyright (c) 2024, Kenneth Myhra <kennethmyhra@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibGfx/Bitmap.h>
#include <LibJS/Runtime/TypedArray.h>
#include <LibWeb/Bindings/ImageDataPrototype.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/HTML/ImageData.h>
#include <LibWeb/WebIDL/Buffers.h>
#include <LibWeb/WebIDL/DOMException.h>
#include <LibWeb/WebIDL/ExceptionOr.h>

namespace Web::HTML {

GC_DEFINE_ALLOCATOR(ImageData);

// https://html.spec.whatwg.org/multipage/canvas.html#dom-imagedata
WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::create(JS::Realm& realm, u32 sw, u32 sh, Optional<ImageDataSettings> const& settings)
{
    // 1. If one or both of sw and sh are zero, then throw an "IndexSizeError" DOMException.
    if (sw == 0 || sh == 0)
        return WebIDL::IndexSizeError::create(realm, "The source width and height must be greater than zero."_string);

    // 2. Initialize this given sw, sh, and settings set to settings.
    // 3. Initialize the image data of this to transparent black.
    return initialize(realm, sh, sw, settings);
}

WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::construct_impl(JS::Realm& realm, u32 sw, u32 sh, Optional<ImageDataSettings> const& settings)
{
    return ImageData::create(realm, sw, sh, settings);
}

// https://html.spec.whatwg.org/multipage/canvas.html#dom-imagedata-with-data
WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::create(JS::Realm& realm, GC::Root<WebIDL::BufferSource> const& data, u32 sw, Optional<u32> sh, Optional<ImageDataSettings> const& settings)
{
    auto& vm = realm.vm();

    if (!is<JS::Uint8ClampedArray>(*data->raw_object()))
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "Uint8ClampedArray");

    auto& uint8_clamped_array_data = static_cast<JS::Uint8ClampedArray&>(*data->raw_object());

    // 1. Let length be the number of bytes in data.
    auto length = uint8_clamped_array_data.byte_length().length();

    // 2. If length is not a nonzero integral multiple of four, then throw an "InvalidStateError" DOMException.
    if (length == 0 || length % 4 != 0)
        return WebIDL::InvalidStateError::create(realm, "Source data must have a non-sero length that is a multiple of four."_string);

    // 3. Let length be length divided by four.
    length = length / 4;

    // 4. If length is not an integral multiple of sw, then throw an "IndexSizeError" DOMException.
    // NOTE: At this step, the length is guaranteed to be greater than zero (otherwise the second step above would have aborted the steps),
    //       so if sw is zero, this step will throw the exception and return.
    if (sw == 0 || length % sw != 0)
        return WebIDL::IndexSizeError::create(realm, "Source width must be a multiple of source data's length."_string);

    // 5. Let height be length divided by sw.
    auto height = length / sw;

    // 6. If sh was given and its value is not equal to height, then throw an "IndexSizeError" DOMException.
    if (sh.has_value() && sh.value() != height)
        return WebIDL::IndexSizeError::create(realm, "Source height must be equal to the calculated height of the data."_string);

    // 7. Initialize this given sw, sh, settings set to settings, and source set to data.
    // FIXME: This seems to be a spec issue, sh is an optional but height always have a value.
    return initialize(realm, height, sw, settings, uint8_clamped_array_data);
}

WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::construct_impl(JS::Realm& realm, GC::Root<WebIDL::BufferSource> const& data, u32 sw, Optional<u32> sh, Optional<ImageDataSettings> const& settings)
{
    return ImageData::create(realm, data, sw, move(sh), settings);
}

// https://html.spec.whatwg.org/multipage/canvas.html#initialize-an-imagedata-object
WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::initialize(JS::Realm& realm, u32 rows, u32 pixels_per_row, Optional<ImageDataSettings> const& settings, GC::Ptr<JS::Uint8ClampedArray> source, Optional<Bindings::PredefinedColorSpace> default_color_space)
{
    auto data = TRY([&]() -> WebIDL::ExceptionOr<GC::Ref<JS::Uint8ClampedArray>> {
        // 1. If source was given, then initialize the data attribute of imageData to source.
        if (source) {
            return GC::Ref<JS::Uint8ClampedArray> { *source };
        }

        Checked<u32> size = rows;
        size *= pixels_per_row;
        size *= sizeof(u32);
        if (size.has_overflow())
            return WebIDL::IndexSizeError::create(realm, "The specified image size could not created"_string);

        // 2. Otherwise (source was not given), initialize the data attribute of imageData to a new Uint8ClampedArray object.
        //    The Uint8ClampedArray object must use a new Canvas Pixel ArrayBuffer for its storage, and must have a zero start
        //    offset and a length equal to the length of its storage, in bytes. The Canvas Pixel ArrayBuffer must have the
        //    correct size to store rows × pixelsPerRow pixels.
        // 3. If the Canvas Pixel ArrayBuffer cannot be allocated, then rethrow the RangeError thrown by JavaScript, and return.
        return TRY(JS::Uint8ClampedArray::create(realm, sizeof(u32) * rows * pixels_per_row));
    }());

    // AD-HOC: Create the bitmap backed by the Uint8ClampedArray.
    auto bitmap = TRY_OR_THROW_OOM(realm.vm(), Gfx::Bitmap::create_wrapper(Gfx::BitmapFormat::RGBA8888, Gfx::AlphaType::Unpremultiplied, Gfx::IntSize(pixels_per_row, rows), pixels_per_row * sizeof(u32), data->data().data()));

    // 4. Initialize the width attribute of imageData to pixelsPerRow.
    // 5. Initialize the height attribute of imageData to rows.

    // 6. If settings was given and settings["colorSpace"] exists, then initialize the colorSpace attribute of imageData to settings["colorSpace"].
    Bindings::PredefinedColorSpace color_space {};
    if (settings.has_value())
        color_space = settings->color_space;
    // 7. Otherwise, if defaultColorSpace was given, then initialize the colorSpace attribute of imageData to defaultColorSpace.
    else if (default_color_space.has_value())
        color_space = *default_color_space;
    // 8. Otherwise, initialize the colorSpace attribute of imageData to "srgb".
    else
        color_space = Bindings::PredefinedColorSpace::Srgb;

    return realm.create<ImageData>(realm, move(bitmap), data, color_space);
}

ImageData::ImageData(JS::Realm& realm, NonnullRefPtr<Gfx::Bitmap> bitmap, GC::Ref<JS::Uint8ClampedArray> data, Bindings::PredefinedColorSpace color_space)
    : PlatformObject(realm)
    , m_bitmap(move(bitmap))
    , m_color_space(color_space)
    , m_data(move(data))
{
}

ImageData::~ImageData() = default;

void ImageData::initialize(JS::Realm& realm)
{
    WEB_SET_PROTOTYPE_FOR_INTERFACE(ImageData);
    Base::initialize(realm);
}

void ImageData::visit_edges(Cell::Visitor& visitor)
{
    Base::visit_edges(visitor);
    visitor.visit(m_data);
}

unsigned ImageData::width() const
{
    return m_bitmap->width();
}

unsigned ImageData::height() const
{
    return m_bitmap->height();
}

JS::Uint8ClampedArray* ImageData::data()
{
    return m_data;
}

const JS::Uint8ClampedArray* ImageData::data() const
{
    return m_data;
}

}