#include <XCEditor/Shell/UIEditorShellCompose.h>

#include <algorithm>

namespace XCEngine::UI::Editor {

namespace {

using ::XCEngine::UI::UIColor;
using ::XCEngine::UI::UIPoint;
using ::XCEngine::UI::UIRect;
using Widgets::AppendUIEditorMenuBarBackground;
using Widgets::AppendUIEditorMenuBarForeground;
using Widgets::AppendUIEditorStatusBarBackground;
using Widgets::AppendUIEditorStatusBarForeground;
using Widgets::BuildUIEditorMenuBarLayout;
using Widgets::BuildUIEditorStatusBarLayout;

float ClampNonNegative(float value) {
    return (std::max)(value, 0.0f);
}

UIRect InsetRect(const UIRect& rect, float inset) {
    const float clampedInset = ClampNonNegative(inset);
    const float insetX = (std::min)(clampedInset, rect.width * 0.5f);
    const float insetY = (std::min)(clampedInset, rect.height * 0.5f);
    return UIRect(
        rect.x + insetX,
        rect.y + insetY,
        (std::max)(0.0f, rect.width - insetX * 2.0f),
        (std::max)(0.0f, rect.height - insetY * 2.0f));
}

UIEditorShellToolbarLayout BuildUIEditorShellToolbarLayout(
    const UIRect& bounds,
    const std::vector<UIEditorShellToolbarButton>& buttons,
    const UIEditorShellToolbarMetrics& metrics) {
    UIEditorShellToolbarLayout layout = {};
    layout.bounds = bounds;
    if (buttons.empty() || bounds.width <= 0.0f || bounds.height <= 0.0f) {
        return layout;
    }

    const float buttonWidth = ClampNonNegative(metrics.buttonWidth);
    const float buttonHeight = ClampNonNegative(metrics.buttonHeight);
    const float buttonGap = ClampNonNegative(metrics.buttonGap);
    const float groupPaddingX = ClampNonNegative(metrics.groupPaddingX);
    const float groupPaddingY = ClampNonNegative(metrics.groupPaddingY);
    const float totalButtonWidth =
        buttonWidth * static_cast<float>(buttons.size()) +
        buttonGap * static_cast<float>((std::max)(std::ptrdiff_t(0), static_cast<std::ptrdiff_t>(buttons.size()) - 1));
    const float groupWidth = totalButtonWidth + groupPaddingX * 2.0f;
    const float groupHeight =
        (std::min)(bounds.height, buttonHeight + groupPaddingY * 2.0f);

    layout.groupRect = UIRect(
        bounds.x + (std::max)(0.0f, (bounds.width - groupWidth) * 0.5f),
        bounds.y + (std::max)(0.0f, (bounds.height - groupHeight) * 0.5f),
        (std::min)(groupWidth, bounds.width),
        groupHeight);

    const float buttonY =
        layout.groupRect.y + (std::max)(0.0f, (layout.groupRect.height - buttonHeight) * 0.5f);
    float buttonX = layout.groupRect.x + groupPaddingX;
    layout.buttonRects.reserve(buttons.size());
    for (std::size_t index = 0; index < buttons.size(); ++index) {
        layout.buttonRects.push_back(UIRect(buttonX, buttonY, buttonWidth, buttonHeight));
        buttonX += buttonWidth + buttonGap;
    }

    return layout;
}

void AppendPlayGlyph(
    ::XCEngine::UI::UIDrawList& drawList,
    const UIRect& rect,
    const UIColor& color,
    float thickness) {
    const UIPoint a(rect.x + rect.width * 0.38f, rect.y + rect.height * 0.27f);
    const UIPoint b(rect.x + rect.width * 0.38f, rect.y + rect.height * 0.73f);
    const UIPoint c(rect.x + rect.width * 0.70f, rect.y + rect.height * 0.50f);
    drawList.AddLine(a, b, color, thickness);
    drawList.AddLine(a, c, color, thickness);
    drawList.AddLine(b, c, color, thickness);
}

