#include <XCEditor/Shell/UIEditorShellCompose.h>

#include <algorithm>

namespace XCEngine::UI::Editor {

namespace {

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));
}

} // namespace

UIEditorShellComposeLayout BuildUIEditorShellComposeLayout(
    const UIRect& bounds,
    const std::vector<Widgets::UIEditorMenuBarItem>& menuBarItems,
    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 statusBarHeight = ClampNonNegative(metrics.statusBarMetrics.barHeight);
    const float sectionGap = ClampNonNegative(metrics.sectionGap);
    const float availableHeight = layout.contentRect.height;
    const float combinedBars = menuBarHeight + statusBarHeight;
    const float gapBudget = combinedBars > 0.0f ? sectionGap * 2.0f : 0.0f;
    const float clampedGapBudget = (std::min)(gapBudget, availableHeight);
    const float workspaceHeight =
        (std::max)(0.0f, availableHeight - combinedBars - clampedGapBudget);

    float cursorY = layout.contentRect.y;
    if (menuBarHeight > 0.0f) {
        layout.menuBarRect = UIRect(
            layout.contentRect.x,
            cursorY,
            layout.contentRect.width,
            menuBarHeight);
        cursorY += menuBarHeight + sectionGap;
    }

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

    if (statusBarHeight > 0.0f) {
        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.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.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.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.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.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);

    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