#include <gtest/gtest.h>

#include <XCEngine/UI/Layout/LayoutEngine.h>

namespace {

using XCEngine::UI::UIRect;
using XCEngine::UI::UISize;
using XCEngine::UI::Layout::ArrangeOverlayLayout;
using XCEngine::UI::Layout::ArrangeStackLayout;
using XCEngine::UI::Layout::MeasureOverlayLayout;
using XCEngine::UI::Layout::MeasureStackLayout;
using XCEngine::UI::Layout::UILayoutAlignment;
using XCEngine::UI::Layout::UILayoutAxis;
using XCEngine::UI::Layout::UILayoutConstraints;
using XCEngine::UI::Layout::UILayoutItem;
using XCEngine::UI::Layout::UILayoutLength;
using XCEngine::UI::Layout::UILayoutThickness;
using XCEngine::UI::Layout::UIOverlayLayoutOptions;
using XCEngine::UI::Layout::UIStackLayoutOptions;

void ExpectRect(
    const UIRect& rect,
    float x,
    float y,
    float width,
    float height) {
    EXPECT_FLOAT_EQ(rect.x, x);
    EXPECT_FLOAT_EQ(rect.y, y);
    EXPECT_FLOAT_EQ(rect.width, width);
    EXPECT_FLOAT_EQ(rect.height, height);
}

} // namespace

TEST(UI_Layout, MeasureHorizontalStackAccumulatesSpacingPaddingAndCrossExtent) {
    UIStackLayoutOptions options = {};
    options.axis = UILayoutAxis::Horizontal;
    options.spacing = 5.0f;
    options.padding = UILayoutThickness::Symmetric(10.0f, 6.0f);

    std::vector<UILayoutItem> items(2);
    items[0].desiredContentSize = UISize(40.0f, 20.0f);
    items[1].desiredContentSize = UISize(60.0f, 30.0f);

    const auto result = MeasureStackLayout(options, items);

    EXPECT_FLOAT_EQ(result.desiredSize.width, 125.0f);
    EXPECT_FLOAT_EQ(result.desiredSize.height, 42.0f);
}

TEST(UI_Layout, ArrangeHorizontalStackDistributesRemainingSpaceToStretchChildren) {
    UIStackLayoutOptions options = {};
    options.axis = UILayoutAxis::Horizontal;
    options.spacing = 5.0f;
    options.padding = UILayoutThickness::Uniform(10.0f);

    std::vector<UILayoutItem> items(3);
    items[0].width = UILayoutLength::Pixels(100.0f);
    items[0].desiredContentSize = UISize(10.0f, 20.0f);

    items[1].width = UILayoutLength::Stretch(1.0f);
    items[1].desiredContentSize = UISize(30.0f, 20.0f);

    items[2].width = UILayoutLength::Pixels(50.0f);
    items[2].desiredContentSize = UISize(10.0f, 20.0f);

    const auto result = ArrangeStackLayout(options, items, UIRect(0.0f, 0.0f, 300.0f, 80.0f));

    ExpectRect(result.children[0].arrangedRect, 10.0f, 10.0f, 100.0f, 20.0f);
    ExpectRect(result.children[1].arrangedRect, 115.0f, 10.0f, 120.0f, 20.0f);
    ExpectRect(result.children[2].arrangedRect, 240.0f, 10.0f, 50.0f, 20.0f);
}

TEST(UI_Layout, ArrangeVerticalStackSupportsCrossAxisStretch) {
    UIStackLayoutOptions options = {};
    options.axis = UILayoutAxis::Vertical;
    options.spacing = 4.0f;
    options.padding = UILayoutThickness::Symmetric(8.0f, 6.0f);

    std::vector<UILayoutItem> items(2);
    items[0].desiredContentSize = UISize(40.0f, 10.0f);
    items[0].horizontalAlignment = UILayoutAlignment::Stretch;
    items[1].desiredContentSize = UISize(60.0f, 20.0f);

    const auto result = ArrangeStackLayout(options, items, UIRect(0.0f, 0.0f, 200.0f, 100.0f));

    ExpectRect(result.children[0].arrangedRect, 8.0f, 6.0f, 184.0f, 10.0f);
    ExpectRect(result.children[1].arrangedRect, 8.0f, 20.0f, 60.0f, 20.0f);
}

TEST(UI_Layout, ArrangeOverlaySupportsCenterAndStretch) {
    UIOverlayLayoutOptions options = {};
    options.padding = UILayoutThickness::Uniform(10.0f);

    std::vector<UILayoutItem> items(2);
    items[0].desiredContentSize = UISize(40.0f, 20.0f);
    items[0].horizontalAlignment = UILayoutAlignment::Center;
    items[0].verticalAlignment = UILayoutAlignment::Center;

    items[1].desiredContentSize = UISize(10.0f, 10.0f);
    items[1].width = UILayoutLength::Stretch();
    items[1].height = UILayoutLength::Stretch();
    items[1].margin = UILayoutThickness::Uniform(5.0f);

    const auto result = ArrangeOverlayLayout(options, items, UIRect(0.0f, 0.0f, 100.0f, 60.0f));

    ExpectRect(result.children[0].arrangedRect, 30.0f, 20.0f, 40.0f, 20.0f);
    ExpectRect(result.children[1].arrangedRect, 15.0f, 15.0f, 70.0f, 30.0f);
}

TEST(UI_Layout, MeasureOverlayRespectsItemMinMaxAndAvailableConstraints) {
    UIOverlayLayoutOptions options = {};

    std::vector<UILayoutItem> items(1);
    items[0].width = UILayoutLength::Pixels(500.0f);
    items[0].desiredContentSize = UISize(10.0f, 10.0f);
    items[0].minSize = UISize(0.0f, 50.0f);
    items[0].maxSize = UISize(200.0f, 120.0f);

    const auto result = MeasureOverlayLayout(
        options,
        items,
        UILayoutConstraints::Bounded(150.0f, 100.0f));

    EXPECT_FLOAT_EQ(result.children[0].measuredSize.width, 150.0f);
    EXPECT_FLOAT_EQ(result.children[0].measuredSize.height, 50.0f);
    EXPECT_FLOAT_EQ(result.desiredSize.width, 150.0f);
    EXPECT_FLOAT_EQ(result.desiredSize.height, 50.0f);
}