#include <XCEditor/Widgets/UIEditorVector4Field.h>

#include <XCEditor/Widgets/UIEditorFieldRowLayout.h>
#include <XCEditor/Widgets/UIEditorNumberField.h>
#include <XCEditor/Widgets/UIEditorTextLayout.h>

#include <algorithm>

namespace XCEngine::UI::Editor::Widgets {

namespace {

using ::XCEngine::UI::UIDrawList;
using ::XCEngine::UI::UIPoint;
using ::XCEngine::UI::UIRect;

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

float ApproximateTextWidth(float fontSize, std::size_t characterCount) {
    return fontSize * 0.55f * static_cast<float>(characterCount);
}

UIEditorNumberFieldSpec BuildComponentNumberSpec(
    const UIEditorVector4FieldSpec& spec,
    std::size_t componentIndex) {
    UIEditorNumberFieldSpec numberSpec = {};
    numberSpec.fieldId = spec.fieldId + "." + std::to_string(componentIndex);
    numberSpec.label.clear();
    numberSpec.value = componentIndex < spec.values.size() ? spec.values[componentIndex] : 0.0;
    numberSpec.step = spec.step;
    numberSpec.minValue = spec.minValue;
    numberSpec.maxValue = spec.maxValue;
    numberSpec.integerMode = spec.integerMode;
    numberSpec.readOnly = spec.readOnly;
    return numberSpec;
}

::XCEngine::UI::UIColor ResolveRowFillColor(
    const UIEditorVector4FieldState& state,
    const UIEditorVector4FieldPalette& palette) {
    if (state.activeTarget != UIEditorVector4FieldHitTargetKind::None) {
        return palette.rowActiveColor;
    }
    if (state.hoveredTarget != UIEditorVector4FieldHitTargetKind::None) {
        return palette.rowHoverColor;
    }
    return palette.surfaceColor;
}

::XCEngine::UI::UIColor ResolveComponentFillColor(
    const UIEditorVector4FieldSpec& spec,
    const UIEditorVector4FieldState& state,
    const UIEditorVector4FieldPalette& palette,
    std::size_t componentIndex) {
    if (spec.readOnly) {
        return palette.readOnlyColor;
    }
    if (state.editing && state.selectedComponentIndex == componentIndex) {
        return palette.componentEditingColor;
    }
    if (state.hoveredComponentIndex == componentIndex) {
        return palette.componentHoverColor;
    }
    return palette.componentColor;
}

::XCEngine::UI::UIColor ResolveComponentBorderColor(
    const UIEditorVector4FieldState& state,
    const UIEditorVector4FieldPalette& palette,
    std::size_t componentIndex) {
    if (state.editing && state.selectedComponentIndex == componentIndex) {
        return palette.componentFocusedBorderColor;
    }
    return palette.componentBorderColor;
}

::XCEngine::UI::UIColor ResolveAxisColor(
    const UIEditorVector4FieldPalette& palette,
    std::size_t componentIndex) {
    switch (componentIndex) {
    case 0u:
        return palette.axisXColor;
    case 1u:
        return palette.axisYColor;
    case 2u:
        return palette.axisZColor;
    case 3u:
    default:
        return palette.axisWColor;
    }
}

} // namespace

bool IsUIEditorVector4FieldPointInside(
    const UIRect& rect,
    const UIPoint& point) {
    return point.x >= rect.x &&
        point.x <= rect.x + rect.width &&
        point.y >= rect.y &&
        point.y <= rect.y + rect.height;
}

double NormalizeUIEditorVector4FieldComponentValue(
    const UIEditorVector4FieldSpec& spec,
    double value) {
    return NormalizeUIEditorNumberFieldValue(BuildComponentNumberSpec(spec, 0u), value);
}

bool TryParseUIEditorVector4FieldComponentValue(
    const UIEditorVector4FieldSpec& spec,
    std::string_view text,
    double& outValue) {
    return TryParseUIEditorNumberFieldValue(BuildComponentNumberSpec(spec, 0u), text, outValue);
}

std::string FormatUIEditorVector4FieldComponentValue(
    const UIEditorVector4FieldSpec& spec,
    std::size_t componentIndex) {
    return FormatUIEditorNumberFieldValue(BuildComponentNumberSpec(spec, componentIndex));
}

