/*
 * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/Format.h>
#include <LibGfx/AffineTransform.h>
#include <LibGfx/Orientation.h>
#include <LibGfx/Point.h>
#include <LibGfx/Size.h>
#include <LibGfx/TextAlignment.h>
#include <math.h>

namespace Gfx {

template<typename T>
T abst(T value)
{
    return value < 0 ? -value : value;
}

template<typename T>
class Rect {
public:
    Rect() = default;

    Rect(T x, T y, T width, T height)
        : m_location(x, y)
        , m_size(width, height)
    {
    }

    template<typename U>
    Rect(U x, U y, U width, U height)
        : m_location(x, y)
        , m_size(width, height)
    {
    }

    Rect(Point<T> const& location, Size<T> const& size)
        : m_location(location)
        , m_size(size)
    {
    }

    template<typename U>
    Rect(Point<U> const& location, Size<U> const& size)
        : m_location(location)
        , m_size(size)
    {
    }

    template<typename U>
    explicit Rect(Rect<U> const& other)
        : m_location(other.location())
        , m_size(other.size())
    {
    }

    [[nodiscard]] ALWAYS_INLINE T x() const { return location().x(); }
    [[nodiscard]] ALWAYS_INLINE T y() const { return location().y(); }
    [[nodiscard]] ALWAYS_INLINE T width() const { return m_size.width(); }
    [[nodiscard]] ALWAYS_INLINE T height() const { return m_size.height(); }

    ALWAYS_INLINE void set_x(T x) { m_location.set_x(x); }
    ALWAYS_INLINE void set_y(T y) { m_location.set_y(y); }
    ALWAYS_INLINE void set_width(T width) { m_size.set_width(width); }
    ALWAYS_INLINE void set_height(T height) { m_size.set_height(height); }

    [[nodiscard]] ALWAYS_INLINE Point<T> const& location() const { return m_location; }
    [[nodiscard]] ALWAYS_INLINE Size<T> const& size() const { return m_size; }

    [[nodiscard]] ALWAYS_INLINE bool is_null() const { return width() == 0 && height() == 0; }
    [[nodiscard]] ALWAYS_INLINE bool is_empty() const { return width() <= 0 || height() <= 0; }

    ALWAYS_INLINE void translate_by(T dx, T dy) { m_location.translate_by(dx, dy); }
    ALWAYS_INLINE void translate_by(T dboth) { m_location.translate_by(dboth); }
    ALWAYS_INLINE void translate_by(Point<T> const& delta) { m_location.translate_by(delta); }

    ALWAYS_INLINE void scale_by(T dx, T dy)
    {
        m_location.scale_by(dx, dy);
        m_size.scale_by(dx, dy);
    }
    ALWAYS_INLINE void scale_by(T dboth) { scale_by(dboth, dboth); }
    ALWAYS_INLINE void scale_by(Point<T> const& delta) { scale_by(delta.x(), delta.y()); }

    void transform_by(AffineTransform const& transform) { *this = transform.map(*this); }

    [[nodiscard]] Point<T> center() const
    {
        return { x() + width() / 2, y() + height() / 2 };
    }

    ALWAYS_INLINE void set_location(Point<T> const& location)
    {
        m_location = location;
    }

    ALWAYS_INLINE void set_size(Size<T> const& size)
    {
        m_size = size;
    }

    void set_size_around(Size<T> const&, Point<T> const& fixed_point);

    void set_size(T width, T height)
    {
        m_size.set_width(width);
        m_size.set_height(height);
    }

    void inflate(T w, T h)
    {
        set_x(x() - w / 2);
        set_width(width() + w);
        set_y(y() - h / 2);
        set_height(height() + h);
    }

    void inflate(Size<T> const& size)
    {
        set_x(x() - size.width() / 2);
        set_width(width() + size.width());
        set_y(y() - size.height() / 2);
        set_height(height() + size.height());
    }

    void shrink(T w, T h)
    {
        set_x(x() + w / 2);
        set_width(width() - w);
        set_y(y() + h / 2);
        set_height(height() - h);
    }

    void shrink(Size<T> const& size)
    {
        set_x(x() + size.width() / 2);
        set_width(width() - size.width());
        set_y(y() + size.height() / 2);
        set_height(height() - size.height());
    }

