#pragma once

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

#include <algorithm>
#include <cstddef>
#include <string>
#include <string_view>

namespace XCEngine::UI::Editor::Internal::VectorFieldWidgetShared {

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

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

inline ::XCEngine::UI::UIColor DefaultAxisPlaceholderColor() {
    return ::XCEngine::UI::UIColor(0.67f, 0.67f, 0.67f, 1.0f);
}

inline void OverrideMetricIfDefault(
    float& value,
    float placeholder,
    float replacement) {
    if (Widgets::AreUIEditorFieldMetricsEqual(value, placeholder)) {
        value = replacement;
    }
}

inline void OverrideColorIfDefault(
    ::XCEngine::UI::UIColor& value,
    const ::XCEngine::UI::UIColor& placeholder,
    const ::XCEngine::UI::UIColor& replacement) {
    if (Widgets::AreUIEditorFieldColorsEqual(value, placeholder)) {
        value = replacement;
    }
}

inline const ::XCEngine::UI::UIColor& ResolveAxisTokenColor(
    const Widgets::UIEditorInspectorFieldStyleTokens& tokens,
    std::size_t componentIndex) {
    switch (componentIndex) {
    case 0u:
        return tokens.axisXColor;
    case 1u:
        return tokens.axisYColor;
    case 2u:
        return tokens.axisZColor;
    default:
        return tokens.axisWColor;
    }
}

template <typename Traits>
typename Traits::Metrics ResolveMetrics(const typename Traits::Metrics& metrics) {
    const auto& tokens = Widgets::GetUIEditorInspectorFieldStyleTokens();

    typename Traits::Metrics resolved = metrics;
    OverrideMetricIfDefault(
        resolved.controlTrailingInset,
        8.0f,
        tokens.controlTrailingInset);
    OverrideMetricIfDefault(
        resolved.componentMinWidth,
        72.0f,
        tokens.vectorComponentMinWidth);
    OverrideMetricIfDefault(
        resolved.componentPrefixWidth,
        9.0f,
        tokens.vectorPrefixWidth);
    OverrideMetricIfDefault(
        resolved.componentLabelGap,
        4.0f,
        tokens.vectorPrefixGap);

    return resolved;
}

template <typename Traits>
typename Traits::Palette ResolvePalette(const typename Traits::Palette& palette) {
    const auto& tokens = Widgets::GetUIEditorInspectorFieldStyleTokens();

    typename Traits::Palette resolved = palette;
    OverrideColorIfDefault(
        resolved.componentColor,
        ::XCEngine::UI::UIColor(0.18f, 0.18f, 0.18f, 1.0f),
        tokens.controlColor);
    OverrideColorIfDefault(
        resolved.componentHoverColor,
        ::XCEngine::UI::UIColor(0.21f, 0.21f, 0.21f, 1.0f),
        tokens.controlHoverColor);
    OverrideColorIfDefault(
        resolved.componentEditingColor,
        ::XCEngine::UI::UIColor(0.24f, 0.24f, 0.24f, 1.0f),
        tokens.controlEditingColor);
    OverrideColorIfDefault(
        resolved.readOnlyColor,
        ::XCEngine::UI::UIColor(0.17f, 0.17f, 0.17f, 1.0f),
        tokens.controlReadOnlyColor);
    OverrideColorIfDefault(
        resolved.componentBorderColor,
        ::XCEngine::UI::UIColor(0.14f, 0.14f, 0.14f, 1.0f),
        tokens.controlBorderColor);
    OverrideColorIfDefault(
        resolved.componentFocusedBorderColor,
        ::XCEngine::UI::UIColor(0.20f, 0.20f, 0.20f, 1.0f),
        tokens.controlFocusedBorderColor);
    OverrideColorIfDefault(
        resolved.prefixColor,
        ::XCEngine::UI::UIColor(0.0f, 0.0f, 0.0f, 0.0f),
        tokens.prefixColor);
    OverrideColorIfDefault(
        resolved.prefixBorderColor,
        ::XCEngine::UI::UIColor(0.0f, 0.0f, 0.0f, 0.0f),
        tokens.prefixBorderColor);
    OverrideColorIfDefault(
        resolved.labelColor,
        ::XCEngine::UI::UIColor(0.80f, 0.80f, 0.80f, 1.0f),
        tokens.labelColor);
    OverrideColorIfDefault(
        resolved.valueColor,
        ::XCEngine::UI::UIColor(0.92f, 0.92f, 0.92f, 1.0f),
        tokens.valueColor);
    OverrideColorIfDefault(
        resolved.readOnlyValueColor,
        ::XCEngine::UI::UIColor(0.62f, 0.62f, 0.62f, 1.0f),
        tokens.readOnlyValueColor);

