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

#pragma once

#include <AK/Optional.h>
#include <LibGfx/Forward.h>
#include <LibWeb/HTML/HTMLElement.h>
#include <LibWeb/Painting/DisplayListResourceIds.h>
#include <LibWeb/WebIDL/Types.h>

namespace Web::HTML {

class HTMLCanvasElement final : public HTMLElement {
    WEB_PLATFORM_OBJECT(HTMLCanvasElement, HTMLElement);
    GC_DECLARE_ALLOCATOR(HTMLCanvasElement);

public:
    static constexpr bool OVERRIDES_FINALIZE = true;

    using RenderingContext = Variant<GC::Ref<CanvasRenderingContext2D>, GC::Ref<WebGL::WebGLRenderingContext>, GC::Ref<WebGL::WebGL2RenderingContext>, Empty>;

    virtual ~HTMLCanvasElement() override;

    Gfx::IntSize bitmap_size_for_canvas(size_t minimum_width = 0, size_t minimum_height = 0) const;

    JS::ThrowCompletionOr<RenderingContext> get_context(String const& type, JS::Value options);
    enum class HasOrCreatedContext {
        No,
        Yes,
    };
    JS::ThrowCompletionOr<HasOrCreatedContext> create_2d_context(JS::Value options);

    WebIDL::UnsignedLong width() const;
    WebIDL::UnsignedLong height() const;

    void set_width(WebIDL::UnsignedLong);
    void set_height(WebIDL::UnsignedLong);

    virtual void attribute_changed(Utf16FlyString const& local_name, Optional<Utf16String> const& old_value, Optional<Utf16String> const& value, Optional<Utf16FlyString> const& namespace_) override;

    WebIDL::ExceptionOr<String> to_data_url(StringView type, Optional<JS::Value> quality);
    WebIDL::ExceptionOr<void> to_blob(GC::Ref<WebIDL::CallbackType> callback, StringView type, Optional<JS::Value> quality);
    bool is_origin_clean() const;
    RefPtr<Gfx::Bitmap> get_bitmap_from_surface();

    void prepare_for_compositing();
    void notify_compositor_backing_storage_lost();
    void set_canvas_content_dirty();
    GC::Ptr<HTML::CanvasRenderingContext2D> canvas_rendering_context_2d() const
    {
        if (auto const* context = m_context.get_pointer<GC::Ref<HTML::CanvasRenderingContext2D>>())
            return *context;
        return nullptr;
    }

    Optional<Painting::CanvasId> canvas_id() const;

    Optional<Gfx::IntSize> canvas_surface_content_size() const;

    void ensure_backing_storage();

    void notify_compositor_connection_lost();

    CSS::ComputationContext canvas_font_computation_context();

private:
    HTMLCanvasElement(DOM::Document&, DOM::QualifiedName);

    virtual void initialize(JS::Realm&) override;
    virtual void finalize() override;
    virtual void visit_edges(Cell::Visitor&) override;

    virtual bool is_html_canvas_element() const override { return true; }

    virtual bool is_presentational_hint(Utf16FlyString const&) const override;
    virtual void apply_presentational_hints(Vector<CSS::StyleProperty>&) const override;

    virtual RefPtr<Layout::Node> create_layout_node(CSS::ComputedProperties const&) override;
    virtual void adjust_computed_style(CSS::ComputedProperties::Builder&) override;

    template<typename ContextType>
    JS::ThrowCompletionOr<HasOrCreatedContext> create_webgl_context(JS::Value options);
    WebGL::WebGLRenderingContextBase* webgl_context() const;
    void reset_context_to_default_state();
    void notify_context_about_canvas_size_change();

    Variant<GC::Ref<HTML::CanvasRenderingContext2D>, GC::Ref<WebGL::WebGLRenderingContext>, GC::Ref<WebGL::WebGL2RenderingContext>, Empty> m_context;
    bool m_canvas_content_dirty { false };
};

}

namespace Web::DOM {

template<>
inline bool Node::fast_is<HTML::HTMLCanvasElement>() const { return is_html_canvas_element(); }

}

namespace JS {

template<>
inline bool Object::fast_is<Web::HTML::HTMLCanvasElement>() const
{
    return is_dom_node() && static_cast<Web::DOM::Node const&>(*this).is_html_canvas_element();
}

}