#nullable enable

using Godot;

namespace ShrinkTutorial.Godot;

public partial class ShrinkGodotTutorialOverlay : Control
{
    private readonly Label _title = new();
    private readonly Label _body = new();
    private ShrinkTutorialRunner? _runner;
    private Control? _target;

    public override void _Ready()
    {
        SetAnchorsAndOffsetsPreset(LayoutPreset.FullRect);
        MouseFilter = MouseFilterEnum.Stop;
        var panel = new PanelContainer { CustomMinimumSize = new Vector2(320, 100) };
        panel.Position = new Vector2(24, 24);
        var text = new VBoxContainer();
        text.AddChild(_title);
        text.AddChild(_body);
        panel.AddChild(text);
        AddChild(panel);
    }

    public void Bind(ShrinkTutorialRunner runner)
    {
        if (_runner != null) _runner.StepChanged -= ShowStep;
        _runner = runner;
        _runner.StepChanged += ShowStep;
        if (_runner.CurrentStep != null) ShowStep(_runner.CurrentStep);
    }

    public override void _ExitTree()
    {
        if (_runner != null) _runner.StepChanged -= ShowStep;
        _runner = null;
        _target = null;
    }

    public override void _Process(double delta)
    {
        if (_runner?.CurrentStep is not { } step) return;
        _target = ResolveTarget(step);
        QueueRedraw();
    }

    public override void _Draw()
    {
        var viewport = GetViewportRect();
        if (_target == null)
        {
            DrawRect(viewport, new Color(0, 0, 0, 0.72f));
            return;
        }
        var hole = _target.GetGlobalRect().Grow(8);
        var shade = new Color(0, 0, 0, 0.72f);
        DrawRect(new Rect2(viewport.Position, new Vector2(viewport.Size.X, hole.Position.Y)), shade);
        DrawRect(new Rect2(new Vector2(0, hole.End.Y), new Vector2(viewport.Size.X, viewport.Size.Y - hole.End.Y)), shade);
        DrawRect(new Rect2(new Vector2(0, hole.Position.Y), new Vector2(hole.Position.X, hole.Size.Y)), shade);
        DrawRect(new Rect2(new Vector2(hole.End.X, hole.Position.Y), new Vector2(viewport.Size.X - hole.End.X, hole.Size.Y)), shade);
    }

    public override void _GuiInput(InputEvent @event)
    {
        if (@event is not InputEventMouseButton { Pressed: true }) return;
        var step = _runner?.CurrentStep;
        if (step == null) return;
        if (step.CompleteCondition == ShrinkTutorialCompleteCondition.AnyClick ||
            step.CompleteCondition == ShrinkTutorialCompleteCondition.ClickTarget && _target?.GetGlobalRect().HasPoint(GetGlobalMousePosition()) == true)
            _runner!.CompleteStep();
        AcceptEvent();
    }

    private void ShowStep(ShrinkTutorialStep step)
    {
        _title.Text = step.Title;
        _body.Text = step.Body;
        Visible = true;
    }

    private Control? ResolveTarget(ShrinkTutorialStep step)
    {
        if (step.TargetMode == ShrinkTutorialTargetMode.Path) return GetTree().Root.GetNodeOrNull<Control>(step.Target);
        if (step.TargetMode == ShrinkTutorialTargetMode.AnchorId) return GetTree().GetFirstNodeInGroup("shrink_tutorial_" + step.Target) as Control;
        return null;
    }
}