    for (std::size_t componentIndex = 0u;
         componentIndex < Traits::kComponentCount;
         ++componentIndex) {
        if (Widgets::AreUIEditorFieldColorsEqual(
                Traits::AxisColor(palette, componentIndex),
                DefaultAxisPlaceholderColor())) {
            Traits::AxisColor(resolved, componentIndex) =
                ResolveAxisTokenColor(tokens, componentIndex);
        }
    }

    return resolved;
}

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

template <typename Traits>
Widgets::UIEditorNumberFieldSpec BuildComponentNumberSpec(
    const typename Traits::Spec& spec,
    std::size_t componentIndex) {
    Widgets::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;
}

template <typename Traits>
::XCEngine::UI::UIColor ResolveRowFillColor(
    const typename Traits::State& state,
    const typename Traits::Palette& palette) {
    if (state.activeTarget != Traits::kNoneHitTargetKind) {
        return palette.rowActiveColor;
    }
    if (state.hoveredTarget != Traits::kNoneHitTargetKind) {
        return palette.rowHoverColor;
    }
    return palette.surfaceColor;
}

template <typename Traits>
::XCEngine::UI::UIColor ResolveComponentFillColor(
    const typename Traits::Spec& spec,
    const typename Traits::State& state,
    const typename Traits::Palette& 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;
}

template <typename Traits>
::XCEngine::UI::UIColor ResolveComponentBorderColor(
    const typename Traits::State& state,
    const typename Traits::Palette& palette,
    std::size_t componentIndex) {
    if (state.editing && state.selectedComponentIndex == componentIndex) {
        return palette.componentFocusedBorderColor;
    }
    return palette.componentBorderColor;
}

inline bool IsPointInside(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;
}

template <typename Traits>
double NormalizeComponentValue(
    const typename Traits::Spec& spec,
    double value) {
    return Widgets::NormalizeUIEditorNumberFieldValue(
        BuildComponentNumberSpec<Traits>(spec, 0u),
        value);
}

template <typename Traits>
bool TryParseComponentValue(
    const typename Traits::Spec& spec,
    std::string_view text,
    double& outValue) {
    return Widgets::TryParseUIEditorNumberFieldValue(
        BuildComponentNumberSpec<Traits>(spec, 0u),
        text,
        outValue);
}

template <typename Traits>
std::string FormatComponentValue(
    const typename Traits::Spec& spec,
    std::size_t componentIndex) {
    return Widgets::FormatUIEditorNumberFieldValue(
        BuildComponentNumberSpec<Traits>(spec, componentIndex));
}

template <typename Traits>
typename Traits::Layout BuildLayout(
    const UIRect& bounds,
    const typename Traits::Spec&,
    const typename Traits::Metrics& metrics) {
    static_assert(Traits::kComponentCount > 0u);

    const typename Traits::Metrics resolvedMetrics = ResolveMetrics<Traits>(metrics);
    const float gapCount = static_cast<float>(Traits::kComponentCount - 1u);
    const float requiredControlWidth =
        resolvedMetrics.componentMinWidth * static_cast<float>(Traits::kComponentCount) +
        resolvedMetrics.componentGap * gapCount;
    const Widgets::UIEditorFieldRowLayout hostLayout =
        Widgets::BuildUIEditorFieldRowLayout(
            bounds,
            requiredControlWidth,
            Widgets::UIEditorFieldRowLayoutMetrics{
                resolvedMetrics.rowHeight,
                resolvedMetrics.horizontalPadding,
                resolvedMetrics.labelControlGap,
                resolvedMetrics.controlColumnStart,
                resolvedMetrics.sharedControlColumnMinWidth,
                resolvedMetrics.controlTrailingInset,
                resolvedMetrics.controlInsetY,
            });
    const float componentWidth = ClampNonNegative(
        (hostLayout.controlRect.width - resolvedMetrics.componentGap * gapCount) /
        static_cast<float>(Traits::kComponentCount));

    typename Traits::Layout 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 + resolvedMetrics.componentGap) *
                static_cast<float>(componentIndex);
        const UIRect componentRect(
            componentX,
            layout.controlRect.y,
            componentWidth,
            layout.controlRect.height);
        const float prefixWidth =
            (std::min)(resolvedMetrics.componentPrefixWidth, componentRect.width);
        const float labelGap = ClampNonNegative(resolvedMetrics.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;
}

template <typename Traits>
typename Traits::HitTarget HitTest(
    const typename Traits::Layout& layout,
    const UIPoint& point) {
    for (std::size_t componentIndex = 0u;
         componentIndex < layout.componentRects.size();
         ++componentIndex) {
        if (IsPointInside(layout.componentRects[componentIndex], point)) {
            return { Traits::kComponentHitTargetKind, componentIndex };
        }
    }

