/**
 * Model vs Model Battle Script
 *
 * This script enables different ONNX model versions to battle against each other.
 * Features:
 * - Fair color rotation (each model plays equal games as Black and White)
 * - Fixed board size
 * - Win rate statistics
 * - Optional MCTS search (disabled by default)
 *
 * Usage: npx tsx tools/modelBattle.ts [options]
 */

import * as ort from "onnxruntime-node";
import * as path from "path";
import * as fs from "fs";
import { TrigoGame, StoneType } from "../inc/trigo/game";
import { ModelInferencer } from "../inc/modelInferencer";
import { TrigoTreeAgent } from "../inc/trigoTreeAgent";
import { TrigoEvaluationAgent } from "../inc/trigoEvaluationAgent";
import { MCTSAgent, MCTSConfig } from "../inc/mctsAgent";
import type { Move, BoardShape } from "../inc/trigo/types";
import { loadEnvConfig, getOnnxSessionOptions } from "../inc/config";


// ============================================================================
// Constants
// ============================================================================

const DEFAULT_VOCAB_SIZE = 128;
const DEFAULT_SEQ_LEN = 256;
const DEFAULT_NUM_GAMES = 10;
const DEFAULT_TEMPERATURE = 1.0;
const DEFAULT_MAX_MOVES = 300;
const DEFAULT_MCTS_SIMULATIONS = 600;
const DEFAULT_MCTS_CPUCT = 1.0;
const DEFAULT_MCTS_DIRICHLET_ALPHA = 0.03;
const DEFAULT_MCTS_DIRICHLET_EPSILON = 0.0;  // Zero noise for deterministic evaluation
const DEFAULT_KOMI = 0.5;  // Komi: Black compensates White (White's advantage)


// ============================================================================
// Interfaces
// ============================================================================

interface BattleConfig {
	model1Dir: string;
	model2Dir: string;
	model1TreePath: string;
	model2TreePath: string;
	model1EvalPath?: string;
	model2EvalPath?: string;
	boardShape: BoardShape;
	numGames: number;
	temperature: number;
	maxMoves: number;
	useMCTS: boolean;
	mctsSimulations: number;
	mctsCPuct: number;
	mctsDirichletAlpha: number;
	mctsDirichletEpsilon: number;
	outputDir?: string;
	verbose: boolean;
	vocabSize: number;
	seqLen: number;
}


interface BattleResult {
	gameId: number;
	model1AsBlack: boolean;
	winner: "model1" | "model2" | "draw";
	model1Score: number;
	model2Score: number;
	scoreDiff: number;
	moveCount: number;
	duration: number;
	tgn?: string;  // TGN format game record
}


interface BattleStatistics {
	totalGames: number;
	model1Wins: number;
	model2Wins: number;
	draws: number;
	model1WinRate: number;
	model2WinRate: number;
	model1AsBlackWins: number;
	model1AsWhiteWins: number;
	model2AsBlackWins: number;
	model2AsWhiteWins: number;
	averageGameLength: number;
	averageScoreDiff: number;
	totalTime: number;
	results: BattleResult[];
}


type Agent = TrigoTreeAgent | MCTSAgent;


// ============================================================================
// Argument Parsing
// ============================================================================

function printUsage(): void {
	console.log(`
Usage: npx tsx tools/modelBattle.ts [options]

Required:
  --model1 <path>                Model 1 base path (without suffix, e.g., ./dir/ModelName)
  --model2 <path>                Model 2 base path (without suffix, e.g., ./dir/ModelName)
  --board <shape>                Board shape "X*Y*Z" (e.g., "5*5*5")

Options:
  --games <n>                    Number of games (default: 10, must be even)
  --temperature <t>              Sampling temperature (default: 1.0)
  --max-moves <n>                Maximum moves per game (default: 300)
  --output <dir>                 Output directory for results
  --verbose                      Enable verbose logging

MCTS Options:
  --use-mcts                     Enable MCTS for move selection (requires evaluation model)
  --mcts-simulations <n>         MCTS simulations per move (default: 600)
  --mcts-cpuct <f>               PUCT exploration constant (default: 1.0)
  --mcts-dirichlet-alpha <f>     Dirichlet noise alpha (default: 0.03)
  --mcts-dirichlet-epsilon <f>   Dirichlet noise epsilon (default: 0.25)
  --help                         Show this help message

Model Path Format:
  Provide the base path WITHOUT the suffix. The script auto-appends:
    - _tree.onnx        -> Tree model (required)
    - _evaluation.onnx  -> Evaluation model (auto-detected, required for MCTS)