UIEditorVector4FieldLayout BuildUIEditorVector4FieldLayout(
    const UIRect& bounds,
    const UIEditorVector4FieldSpec&,
    const UIEditorVector4FieldMetrics& metrics) {
    const float requiredControlWidth = metrics.componentMinWidth * 4.0f + metrics.componentGap * 3.0f;
    const UIEditorFieldRowLayout hostLayout = BuildUIEditorFieldRowLayout(
        bounds,
        requiredControlWidth,
        UIEditorFieldRowLayoutMetrics {
            metrics.rowHeight,
            metrics.horizontalPadding,
            metrics.labelControlGap,
            metrics.controlColumnStart,
            metrics.controlTrailingInset,
            metrics.controlInsetY,
        });
    const float componentWidth =
        ClampNonNegative((hostLayout.controlRect.width - metrics.componentGap * 3.0f) / 4.0f);

    UIEditorVector4FieldLayout layout = {};
    layout.bounds = hostLayout.bounds;
    layout.labelRect = hostLayout.labelRect;
    layout.controlRect = hostLayout.controlRect;

    for (std::size_t componentIndex = 0u; componentIndex < layout.componentRects.size(); ++componentIndex) {
        const float componentX =
            layout.controlRect.x + (componentWidth + metrics.componentGap) * static_cast<float>(componentIndex);
        const UIRect componentRect(componentX, layout.controlRect.y, componentWidth, layout.controlRect.height);
        const float prefixWidth = (std::min)(metrics.componentPrefixWidth, componentRect.width);
        const float labelGap = ClampNonNegative(metrics.componentLabelGap);
        const float valueX = componentRect.x + prefixWidth + labelGap;
        layout.componentRects[componentIndex] = componentRect;
        layout.componentPrefixRects[componentIndex] =
            UIRect(componentRect.x, componentRect.y, prefixWidth, componentRect.height);
        layout.componentValueRects[componentIndex] =
            UIRect(
                valueX,
                componentRect.y,
                ClampNonNegative(componentRect.width - prefixWidth - labelGap),
                componentRect.height);
    }

    return layout;
}

UIEditorVector4FieldHitTarget HitTestUIEditorVector4Field(
    const UIEditorVector4FieldLayout& layout,
    const UIPoint& point) {
    for (std::size_t componentIndex = 0u; componentIndex < layout.componentRects.size(); ++componentIndex) {
        if (IsUIEditorVector4FieldPointInside(layout.componentRects[componentIndex], point)) {
            return { UIEditorVector4FieldHitTargetKind::Component, componentIndex };
        }
    }
    if (IsUIEditorVector4FieldPointInside(layout.bounds, point)) {
        return { UIEditorVector4FieldHitTargetKind::Row, UIEditorVector4FieldInvalidComponentIndex };
    }
    return {};
}

void AppendUIEditorVector4FieldBackground(
    UIDrawList& drawList,
    const UIEditorVector4FieldLayout& layout,
    const UIEditorVector4FieldSpec& spec,
    const UIEditorVector4FieldState& state,
    const UIEditorVector4FieldPalette& palette,
    const UIEditorVector4FieldMetrics& metrics) {
    if (ResolveRowFillColor(state, palette).a > 0.0f) {
        drawList.AddFilledRect(layout.bounds, ResolveRowFillColor(state, palette), metrics.cornerRounding);
    }
    if ((state.focused ? palette.focusedBorderColor.a : palette.borderColor.a) > 0.0f) {
        drawList.AddRectOutline(
            layout.bounds,
            state.focused ? palette.focusedBorderColor : palette.borderColor,
            state.focused ? metrics.focusedBorderThickness : metrics.borderThickness,
            metrics.cornerRounding);
    }

