Chessistics/Scripts/Main.cs

using Godot;
using System;
using System.Collections.Generic;
using System.Linq;
using Chessistics.Engine.Commands;
using Chessistics.Engine.Events;
using Chessistics.Engine.Loading;
using Chessistics.Engine.Model;
using Chessistics.Engine.Simulation;
using Chessistics.Scripts.Board;
using Chessistics.Scripts.Input;
using Chessistics.Scripts.Pieces;
using Chessistics.Scripts.Presentation;
using Chessistics.Scripts.UI;

namespace Chessistics.Scripts;

public partial class Main : Node2D
{
	private GameSim? _sim;
	private LevelDef? _currentLevel;
	private int _currentLevelIndex;

	// Views
	private BoardView _boardView = null!;
	private InputMapper _inputMapper = null!;
	private EventAnimator _eventAnimator = null!;

	// UI
	private CanvasLayer _uiLayer = null!;
	private ObjectivePanel _objectivePanel = null!;
	private PieceStockPanel _pieceStockPanel = null!;
	private DetailPanel _detailPanel = null!;
	private ControlBar _controlBar = null!;
	private MetricsOverlay _metricsOverlay = null!;
	private LevelSelectScreen _levelSelectScreen = null!;
	private Label _levelTitle = null!;
	private PanelContainer _sidePanel = null!;
	private PanelContainer _controlBarWrapper = null!;
	private Camera2D _camera = null!;
	private ColorRect _fadeOverlay = null!;

	// Simulation timer
	private Godot.Timer _simTimer = null!;
	private float _simInterval = 1.0f;
	private bool _running;
	private bool _panning;

	private static readonly string[] LevelFiles = ["level_01.json", "level_02.json", "level_03.json", "level_04.json", "level_05.json", "level_06.json"];

	private const float SidePanelWidth = 280f;
	private const float ControlBarHeight = 48f;

	private static readonly Color BackgroundColor = new("#2D2D2D");

	public override void _Ready()
	{
		RenderingServer.SetDefaultClearColor(BackgroundColor);

		BuildSceneTree();
		ConnectSignals();
		ShowLevelSelect();

		// Fade in from black on startup
		FadeIn(0.5f);
	}

	public override void _UnhandledInput(InputEvent @event)
	{
		if (@event is InputEventMouseButton mb)
		{
			if (mb.ButtonIndex == MouseButton.Middle)
				_panning = mb.Pressed;
		}
		else if (@event is InputEventMouseMotion motion && _panning)
		{
			_camera.Position -= motion.Relative / _camera.Zoom;
		}
	}

	private void FadeIn(float duration)
	{
		_fadeOverlay.Color = new Color(0, 0, 0, 1);
		var tween = CreateTween();
		tween.TweenProperty(_fadeOverlay, "color:a", 0f, duration)
			.SetEase(Tween.EaseType.Out);
	}

	private void FadeOut(float duration, Action onComplete)
	{
		_fadeOverlay.Color = new Color(0, 0, 0, 0);
		var tween = CreateTween();
		tween.TweenProperty(_fadeOverlay, "color:a", 1f, duration)
			.SetEase(Tween.EaseType.In);
		tween.TweenCallback(Callable.From(onComplete));
	}

	private void BuildSceneTree()
	{
		// Camera
		_camera = new Camera2D { Enabled = true };
		AddChild(_camera);

		// SFX
		var sfx = new SfxManager();
		AddChild(sfx);

		// Board
		_boardView = new BoardView();
		AddChild(_boardView);

		// Input
		_inputMapper = new InputMapper();
		_inputMapper.Initialize(_boardView);
		AddChild(_inputMapper);

		// Animator
		_eventAnimator = new EventAnimator();
		AddChild(_eventAnimator);

		// Sim timer
		_simTimer = new Godot.Timer { OneShot = false, WaitTime = _simInterval };
		_simTimer.Timeout += OnSimTimerTick;
		AddChild(_simTimer);

		// --- UI Layer ---
		_uiLayer = new CanvasLayer();
		AddChild(_uiLayer);

		// Root control anchored to viewport (required for child anchoring)
		var uiRoot = new Control();
		uiRoot.SetAnchorsPreset(Control.LayoutPreset.FullRect);
		uiRoot.MouseFilter = Control.MouseFilterEnum.Ignore;
		_uiLayer.AddChild(uiRoot);

