// Copyright Epic Games, Inc. All Rights Reserved.

#include "Insights/ViewModels/TooltipDrawState.h"

#include "Fonts/FontMeasure.h"
#include "Fonts/SlateFontInfo.h"
#include "Styling/CoreStyle.h"

// Insights
#include "Insights/Common/PaintUtils.h"
#include "Insights/InsightsStyle.h"

////////////////////////////////////////////////////////////////////////////////////////////////////

FLinearColor FTooltipDrawState::DefaultTitleColor(0.9f, 0.9f, 0.5f, 1.0f);
FLinearColor FTooltipDrawState::DefaultNameColor(0.6f, 0.6f, 0.6f, 1.0f);
FLinearColor FTooltipDrawState::DefaultValueColor(1.0f, 1.0f, 1.0f, 1.0f);

////////////////////////////////////////////////////////////////////////////////////////////////////

FTooltipDrawState::FTooltipDrawState()
    : WhiteBrush(FInsightsStyle::Get().GetBrush("WhiteBrush")), Font(FCoreStyle::GetDefaultFontStyle("Regular", 8)), BackgroundColor(0.05f, 0.05f, 0.05f, 1.0f), Size(0.0f, 0.0f), DesiredSize(0.0f, 0.0f), Position(0.0f, 0.0f), ValueOffsetX(0.0f), NewLineY(0.0f), Opacity(0.0f), DesiredOpacity(0.0f), Texts()
{
}

////////////////////////////////////////////////////////////////////////////////////////////////////

FTooltipDrawState::~FTooltipDrawState()
{
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::Reset()
{
    Opacity        = 0.0f;
    DesiredOpacity = 0.0f;

    ResetContent();
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::ResetContent()
{
    Texts.Reset();

    ValueOffsetX = 0.0f;
    NewLineY     = BorderY;
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::AddTitle(const FString& Title)
{
    const TSharedRef<FSlateFontMeasure> FontMeasureService = FSlateApplication::Get().GetRenderer()->GetFontMeasureService();

    const FVector2D TextSize                               = FontMeasureService->Measure(Title, Font);
    Texts.Add({BorderX, NewLineY, TextSize, Title, DefaultTitleColor, FDrawTextType::Title});

    NewLineY += DefaultTitleHeight;
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::AddTitle(const FString& Title, const FLinearColor& Color)
{
    const TSharedRef<FSlateFontMeasure> FontMeasureService = FSlateApplication::Get().GetRenderer()->GetFontMeasureService();

    const FVector2D TextSize                               = FontMeasureService->Measure(Title, Font);
    Texts.Add({BorderX, NewLineY, TextSize, Title, Color, FDrawTextType::Misc});

    NewLineY += DefaultTitleHeight;
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::AddNameValueTextLine(const FString& Name, const FString& Value)
{
    const TSharedRef<FSlateFontMeasure> FontMeasureService = FSlateApplication::Get().GetRenderer()->GetFontMeasureService();

    const FVector2D NameTextSize                           = FontMeasureService->Measure(Name, Font);
    Texts.Add({0.0f, NewLineY, NameTextSize, Name, DefaultNameColor, FDrawTextType::Name});

    const FVector2D ValueTextSize = FontMeasureService->Measure(Value, Font);
    Texts.Add({0.0f, NewLineY, ValueTextSize, Value, DefaultValueColor, FDrawTextType::Value});

    NewLineY += DefaultLineHeight;
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::AddTextLine(const FString& Text, const FLinearColor& Color)
{
    const TSharedRef<FSlateFontMeasure> FontMeasureService = FSlateApplication::Get().GetRenderer()->GetFontMeasureService();

    const FVector2D TextSize                               = FontMeasureService->Measure(Text, Font);
    Texts.Add({BorderX, NewLineY, TextSize, Text, Color, FDrawTextType::Misc});

    NewLineY += DefaultLineHeight;
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::AddTextLine(const float X, const float Y, const FString& Text, const FLinearColor& Color)
{
    const TSharedRef<FSlateFontMeasure> FontMeasureService = FSlateApplication::Get().GetRenderer()->GetFontMeasureService();

    const FVector2D TextSize                               = FontMeasureService->Measure(Text, Font);
    Texts.Add({X, Y, TextSize, Text, Color, FDrawTextType::Misc});
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::UpdateLayout()
{
    ValueOffsetX = 0.0f;
    for (const FDrawTextInfo& TextInfo: Texts)
    {
        if (TextInfo.Type == FDrawTextType::Name)
        {
            if (ValueOffsetX < TextInfo.TextSize.X)
            {
                ValueOffsetX = TextInfo.TextSize.X;
            }
        }
    }
    ValueOffsetX += BorderX;