void AppendPauseGlyph(
    ::XCEngine::UI::UIDrawList& drawList,
    const UIRect& rect,
    const UIColor& color,
    float thickness) {
    const float top = rect.y + rect.height * 0.26f;
    const float bottom = rect.y + rect.height * 0.74f;
    const float left = rect.x + rect.width * 0.40f;
    const float right = rect.x + rect.width * 0.60f;
    drawList.AddLine(UIPoint(left, top), UIPoint(left, bottom), color, thickness);
    drawList.AddLine(UIPoint(right, top), UIPoint(right, bottom), color, thickness);
}

void AppendStepGlyph(
    ::XCEngine::UI::UIDrawList& drawList,
    const UIRect& rect,
    const UIColor& color,
    float thickness) {
    const UIPoint a(rect.x + rect.width * 0.30f, rect.y + rect.height * 0.27f);
    const UIPoint b(rect.x + rect.width * 0.30f, rect.y + rect.height * 0.73f);
    const UIPoint c(rect.x + rect.width * 0.58f, rect.y + rect.height * 0.50f);
    const float barX = rect.x + rect.width * 0.70f;
    drawList.AddLine(a, b, color, thickness);
    drawList.AddLine(a, c, color, thickness);
    drawList.AddLine(b, c, color, thickness);
    drawList.AddLine(
        UIPoint(barX, rect.y + rect.height * 0.25f),
        UIPoint(barX, rect.y + rect.height * 0.75f),
        color,
        thickness);
}

void AppendToolbarGlyph(
    ::XCEngine::UI::UIDrawList& drawList,
    const UIRect& rect,
    UIEditorShellToolbarGlyph glyph,
    const UIColor& color,
    float thickness) {
    switch (glyph) {
    case UIEditorShellToolbarGlyph::Play:
        AppendPlayGlyph(drawList, rect, color, thickness);
        break;
    case UIEditorShellToolbarGlyph::Pause:
        AppendPauseGlyph(drawList, rect, color, thickness);
        break;
    case UIEditorShellToolbarGlyph::Step:
        AppendStepGlyph(drawList, rect, color, thickness);
        break;
    default:
        break;
    }
}

void AppendUIEditorShellToolbar(
    ::XCEngine::UI::UIDrawList& drawList,
    const UIEditorShellToolbarLayout& layout,
    const std::vector<UIEditorShellToolbarButton>& buttons,
    const UIEditorShellToolbarPalette& palette,
    const UIEditorShellToolbarMetrics& metrics) {
    if (layout.bounds.width <= 0.0f || layout.bounds.height <= 0.0f) {
        return;
    }

    drawList.AddFilledRect(layout.bounds, palette.barColor);
    drawList.AddLine(
        UIPoint(layout.bounds.x, layout.bounds.y + layout.bounds.height - 1.0f),
        UIPoint(layout.bounds.x + layout.bounds.width, layout.bounds.y + layout.bounds.height - 1.0f),
        palette.groupBorderColor,
        metrics.borderThickness);

    if (buttons.empty() || layout.groupRect.width <= 0.0f || layout.groupRect.height <= 0.0f) {
        return;
    }

    drawList.AddFilledRect(
        layout.groupRect,
        palette.groupColor,
        metrics.groupCornerRounding);
    drawList.AddRectOutline(
        layout.groupRect,
        palette.groupBorderColor,
        metrics.borderThickness,
        metrics.groupCornerRounding);

    const std::size_t buttonCount = (std::min)(buttons.size(), layout.buttonRects.size());
    for (std::size_t index = 0; index < buttonCount; ++index) {
        const UIRect& buttonRect = layout.buttonRects[index];
        drawList.AddFilledRect(
            buttonRect,
            palette.buttonColor,
            metrics.buttonCornerRounding);
        drawList.AddRectOutline(
            buttonRect,
            palette.buttonBorderColor,
            metrics.borderThickness,
            metrics.buttonCornerRounding);
        AppendToolbarGlyph(
            drawList,
            buttonRect,
            buttons[index].glyph,
            palette.iconColor,
            metrics.iconThickness);
    }
}

