using System.Collections;
using System.Collections.Generic;
using UnityEngine;

using System.Linq;
using Hashtable = ExitGames.Client.Photon.Hashtable;

using BoardState = System.Collections.Generic.List<System.Collections.Generic.List<TileInfo>>;
using ExitGames.Client.Photon;

using EntityNetwork;

public class GameBoard : EntityBase, IAutoSerialize, IAutoDeserialize {
	public const int COLUMN = 6, ROW = 12;

  public GameBoardRender render;

	[System.NonSerialized]
	public BoardState board;
	private BoardState lastSentBoard;

  public bool active;

	public enum DelayState { None, Collapse, Combo, Loss }
	public DelayState delayState = DelayState.None;

	// TIL I need to always have an update timer or the dispatcher doesn't get created
	[NetVar('n',true,true,100)]
	public int NextDrop;
	[NetVar('c',true,true)]
	public int CurrentDrop;

	public (TileInfo left, TileInfo right) currentPair {
		get => TileInfo.FromPairInt(CurrentDrop);
		set => CurrentDrop = TileInfo.ToPairInt(value);
	}
	public (TileInfo left, TileInfo right) nextPair {
		get => TileInfo.FromPairInt(NextDrop);
		set => NextDrop = TileInfo.ToPairInt(value);
	}

	// Simple reference rotation
	public void SwapTiles() {
		var pair = currentPair;
		currentPair = nextPair;
		nextPair = pair;
	}

	[Header("Settings")]
	// Tile timing
	private int TilesUntilActivator = 3;
	int nextActivator = -1;
	private int ActivatorsUntilSpecial = 10;
	int nextSpecial = -1;

	public float nextRootX = -1, nextRootY = 12;

	TileColor lastActivatorColor;
	public void ReplaceNextTile() {
		(TileInfo left, TileInfo right) pair = (TileInfo.CreateRandomBlockTile(), TileInfo.CreateRandomBlockTile());
		--nextActivator;
		if (nextActivator < 1) {
			nextActivator = TilesUntilActivator;
			var activator = TileInfo.CreateRandomActivatorTile();
			while (activator.color == lastActivatorColor)
				activator = TileInfo.CreateRandomActivatorTile();

			lastActivatorColor = activator.color;
			
			if (++nextSpecial >= ActivatorsUntilSpecial) {
				nextSpecial = 0;
				activator.kind = TileKind.Special;
			}

			if (Random.value > 0.5f) {
				pair.left = activator;
			} else {
				pair.right = activator;
			}
		}

		nextPair = pair;
	}

	public float airCollapseTime = 1f;
	public float activationSpreadTime = 0.5f;
	public int dropHeight = 12; // Y value to drop from

	[Header("Scoring")]
	[NetVar('C',true,true)]
	public int Combo; // Increments on successively chained combos
	[NetVar('S',true,true)]
	public int score = 0;
	

	#region GameLogic
	// Time without moving that the game will kill you if you have lethal trash
	public float AutoDeathTime = 10f; 

	public float timeInState = 0;
	public DelayState lastState = DelayState.None;
	void GameLogic() {
		if (delayState != lastState) {
			timeInState = 0;
		}
		lastState = delayState;

		timeInState += Time.deltaTime;

		// Handle player input always, but block dropping when in a state
		if (!AIEnabled)
			PlayerInput();

		switch (delayState) {
			case DelayState.Collapse:
				if (timeInState > airCollapseTime) {
					board = Collapse(board); // Remove air 
					board = SpecialActivation(board, out bool didSpecial);
					board = ActivateOnce(board, out bool didActivate);
					if (didActivate || didSpecial) {
						delayState = DelayState.Combo;
						++Combo;
					} else {
						Combo = 0;

						ApplyTrash();

						delayState = DelayState.None;
					}
				}
				return;
			case DelayState.Combo:
				if (timeInState > activationSpreadTime) {
					board = ActivateOnce(board, out bool didActivate);
					if (didActivate) {
						timeInState = 0;
						return;
					} else {
						int scoreValue = CountActivations(board) * Combo;

						// Score increments too slow, make it get bigger!
						score += scoreValue * scoreValue;
						SendTrash(scoreValue - 3);