    [[nodiscard]] Rect<T> translated(T dx, T dy) const
    {
        Rect<T> rect = *this;
        rect.translate_by(dx, dy);
        return rect;
    }

    [[nodiscard]] Rect<T> translated(Point<T> const& delta) const
    {
        Rect<T> rect = *this;
        rect.translate_by(delta);
        return rect;
    }

    [[nodiscard]] Rect<T> scaled(T sx, T sy) const
    {
        Rect<T> rect = *this;
        rect.scale_by(sx, sy);
        return rect;
    }

    [[nodiscard]] Rect<T> scaled(Point<T> const& s) const
    {
        Rect<T> rect = *this;
        rect.scale_by(s);
        return rect;
    }

    [[nodiscard]] Rect<T> transformed(AffineTransform const& transform) const
    {
        Rect<T> rect = *this;
        rect.transform_by(transform);
        return rect;
    }

    [[nodiscard]] Rect<T> shrunken(T w, T h) const
    {
        Rect<T> rect = *this;
        rect.shrink(w, h);
        return rect;
    }

    [[nodiscard]] Rect<T> shrunken(Size<T> const& size) const
    {
        Rect<T> rect = *this;
        rect.shrink(size);
        return rect;
    }

    [[nodiscard]] Rect<T> inflated(T w, T h) const
    {
        Rect<T> rect = *this;
        rect.inflate(w, h);
        return rect;
    }

    [[nodiscard]] Rect<T> inflated(Size<T> const& size) const
    {
        Rect<T> rect = *this;
        rect.inflate(size);
        return rect;
    }

    Rect<T> take_from_right(T w)
    {
        if (w > width())
            w = width();
        Rect<T> rect = *this;
        set_width(width() - w);
        rect.set_x(x() + width());
        rect.set_width(w);
        return rect;
    }

    Rect<T> take_from_left(T w)
    {
        if (w > width())
            w = width();
        Rect<T> rect = *this;
        set_x(x() + w);
        set_width(width() - w);
        rect.set_width(w);
        return rect;
    }

    Rect<T> take_from_top(T h)
    {
        if (h > height())
            h = height();
        Rect<T> rect = *this;
        set_y(y() + h);
        set_height(height() - h);
        rect.set_height(h);
        return rect;
    }

    Rect<T> take_from_bottom(T h)
    {
        if (h > height())
            h = height();
        Rect<T> rect = *this;
        set_height(height() - h);
        rect.set_y(y() + height());
        rect.set_height(h);
        return rect;
    }

    [[nodiscard]] bool contains_vertically(T y) const
    {
        return y >= top() && y <= bottom();
    }

    [[nodiscard]] bool contains_horizontally(T x) const
    {
        return x >= left() && x <= right();
    }

    [[nodiscard]] bool contains(T x, T y) const
    {
        return x >= m_location.x() && x <= right() && y >= m_location.y() && y <= bottom();
    }

    [[nodiscard]] ALWAYS_INLINE bool contains(Point<T> const& point) const
    {
        return contains(point.x(), point.y());
    }

    [[nodiscard]] bool contains(Rect<T> const& other) const
    {
        return left() <= other.left()
            && right() >= other.right()
            && top() <= other.top()
            && bottom() >= other.bottom();
    }

    template<typename Container>
    [[nodiscard]] bool contains(Container const& others) const
    {
        bool have_any = false;
        for (auto const& other : others) {
            if (!contains(other))
                return false;
            have_any = true;
        }
        return have_any;
    }

    [[nodiscard]] ALWAYS_INLINE int primary_offset_for_orientation(Orientation orientation) const { return m_location.primary_offset_for_orientation(orientation); }
    ALWAYS_INLINE void set_primary_offset_for_orientation(Orientation orientation, int value) { m_location.set_primary_offset_for_orientation(orientation, value); }
    [[nodiscard]] ALWAYS_INLINE int secondary_offset_for_orientation(Orientation orientation) const { return m_location.secondary_offset_for_orientation(orientation); }
    ALWAYS_INLINE void set_secondary_offset_for_orientation(Orientation orientation, int value) { m_location.set_secondary_offset_for_orientation(orientation, value); }

