using Godot;
using System;

public class GridCursor : Sprite
{
    [Export]
    public NodePath Grid { get; set; }
    private WorldGrid _grid;
    private ShaderMaterial _material;

    #region Animation
    [Export]
    private Curve _pulseShape;
    [Export]
    private float _pulseRate = 1.0f;
    private float PulsePeriod => 1.0f / _pulseRate;
    #endregion

    private float _elapsed = 0.0f;
    private bool _pulsing = false;

    private const string T = "t";

    public override void _Ready()
    {
        _grid = GetNode<WorldGrid>(Grid);
        _material = (ShaderMaterial)Material;
    }

    public override void _Input(InputEvent @event)
    {
        base._Input(@event);

        if (@event is InputEventMouseMotion mouseMoveEvent)
        {
            var pos = mouseMoveEvent.Position;
            _grid.GetGridPos(pos, out var x, out var y);
            this.Visible = _grid.IsInBounds(x, y);
            var position = new Vector2(x + .5f, y + .5f) * _grid.CellSize;
            this.Position = position;
        }
        else if (@event is InputEventMouseButton mouseButtonEvent)
        {
            switch ((ButtonList)mouseButtonEvent.ButtonIndex)
            {
                case ButtonList.Left:
                    if (mouseButtonEvent.Pressed)
                    {
                        var pos = mouseButtonEvent.Position;
                        _grid.GetGridPos(pos, out var x, out var y);
                        _grid.SetTileValue(x, y, 1.0f);
                        _material.SetShaderParam(T, 1f);
                    }
                    else
                    {
                        _material.SetShaderParam(T, 0f);
                    }
                    break;
            }
        }
    }

    public override void _Process(float delta)
    {
        _elapsed += delta * _pulseRate;

        if (!_pulsing)
        {
            _material.SetShaderParam(T, 1f);
            return;
        }

        var a = _pulseShape.Interpolate(_elapsed % 1.0f);
        _material.SetShaderParam(T, a);
    }


    public void _on_Interaction_Mode_OnInteractionModeChanged(InteractionMode.Mode oldMode, InteractionMode.Mode newMode)
    {
        switch (newMode)
        {
            case InteractionMode.Mode.SELECT:
                _pulsing = false;
                break;

            case InteractionMode.Mode.BUILD:
                _pulsing = true;
                break;
        }
    }
}