    if (IsPointInside(layout.bounds, point)) {
        return { Traits::kRowHitTargetKind, Traits::kInvalidComponentIndex };
    }

    return {};
}

template <typename Traits>
void AppendBackground(
    UIDrawList& drawList,
    const typename Traits::Layout& layout,
    const typename Traits::Spec& spec,
    const typename Traits::State& state,
    const typename Traits::Palette& palette,
    const typename Traits::Metrics& metrics) {
    const typename Traits::Palette resolvedPalette = ResolvePalette<Traits>(palette);
    const typename Traits::Metrics resolvedMetrics = ResolveMetrics<Traits>(metrics);

    if (ResolveRowFillColor<Traits>(state, resolvedPalette).a > 0.0f) {
        drawList.AddFilledRect(
            layout.bounds,
            ResolveRowFillColor<Traits>(state, resolvedPalette),
            resolvedMetrics.cornerRounding);
    }
    if ((state.focused
             ? resolvedPalette.focusedBorderColor.a
             : resolvedPalette.borderColor.a) > 0.0f) {
        drawList.AddRectOutline(
            layout.bounds,
            state.focused
                ? resolvedPalette.focusedBorderColor
                : resolvedPalette.borderColor,
            state.focused
                ? resolvedMetrics.focusedBorderThickness
                : resolvedMetrics.borderThickness,
            resolvedMetrics.cornerRounding);
    }

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

template <typename Traits>
void AppendForeground(
    UIDrawList& drawList,
    const typename Traits::Layout& layout,
    const typename Traits::Spec& spec,
    const typename Traits::State& state,
    const typename Traits::Palette& palette,
    const typename Traits::Metrics& metrics) {
    const typename Traits::Palette resolvedPalette = ResolvePalette<Traits>(palette);
    const typename Traits::Metrics resolvedMetrics = ResolveMetrics<Traits>(metrics);

    drawList.PushClipRect(
        Widgets::ResolveUIEditorTextClipRect(
            layout.labelRect,
            resolvedMetrics.labelFontSize));
    drawList.AddText(
        UIPoint(
            layout.labelRect.x,
            Widgets::ResolveUIEditorTextTop(
                layout.labelRect,
                resolvedMetrics.labelFontSize,
                resolvedMetrics.labelTextInsetY)),
        spec.label,
        resolvedPalette.labelColor,
        resolvedMetrics.labelFontSize);
    drawList.PopClipRect();

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

        drawList.PushClipRect(
            Widgets::ResolveUIEditorTextClipRect(
                layout.componentValueRects[componentIndex],
                resolvedMetrics.valueFontSize));
        drawList.AddText(
            UIPoint(
                layout.componentValueRects[componentIndex].x +
                    resolvedMetrics.valueTextInsetX,
                Widgets::ResolveUIEditorTextTop(
                    layout.componentValueRects[componentIndex],
                    resolvedMetrics.valueFontSize,
                    resolvedMetrics.valueTextInsetY)),
            state.editing && state.selectedComponentIndex == componentIndex
                ? state.displayTexts[componentIndex]
                : FormatComponentValue<Traits>(spec, componentIndex),
            spec.readOnly
                ? resolvedPalette.readOnlyValueColor
                : resolvedPalette.valueColor,
            resolvedMetrics.valueFontSize);
        if (state.editing && state.selectedComponentIndex == componentIndex) {
            Widgets::AppendUIEditorTextCaret(
                drawList,
                layout.componentValueRects[componentIndex],
                state.displayTexts[componentIndex],
                state.caretOffset,
                state.caretBlinkStartNanoseconds,
                resolvedPalette.valueColor,
                resolvedMetrics.valueFontSize,
                resolvedMetrics.valueTextInsetX,
                resolvedMetrics.valueTextInsetY);
        }
        drawList.PopClipRect();
    }
}

template <typename Traits>
void AppendField(
    UIDrawList& drawList,
    const UIRect& bounds,
    const typename Traits::Spec& spec,
    const typename Traits::State& state,
    const typename Traits::Palette& palette,
    const typename Traits::Metrics& metrics) {
    const typename Traits::Palette resolvedPalette = ResolvePalette<Traits>(palette);
    const typename Traits::Metrics resolvedMetrics = ResolveMetrics<Traits>(metrics);
    const typename Traits::Layout layout =
        BuildLayout<Traits>(bounds, spec, resolvedMetrics);
    AppendBackground<Traits>(
        drawList,
        layout,
        spec,
        state,
        resolvedPalette,
        resolvedMetrics);
    AppendForeground<Traits>(
        drawList,
        layout,
        spec,
        state,
        resolvedPalette,
        resolvedMetrics);
}

} // namespace XCEngine::UI::Editor::Internal::VectorFieldWidgetShared