    DesiredSize.Set(BorderX, NewLineY + BorderY);
    for (const FDrawTextInfo& TextInfo: Texts)
    {
        float RightX;
        switch (TextInfo.Type)
        {
            case FDrawTextType::Name:
                RightX = ValueOffsetX;
                break;

            case FDrawTextType::Value:
                RightX = ValueOffsetX + NameValueDX + TextInfo.TextSize.X;
                break;

            default:
                RightX = TextInfo.X + TextInfo.TextSize.X;
        }
        if (DesiredSize.X < RightX)
        {
            DesiredSize.X = RightX;
        }
    }
    DesiredSize.X += BorderX;
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::Update()
{
    if (Size.X != DesiredSize.X)
    {
        Size.X = Size.X * 0.75f + DesiredSize.X * 0.25f;

        if (FMath::IsNearlyEqual(Size.X, DesiredSize.X))
        {
            Size.X = DesiredSize.X;
        }
    }

    if (Size.Y != DesiredSize.Y)
    {
        Size.Y = Size.Y * 0.5f + DesiredSize.Y * 0.5f;

        if (FMath::IsNearlyEqual(Size.Y, DesiredSize.Y))
        {
            Size.Y = DesiredSize.Y;
        }
    }

    float RealDesiredOpacity;
    if (DesiredSize.X > 1.0f)
    {
        const float DesiredOpacityByTooltipWidth = 1.0f - FMath::Abs(Size.X - DesiredSize.X) / DesiredSize.X;

        if (FMath::IsNearlyEqual(DesiredOpacity, DesiredOpacityByTooltipWidth, 0.001f))
        {
            RealDesiredOpacity = DesiredOpacity;
        }
        else
        {
            RealDesiredOpacity = FMath::Min(DesiredOpacity, DesiredOpacityByTooltipWidth);
        }
    }
    else
    {
        RealDesiredOpacity = 0.0f;
    }

    if (Opacity != RealDesiredOpacity)
    {
        if (Opacity < RealDesiredOpacity)
        {
            // slow fade in
            Opacity = Opacity * 0.9f + RealDesiredOpacity * 0.1f;
        }
        else
        {
            // fast fade out
            Opacity = Opacity * 0.75f + RealDesiredOpacity * 0.25f;
        }

        if (FMath::IsNearlyEqual(Opacity, RealDesiredOpacity, 0.001f))
        {
            Opacity = RealDesiredOpacity;
        }
    }
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::SetPosition(const FVector2D& MousePosition, const float MinX, const float MaxX, const float MinY, const float MaxY)
{
    Position.X = FMath::Max(MinX, FMath::Min(MousePosition.X + 12.0f, MaxX - Size.X));
    Position.Y = FMath::Max(MinY, FMath::Min(MousePosition.Y + 15.0f, MaxY - Size.Y));
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void FTooltipDrawState::Draw(const FDrawContext& DrawContext) const
{
    if (Opacity > 0.0f && Size.X > 0.0f && Size.Y > 0.0f)
    {
        // Draw background.
        DrawContext.DrawBox(Position.X, Position.Y, Size.X, Size.Y, WhiteBrush, BackgroundColor.CopyWithNewOpacity(Opacity));
        if (Size.X < DesiredSize.X)
        {
            DrawContext.DrawBox(Position.X + Size.X, Position.Y, DesiredSize.X - Size.X, Size.Y, WhiteBrush, BackgroundColor.CopyWithNewOpacity(Opacity * 0.5f));
        }
        DrawContext.LayerId++;

        // Draw border.
        // DrawContext.DrawBox(Position.X, Position.Y, Size.X, Size.Y, BorderBrush, BorderColor.CopyWithNewOpacity(Opacity));
        // DrawContext.LayerId++;

        // Draw cached texts.
        for (const FDrawTextInfo& TextInfo: Texts)
        {
            float X = Position.X;
            switch (TextInfo.Type)
            {
                case FDrawTextType::Name:
                    X += ValueOffsetX - TextInfo.TextSize.X;
                    break;

                case FDrawTextType::Value:
                    X += ValueOffsetX + NameValueDX;
                    break;

                default:
                    X += TextInfo.X;
            }
            DrawContext.DrawText(X, Position.Y + TextInfo.Y, TextInfo.Text, Font, TextInfo.Color.CopyWithNewOpacity(Opacity));
        }
        DrawContext.LayerId++;
    }
}

////////////////////////////////////////////////////////////////////////////////////////////////////