		// Level title bar (top-left)
		var titleBar = new HBoxContainer();
		titleBar.SetAnchorsPreset(Control.LayoutPreset.TopLeft);
		titleBar.OffsetLeft = 12;
		titleBar.OffsetTop = 8;
		titleBar.AddThemeConstantOverride("separation", 12);

		var backButton = new Button { Text = "← Menu", CustomMinimumSize = new Vector2(70, 28) };
		backButton.AddThemeFontSizeOverride("font_size", 11);
		var backStyle = new StyleBoxFlat
		{
			BgColor = new Color("#2A2A2E"),
			BorderColor = new Color("#444448"),
			BorderWidthBottom = 1, BorderWidthTop = 1, BorderWidthLeft = 1, BorderWidthRight = 1,
			CornerRadiusTopLeft = 4, CornerRadiusTopRight = 4,
			CornerRadiusBottomLeft = 4, CornerRadiusBottomRight = 4,
			ContentMarginLeft = 8, ContentMarginRight = 8,
			ContentMarginTop = 2, ContentMarginBottom = 2
		};
		backButton.AddThemeStyleboxOverride("normal", backStyle);
		backButton.Pressed += OnBackToMenu;
		titleBar.AddChild(backButton);

		_levelTitle = new Label { Text = "CHESSISTICS" };
		_levelTitle.AddThemeFontSizeOverride("font_size", 20);
		_levelTitle.MouseFilter = Control.MouseFilterEnum.Ignore;
		titleBar.AddChild(_levelTitle);

		uiRoot.AddChild(titleBar);

		// --- Side Panel (anchored to right edge) ---
		_sidePanel = new PanelContainer();
		_sidePanel.AnchorLeft = 1.0f;
		_sidePanel.AnchorRight = 1.0f;
		_sidePanel.AnchorTop = 0.0f;
		_sidePanel.AnchorBottom = 1.0f;
		_sidePanel.OffsetLeft = -SidePanelWidth;
		_sidePanel.OffsetRight = 0;
		_sidePanel.OffsetTop = 0;
		_sidePanel.OffsetBottom = -ControlBarHeight;

		var sidePanelStyle = new StyleBoxFlat
		{
			BgColor = new Color(0.14f, 0.14f, 0.16f, 0.97f),
			BorderColor = new Color(0.25f, 0.25f, 0.28f),
			BorderWidthLeft = 1,
			ContentMarginLeft = 16,
			ContentMarginRight = 16,
			ContentMarginTop = 16,
			ContentMarginBottom = 16
		};
		_sidePanel.AddThemeStyleboxOverride("panel", sidePanelStyle);

		var sideScroll = new ScrollContainer
		{
			HorizontalScrollMode = ScrollContainer.ScrollMode.Disabled,
			SizeFlagsVertical = Control.SizeFlags.ExpandFill
		};

		var sideVBox = new VBoxContainer();
		sideVBox.AddThemeConstantOverride("separation", 12);

		_objectivePanel = new ObjectivePanel();
		sideVBox.AddChild(_objectivePanel);
		sideVBox.AddChild(new HSeparator());

		_pieceStockPanel = new PieceStockPanel();
		sideVBox.AddChild(_pieceStockPanel);

		_detailPanel = new DetailPanel();
		sideVBox.AddChild(_detailPanel);

		sideScroll.AddChild(sideVBox);
		_sidePanel.AddChild(sideScroll);
		uiRoot.AddChild(_sidePanel);

		// --- Control Bar (anchored to bottom, left of side panel) ---
		_controlBarWrapper = new PanelContainer();
		_controlBarWrapper.AnchorLeft = 0.0f;
		_controlBarWrapper.AnchorRight = 1.0f;
		_controlBarWrapper.AnchorTop = 1.0f;
		_controlBarWrapper.AnchorBottom = 1.0f;
		_controlBarWrapper.OffsetTop = -ControlBarHeight;
		_controlBarWrapper.OffsetRight = -SidePanelWidth;

		var controlBarStyle = new StyleBoxFlat
		{
			BgColor = new Color(0.11f, 0.11f, 0.13f, 0.97f),
			BorderColor = new Color(0.25f, 0.25f, 0.28f),
			BorderWidthTop = 1,
			ContentMarginLeft = 12,
			ContentMarginRight = 12,
			ContentMarginTop = 4,
			ContentMarginBottom = 4
		};
		_controlBarWrapper.AddThemeStyleboxOverride("panel", controlBarStyle);

