using Chess;
using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Forms;
using static Chess.Piece;

namespace ChessPanel
{
    public partial class ChessBoard : Panel
    {
        public Field[,] fields;
        public PieceColor activePlayer;
        private int gridSize = 8;
        public bool isSaved = true;
        Dictionary<Vector, PieceTeam> validTargetSpots = new Dictionary<Vector, PieceTeam>();
        private Vector? selectedField;
        private Vector? SelectedField
        {
            get { return selectedField; }
            set { selectedField = value; HighlightValidTargetSpots(); }
        }
        private void HighlightValidTargetSpots()
        {
            if (selectedField.HasValue && fields[(int)selectedField.Value.X, (int)selectedField.Value.Y].CurrentPiece != null) // Wenn das neu ausgewählte Feld eine Figur enthält, wird diese ausgewählt
            {
                fields[(int)selectedField.Value.X, (int)selectedField.Value.Y].Select();
            }
            ResetValidTargetSpots();
            if (selectedField.HasValue)
            {
                if (fields[(int)selectedField.Value.X, (int)selectedField.Value.Y].CurrentPiece != null)
                {
                    validTargetSpots = fields[(int)selectedField.Value.X, (int)selectedField.Value.Y].CurrentPiece.GetValidTargetFields(fields, new Vector(selectedField.Value.X, selectedField.Value.Y));
                }
                foreach (var item in validTargetSpots)
                {
                    fields[(int)item.Key.X, (int)item.Key.Y].Highlight(item.Value);
                }
            }
        }
        /// <summary>
        /// Setzt die Markierungen sowie die Liste der möglichen Zielfelder zurück
        /// </summary>
        private void ResetValidTargetSpots()
        {
            foreach (var item in validTargetSpots)
            {
                fields[(int)item.Key.X, (int)item.Key.Y].Deselect();
            }
            validTargetSpots.Clear(); // Markierung der Zielfelder zurücksetzen
        }
        public int GridSize
        {
            get { return gridSize; }
            set { gridSize = value; }
        }
        public ChessBoard()
        {
            this.DoubleBuffered = true;
            this.SuspendLayout();
            this.Resize += new System.EventHandler(this.ChessBoard_Resize);
            InitializeGrid();
            InitializePieces();
            activePlayer = PieceColor.White;
            this.ResumeLayout(false);
        }
        private void ToggleActivePlayer() => activePlayer = activePlayer == PieceColor.White ? PieceColor.Black : PieceColor.White;
        private void DoPieceMove(Vector location, Vector newLocation, bool togglePlayer = true)
        {
            isSaved = false;
            #region Castling
            if (fields[(int)location.X, (int)location.Y].CurrentPiece.type == PieceType.King && Math.Abs(newLocation.X - location.X) == 2)
                DoPieceMove(new Vector(((newLocation.X - location.X == -2) ? 0 : 7), location.Y), new Vector(location.X + (newLocation.X - location.X) / 2, location.Y), false /*Dont Toggle Player*/); // Move Rook 
            #endregion
            #region EnPassant     
            foreach (var item in fields) // Reset Enpassant Possible states each move
            {
                if (item.CurrentPiece != null)
                    if (item.CurrentPiece.type == PieceType.Pawn)
                    {
                        item.CurrentPiece.EnPassantPossible = false;
                    }
            }
            if (fields[(int)location.X, (int)location.Y].CurrentPiece.type == PieceType.Pawn && !fields[(int)location.X, (int)location.Y].CurrentPiece.HasMoved)
                fields[(int)location.X, (int)location.Y].CurrentPiece.EnPassantPossible = true;
            if (fields[(int)location.X, (int)location.Y].CurrentPiece.type == PieceType.Pawn && newLocation.X != location.X && fields[(int)newLocation.X, (int)newLocation.Y].IsEmpty)
                fields[(int)newLocation.X, (int)newLocation.Y + (fields[(int)location.X, (int)location.Y].CurrentPiece.color == PieceColor.White ? 1 : -1)].CurrentPiece = null;
            #endregion
            fields[(int)location.X, (int)location.Y].CurrentPiece.HasMoved = true; // Figur Bereits bewegt Status aktualisieren
            fields[(int)newLocation.X, (int)newLocation.Y].CurrentPiece = fields[(int)location.X, (int)location.Y].CurrentPiece; // Figur an neue Position kopieren
            fields[(int)location.X, (int)location.Y].CurrentPiece = null; // Alte Kopie der Figur löschen
            if (togglePlayer)
                ToggleActivePlayer();
        }
        private void InitializePieces()
        {
            fields[0, 0].CurrentPiece = new Rook(PieceColor.Black);
            fields[7, 0].CurrentPiece = new Rook(PieceColor.Black);
            fields[0, 7].CurrentPiece = new Rook(PieceColor.White);
            fields[7, 7].CurrentPiece = new Rook(PieceColor.White);

            fields[1, 0].CurrentPiece = new Knight(PieceColor.Black);
            fields[6, 0].CurrentPiece = new Knight(PieceColor.Black);
            fields[1, 7].CurrentPiece = new Knight(PieceColor.White);
            fields[6, 7].CurrentPiece = new Knight(PieceColor.White);

