fix: minmax properly when ai is O

packages/ai/src/game.ts

@@ -13,6 +13,7 @@ const debug = false
 
 interface Options {
  maxDepth: number
+ humanPlayer: number
  aiPlayer: number
 }
 
@@ -28,9 +29,9 @@ function minimax(
  const board = new Board(initial.size, initial)
  board.update_cell_owner(selectedCell.x, selectedCell.y, player)
  if (board.check_win_at(selectedCell.x, selectedCell.y)) {
- return player === 1 ? -100 - depth : 100 + depth
+ return opts.humanPlayer === player ? -100 - depth : 100 + depth
  } else if (board.check_is_full() || depth === 0) {
- return player === 1 ? -10 - depth : 10 + depth
+ return opts.humanPlayer === player ? -10 - depth : 10 + depth
  }
  let value: number
  if (isMaximizing) {
@@ -51,8 +52,9 @@ function minimax(
 }
 
 export const gameActions = {
- play(symbol: 'x' | 'o', gridsize = 3, depth = 6) {
- board.set(new Board(gridsize))
+ play(symbol: 'x' | 'o', size = 3, depth = 6) {
+ board.set(new Board(size))
+ gridSize.set(size)
  player.set(symbol)
  searchDepth.set(depth)
  if (symbol === 'o') {
@@ -66,11 +68,10 @@ export const gameActions = {
  return
  }
  const playerNumber = get(player) === 'x' ? 1 : 2
- console.log('select ', playerNumber)
  b.update_cell_owner(cell.x, cell.y, playerNumber)
  let ended = true
  if (b.check_win_at(cell.x, cell.y)) {
- gameStatus.set('x-won')
+ gameStatus.set(playerNumber === 1 ? 'x-won' : 'o-won')
  } else if (b.check_is_full()) {
  gameStatus.set('tie')
  } else {
@@ -86,14 +87,15 @@ export const gameActions = {
  const b = get(board)
  let aiMove: Cell | undefined
  let bestValue = Number.NEGATIVE_INFINITY
+ const aiNumber = get(player) === 'x' ? 2 : 1
  const opts = {
  maxDepth: 10,
- aiPlayer: 2,
+ humanPlayer: aiNumber === 1 ? 2 : 1,
+ aiPlayer: aiNumber,
  }
  iterations = 0
- const aiNumber = get(player) === 'x' ? 2 : 1
  b.get_available_moves().forEach(c => {
- const value = minimax(c, b, 9, aiNumber, false, opts)
+ const value = minimax(c, b, get(searchDepth), aiNumber, false, opts)
  if (value > bestValue) {
  aiMove = c
  bestValue = value
@@ -105,7 +107,7 @@ export const gameActions = {
  console.log(`best: ${aiMove.x} ${aiMove.y} ${bestValue} at iterations ${iterations} \n`)
  b.update_cell_owner(aiMove.x, aiMove.y, aiNumber)
  if (b.check_win_at(aiMove.x, aiMove.y)) {
- gameStatus.set('o-won')
+ gameStatus.set(aiNumber === 2 ? 'o-won' : 'x-won')
  } else if (b.check_is_full()) {
  gameStatus.set('tie')
  }