						// TODO - Trigger animation for attacking

						GhostActivations(); // Cool FX!
						board = ClearActivation(board);
						//board = Collapse(board); // Turns out THIS is what breaks the cool collapse effects
						// Overriding this like a dirty fellow to let me add negative buffer time
						timeInState = -0.5f * airCollapseTime; // Take 1.5x longer to collapse from combo chain
						lastState = DelayState.Collapse;
						delayState = DelayState.Collapse;
						return;
					}
				}
				return;
			case DelayState.None:
				if (HighestStack(board) >= 13) {
					delayState = DelayState.Loss;

					StartCoroutine(HandleLoss(3f));
					// TODO - Do a bunch of networking silliness to end the game here
				}

				// If the player isn't taking actions, trash won't appear, so make instakills kill through inaction
				if (timeInState > AutoDeathTime) {
					var incomingHeight = HighestStackWithTrash(board, incomingTrash);
					if (incomingHeight > ROW) {
						ApplyTrash();
					} else {
						timeInState = 0; // Reset the time in state before we check autodeath again
					}
				}
				return;
		}
	}

	// Draw the big collapse of pieces after a few seconds
	IEnumerator HandleLoss(float timer) {
    if (board == null) yield break;

		// Wait three seconds before doing the crumble so they can watch in dismay
		// at the piles of trash that killed them
    active = false;

		yield return new WaitForSeconds(timer);
		// First, crumble the board to be really cool
		for(int x = 0; x < board.Count; ++x) {
			var col = board[x];
			for(int y = 0; y < col.Count; ++y) {
				render.Crumble(col[y], (x, y));
			}
		}

		// Now, re-initialize the board, so those falling pieces are the last of our board
		board = BoardStateExtension.Initialize();
    render.RebuildStack(board);
    render.Render(board);
	}
	#endregion

	#region Input
	/// <summary>
	/// Awaiting control stick neutral for control inputs to return
	/// </summary>
	public bool awaitingNeutral;
	public static float inputThreshold = 0.3f;

	public void PlayerInput() {
		float rightIntent = Input.GetAxisRaw("Horizontal");
		float upIntent = Input.GetAxisRaw("Rotate");

		var max = Mathf.Max(Mathf.Abs(rightIntent), Mathf.Abs(upIntent));
		if (max > 0.3f) {
			if (!awaitingNeutral) {
				if (rightIntent > 0.2f) {
					dropColumn += 1;
				} else if (rightIntent < -0.2f) {
					dropColumn -= 1;
				}

				if (upIntent > 0.2f) {
					playerRotation += 1;
				} else if (upIntent < -0.2f) {
					playerRotation -= 1;
				}

				// Shitty wrapping
				if (playerRotation > 3)
					playerRotation = 0;
				if (playerRotation < 0)
					playerRotation = 3;

				dropColumn = ClampRotatedPosition(playerRotation);
				dropHeight = playerRotation != 3 ? 12 : 13; // Shift the drop height based on rotation
			}
			awaitingNeutral = true;
		} else {
			awaitingNeutral = false;
		}
		
		if (Input.GetButtonDown("Drop")) {
			if (delayState == DelayState.None) {
				board = Collapse(board);
				board = DropNow(board);
			}
		}

		if (Input.GetButtonDown("Swap")) {
			SwapTiles();
		}
	}


	public BoardState DropNow(BoardState bs) {
		bs = Place(bs, currentPair, playerRotation, dropColumn);
		//this[dropColumn, dropHeight] = TileInfo.CreateRandomBlockTile();
		bs = ReduceCountdowns(bs);
		bs = Collapse(bs);
		delayState = DelayState.Collapse;

		SwapTiles();
		ReplaceNextTile();

		return bs;
	}
	#endregion

	#region placement
	[NetVar('p',true,true)]
	public int dropColumn;
	[NetVar('r', true, true)]
	public int playerRotation = 0;
	// Rotations (Coordinate is always on left)
	// 0 - L/R