    [[nodiscard]] ALWAYS_INLINE int primary_size_for_orientation(Orientation orientation) const { return m_size.primary_size_for_orientation(orientation); }
    [[nodiscard]] ALWAYS_INLINE int secondary_size_for_orientation(Orientation orientation) const { return m_size.secondary_size_for_orientation(orientation); }
    ALWAYS_INLINE void set_primary_size_for_orientation(Orientation orientation, int value) { m_size.set_primary_size_for_orientation(orientation, value); }
    ALWAYS_INLINE void set_secondary_size_for_orientation(Orientation orientation, int value) { m_size.set_secondary_size_for_orientation(orientation, value); }

    [[nodiscard]] T first_edge_for_orientation(Orientation orientation) const
    {
        if (orientation == Orientation::Vertical)
            return top();
        return left();
    }

    [[nodiscard]] T last_edge_for_orientation(Orientation orientation) const
    {
        if (orientation == Orientation::Vertical)
            return bottom();
        return right();
    }

    [[nodiscard]] ALWAYS_INLINE T left() const { return x(); }
    [[nodiscard]] ALWAYS_INLINE T right() const { return x() + width() - 1; }
    [[nodiscard]] ALWAYS_INLINE T top() const { return y(); }
    [[nodiscard]] ALWAYS_INLINE T bottom() const { return y() + height() - 1; }

    ALWAYS_INLINE void set_left(T left)
    {
        set_x(left);
    }

    ALWAYS_INLINE void set_top(T top)
    {
        set_y(top);
    }

    ALWAYS_INLINE void set_right(T right)
    {
        set_width(right - x() + 1);
    }

    ALWAYS_INLINE void set_bottom(T bottom)
    {
        set_height(bottom - y() + 1);
    }

    void set_right_without_resize(T new_right)
    {
        int delta = new_right - right();
        translate_by(delta, 0);
    }

    void set_bottom_without_resize(T new_bottom)
    {
        int delta = new_bottom - bottom();
        translate_by(0, delta);
    }

    [[nodiscard]] bool intersects_vertically(Rect<T> const& other) const
    {
        return top() <= other.bottom() && other.top() <= bottom();
    }

    [[nodiscard]] bool intersects_horizontally(Rect<T> const& other) const
    {
        return left() <= other.right() && other.left() <= right();
    }

    [[nodiscard]] bool intersects(Rect<T> const& other) const
    {
        return left() <= other.right()
            && other.left() <= right()
            && top() <= other.bottom()
            && other.top() <= bottom();
    }

    template<typename Container>
    [[nodiscard]] bool intersects(Container const& others) const
    {
        for (auto const& other : others) {
            if (intersects(other))
                return true;
        }
        return false;
    }

    template<typename Container, typename Function>
    IterationDecision for_each_intersected(Container const& others, Function f) const
    {
        if (is_empty())
            return IterationDecision::Continue;
        for (auto const& other : others) {
            auto intersected_rect = intersected(other);
            if (!intersected_rect.is_empty()) {
                IterationDecision decision = f(intersected_rect);
                if (decision != IterationDecision::Continue)
                    return decision;
            }
        }
        return IterationDecision::Continue;
    }

    [[nodiscard]] Vector<Rect<T>, 4> shatter(Rect<T> const& hammer) const;

    template<class U>
    [[nodiscard]] bool operator==(Rect<U> const& other) const
    {
        return location() == other.location() && size() == other.size();
    }

    template<class U>
    [[nodiscard]] bool operator!=(Rect<U> const& other) const
    {
        return !(*this == other);
    }

    [[nodiscard]] Rect<T> operator*(T factor) const { return { m_location * factor, m_size * factor }; }

    Rect<T>& operator*=(T factor)
    {
        m_location *= factor;
        m_size *= factor;
        return *this;
    }

    void intersect(Rect<T> const&);

    [[nodiscard]] static Rect<T> centered_on(Point<T> const& center, Size<T> const& size)
    {
        return { { center.x() - size.width() / 2, center.y() - size.height() / 2 }, size };
    }

    [[nodiscard]] static Rect<T> from_two_points(Point<T> const& a, Point<T> const& b)
    {
        return { min(a.x(), b.x()), min(a.y(), b.y()), abst(a.x() - b.x()), abst(a.y() - b.y()) };
    }

    [[nodiscard]] static Rect<T> intersection(Rect<T> const& a, Rect<T> const& b)
    {
        Rect<T> r = a;
        r.intersect(b);
        return r;
    }