Examples:
  # Battle two models on 5x5x5 board for 20 games
  npx tsx tools/modelBattle.ts \\
    --model1 ./public/onnx/20251215-trigo-value-llama-l6-h64-251211/LlamaCausalLM_ep0045 \\
    --model2 ./public/onnx/20251204-trigo-value-gpt2-l6-h64-251125-lr500/GPT2LMHeadModel_ep0100 \\
    --board "5*5*5" --games 20

  # Battle with MCTS enabled
  npx tsx tools/modelBattle.ts \\
    --model1 ./public/onnx/model_v1/Model_ep0100 \\
    --model2 ./public/onnx/model_v2/Model_ep0100 \\
    --board "5*5*5" --games 20 --use-mcts --mcts-simulations 400
`);
}


function parseBoardShape(shapeStr: string): BoardShape | null {
	const match = shapeStr.match(/^(\d+)\*(\d+)\*(\d+)$/);
	if (!match) return null;
	return {
		x: parseInt(match[1], 10),
		y: parseInt(match[2], 10),
		z: parseInt(match[3], 10)
	};
}


/**
 * Resolve model paths from base path (without suffix)
 * Auto-appends _tree.onnx and _evaluation.onnx suffixes
 * Returns { treePath, evalPath } or null if tree model not found
 */
function resolveModelPaths(basePath: string): { treePath: string; evalPath?: string } | null {
	const treePath = `${basePath}_tree.onnx`;
	const evalPath = `${basePath}_evaluation.onnx`;

	if (!fs.existsSync(treePath)) {
		console.error(`Tree model not found: ${treePath}`);
		return null;
	}

	return {
		treePath,
		evalPath: fs.existsSync(evalPath) ? evalPath : undefined
	};
}


/**
 * Check if next argument exists and is not a flag
 */
function requireNextArg(args: string[], i: number, flag: string): string | null {
	const next = args[i + 1];
	if (!next || next.startsWith("-")) {
		console.error(`Error: ${flag} requires a value`);
		printUsage();
		return null;
	}
	return next;
}


/**
 * Parse and validate integer argument
 */
function parseIntArg(value: string, flag: string, minValue?: number): number | null {
	const n = parseInt(value, 10);
	if (Number.isNaN(n)) {
		console.error(`Error: Invalid integer for ${flag}: ${value}`);
		return null;
	}
	if (minValue !== undefined && n < minValue) {
		console.error(`Error: ${flag} must be >= ${minValue}`);
		return null;
	}
	return n;
}


/**
 * Parse and validate float argument
 */
function parseFloatArg(value: string, flag: string, minValue?: number): number | null {
	const n = parseFloat(value);
	if (Number.isNaN(n) || !Number.isFinite(n)) {
		console.error(`Error: Invalid number for ${flag}: ${value}`);
		return null;
	}
	if (minValue !== undefined && n < minValue) {
		console.error(`Error: ${flag} must be >= ${minValue}`);
		return null;
	}
	return n;
}


function parseArgs(): BattleConfig | null {
	const args = process.argv.slice(2);

	if (args.includes("--help") || args.includes("-h")) {
		printUsage();
		return null;
	}

	let model1Base = "";
	let model2Base = "";
	let boardShape: BoardShape = { x: 5, y: 5, z: 5 };
	let boardSpecified = false;
	let numGames = DEFAULT_NUM_GAMES;
	let temperature = DEFAULT_TEMPERATURE;
	let maxMoves = DEFAULT_MAX_MOVES;
	let useMCTS = false;
	let mctsSimulations = DEFAULT_MCTS_SIMULATIONS;
	let mctsCPuct = DEFAULT_MCTS_CPUCT;
	let mctsDirichletAlpha = DEFAULT_MCTS_DIRICHLET_ALPHA;
	let mctsDirichletEpsilon = DEFAULT_MCTS_DIRICHLET_EPSILON;
	let outputDir: string | undefined;
	let verbose = false;

	for (let i = 0; i < args.length; i++) {
		const arg = args[i];