		_controlBar = new ControlBar();
		_controlBarWrapper.AddChild(_controlBar);
		uiRoot.AddChild(_controlBarWrapper);

		// --- Metrics Overlay (centered in board area) ---
		var metricsCenter = new CenterContainer();
		metricsCenter.SetAnchorsPreset(Control.LayoutPreset.FullRect);
		metricsCenter.OffsetRight = -SidePanelWidth;
		metricsCenter.OffsetBottom = -ControlBarHeight;
		metricsCenter.MouseFilter = Control.MouseFilterEnum.Ignore;

		_metricsOverlay = new MetricsOverlay();
		_metricsOverlay.CustomMinimumSize = new Vector2(340, 260);
		metricsCenter.AddChild(_metricsOverlay);
		uiRoot.AddChild(metricsCenter);

		// --- Level Select Screen (full viewport) ---
		_levelSelectScreen = new LevelSelectScreen();
		_levelSelectScreen.SetAnchorsPreset(Control.LayoutPreset.FullRect);
		uiRoot.AddChild(_levelSelectScreen);

		// --- Fade overlay (on top of everything) ---
		_fadeOverlay = new ColorRect
		{
			Color = new Color(0, 0, 0, 1),
			MouseFilter = Control.MouseFilterEnum.Ignore
		};
		_fadeOverlay.SetAnchorsPreset(Control.LayoutPreset.FullRect);
		uiRoot.AddChild(_fadeOverlay);

		// Initialize animator
		_eventAnimator.Initialize(_boardView, _objectivePanel, _controlBar, _metricsOverlay);
	}

	private void ConnectSignals()
	{
		_levelSelectScreen.LevelSelected += OnLevelSelected;
		_pieceStockPanel.PieceSelected += OnPieceKindSelected;
		_inputMapper.PlacementRequested += OnPlacementRequested;
		_inputMapper.Cancelled += OnPlacementCancelled;
		_controlBar.PlayPressed += OnPlay;
		_controlBar.PausePressed += OnPause;
		_controlBar.StepPressed += OnStep;
		_controlBar.StopPressed += OnStop;
		_controlBar.SpeedChanged += OnSpeedChanged;
		_eventAnimator.TurnAnimationCompleted += OnTurnAnimationCompleted;
		_eventAnimator.VictoryReached += OnVictory;
		_metricsOverlay.RetryPressed += OnRetry;
		_metricsOverlay.NextLevelPressed += OnNextLevel;
		_detailPanel.RemoveRequested += OnRemoveRequested;
		_inputMapper.CellClicked += OnCellClicked;
	}

	private void OnCellClicked(int col, int row)
	{
		if (_sim == null) return;
		var snap = _sim.GetSnapshot();
		if (snap.Phase != SimPhase.Edit) return;

		_boardView.ClearHighlights();

		var coords = new Coords(col, row);
		var piece = snap.Pieces.FirstOrDefault(p => p.StartCell == coords || p.EndCell == coords);
		if (piece != null)
		{
			_detailPanel.ShowPiece(piece);

			// Highlight start and end cells to show trajectory
			var pieceColor = PieceView.GetPieceColor(piece.Kind);
			var highlightColor = new Color(pieceColor, 0.3f);
			_boardView.HighlightCells([piece.StartCell, piece.EndCell], highlightColor);
		}
		else
		{
			_detailPanel.Hide();
		}
	}

	// --- Level Management ---

	private void ShowLevelSelect()
	{
		_levelSelectScreen.Visible = true;
		_boardView.Visible = false;
		_sidePanel.Visible = false;
		_controlBarWrapper.Visible = false;
		_levelTitle.Visible = false;
	}

	private void OnLevelSelected(int levelIndex)
	{
		SfxManager.Instance?.PlayClick();
		_currentLevelIndex = levelIndex;

