/*

 * Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>

 *

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

 */

#pragma once

#include <AK/Concepts.h>

#include <AK/Format.h>

#include <AK/Forward.h>

#include <LibGfx/Forward.h>

namespace Gfx {

class AffineTransform {

public:

    AffineTransform()

        : m_values { 1, 0, 0, 1, 0, 0 }

    {

    }

    AffineTransform(float a, float b, float c, float d, float e, float f)

        : m_values { a, b, c, d, e, f }

    {

    }

    [[nodiscard]] bool is_identity() const

    {

        return m_values[0] == 1 && m_values[1] == 0 && m_values[2] == 0 && m_values[3] == 1 && m_values[4] == 0 && m_values[5] == 0;

    }

    [[nodiscard]] bool is_identity_or_translation() const

    {

        return m_values[0] == 1 && m_values[1] == 0 && m_values[2] == 0 && m_values[3] == 1;

    }

    enum class AllowNegativeScaling {

        No,

        Yes,

    };

    [[nodiscard]] bool is_identity_or_translation_or_scale(AllowNegativeScaling allow_negative_scaling) const

    {

        if (allow_negative_scaling == AllowNegativeScaling::No && (m_values[0] < 0 || m_values[3] < 0))

            return false;

        return m_values[1] == 0 && m_values[2] == 0;

    }

    void map(float unmapped_x, float unmapped_y, float& mapped_x, float& mapped_y) const;

    template<Arithmetic T>

    Point<T> map(Point<T>) const;

    template<Arithmetic T>

    Size<T> map(Size<T>) const;

    template<Arithmetic T>

    Rect<T> map(Rect<T> const&) const;

    Quad<float> map_to_quad(Rect<float> const&) const;

    [[nodiscard]] ALWAYS_INLINE float a() const { return m_values[0]; }

    [[nodiscard]] ALWAYS_INLINE float b() const { return m_values[1]; }

    [[nodiscard]] ALWAYS_INLINE float c() const { return m_values[2]; }

    [[nodiscard]] ALWAYS_INLINE float d() const { return m_values[3]; }

    [[nodiscard]] ALWAYS_INLINE float e() const { return m_values[4]; }

    [[nodiscard]] ALWAYS_INLINE float f() const { return m_values[5]; }

    [[nodiscard]] float x_scale() const;

    [[nodiscard]] float y_scale() const;

    [[nodiscard]] FloatPoint scale() const;

    [[nodiscard]] float x_translation() const;

    [[nodiscard]] float y_translation() const;

    [[nodiscard]] FloatPoint translation() const;

    [[nodiscard]] float rotation() const;

    AffineTransform& scale(float sx, float sy);

    AffineTransform& scale(FloatPoint s);

    AffineTransform& set_scale(float sx, float sy);

    AffineTransform& set_scale(FloatPoint s);

    AffineTransform& translate(float tx, float ty);

    AffineTransform& translate(FloatPoint t);

    AffineTransform& set_translation(float tx, float ty);

    AffineTransform& set_translation(FloatPoint t);

    AffineTransform& rotate_radians(float);

    AffineTransform& skew_radians(float x_radians, float y_radians);

    AffineTransform& multiply(AffineTransform const&);

    float determinant() const;

    Optional<AffineTransform> inverse() const;

private:

    float m_values[6] { 0 };

};

}

template<>

struct AK::Formatter<Gfx::AffineTransform> : Formatter<FormatString> {

    ErrorOr<void> format(FormatBuilder& builder, Gfx::AffineTransform const& value)

    {

        return Formatter<FormatString>::format(builder, "[{} {} {} {} {} {}]"sv, value.a(), value.b(), value.c(), value.d(), value.e(), value.f());

    }

};