	// 1 - L
	//     R

	// 2 - R/L

	// 3 - R
	//     L

  private ((int x, int y) left, (int x, int y) right) GetPlacePosition(BoardState bs, int placeRotation, int dropColumn){
    (int x, int y) left = (dropColumn, dropHeight), right = (dropColumn, dropHeight);
    switch(placeRotation){
      case 0:
        right.x += 1;
        break;
      case 1:
        right.y += 1;
        break;
      case 2:
        right.x -= 1;
        break;
      case 3:
        right.y -= 1;
        break;
    }
    return (left, right);
  }

	public BoardState Place(BoardState bs,(TileInfo left, TileInfo right) pair, int placeRotation, int dropColumn) {
		//Debug.LogFormat("Placing tile frame {0}",Time.frameCount);
		(int x, int y) dropLeft = (dropColumn, dropHeight), dropRight = (dropColumn, dropHeight);
		switch(placeRotation) {
			case 0:
				dropRight.x += 1;
				break;
			case 1:
				dropRight.y += 1;
				break;
			case 2:
				dropRight.x -= 1;
				break;
			case 3:
				dropRight.y -= 1;
				break;
		}
		// Fix an issue with placing tiles in the wrong order not working right
		if (dropRight.y < dropLeft.y) {
			// Texel - Switch to modifying the passed board state, instead of the authority board state
			bs.SetTile(pair.right, dropRight.x, dropRight.y);
			bs.SetTile(pair.left, dropLeft.x, dropLeft.y);
			//this[dropRight.x, dropRight.y] = pair.right;
			//this[dropLeft.x, dropLeft.y] = pair.left;
		} else {
			bs.SetTile(pair.left, dropLeft.x, dropLeft.y);
			bs.SetTile(pair.right, dropRight.x, dropRight.y);
			
			//this[dropLeft.x, dropLeft.y] = pair.left;
			//this[dropRight.x, dropRight.y] = pair.right;
		}


		return bs;
	}

	public int ClampRotatedPosition(int sourceRotation) {
		switch(sourceRotation) {
			case 0:
				return Mathf.Clamp(dropColumn, 0, COLUMN-2);
			case 1:
			case 3:
				return Mathf.Clamp(dropColumn, 0, COLUMN-1);
			case 2:
				return Mathf.Clamp(dropColumn, 1,	COLUMN-1);
			default:
				throw new System.IndexOutOfRangeException("Rotation is out of bounds you dolt");
		}
	}
	#endregion

	#region network
	// Serialize/Deserialize network board state
	public override void Deserialize(Hashtable h) {
		base.Deserialize(h);
    //Debug.Log("Deserializing");
    
		if (h.TryGetValue('b', out var val)) {
			board.FromHashtable((Hashtable)val);
      //Debug.Log(val.ToString());
		}
	}
	public override void Serialize(Hashtable h) {
		base.Serialize(h);
    //Debug.Log("Serializing");

		h.Add('b', board.ToHashtable());
		lastSentBoard = board.Copy();
		stateDirty = false;
	}

	// Would be a lot better if we could get a good hash off of the board, but the data is too regular we'd collide constantly
	void checkDirty() {
		if (lastSentBoard != null && !board.Matches(lastSentBoard)) {
			stateDirty = true;
			return;
		}
	}
	#endregion

	#region trash
	BoardState ReduceCountdowns(BoardState bs) {
		for(int i = 0; i < bs.Count; ++i) {
			var col = bs[i];
			for(int y = 0; y < col.Count; ++y) {
				var tile = col[y];
        if (tile.kind == TileKind.Trash){
          tile.counter--;
          if (tile.counter == 0){ // Revert tiles to blocks
            tile.kind = TileKind.Block;
          }
        }
			}
		}
		
		return bs;
	}

	// Funny how THIS one is super easy, but once trash is involved it's hard
	int HighestStack(BoardState bs) => bs.Max(t => t.Count);

