using Godot;
using MaxEffort.Code.Core;

namespace MaxEffort.Code.Systems;

[GlobalClass]
public partial class CameraShakeSystem : Node
{
    [Export] private Camera2D _camera;
    [Export] private float _decayRate = 0.8f;  // How fast shaking stops
    [Export] private float _maxOffset = 20.0f; // Max pixels to shake
    [Export] private float _maxRoll = 0.1f;    // Max rotation (radians)
    
    private float _trauma = 0f; // Current shake intensity (0 to 1)
    private float _currentFocus = 0f;
    private RandomNumberGenerator _rng = new();
    
    public override void _Ready()
    {
        EventBus.OnCameraTrauma += AddTrauma;
        EventBus.OnFocusChanged += OnFocusChanged;
    }

    public override void _ExitTree()
    {
        EventBus.OnCameraTrauma -= AddTrauma;
        EventBus.OnFocusChanged -= OnFocusChanged;
    }

    public override void _Process(double delta)
    {
        if (_camera == null) return;
        
        if (_currentFocus > 0.75f)
        {
            AddTrauma(1.5f * (float)delta); 
        }
        
        if (_trauma > 0)
        {
            _trauma -= _decayRate * (float)delta;
            _trauma = Mathf.Max(0, _trauma);

            var shake = _trauma * _trauma;
            
            var offsetX = _maxOffset * shake * _rng.RandfRange(-1, 1);
            var offsetY = _maxOffset * shake * _rng.RandfRange(-1, 1);
            var rotation = _maxRoll * shake * _rng.RandfRange(-1, 1);

            _camera.Offset = new Vector2(offsetX, offsetY);
            _camera.Rotation = rotation;
        }
        else
        {
            if (_camera.Offset != Vector2.Zero) 
            {
                _camera.Offset = _camera.Offset.Lerp(Vector2.Zero, (float)delta * 5f);
                _camera.Rotation = Mathf.Lerp(_camera.Rotation, 0, (float)delta * 5f);
            }
        }
    }
    
    private void OnFocusChanged(float focus)
    {
        _currentFocus = focus;
    }
    
    private void AddTrauma(float amount)
    {
        _trauma = Mathf.Clamp(_trauma + amount, 0f, 1f);
    }
}