import { mutableSignal } from "boardgame-core";
import {
  createGridInventory,
  createItemIn,
  data,
  GameItemMeta,
  placeItem,
  removeItemFromGrid,
  validatePlacement,
} from "boardgame-core/samples/slay-the-spire-like";

function genId() {
  return Math.random().toString(16).slice(-8);
}

export type InventorySignal = ReturnType<typeof createInventorySignal>;

export function createInventorySignal() {
  const inventory = createGridInventory<GameItemMeta>(4, 6);

  const startingItems = data.desert.getStartingItems();
  for (const d of startingItems) {
    createItemIn(inventory, `${d.id}-${genId()}`, d);
  }

  return mutableSignal(inventory);
}

/**
 * Move an item to a new position in the inventory.
 * Returns true if the move was successful, false if the new position is invalid.
 */
export function moveItem(
  inventorySignal: InventorySignal,
  itemId: string,
  newX: number,
  newY: number,
): boolean {
  const inventory = inventorySignal.value;
  const item = inventory.items.get(itemId);

  if (!item) {
    return false;
  }

  const newTransform = {
    ...item.transform,
    offset: { x: newX, y: newY },
  };
  const validation = validatePlacement(inventory, item.shape, newTransform);
  if (!validation.valid) return false;

  inventorySignal.produce((inv) => {
    const item = inv.items.get(itemId)!;
    removeItemFromGrid(inv, itemId);
    item.transform = newTransform;
    placeItem(inv, item);
  });

  return true;
}