	/// <summary>
	/// Calculate the highest stack with trash.
	/// </summary>
	int HighestStackWithTrash(BoardState bs, int amount) {
		var stackHeights = new List<int>();
		for(int c = 0; c < bs.Count; ++c)
			stackHeights.Add(bs[c].Count);

		var cursorHead = trashCursorHead;
		while (amount > 0) {
			--amount;
			stackHeights[cursorHead] += 1;

			if (cursorHead >= COLUMN) {
				cursorHead = 0;
			}
		}

		return stackHeights.Max();
	}

	public int incomingTrash = 0;

	void SendTrash(int amount) {
		if (amount < 1) return;
		// Uncached find? Blasphamy! Also whatever fukkit
		var otherBoards = FindObjectsOfType<GameBoard>().Where(t => t != this);
		foreach (var other in otherBoards) {
			other.RaiseEvent('t', true, amount);
		}
	}

	[NetEvent('t')]
	void AddTrashNetwork(int i) {
		incomingTrash += i;
	}

	// Column to drop trash
	int trashCursorHead = 0;
	void ApplyTrash() {
		if (incomingTrash > 0) {
			delayState = DelayState.Collapse;
			timeInState = 0;
		}
		while (incomingTrash > 0) {
			--incomingTrash;

			var trash = TileInfo.CreateRandomTrashTile();
			board[trashCursorHead].Add(trash);

			trashCursorHead += 1;
			if (trashCursorHead >= COLUMN)
				trashCursorHead = 0;
		}
	}
	#endregion

	#region activation
	BoardState ClearActivation(BoardState bs) {
		foreach(var col in bs) {
			for(int y = 0; y < col.Count; ++y) {
				var tile = col[y];
				if (tile.kind.Equals(TileKind.Activiting)){
					TileInfo.SetAirTile(tile);
				}
			}
		}
		return bs;
	}

	// Activate all special tiles
	BoardState SpecialActivation(BoardState bs, out bool didActivate) {
		
		didActivate = false;
		//return bs; // Test short-circuit

		for (int x = 0; x < bs.Count; ++x) {
			var col = bs[x];
			for (int y = 0; y < col.Count; ++y) {
				var tile = col[y];
				if (tile.kind == TileKind.Special) {
					if (y > 0) {
						// Get the color of the tile we are on top of
						var under = col[y - 1];
						tile.kind = TileKind.Activiting;
						tile.color = under.color;
						bs = ActivateAllColor(bs, under.color);
						didActivate = true;
					} else {
						// Special tile is on the bottom, swap it to a random activating tile
						tile = TileInfo.CreateRandomActivatorTile();
					}
				}
			}
		}
		return bs;
	}

	BoardState ActivateAllColor(BoardState bs,TileColor tc) {
		for (int x = 0; x < bs.Count; ++x) {
			var col = bs[x];
			for (int y = 0; y < col.Count; ++y) {
				var tile = col[y];
				if (tile.color == tc) {
					tile.kind = TileKind.Activiting;
				}
			}
		}

		return bs;
	}

	int CountActivations(BoardState bs) {
		int total = 0;
		foreach(var col in bs) {
			total += col.Count(t => t.kind.Equals(TileKind.Activiting));
		}

		return total;
	}

	void GhostActivations() {
		for(int x = 0; x < board.Count; ++x) {
			var col = board[x];
			for (int y = 0; y < col.Count; ++y) {
				var tile = col[y];
				if (tile.kind.Equals(TileKind.Activiting)) {
					render.Ghost(tile, (x, y));
				}
			}
		}
	}

	BoardState ActivateColorOnce(BoardState bs,TileColor tc,out bool success) {
		success = false;
		for(int x = 0; x < bs.Count; ++x) {
			var col = bs[x];
			for (int y = 0; y < col.Count; ++y) {
				//var tile = this[x, y];
				var tile = bs.tile(x, y);
				if (tile.kind.Equals(TileKind.Activator) || tile.kind.Equals(TileKind.Activiting)) {
					// Check adjacency for tiles to activate, filtering for unactivated blocks or other activators of our color
					var neighbors = Neighbors(x, y,bs).Where(t => t.kind.Equals(TileKind.Block) || t.kind.Equals(TileKind.Activator)).Where(t => t.color.Equals(tile.color));
					foreach(var neighbor in neighbors) {
						success = true;
						tile.kind = TileKind.Activiting;
						neighbor.kind = TileKind.Activiting;
					}
				}
			}
		}
		return bs;
	}

