class PuzzleState {
  constructor({ imageKey, imagePath, pieceCount, roomCode, cols, rows, pieces, groups, completed, bgKey, bgPath }) {
    this.imageKey   = imageKey;
    this.imagePath  = imagePath;
    this.pieceCount = pieceCount;
    this.roomCode   = roomCode;
    this.cols       = cols;
    this.rows       = rows;
    this.pieces     = pieces;   // PieceData[]
    this.groups     = groups;   // number[][] — each inner array is one group's piece IDs
    this.completed  = completed || false;
    this.bgKey      = bgKey  || 'bg_dark_wood';
    this.bgPath     = bgPath || 'assets/images/ui/dark_wood.jpg';
  }

  serialize() {
    return {
      imageKey:   this.imageKey,
      imagePath:  this.imagePath,
      pieceCount: this.pieceCount,
      roomCode:   this.roomCode,
      cols:       this.cols,
      rows:       this.rows,
      pieces:     this.pieces.map(p => ({
        id:       p.id,
        gridRow:  p.gridRow,
        gridCol:  p.gridCol,
        edges:    p.edges,
        x:        p.x,
        y:        p.y
      })),
      groups:     this.groups,
      completed:  this.completed,
      bgKey:      this.bgKey,
      bgPath:     this.bgPath,
    };
  }

  static deserialize(obj) {
    return new PuzzleState(obj);
  }
}