} // namespace

UIEditorShellComposeLayout BuildUIEditorShellComposeLayout(
    const UIRect& bounds,
    const std::vector<Widgets::UIEditorMenuBarItem>& menuBarItems,
    const std::vector<UIEditorShellToolbarButton>& toolbarButtons,
    const std::vector<Widgets::UIEditorStatusBarSegment>& statusSegments,
    const UIEditorShellComposeMetrics& metrics) {
    UIEditorShellComposeLayout layout = {};
    layout.bounds = UIRect(
        bounds.x,
        bounds.y,
        ClampNonNegative(bounds.width),
        ClampNonNegative(bounds.height));
    layout.contentRect = InsetRect(layout.bounds, metrics.outerPadding);

    const float menuBarHeight = ClampNonNegative(metrics.menuBarMetrics.barHeight);
    const float toolbarHeight = ClampNonNegative(metrics.toolbarMetrics.barHeight);
    const float statusBarHeight = ClampNonNegative(metrics.statusBarMetrics.barHeight);
    const float sectionGap = ClampNonNegative(metrics.sectionGap);
    const bool hasMenuBar = menuBarHeight > 0.0f && !menuBarItems.empty();
    const bool hasToolbar = toolbarHeight > 0.0f && !toolbarButtons.empty();
    const bool hasStatusBar = statusBarHeight > 0.0f && !statusSegments.empty();

    float gapCount = 0.0f;
    if (hasMenuBar) {
        gapCount += 1.0f;
    }
    if (hasToolbar) {
        gapCount += 1.0f;
    }
    if (hasStatusBar) {
        gapCount += 1.0f;
    }

    const float availableHeight = layout.contentRect.height;
    const float consumedHeight =
        (hasMenuBar ? menuBarHeight : 0.0f) +
        (hasToolbar ? toolbarHeight : 0.0f) +
        (hasStatusBar ? statusBarHeight : 0.0f) +
        sectionGap * gapCount;
    const float workspaceHeight =
        (std::max)(0.0f, availableHeight - consumedHeight);

    float cursorY = layout.contentRect.y;
    if (hasMenuBar) {
        layout.menuBarRect = UIRect(
            layout.contentRect.x,
            cursorY,
            layout.contentRect.width,
            menuBarHeight);
        cursorY += menuBarHeight + sectionGap;
    }

    if (hasToolbar) {
        layout.toolbarRect = UIRect(
            layout.contentRect.x,
            cursorY,
            layout.contentRect.width,
            toolbarHeight);
        cursorY += toolbarHeight + sectionGap;
    }

    layout.workspaceRect = UIRect(
        layout.contentRect.x,
        cursorY,
        layout.contentRect.width,
        workspaceHeight);

    if (hasStatusBar) {
        layout.statusBarRect = UIRect(
            layout.contentRect.x,
            layout.contentRect.y + layout.contentRect.height - statusBarHeight,
            layout.contentRect.width,
            statusBarHeight);
    }

    layout.menuBarLayout =
        BuildUIEditorMenuBarLayout(layout.menuBarRect, menuBarItems, metrics.menuBarMetrics);
    layout.toolbarLayout =
        BuildUIEditorShellToolbarLayout(layout.toolbarRect, toolbarButtons, metrics.toolbarMetrics);
    layout.statusBarLayout =
        BuildUIEditorStatusBarLayout(layout.statusBarRect, statusSegments, metrics.statusBarMetrics);
    return layout;
}

UIEditorShellComposeRequest ResolveUIEditorShellComposeRequest(
    const UIRect& bounds,
    const UIEditorPanelRegistry& panelRegistry,
    const UIEditorWorkspaceModel& workspace,
    const UIEditorWorkspaceSession& session,
    const UIEditorShellComposeModel& model,
    const Widgets::UIEditorDockHostState& dockHostState,
    const UIEditorShellComposeState& state,
    const UIEditorShellComposeMetrics& metrics) {
    UIEditorShellComposeRequest request = {};
    request.layout = BuildUIEditorShellComposeLayout(
        bounds,
        model.menuBarItems,
        model.toolbarButtons,
        model.statusSegments,
        metrics);
    request.workspaceRequest = ResolveUIEditorWorkspaceComposeRequest(
        request.layout.workspaceRect,
        panelRegistry,
        workspace,
        session,
        model.workspacePresentations,
        dockHostState,
        metrics.dockHostMetrics,
        metrics.viewportMetrics);
    request.layout.menuBarLayout = BuildUIEditorMenuBarLayout(
        request.layout.menuBarRect,
        model.menuBarItems,
        metrics.menuBarMetrics);
    request.layout.toolbarLayout = BuildUIEditorShellToolbarLayout(
        request.layout.toolbarRect,
        model.toolbarButtons,
        metrics.toolbarMetrics);
    request.layout.statusBarLayout = BuildUIEditorStatusBarLayout(
        request.layout.statusBarRect,
        model.statusSegments,
        metrics.statusBarMetrics);
    (void)state;
    return request;
}