	BoardState ActivateColorOnceSplit(BoardState bs, TileColor tc, out bool success) {
		success = false;
		var activable = new List<(int x, int y)>();
		for (int x = 0; x < bs.Count; ++x) {
			var col = bs[x];
			for(int y = 0; y < col.Count; ++y) {
				var tile = bs.tile(x, y);//this[x, y];
				if (tile.color != tc) continue;
				if (tile.kind.Equals(TileKind.Activator) || tile.kind.Equals(TileKind.Activiting))
					activable.Add((x, y));
			}
		}

		foreach(var potential in activable) {
			var tile = bs.tile(potential.x, potential.y);//this[potential.x, potential.y];
			if (tile.kind.Equals(TileKind.Activator) || tile.kind.Equals(TileKind.Activiting)) {
				// Check adjacency for tiles to activate, filtering for unactivated blocks or other activators of our color
				var neighbors = Neighbors(potential.x, potential.y,bs).Where(t => t.kind.Equals(TileKind.Block) || t.kind.Equals(TileKind.Activator)).Where(t => t.color.Equals(tile.color));
				foreach (var neighbor in neighbors) {
					success = true;
					tile.kind = TileKind.Activiting;
					neighbor.kind = TileKind.Activiting;
				}
			}
		}

		return bs;
	}

	BoardState ActivateColor(BoardState bs, TileColor tc) {
		bool didActivate;
		do {
			bs = ActivateColorOnce(bs, tc, out didActivate);
		} while (didActivate);

		return bs;
	}

	BoardState ActivateOnce(BoardState bs, out bool success) {
		var colors = (TileColor[])System.Enum.GetValues(typeof(TileColor));
		success = false;
		foreach(var tc in colors) {
			//bs = ActivateColorOnce(bs,tc, out bool colorSuccess);
			bs = ActivateColorOnceSplit(bs, tc, out bool colorSuccess);
			if (colorSuccess) success = true;
		}
		return bs;
	}

	BoardState Activate(BoardState bs) {
		var colors = (TileColor[])System.Enum.GetValues(typeof(TileColor));
		foreach(var tc in colors) {
			bs = ActivateColor(bs, tc);
		}
		return bs;
	}
	#endregion

	static BoardState Collapse(BoardState bs) {
		for(int i = 0; i < bs.Count; ++i) {
			bs[i] = Collapse(bs[i]);
		}
		return bs;
	}

	static List<TileInfo> Collapse(List<TileInfo> ti) {
		return ti.Where(t => t.kind != TileKind.Air).ToList();
	}

	bool stateDirty = false;

  [Header("Network")]
  public float networkTick = 0.1f;
  private float nextNetworkTick;

	public void Update() {
    if (!active) {
      render.RenderName();
      return;
    }

		if (isMine) {
			//checkDirty();

      render.RebuildStack(board);
			GameLogic();
      render.RebuildStack(board);

			if (Time.time >= nextNetworkTick && NetworkManager.inRoom){
        UpdateNow();
        nextNetworkTick = Time.time + networkTick;
      }
				
		}

    render.Render(board);
		// HACK So uh, there's an issue with air tiles taking two renders to be removed right, so uh, two renders it is. - Texel
		// Seriously I can't believe this works this is dirty

    // It does make it render twice as fast, I have idea
    // i fix by doing two rebuild stacks >:)
		// render.Render(board);

		render.SetComboLevel(Combo);
		render.SetScoreValue(score);

    var pair = currentPair;
    var pairp = GetPlacePosition(board, playerRotation, dropColumn);
    render.RenderPlacement(pair.left, pair.right, pairp.left, pairp.right);

    render.RenderName();
	}

	public override void Awake() {
		base.Awake();
		
    Register();
	}

  public void Setup(){
    board = BoardStateExtension.Initialize();

		StopAI();
		// This is to reset the AI

		// Build the list of possible placements the AI may use
		PossiblePlacements = GetAllPossibilities();

		lastActivatorColor = TileInfo.CreateRandomActivatorTile().color;

    nextActivator = TilesUntilActivator;
		nextSpecial = ActivatorsUntilSpecial;
    delayState = DelayState.None;
		timeInState = 0;

