shared/checkWin.ts

import type { Cell } from './types.ts'
import { BitBoard, bitBoardWinResult } from './bot/BitBoard.ts'

export function checkWin(
  board: Map<string, Cell> | BitBoard,
  x: number,
  y: number,
  playerId: string,
  noOverlines?: boolean,
): { won: boolean; cells: { x: number; y: number }[] } {
  if (board instanceof BitBoard) {
    const player = Number(playerId)
    if (player !== 0 && player !== 1) return { won: false, cells: [] }
    return bitBoardWinResult(board, x, y, player, noOverlines)
  }

  const directions = [[1, 0], [0, 1], [1, 1], [1, -1]]

  for (const [dx, dy] of directions) {
    const cells: { x: number; y: number }[] = [{ x, y }]
    let count = 1

    let cx = x + dx
    let cy = y + dy
    while (board.get(`${cx}:${cy}`)?.playerId === playerId) {
      cells.push({ x: cx, y: cy })
      count++
      cx += dx
      cy += dy
    }
    const posEnd = board.get(`${cx}:${cy}`)

    let nx = x - dx
    let ny = y - dy
    while (board.get(`${nx}:${ny}`)?.playerId === playerId) {
      cells.push({ x: nx, y: ny })
      count++
      nx -= dx
      ny -= dy
    }
    const negEnd = board.get(`${nx}:${ny}`)

    if (count >= 5) {
      if (noOverlines && count > 5) continue
      const bothBlocked = posEnd !== undefined && negEnd !== undefined
      if (!bothBlocked) {
        return { won: true, cells }
      }
    }
  }

  return { won: false, cells: [] }
}