		// Fade out, load, fade in
		FadeOut(0.25f, () =>
		{
			LoadLevel(levelIndex);
			FadeIn(0.3f);
		});
	}

	private void LoadLevel(int index)
	{
		if (index < 0 || index >= LevelFiles.Length) return;

		var path = $"res://Data/levels/{LevelFiles[index]}";
		var file = Godot.FileAccess.Open(path, Godot.FileAccess.ModeFlags.Read);
		if (file == null)
		{
			GD.PrintErr($"Cannot open level file: {path}");
			return;
		}

		var json = file.GetAsText();
		file.Close();

		_currentLevel = LevelLoader.Load(json);
		_sim = new GameSim(_currentLevel);

		_levelSelectScreen.Visible = false;
		_boardView.Visible = true;
		_sidePanel.Visible = true;
		_controlBarWrapper.Visible = true;
		_levelTitle.Visible = true;

		_boardView.BuildBoard(_currentLevel);
		_objectivePanel.Setup(_currentLevel.Demands);
		_pieceStockPanel.Setup(_currentLevel.Stock);
		_controlBar.UpdateForPhase(SimPhase.Edit);
		_controlBar.ResetTurn();
		_metricsOverlay.Hide();
		_detailPanel.Hide();
		_eventAnimator.ClearAll();

		_levelTitle.Text = $"CHESSISTICS — {_currentLevel.Name}";

		// Center camera on board
		// Board X spans 0..W*Cell, Y spans -(H-1)*Cell .. Cell
		_camera.Position = new Vector2(
			_currentLevel.Width * BoardView.CellSize / 2f,
			-_currentLevel.Height * BoardView.CellSize / 2f + BoardView.CellSize
		);
		_camera.Offset = new Vector2(-SidePanelWidth / 2f, -ControlBarHeight / 2f);

		var snapshot = _sim.GetSnapshot();
		GD.Print($"[Main] LoadLevel — snapshot null? {snapshot == null}, width={snapshot?.Width}, height={snapshot?.Height}");
		_inputMapper.SetSnapshot(snapshot);
	}

	// --- Edit Phase ---

	private void OnPieceKindSelected(int kindIndex)
	{
		_inputMapper.SelectPieceKind((PieceKind)kindIndex);
	}

	private void OnPlacementRequested(int kindIndex, int startCol, int startRow, int endCol, int endRow)
	{
		if (_sim == null) return;

		var kind = (PieceKind)kindIndex;
		var start = new Coords(startCol, startRow);
		var end = new Coords(endCol, endRow);

		var events = _sim.ProcessCommand(new PlacePieceCommand(kind, start, end));
		HandleEditEvents(events);
		_inputMapper.SetSnapshot(_sim.GetSnapshot());
	}

	private void OnPlacementCancelled()
	{
		_pieceStockPanel.ClearSelection();
	}

	private void OnRemoveRequested(int pieceId)
	{
		if (_sim == null) return;

		var events = _sim.ProcessCommand(new RemovePieceCommand(pieceId));
		HandleEditEvents(events);
		_inputMapper.SetSnapshot(_sim.GetSnapshot());
	}

	private void HandleEditEvents(IReadOnlyList<IWorldEvent> events)
	{
		foreach (var evt in events)
		{
			switch (evt)
			{
				case PiecePlacedEvent placed:
					CreatePieceVisual(placed);
					UpdateStockFromSnapshot();
					break;

				case PieceRemovedEvent removed:
					_eventAnimator.UnregisterPiece(removed.PieceId);
					UpdateStockFromSnapshot();
					_detailPanel.Hide();
					break;

				case PlacementRejectedEvent rejected:
					GD.Print($"Placement rejected: {rejected.Reason}");
					break;

				case CommandRejectedEvent rejected:
					GD.Print($"Command rejected: {rejected.Reason}");
					break;
			}
		}
	}

	private void CreatePieceVisual(PiecePlacedEvent placed)
	{
		SfxManager.Instance?.PlayPlace();

		var pieceView = new PieceView();
		pieceView.Setup(placed.PieceId, placed.Kind, placed.Start, placed.End, _boardView);
		_boardView.AddChild(pieceView);

		var color = PieceView.GetPieceColor(placed.Kind);

		var trajectView = new TrajectView();
		trajectView.Setup(placed.PieceId,
			_boardView.CoordsToPixel(placed.Start),
			_boardView.CoordsToPixel(placed.End),
			color);
		_boardView.AddChild(trajectView);