    [[nodiscard]] ALWAYS_INLINE Rect<T> intersected(Rect<T> const& other) const
    {
        return intersection(*this, other);
    }

    [[nodiscard]] Vector<Point<T>, 2> intersected(Line<T> const&) const;
    [[nodiscard]] float center_point_distance_to(Rect<T> const&) const;
    [[nodiscard]] Vector<Point<T>, 2> closest_outside_center_points(Rect<T> const&) const;
    [[nodiscard]] float outside_center_point_distance_to(Rect<T> const&) const;
    [[nodiscard]] Rect<T> constrained_to(Rect<T> const&) const;
    [[nodiscard]] Rect<T> aligned_within(Size<T> const&, Point<T> const&, TextAlignment = TextAlignment::Center) const;
    [[nodiscard]] Point<T> closest_to(Point<T> const&) const;

    class RelativeLocation {
        friend class Rect<T>;

        RelativeLocation(Rect<T> const& base_rect, Rect<T> const& other_rect);

    public:
        RelativeLocation() = default;

        bool top_left() const { return m_top_left; }
        bool top() const { return m_top; }
        bool top_right() const { return m_top_right; }
        bool left() const { return m_left; }
        bool right() const { return m_right; }
        bool bottom_left() const { return m_bottom_left; }
        bool bottom() const { return m_bottom; }
        bool bottom_right() const { return m_bottom_right; }
        bool anywhere_above() const { return m_top_left || m_top || m_top_right; }
        bool anywhere_below() const { return m_bottom_left || m_bottom || m_bottom_right; }
        bool anywhere_left() const { return m_top_left || m_left || m_bottom_left; }
        bool anywhere_right() const { return m_top_right || m_right || m_bottom_right; }

    private:
        bool m_top_left : 1 { false };
        bool m_top : 1 { false };
        bool m_top_right : 1 { false };
        bool m_left : 1 { false };
        bool m_right : 1 { false };
        bool m_bottom_left : 1 { false };
        bool m_bottom : 1 { false };
        bool m_bottom_right : 1 { false };
    };
    [[nodiscard]] RelativeLocation relative_location_to(Rect<T> const& other) const
    {
        return RelativeLocation(*this, other);
    }

    enum class Side {
        None = 0,
        Left,
        Top,
        Right,
        Bottom
    };
    [[nodiscard]] Side side(Point<T> const& point) const
    {
        if (is_empty())
            return Side::None;
        if (point.y() == y() || point.y() == bottom())
            return (point.x() >= x() && point.x() <= right()) ? (point.y() == y() ? Side::Top : Side::Bottom) : Side::None;
        if (point.x() == x() || point.x() == right())
            return (point.y() > y() && point.y() < bottom()) ? (point.x() == x() ? Side::Left : Side::Right) : Side::None;
        return Side::None;
    }

    [[nodiscard]] Rect<T> rect_on_side(Side side, Rect<T> const& other) const
    {
        switch (side) {
        case Side::None:
            break;
        case Side::Left:
            // Return the area in other that is to the left of this rect
            if (other.x() < x()) {
                if (other.right() >= x())
                    return { other.location(), { x() - other.x(), other.height() } };
                else
                    return other;
            }
            break;
        case Side::Top:
            // Return the area in other that is above this rect
            if (other.y() < y()) {
                if (other.bottom() >= y())
                    return { other.location(), { other.width(), y() - other.y() } };
                else
                    return other;
            }
            break;
        case Side::Right:
            // Return the area in other that is to the right of this rect
            if (other.right() >= x()) {
                if (other.x() <= right())
                    return { { right() + 1, other.y() }, { other.width() - (right() - other.x()), other.height() } };
                else
                    return other;
            }
            break;
        case Side::Bottom:
            // Return the area in other that is below this rect
            if (other.bottom() >= y()) {
                if (other.y() <= bottom())
                    return { { other.x(), bottom() + 1 }, { other.width(), other.height() - (bottom() - other.y()) } };
                else
                    return other;
            }
            break;
        }
        return {};
    }

    template<typename Container>
    static bool disperse(Container& rects)
    {
        auto has_intersecting = [&]() {
            for (auto& rect : rects) {
                for (auto& other_rect : rects) {
                    if (&rect == &other_rect)
                        continue;
                    if (rect.intersects(other_rect))
                        return true;
                }
            }
            return false;
        };

