import { signal, type Signal } from '@preact/signals';

export interface ValidMove {
  card: string;
  fromX: number;
  fromY: number;
  toX: number;
  toY: number;
}

export interface OnitamaUIState {
  selectedPiece: { x: number; y: number } | null;
  selectedCard: string | null;
  validMoves: ValidMove[];
}

export function createOnitamaUIState(): Signal<OnitamaUIState> {
  return signal<OnitamaUIState>({
    selectedPiece: null,
    selectedCard: null,
    validMoves: [],
  });
}

export function clearSelection(uiState: Signal<OnitamaUIState>): void {
  uiState.value = {
    selectedPiece: null,
    selectedCard: null,
    validMoves: [],
  };
}

export function selectPiece(
  uiState: Signal<OnitamaUIState>,
  x: number,
  y: number
): void {
  uiState.value = {
    ...uiState.value,
    selectedPiece: { x, y },
    selectedCard: null,
  };
}

export function selectCard(
  uiState: Signal<OnitamaUIState>,
  card: string
): void {
  // 如果点击已选中的卡牌，取消选择
  if (uiState.value.selectedCard === card) {
    uiState.value = {
      selectedPiece: null,
      selectedCard: null,
      validMoves: [],
    };
  } else {
    // 选择新卡牌，清除棋子选择
    uiState.value = {
      selectedPiece: null,
      selectedCard: card,
      validMoves: [],
    };
  }
}

export function deselectCard(
  uiState: Signal<OnitamaUIState>
): void {
  uiState.value = {
    ...uiState.value,
    selectedCard: null,
    selectedPiece: null,
    validMoves: [],
  };
}

export function setValidMoves(
  uiState: Signal<OnitamaUIState>,
  moves: ValidMove[]
): void {
  uiState.value = {
    ...uiState.value,
    validMoves: moves,
  };
}