/*

 * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>

 * Copyright (c) 2023, MacDue <macdue@dueutil.tech>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#pragma once

#include <AK/Variant.h>

#include <AK/Vector.h>

#include <LibGfx/AffineTransform.h>

#include <LibGfx/Color.h>

#include <LibGfx/Font/Font.h>

#include <LibGfx/PaintStyle.h>

#include <LibGfx/PathClipper.h>

#include <LibWeb/Bindings/CanvasRenderingContext2DPrototype.h>

#include <LibWeb/HTML/CanvasGradient.h>

#include <LibWeb/HTML/CanvasPattern.h>

namespace Web::HTML {

// https://html.spec.whatwg.org/multipage/canvas.html#canvasstate

class CanvasState {

public:

    virtual ~CanvasState() = default;

    void save();

    void restore();

    void reset();

    bool is_context_lost();

    using FillOrStrokeVariant = Variant<Gfx::Color, JS::Handle<CanvasGradient>, JS::Handle<CanvasPattern>>;

    struct FillOrStrokeStyle {

        FillOrStrokeStyle(Gfx::Color color)

            : m_fill_or_stroke_style(color)

        {

        }

        FillOrStrokeStyle(JS::Handle<CanvasGradient> gradient)

            : m_fill_or_stroke_style(gradient)

        {

        }

        FillOrStrokeStyle(JS::Handle<CanvasPattern> pattern)

            : m_fill_or_stroke_style(pattern)

        {

        }

        NonnullRefPtr<Gfx::PaintStyle> to_gfx_paint_style();

        Optional<Gfx::Color> as_color() const;

        Gfx::Color to_color_but_fixme_should_accept_any_paint_style() const;

        using JsFillOrStrokeStyle = Variant<String, JS::Handle<CanvasGradient>, JS::Handle<CanvasPattern>>;

        JsFillOrStrokeStyle to_js_fill_or_stroke_style() const

        {

            return m_fill_or_stroke_style.visit(

                [&](Gfx::Color color) -> JsFillOrStrokeStyle {

                    return color.to_string(Gfx::Color::HTMLCompatibleSerialization::Yes);

                },

                [&](auto handle) -> JsFillOrStrokeStyle {

                    return handle;

                });

Unexecuted instantiation: AK::Variant<AK::String, JS::Handle<Web::HTML::CanvasGradient>, JS::Handle<Web::HTML::CanvasPattern> > Web::HTML::CanvasState::FillOrStrokeStyle::to_js_fill_or_stroke_style() const::{lambda(auto:1)#1}::operator()<JS::Handle<Web::HTML::CanvasPattern> >(JS::Handle<Web::HTML::CanvasPattern>) const

Unexecuted instantiation: AK::Variant<AK::String, JS::Handle<Web::HTML::CanvasGradient>, JS::Handle<Web::HTML::CanvasPattern> > Web::HTML::CanvasState::FillOrStrokeStyle::to_js_fill_or_stroke_style() const::{lambda(auto:1)#1}::operator()<JS::Handle<Web::HTML::CanvasGradient> >(JS::Handle<Web::HTML::CanvasGradient>) const

        }

    private:

        FillOrStrokeVariant m_fill_or_stroke_style;

        RefPtr<Gfx::PaintStyle> m_color_paint_style { nullptr };

    };

    // https://html.spec.whatwg.org/multipage/canvas.html#drawing-state

    struct DrawingState {

        Gfx::AffineTransform transform;

        FillOrStrokeStyle fill_style { Gfx::Color::Black };

        FillOrStrokeStyle stroke_style { Gfx::Color::Black };

        float line_width { 1 };

        Bindings::CanvasLineCap line_cap { Bindings::CanvasLineCap::Butt };

        Bindings::CanvasLineJoin line_join { Bindings::CanvasLineJoin::Miter };

        float miter_limit { 10 };

        Vector<double> dash_list;

        float line_dash_offset { 0 };

        bool image_smoothing_enabled { true };

        Bindings::ImageSmoothingQuality image_smoothing_quality { Bindings::ImageSmoothingQuality::Low };

        float global_alpha = { 1 };

        Optional<Gfx::ClipPath> clip;

        RefPtr<CSS::CSSStyleValue> font_style_value { nullptr };

        RefPtr<Gfx::Font const> current_font { nullptr };

        Bindings::CanvasTextAlign text_align { Bindings::CanvasTextAlign::Start };

        Bindings::CanvasTextBaseline text_baseline { Bindings::CanvasTextBaseline::Alphabetic };

    };

    DrawingState& drawing_state() { return m_drawing_state; }

    DrawingState const& drawing_state() const { return m_drawing_state; }

    void clear_drawing_state_stack() { m_drawing_state_stack.clear(); }

    void reset_drawing_state() { m_drawing_state = {}; }

    virtual void reset_to_default_state() = 0;

protected:

    CanvasState() = default;

private:

    DrawingState m_drawing_state;

    Vector<DrawingState> m_drawing_state_stack;

    // https://html.spec.whatwg.org/multipage/canvas.html#concept-canvas-context-lost

    bool m_context_lost { false };

};

}