    ReplaceNextTile();
    SwapTiles();
    ReplaceNextTile();

    if (isMine){
      foreach(var c in board){
        c.Add(TileInfo.CreateRandomBlockTile());
        c.Add(TileInfo.CreateRandomBlockTile());
      }
    }

    active = true;
  }

  public void Stop(){
    StopAI();
    active = false;
  }

  public void Clear(){
    delayState = DelayState.None;
    StartCoroutine(HandleLoss(0f));
  }

	public IEnumerable<TileInfo> Neighbors(int x, int y, BoardState bs) {
		var self = bs.tile(x, y);
		var neighborsWithNull = new[] { bs.tile(x + 1, y), bs.tile(x - 1, y), bs.tile(x, y + 1), bs.tile(x, y - 1) };
		return neighborsWithNull.Where(t => t != null).Where(t => t != self);

		/*var self = this[x, y];
		var neighborsWithNull = new[] { this[x + 1, y], this[x - 1, y], this[x, y + 1], this[x, y - 1] };
		return neighborsWithNull.Where(t => t != null).Where(t=>t!=self);*/
	}

	public TileInfo this[int x, int y] {
		get {
			// Pass null on sides/top, or anywhere where x, y doesn't exist.
			if (x < 0 || x >= board.Count) return null;
			if (y < 0) return null;

			var col = board[x];

			if (y < col.Count) return col[y];
			return null;
		}
		set {
			var col = board[x];

			// Set value or append to end
			if (y < col.Count) col[y] = value;
			else col.Add(value);    // Added else. Otherwises, any set would have grown board -- Ebony
		}
	}

	#region AI
	List<(int r, int c)> PossiblePlacements;

	/// <summary>
	/// Given input board state, return the end result for number of tiles that would be sent in an attack
	/// This is destructive to the input board state
	/// </summary>
	int ProjectAttack(BoardState bs) {
		int total = 0;
		int comboLength = 0;

		bool repeat = false;
		do {
			repeat = false;
			bs = Collapse(bs);
			bs = Activate(bs);
			bs = SpecialActivation(bs, out bool didActivate);

			var newActivations = CountActivations(bs);
			if (newActivations > 0) {
				comboLength += 1;
				repeat = true;

				if (newActivations > 3) total += (newActivations - 3) * comboLength;
				bs = ClearActivation(bs);
			}
		} while (repeat);

		return total;
	}

	// Generates actual subset of possible moves 
	List<(int simRotation, int simCol)> GetAllPossibilities() {
		var Considerables = new List<(int r, int c)>();
		for(int col = 0; col < COLUMN; ++col) {
			Considerables.AddRange(new[] {
				(0,col), (1,col), (2,col), (3,col)
			});
		}

		for(int i = 0; i < Considerables.Count; ++i) {
			Considerables[i] = ClampPossibility(Considerables[i]);
		}
		return Considerables.Distinct().ToList();
	}

	(int r, int c) ClampPossibility((int r, int c) possibility) {
		int oldDrop = dropColumn;
		dropColumn = possibility.c;
		possibility.c = ClampRotatedPosition(possibility.r);
		dropColumn = oldDrop;

		return possibility;
	}

	float averageConnectedSize(BoardState bs) {
		int maxRed =0, maxGreen=0, maxBlue=0, maxYellow=0;
		for (int i = 0; i < bs.Count; ++i) {
			(int count, TileColor color) cluster = ExposedClusterSize(bs, i);
			switch(cluster.color) {
				case TileColor.Blue:
					maxBlue = Mathf.Max(maxBlue, cluster.count);
					break;
				case TileColor.Green:
					maxGreen = Mathf.Max(maxGreen, cluster.count);
					break;
				case TileColor.Red:
					maxRed = Mathf.Max(maxRed, cluster.count);
					break;
				case TileColor.Yellow:
					maxYellow = Mathf.Max(maxYellow, cluster.count);
					break;
			}
		}

		return (maxRed + maxGreen + maxBlue + maxYellow) * 0.25f;
	}

	// Texel - I gave up writing this and made it use a board copy destructively
	(int count, TileColor color) ExposedClusterSize(BoardState bs, int col) {
		var bc = bs.Copy();
		//ReduceToBlocksOnly(bc);

