hexo/public/ai-bot.js

/**
 * AI Bot for Hexo game
 * Controls computer-controlled players
 */

import { CELL_TYPES } from './map.js';

export class AIBot {
  constructor(playerId, map, gameUI) {
    this.playerId = playerId;
    this.map = map;
    this.gameUI = gameUI;
    this.thinkingTime = 1000; // ms delay between moves
  }

  /**
   * Execute AI turn - makes MULTIPLE moves until no valid moves remain, then ends turn
   * According to game rules, ANY cell with strength > 1 can move if it has valid targets
   */
  async playTurn() {
    console.log(`[AI-BOT P${this.playerId}] === Turn started ===`);
    console.log(`[AI-BOT P${this.playerId}] Thinking...`);

    try {
      // Get all player cells
      let playerCells = this.map.getPlayerCells(this.playerId);

      console.log(`[AI-BOT P${this.playerId}] Has ${playerCells.length} cells`);

      if (playerCells.length === 0) {
        console.log(`[AI-BOT P${this.playerId}] No cells, ending turn`);
        await this.wait(this.thinkingTime);
        this.gameUI.endTurn();
        return;
      }

      let moveCount = 0;
      let consecutiveNoMoves = 0;
      const maxConsecutiveNoMoves = 3; // Prevent infinite loops
      const maxMovesPerTurn = 50; // Maximum moves per turn to prevent infinite loops in tests

      // Loop: keep finding and executing moves until no more valid moves exist
      while (consecutiveNoMoves < maxConsecutiveNoMoves && moveCount < maxMovesPerTurn) {
        // Re-fetch player cells each iteration (board state changes)
        playerCells = this.map.getPlayerCells(this.playerId);

        if (playerCells.length === 0) {
          console.log(`[AI-BOT P${this.playerId}] No cells remaining, ending turn`);
          break;
        }

        // Find all possible moves from current board state
        const moves = this.findPossibleMoves(playerCells);

        console.log(`[AI-BOT P${this.playerId}] Found ${moves.length} possible moves (move #${moveCount + 1})`);

        if (moves.length === 0) {
          // No moves available this iteration
          consecutiveNoMoves++;
          console.log(`[AI-BOT P${this.playerId}] No valid moves this iteration (${consecutiveNoMoves}/${maxConsecutiveNoMoves})`);

          if (consecutiveNoMoves >= maxConsecutiveNoMoves) {
            console.log(`[AI-BOT P${this.playerId}] No more valid moves after ${moveCount} moves, ending turn`);
            break;
          }

          // Small delay before re-checking
          await this.wait(200);
          continue;
        }

        // Reset counter when we find valid moves
        consecutiveNoMoves = 0;

        // Check if we've reached max moves limit
        if (moveCount >= maxMovesPerTurn) {
          console.log(`[AI-BOT P${this.playerId}] Reached max moves limit (${maxMovesPerTurn}), ending turn`);
          break;
        }

        // Sort moves by priority (attack > expand > reinforce)
        moves.sort((a, b) => this.movePriority(b) - this.movePriority(a));

        // Execute best move
        const bestMove = moves[0];
        console.log(`[AI-BOT P${this.playerId}] Selected move: from (${bestMove.from.q},${bestMove.from.r}) to (${bestMove.to.q},${bestMove.to.r}), type=${bestMove.type}, attackStr=${bestMove.attackStrength}, defStr=${bestMove.defenseStrength}`);

        // Wait for thinking time between moves
        await this.wait(this.thinkingTime);

        // Execute the move
        this.gameUI.selectedCell = bestMove.from;
        this.gameUI.currentTarget = bestMove.to;
        this.gameUI.executeAttack();

        moveCount++;
        console.log(`[AI-BOT P${this.playerId}] Move #${moveCount} executed`);

        // Clear selection after move (if method exists)
        if (typeof this.gameUI.cancelSelection === 'function') {
          this.gameUI.cancelSelection();
        }
      }

      // End turn after all moves are executed
      console.log(`[AI-BOT P${this.playerId}] Total moves this turn: ${moveCount}`);
      console.log(`[AI-BOT P${this.playerId}] Calling endTurn()`);
      this.gameUI.endTurn();

      console.log(`[AI-BOT P${this.playerId}] === Turn completed ===`);
    } catch (error) {
      console.error(`[AI-BOT P${this.playerId}] Error during turn:`, error);
      // Still end turn on error to prevent game from getting stuck
      this.gameUI.endTurn();
      throw error; // Re-throw so caller knows there was an error
    }
  }

  /**
   * Find all possible moves for AI
   */
  findPossibleMoves(playerCells) {
    const moves = [];

    for (const cell of playerCells) {
      if (cell.getStrength() <= 1) continue;

      const neighbors = this.map.getNeighbors(cell.q, cell.r);
      
      for (const neighbor of neighbors) {
        // Skip own cells
        if (neighbor.getOwner() === this.playerId) continue;

        const attackStrength = cell.getStrength() - 1;
        const defenseStrength = neighbor.getStrength();

        moves.push({
          from: cell,
          to: neighbor,
          attackStrength,
          defenseStrength,
          type: neighbor.type === CELL_TYPES.EMPTY ? 'expand' : 'attack'
        });
      }
    }

    return moves;
  }

  /**
   * Calculate move priority (higher = better)
   */
  movePriority(move) {
    let priority = 0;

    // Prefer attacks on weak enemies
    if (move.type === 'attack') {
      if (move.attackStrength > move.defenseStrength) {
        priority += 100; // Likely to win
        priority += move.attackStrength - move.defenseStrength;
      } else {
        priority -= 50; // Risky attack
      }
    }

    // Prefer expanding to empty cells
    if (move.type === 'expand') {
      priority += 50;
      priority += move.attackStrength; // Stronger placement = better
    }

    // Prefer moves that create strong positions
    priority += move.attackStrength * 0.5;

    return priority;
  }

  /**
   * Execute a move
   */
  executeMove(move) {
    this.gameUI.selectedCell = move.from;
    this.gameUI.currentTarget = move.to;
    this.gameUI.executeAttack();
  }

  /**
   * Wait for specified time
   */
  wait(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
  }
}