        if (!has_intersecting())
            return false;

        auto calc_delta = [&](Rect<T> const& rect) -> Point<T> {
            auto rect_center = rect.center();
            Point<T> center_sum;
            for (auto& other_rect : rects) {
                if (&other_rect == &rect)
                    continue;
                if (rect.intersects(other_rect))
                    center_sum += rect_center - other_rect.center();
            }
            double m = sqrt((double)center_sum.x() * (double)center_sum.x() + (double)center_sum.y() * (double)center_sum.y());
            if (m != 0.0)
                return { (double)center_sum.x() / m + 0.5, (double)center_sum.y() / m + 0.5 };
            return {};
        };

        Vector<Point<T>, 8> deltas;
        do {
            bool changes = false;

            deltas.clear_with_capacity();
            for (auto& rect : rects) {
                auto delta = calc_delta(rect);
                if (!delta.is_null())
                    changes = true;
                deltas.append(delta);
            }

            // TODO: If we have no changes we would loop infinitely!
            // Figure out some way to resolve this. Maybe randomly moving an intersecting rect?
            VERIFY(changes);

            size_t i = 0;
            for (auto& rect : rects)
                rect.translate_by(deltas[i++]);

        } while (has_intersecting());
        return true;
    }

    [[nodiscard]] bool is_adjacent(Rect<T> const& other) const
    {
        if (is_empty() || other.is_empty())
            return false;
        if (intersects(other))
            return false;
        if (other.x() + other.width() == x() || other.x() == x() + width())
            return max(top(), other.top()) <= min(bottom(), other.bottom());
        if (other.y() + other.height() == y() || other.y() == y() + height())
            return max(left(), other.left()) <= min(right(), other.right());
        return false;
    }

    [[nodiscard]] static Rect<T> centered_at(Point<T> const& point, Size<T> const& size)
    {
        return { { point.x() - size.width() / 2, point.y() - size.height() / 2 }, size };
    }

    [[nodiscard]] Rect<T> united(Rect<T> const&) const;

    [[nodiscard]] Point<T> top_left() const { return { left(), top() }; }
    [[nodiscard]] Point<T> top_right() const { return { right(), top() }; }
    [[nodiscard]] Point<T> bottom_left() const { return { left(), bottom() }; }
    [[nodiscard]] Point<T> bottom_right() const { return { right(), bottom() }; }

    void align_within(Rect<T> const&, TextAlignment);

    void center_within(Rect<T> const& other)
    {
        center_horizontally_within(other);
        center_vertically_within(other);
    }

    [[nodiscard]] Rect centered_within(Rect const& other) const
    {
        Rect rect { *this };
        rect.center_horizontally_within(other);
        rect.center_vertically_within(other);
        return rect;
    }

    void center_horizontally_within(Rect<T> const& other)
    {
        set_x(other.center().x() - width() / 2);
    }

    void center_vertically_within(Rect<T> const& other)
    {
        set_y(other.center().y() - height() / 2);
    }

    template<typename U>
    [[nodiscard]] ALWAYS_INLINE Rect<U> to_type() const
    {
        return Rect<U>(*this);
    }

    [[nodiscard]] String to_string() const;

private:
    Point<T> m_location;
    Size<T> m_size;
};

using IntRect = Rect<int>;
using FloatRect = Rect<float>;

[[nodiscard]] ALWAYS_INLINE IntRect enclosing_int_rect(FloatRect const& float_rect)
{
    int x1 = floorf(float_rect.x());
    int y1 = floorf(float_rect.y());
    int x2 = ceilf(float_rect.x() + float_rect.width());
    int y2 = ceilf(float_rect.y() + float_rect.height());
    return Gfx::IntRect::from_two_points({ x1, y1 }, { x2, y2 });
}

}

namespace AK {

template<typename T>
struct Formatter<Gfx::Rect<T>> : Formatter<StringView> {
    void format(FormatBuilder& builder, const Gfx::Rect<T>& value)
    {
        Formatter<StringView>::format(builder, value.to_string());
    }
};

}

namespace IPC {

bool decode(Decoder&, Gfx::IntRect&);
bool encode(Encoder&, const Gfx::IntRect&);

}