		int startX = col;
		int startY = bc[col].Count - 1;
		if (startY < 0) return (0, TileColor.Blue); // Oops can't eval an empty col

		var tile = bc.tile(startX, startY);

		tile.kind = TileKind.Activator;
		//ProjectAttack(bc);
		bc = Activate(bc);

		return (CountActivations(bc),tile.color);
	}

	void ReduceToBlocksOnly(BoardState bs) {
		for(int x = 0; x < bs.Count; ++x) {
			var col = bs[x];
			for(int y = 0; y < bs.Count; ++y) {
				var tile = col[y];
				if (tile.kind.Equals(TileKind.Air)) continue;
				tile.kind = TileKind.Block;
				tile.counter = 0;
			}
		}
	}

	/// <summary>
	/// Create an internal copy of the board, simulate the given rotation/col against it.
	/// </summary>
	(int score,float averageConnectedSize, int maxHeight) EvalPossibility(BoardState bs, (int r, int c) possibility) {
		var bc = bs.Copy();
		try {
			bc = Place(bc, currentPair, possibility.r, possibility.c);

			// TODO - Highest connected size
			float connectness = averageConnectedSize(bc);
			int trashValue = ProjectAttack(bc); // Forward simulate the board to it's next stable position
			int tallest = HighestStack(bc);

			return (trashValue, connectness, tallest);
		} catch (System.Exception e) {
			Debug.LogFormat("Possibility ({0}, {1}) has encountered an exception", possibility.r, possibility.c);
			throw (e);
		}
	}
	// Methodology -> Place pieces to fire the longest combo, then place pieces to minimize our tallest stack.
	(int r, int c) GetBestMove(BoardState bs) {
		return PossiblePlacements
			.Select(possiblity => (possiblity, EvalPossibility(bs, possiblity)))
			.OrderByDescending(t => t.Item2.score) // First priority, attacking
			.ThenByDescending(t => t.Item2.maxHeight < 10 ? 1 : 0) // Second priority, not offing ourselves
			.ThenByDescending(t => t.Item2.averageConnectedSize) // Third priority, maximize cluster sizes
			.ThenBy(t => t.Item2.maxHeight) // Fourth priority, keeping our height down
			.Select(t => t.possiblity).First();
	}

	[ContextMenu("Startup AI")]
	public void StartAIDefault() {
		StartAI();
	}

  Coroutine aiThinkCoroutine;

	public void StartAI(float thinkTime = 0.5f) {
		AIEnabled = true;
		AIMoveTime = thinkTime;
		aiThinkCoroutine = StartCoroutine(AIThink());
	}

  public void StopAI(){
    AIEnabled = false;
    if (aiThinkCoroutine != null) StopCoroutine(aiThinkCoroutine);
    aiThinkCoroutine = null;
  }

	public bool AIEnabled = false;
	public float AIMoveTime = 0.5f;
	IEnumerator AIThink() {
		yield return null; // Wait a frame before trying any shit

		int totalMoves = 0;
		while (delayState != DelayState.Loss) {
			if (!AIEnabled)
				yield return new WaitUntil(() => AIEnabled);
			var (r, c) = GetBestMove(board);
			Debug.LogFormat("AI: Column {0}, Rotation {1}", c, r);
			totalMoves += 1;

			// First match rotation
			while (playerRotation != r) {
				yield return new WaitForSeconds(AIMoveTime);
				if (playerRotation < r) ++playerRotation;
				if (playerRotation > r) --playerRotation;

				dropColumn = ClampRotatedPosition(playerRotation);
			}

			// Then move to the right column
			while (dropColumn != c) {
				yield return new WaitForSeconds(AIMoveTime);
				if (dropColumn > c) --dropColumn;
				if (dropColumn < c) ++dropColumn;
			}

			// Wait until we're allowed to drop a piece
			yield return new WaitUntil(() => delayState.Equals(DelayState.None));
			board = DropNow(board);
			// Now wait for it all to settle before repeating
			yield return new WaitUntil(() => delayState.Equals(DelayState.None));
		}

		Debug.LogFormat("AI lost after {0} moves",totalMoves);
	}
	#endregion
}