using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Photon.Pun;

public class BoardManager : MonoBehaviour {
    public static BoardManager Instance { set; get; }
    private bool[,] allowedMoves { set; get; }

    public Chessman[,] Chessmans { set; get; }
    public Chessman selectedChessman;

    private const float TILE_SIZE = 1.0f;
    private const float TILE_OFFSET = 0.5f;

    public int selectionX = -1;
    public int selectionY = -1;

    public List<GameObject> chessmanPrefabs;
    private List<GameObject> activeChessman;

    public bool isWhiteTurn = true;

    public bool Multiplayer = false;

    private void Start() {
        Instance = this;
        SpawnAllChessmans();
    }

    private void Update() {
        DrawChessBoard();
        UpdateSelection();

        if (Input.GetMouseButtonDown(0)) {
            if (selectionX >= 0 && selectionY >= 0) {
                if (selectedChessman == null) {
                    //Select the Chessman
                    SelectChessman(selectionX, selectionY);
                }
                else {
                    //Move the Chessman
                    MoveChessman(selectionX, selectionY);
                }
            }
        }
    }

    private void SelectChessman(int x, int y) {
        if (Chessmans[x,y] == null) {
            Debug.Log("failed1");
            return;
        }
        if (Chessmans[x,y].isWhite != isWhiteTurn) {
            Debug.Log("failed2");
            return;
        }

        bool hasAtleastOneMove = false;
        allowedMoves = Chessmans[x, y].PossibleMove();
        for (int i = 0; i < 8; i++)
            for (int j = 0; j < 8; j++)
                if (allowedMoves[i, j])
                    hasAtleastOneMove = true;

        selectedChessman = Chessmans[x, y];
        BoardHighlights.Instance.HighlightAllowedMoves(allowedMoves);
    }

    private void MoveChessman(int x, int y) {
        if (allowedMoves[x,y]) {
            Chessman c = Chessmans[x, y];

            if (c != null && c.isWhite != isWhiteTurn) {
                //capture a piece

                //if its a kind end game
                if (c.GetType() == typeof(King)) {
                    // End game
                    EndGame();
                    return;
                }

                activeChessman.Remove(c.gameObject);
                Destroy(c.gameObject);
            }

            Chessmans [selectedChessman.CurrentX, selectedChessman.CurrentY] = null;
            selectedChessman.transform.position = GetTileCenter(x, y);
            selectedChessman.SetPosition(x, y);
            Chessmans[x, y] = selectedChessman;
            isWhiteTurn = !isWhiteTurn;
        }
        BoardHighlights.Instance.HideHighlights();
        selectedChessman = null;
    }

    private void UpdateSelection() {
        if (!Camera.main) {
            return;
        }
        RaycastHit hit;
        if (Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), out hit, 50.0f, LayerMask.GetMask("ChessPlane"))) {
            selectionX = (int)hit.point.x;
            selectionY = (int)hit.point.z;
        }
        else {
            selectionX = -1;
            selectionY = -1;
        }
    }

    private void SpawnChessman(int index, int x, int y){
        if (Multiplayer == true) {
            GameObject goM = PhotonNetwork.Instantiate(chessmanPrefabs[index].name, GetTileCenter(x, y), Quaternion.identity) as GameObject;
            goM.transform.SetParent(transform);
            Chessmans[x, y] = goM.GetComponent<Chessman>();
            Chessmans[x, y].SetPosition(x, y);
            activeChessman.Add(goM);
        }
        else if (Multiplayer == false) {
            GameObject go = Instantiate(chessmanPrefabs[index], GetTileCenter(x, y), Quaternion.identity) as GameObject;
            go.transform.SetParent(transform);
            Chessmans[x, y] = go.GetComponent<Chessman>();
            Chessmans[x, y].SetPosition(x, y);
            activeChessman.Add(go);
        }
    }

    public void SpawnAllChessmans() {
        activeChessman = new List<GameObject>();
        Chessmans = new Chessman[8, 8];

        //Spawn White
        SpawnChessman(0, 3, 0); //king
        SpawnChessman(1, 4, 0); //queen
        SpawnChessman(2, 0, 0); //rock1
        SpawnChessman(2, 7, 0); //rock2
        SpawnChessman(3, 2, 0); //bishop1
        SpawnChessman(3, 5, 0); //bishop2
        SpawnChessman(4, 1, 0); //knight1
        SpawnChessman(4, 6, 0); //knight2

        for (int i = 0; i < 8; i++)            //pawns
            SpawnChessman(5, i, 1);

        //Spawn Black
        SpawnChessman(6, 3, 7); //king
        SpawnChessman(7, 4, 7); //queen
        SpawnChessman(8, 0, 7); //rock1
        SpawnChessman(8, 7, 7); //rock2
        SpawnChessman(9, 2, 7); //bishop1
        SpawnChessman(9, 5, 7); //bishop2
        SpawnChessman(10, 1, 7); //knight1
        SpawnChessman(10, 6, 7); //knight2

        for (int i = 0; i < 8; i++)            //pawns
            SpawnChessman(11, i, 6);
    }

    private Vector3 GetTileCenter(int x, int y) {
        Vector3 origin = Vector3.zero;
        origin.x += (TILE_SIZE * x) + TILE_OFFSET;
        origin.z += (TILE_SIZE * y) + TILE_OFFSET;
        return origin;
    }

    private void DrawChessBoard() {
        Vector3 widthLine = Vector3.right * 8;
        Vector3 heightLine = Vector3.forward * 8;

        for (int i = 0; i <= 8; i++) {
            Vector3 start = Vector3.forward * i;
            Debug.DrawLine (start, start + widthLine);
            for (int j = 0; j <= 8; j++) {
                start = Vector3.right * j;
                Debug.DrawLine(start, start + heightLine);
            }
        }

        //Draw selection
        if (selectionX >= 0 && selectionY >= 0) {
            Debug.DrawLine(Vector3.forward * selectionY + Vector3.right * selectionX, Vector3.forward * (selectionY + 1) + Vector3.right * (selectionX + 1));
            Debug.DrawLine(Vector3.forward * (selectionY + 1)+ Vector3.right * selectionX, Vector3.forward * selectionY + Vector3.right * (selectionX + 1));
        }
    }

    private void EndGame () {
        if (isWhiteTurn)
            Debug.Log("White team wins");
        else
            Debug.Log("Black team wins");

        foreach (GameObject go in activeChessman)
            Destroy(go);

        isWhiteTurn = true;
        BoardHighlights.Instance.HideHighlights();
        SpawnAllChessmans();
    }
}