            fields[2, 0].CurrentPiece = new Bishop(PieceColor.Black);
            fields[5, 0].CurrentPiece = new Bishop(PieceColor.Black);
            fields[2, 7].CurrentPiece = new Bishop(PieceColor.White);
            fields[5, 7].CurrentPiece = new Bishop(PieceColor.White);

            fields[4, 0].CurrentPiece = new King(PieceColor.Black);
            fields[3, 0].CurrentPiece = new Queen(PieceColor.Black);

            fields[3, 7].CurrentPiece = new Queen(PieceColor.White);
            fields[4, 7].CurrentPiece = new King(PieceColor.White);
            for (int x = 0; x < 8; x++)
            {
                fields[x, 1].CurrentPiece = new Pawn(PieceColor.Black);
                fields[x, 6].CurrentPiece = new Pawn(PieceColor.White);
            }
        }
        private void InitializeGrid()
        {
            this.fields = new Field[gridSize, gridSize];
            int subPanelEdgeLength = Math.Min(this.Size.Width, this.Size.Height) / gridSize;
            System.Drawing.Size subPanelSize = new System.Drawing.Size(subPanelEdgeLength, subPanelEdgeLength);
            for (int x = 0; x < this.gridSize; x++)
            {
                for (int y = 0; y < this.gridSize; y++)
                {
                    Field field = new Field(x, y);
                    field.Size = subPanelSize;
                    field.Location = new System.Drawing.Point(x * subPanelSize.Width, y * subPanelSize.Height);
                    field.FieldClick += FieldClicked;
                    fields[x, y] = field;
                    this.Controls.Add(fields[x, y]);
                }
            }
        }
        private void FieldClicked(Vector coordinates)
        {
            this.SuspendLayout();
            if (SelectedField.HasValue && validTargetSpots.ContainsKey(coordinates)) // Ein erlaubtes Zielfeld wurde angeklickt
            {
                DoPieceMove(SelectedField.Value, coordinates); // Bewege Figur
                ResetSelectedField(); // Auswahl zurücksetzen
            }
            else
            {
                if (SelectedField == coordinates) // Erneutes Anklicken des Auswahlfeldes
                    ResetSelectedField(); // Auswahl zurücksetzen
                else // Tritt ein, wenn ein Feld angeklickt wurde, dass nicht das Auswahlfeld ist
                {
                    if (SelectedField.HasValue) // Wenn ein Feld ausgewählt ist wird die Auswahl gelöscht falls nicht das Auswahlfeld angeklickt wurde
                        ResetSelectedField(); // Auswahl zurücksetzen
                    if (!fields[(int)coordinates.X, (int)coordinates.Y].IsEmpty && fields[(int)coordinates.X, (int)coordinates.Y].CurrentPiece.color == activePlayer) // Feld wird nur ausgewählt, wenn die Farbe der Figur mit der des aktiven Spielers übereinstimmt
                        SelectedField = coordinates; // Kein Feld ist ausgewählt: Angeklicktes Feld auswählen (!) AKTUALISIERT AUTOMATISCH DIE MARKIERUNGEN
                }
            }
            this.ResumeLayout(false);
        }
        /// <summary>
        /// Löscht die Auswahl des aktuell ausgewählten Feldes
        /// </summary>
        private void ResetSelectedField()
        {
            fields[(int)SelectedField.Value.X, (int)SelectedField.Value.Y].Deselect(); // Auswahl zurücksetzen
            SelectedField = null; // Erlaubte Zielfelder zurücksetzen
        }
        #region Helper Can be deleted
        static readonly string[] Columns = new[] { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "AA", "AB", "AC", "AD", "AE", "AF", "AG", "AH", "AI", "AJ", "AK", "AL", "AM", "AN", "AO", "AP", "AQ", "AR", "AS", "AT", "AU", "AV", "AW", "AX", "AY", "AZ", "BA", "BB", "BC", "BD", "BE", "BF", "BG", "BH" };
        public static string IndexToColumn(int index)
        {
            if (index <= 0)
                throw new IndexOutOfRangeException("index must be a positive number");

            return Columns[index - 1];
        }
        #endregion
        private void ChessBoard_Resize(object sender, EventArgs e)
        {
            RefreshSize();
        }
        private void RefreshSize()
        {
            this.SuspendLayout();
            int subPanelEdgeLength = Math.Min(this.Size.Width, this.Size.Height) / gridSize;
            System.Drawing.Size subPanelSize = new System.Drawing.Size(subPanelEdgeLength, subPanelEdgeLength);
            for (int x = 0; x < this.gridSize; x++)
            {
                for (int y = 0; y < this.gridSize; y++)
                {
                    fields[x, y].Size = subPanelSize;
                    fields[x, y].Location = new System.Drawing.Point(x * subPanelSize.Width, y * subPanelSize.Height);
                }
            }
            this.ResumeLayout(false);
        }
    }
}