    for (std::size_t componentIndex = 0u; componentIndex < layout.componentRects.size(); ++componentIndex) {
        drawList.AddFilledRect(
            layout.componentValueRects[componentIndex],
            ResolveComponentFillColor(spec, state, palette, componentIndex),
            metrics.componentRounding);
        drawList.AddRectOutline(
            layout.componentValueRects[componentIndex],
            ResolveComponentBorderColor(state, palette, componentIndex),
            metrics.borderThickness,
            metrics.componentRounding);
    }
}

void AppendUIEditorVector4FieldForeground(
    UIDrawList& drawList,
    const UIEditorVector4FieldLayout& layout,
    const UIEditorVector4FieldSpec& spec,
    const UIEditorVector4FieldState& state,
    const UIEditorVector4FieldPalette& palette,
    const UIEditorVector4FieldMetrics& metrics) {
    drawList.PushClipRect(ResolveUIEditorTextClipRect(layout.labelRect, metrics.labelFontSize));
    drawList.AddText(
        UIPoint(
            layout.labelRect.x,
            ResolveUIEditorTextTop(layout.labelRect, metrics.labelFontSize, metrics.labelTextInsetY)),
        spec.label,
        palette.labelColor,
        metrics.labelFontSize);
    drawList.PopClipRect();

    for (std::size_t componentIndex = 0u; componentIndex < layout.componentRects.size(); ++componentIndex) {
        drawList.PushClipRect(
            ResolveUIEditorTextClipRect(layout.componentPrefixRects[componentIndex], metrics.prefixFontSize));
        const std::string& componentLabel = spec.componentLabels[componentIndex];
        const float prefixTextX =
            layout.componentPrefixRects[componentIndex].x +
            ClampNonNegative(
                (layout.componentPrefixRects[componentIndex].width -
                 ApproximateTextWidth(metrics.prefixFontSize, componentLabel.size())) *
                0.5f) +
            metrics.prefixTextInsetX;
        drawList.AddText(
            UIPoint(
                prefixTextX,
                ResolveUIEditorTextTop(
                    layout.componentPrefixRects[componentIndex],
                    metrics.prefixFontSize,
                    metrics.prefixTextInsetY)),
            componentLabel,
            ResolveAxisColor(palette, componentIndex),
            metrics.prefixFontSize);
        drawList.PopClipRect();

        drawList.PushClipRect(
            ResolveUIEditorTextClipRect(layout.componentValueRects[componentIndex], metrics.valueFontSize));
        drawList.AddText(
            UIPoint(
                layout.componentValueRects[componentIndex].x + metrics.valueTextInsetX,
                ResolveUIEditorTextTop(
                    layout.componentValueRects[componentIndex],
                    metrics.valueFontSize,
                    metrics.valueTextInsetY)),
            state.editing && state.selectedComponentIndex == componentIndex
                ? state.displayTexts[componentIndex]
                : FormatUIEditorVector4FieldComponentValue(spec, componentIndex),
            spec.readOnly ? palette.readOnlyValueColor : palette.valueColor,
            metrics.valueFontSize);
        drawList.PopClipRect();
    }
}

void AppendUIEditorVector4Field(
    UIDrawList& drawList,
    const UIRect& bounds,
    const UIEditorVector4FieldSpec& spec,
    const UIEditorVector4FieldState& state,
    const UIEditorVector4FieldPalette& palette,
    const UIEditorVector4FieldMetrics& metrics) {
    const UIEditorVector4FieldLayout layout = BuildUIEditorVector4FieldLayout(bounds, spec, metrics);
    AppendUIEditorVector4FieldBackground(drawList, layout, spec, state, palette, metrics);
    AppendUIEditorVector4FieldForeground(drawList, layout, spec, state, palette, metrics);
}

} // namespace XCEngine::UI::Editor::Widgets