UIEditorShellComposeFrame UpdateUIEditorShellCompose(
    UIEditorShellComposeState& state,
    const UIRect& bounds,
    const UIEditorPanelRegistry& panelRegistry,
    const UIEditorWorkspaceModel& workspace,
    const UIEditorWorkspaceSession& session,
    const UIEditorShellComposeModel& model,
    const std::vector<::XCEngine::UI::UIInputEvent>& inputEvents,
    const Widgets::UIEditorDockHostState& dockHostState,
    const UIEditorShellComposeMetrics& metrics) {
    UIEditorShellComposeFrame frame = {};
    frame.layout = BuildUIEditorShellComposeLayout(
        bounds,
        model.menuBarItems,
        model.toolbarButtons,
        model.statusSegments,
        metrics);
    frame.workspaceFrame = UpdateUIEditorWorkspaceCompose(
        state.workspaceState,
        frame.layout.workspaceRect,
        panelRegistry,
        workspace,
        session,
        model.workspacePresentations,
        inputEvents,
        dockHostState,
        metrics.dockHostMetrics,
        metrics.viewportMetrics);
    frame.layout.menuBarLayout = BuildUIEditorMenuBarLayout(
        frame.layout.menuBarRect,
        model.menuBarItems,
        metrics.menuBarMetrics);
    frame.layout.toolbarLayout = BuildUIEditorShellToolbarLayout(
        frame.layout.toolbarRect,
        model.toolbarButtons,
        metrics.toolbarMetrics);
    frame.layout.statusBarLayout = BuildUIEditorStatusBarLayout(
        frame.layout.statusBarRect,
        model.statusSegments,
        metrics.statusBarMetrics);
    return frame;
}

void AppendUIEditorShellCompose(
    ::XCEngine::UI::UIDrawList& drawList,
    const UIEditorShellComposeFrame& frame,
    const UIEditorShellComposeModel& model,
    const UIEditorShellComposeState& state,
    const UIEditorShellComposePalette& palette,
    const UIEditorShellComposeMetrics& metrics) {
    drawList.AddFilledRect(
        frame.layout.bounds,
        palette.surfaceColor,
        metrics.surfaceCornerRounding);
    drawList.AddRectOutline(
        frame.layout.bounds,
        palette.surfaceBorderColor,
        1.0f,
        metrics.surfaceCornerRounding);

    AppendUIEditorMenuBarBackground(
        drawList,
        frame.layout.menuBarLayout,
        model.menuBarItems,
        state.menuBarState,
        palette.menuBarPalette,
        metrics.menuBarMetrics);
    AppendUIEditorMenuBarForeground(
        drawList,
        frame.layout.menuBarLayout,
        model.menuBarItems,
        state.menuBarState,
        palette.menuBarPalette,
        metrics.menuBarMetrics);

    AppendUIEditorShellToolbar(
        drawList,
        frame.layout.toolbarLayout,
        model.toolbarButtons,
        palette.toolbarPalette,
        metrics.toolbarMetrics);

    AppendUIEditorWorkspaceCompose(
        drawList,
        frame.workspaceFrame,
        palette.dockHostPalette,
        metrics.dockHostMetrics,
        palette.viewportPalette,
        metrics.viewportMetrics);

    AppendUIEditorStatusBarBackground(
        drawList,
        frame.layout.statusBarLayout,
        model.statusSegments,
        state.statusBarState,
        palette.statusBarPalette,
        metrics.statusBarMetrics);
    AppendUIEditorStatusBarForeground(
        drawList,
        frame.layout.statusBarLayout,
        model.statusSegments,
        state.statusBarState,
        palette.statusBarPalette,
        metrics.statusBarMetrics);
}

} // namespace XCEngine::UI::Editor