		_eventAnimator.RegisterPiece(placed.PieceId, pieceView, trajectView);
	}

	private void UpdateStockFromSnapshot()
	{
		if (_sim == null) return;
		var snap = _sim.GetSnapshot();
		foreach (var (kind, remaining) in snap.RemainingStock)
			_pieceStockPanel.UpdateCount(kind, remaining);
	}

	// --- Exec Phase ---

	private void OnPlay()
	{
		if (_sim == null) return;

		var snap = _sim.GetSnapshot();
		if (snap.Phase == SimPhase.Edit)
		{
			var events = _sim.ProcessCommand(new StartSimulationCommand());
			foreach (var evt in events)
			{
				if (evt is CommandRejectedEvent r)
				{
					GD.Print($"Cannot start: {r.Reason}");
					return;
				}
			}
		}
		else if (snap.Phase == SimPhase.Paused)
		{
			_sim.ProcessCommand(new ResumeSimulationCommand());
		}

		_running = true;
		_controlBar.UpdateForPhase(SimPhase.Running);
		_simTimer.WaitTime = _simInterval;
		_simTimer.Start();
	}

	private void OnPause()
	{
		if (_sim == null) return;
		_sim.ProcessCommand(new PauseSimulationCommand());
		_running = false;
		_simTimer.Stop();
		_controlBar.UpdateForPhase(SimPhase.Paused);
	}

	private void OnStep()
	{
		if (_sim == null || _eventAnimator.IsAnimating) return;
		var events = _sim.ProcessCommand(new StepSimulationCommand());
		_eventAnimator.ProcessEvents(events);
		_controlBar.UpdateForPhase(_sim.GetSnapshot().Phase);
	}

	private void OnStop()
	{
		if (_sim == null) return;
		_running = false;
		_simTimer.Stop();
		_sim.ProcessCommand(new StopSimulationCommand());

		// Full visual rebuild: clear everything and recreate from snapshot
		_eventAnimator.ClearAll();
		var snap = _sim.GetSnapshot();
		foreach (var ps in snap.Pieces)
		{
			var pieceView = new PieceView();
			pieceView.Setup(ps.Id, ps.Kind, ps.StartCell, ps.EndCell, _boardView);
			_boardView.AddChild(pieceView);

			var color = PieceView.GetPieceColor(ps.Kind);
			var trajectView = new TrajectView();
			trajectView.Setup(ps.Id,
				_boardView.CoordsToPixel(ps.StartCell),
				_boardView.CoordsToPixel(ps.EndCell),
				color);
			_boardView.AddChild(trajectView);

			_eventAnimator.RegisterPiece(ps.Id, pieceView, trajectView);
		}

		_controlBar.UpdateForPhase(SimPhase.Edit);
		_controlBar.ResetTurn();
		_metricsOverlay.Hide();
		_inputMapper.SetSnapshot(snap);

		if (_currentLevel != null)
			_objectivePanel.Setup(_currentLevel.Demands);
	}

	private void OnSpeedChanged(float interval)
	{
		_simInterval = interval;
		if (_simTimer.TimeLeft > 0)
			_simTimer.WaitTime = interval;
	}

	private void OnSimTimerTick()
	{
		if (_sim == null || _eventAnimator.IsAnimating) return;

		var events = _sim.ProcessCommand(new StepSimulationCommand());
		_eventAnimator.ProcessEvents(events);
	}

	private void OnTurnAnimationCompleted()
	{
		if (_sim == null) return;
		var phase = _sim.GetSnapshot().Phase;
		_controlBar.UpdateForPhase(phase);

		if (phase == SimPhase.Victory || phase == SimPhase.Defeat)
		{
			_running = false;
			_simTimer.Stop();
		}
	}

	private void OnVictory()
	{
		_running = false;
		_simTimer.Stop();
	}

	// --- Navigation ---

	private void OnRetry()
	{
		LoadLevel(_currentLevelIndex);
	}

	private void OnNextLevel()
	{
		if (_currentLevelIndex + 1 < LevelFiles.Length)
			LoadLevel(_currentLevelIndex + 1);
		else
			ShowLevelSelect();
	}

	private void OnBackToMenu()
	{
		SfxManager.Instance?.PlayClick();
		_running = false;
		_simTimer.Stop();
		_eventAnimator.ClearAll();

		FadeOut(0.2f, () =>
		{
			ShowLevelSelect();
			FadeIn(0.3f);
		});
	}
}