		switch (arg) {
			case "--model1": {
				const value = requireNextArg(args, i, "--model1");
				if (!value) return null;
				model1Base = value;
				i++;
				break;
			}
			case "--model2": {
				const value = requireNextArg(args, i, "--model2");
				if (!value) return null;
				model2Base = value;
				i++;
				break;
			}
			case "--board": {
				const value = requireNextArg(args, i, "--board");
				if (!value) return null;
				const shape = parseBoardShape(value);
				if (!shape) {
					console.error(`Invalid board shape: ${value}. Use format "X*Y*Z" (e.g., "5*5*5")`);
					return null;
				}
				boardShape = shape;
				boardSpecified = true;
				i++;
				break;
			}
			case "--games": {
				const value = requireNextArg(args, i, "--games");
				if (!value) return null;
				const parsed = parseIntArg(value, "--games", 1);
				if (parsed === null) return null;
				numGames = parsed;
				i++;
				break;
			}
			case "--temperature": {
				const value = requireNextArg(args, i, "--temperature");
				if (!value) return null;
				const parsed = parseFloatArg(value, "--temperature", 0);
				if (parsed === null) return null;
				temperature = parsed;
				i++;
				break;
			}
			case "--max-moves": {
				const value = requireNextArg(args, i, "--max-moves");
				if (!value) return null;
				const parsed = parseIntArg(value, "--max-moves", 1);
				if (parsed === null) return null;
				maxMoves = parsed;
				i++;
				break;
			}
			case "--output": {
				const value = requireNextArg(args, i, "--output");
				if (!value) return null;
				outputDir = value;
				i++;
				break;
			}
			case "--verbose":
				verbose = true;
				break;
			case "--use-mcts":
				useMCTS = true;
				break;
			case "--mcts-simulations": {
				const value = requireNextArg(args, i, "--mcts-simulations");
				if (!value) return null;
				const parsed = parseIntArg(value, "--mcts-simulations", 1);
				if (parsed === null) return null;
				mctsSimulations = parsed;
				i++;
				break;
			}
			case "--mcts-cpuct": {
				const value = requireNextArg(args, i, "--mcts-cpuct");
				if (!value) return null;
				const parsed = parseFloatArg(value, "--mcts-cpuct", 0);
				if (parsed === null) return null;
				mctsCPuct = parsed;
				i++;
				break;
			}
			case "--mcts-dirichlet-alpha": {
				const value = requireNextArg(args, i, "--mcts-dirichlet-alpha");
				if (!value) return null;
				const parsed = parseFloatArg(value, "--mcts-dirichlet-alpha", 0);
				if (parsed === null) return null;
				mctsDirichletAlpha = parsed;
				i++;
				break;
			}
			case "--mcts-dirichlet-epsilon": {
				const value = requireNextArg(args, i, "--mcts-dirichlet-epsilon");
				if (!value) return null;
				const parsed = parseFloatArg(value, "--mcts-dirichlet-epsilon", 0);
				if (parsed === null) return null;
				mctsDirichletEpsilon = parsed;
				i++;
				break;
			}
			default:
				if (arg.startsWith("-")) {
					console.error(`Unknown option: ${arg}`);
					printUsage();
					return null;
				}
		}
	}

	// Validation
	if (!model1Base) {
		console.error("Error: --model1 is required");
		printUsage();
		return null;
	}
	if (!model2Base) {
		console.error("Error: --model2 is required");
		printUsage();
		return null;
	}
	if (!boardSpecified) {
		console.error("Error: --board is required");
		printUsage();
		return null;
	}

	// Resolve model paths
	const model1Paths = resolveModelPaths(model1Base);
	if (!model1Paths) {
		return null;
	}

	const model2Paths = resolveModelPaths(model2Base);
	if (!model2Paths) {
		return null;
	}

	// Ensure even number of games for fairness
	if (numGames % 2 !== 0) {
		numGames++;
		console.log(`Note: Adjusted games to ${numGames} (must be even for fair color rotation)`);
	}

	// Check MCTS requirements
	if (useMCTS) {
		if (!model1Paths.evalPath) {
			console.error(`Error: Evaluation model not found for model1 (expected: ${model1Base}_evaluation.onnx)`);
			return null;
		}
		if (!model2Paths.evalPath) {
			console.error(`Error: Evaluation model not found for model2 (expected: ${model2Base}_evaluation.onnx)`);
			return null;
		}
	}

	// Calculate max moves if not explicitly set (2× board size)
	if (maxMoves === DEFAULT_MAX_MOVES && boardSpecified) {
		const boardSize = boardShape.x * boardShape.y * boardShape.z;
		maxMoves = boardSize * 2;
	}

	return {
		model1Dir: path.dirname(model1Base),
		model2Dir: path.dirname(model2Base),
		model1TreePath: model1Paths.treePath,
		model2TreePath: model2Paths.treePath,
		model1EvalPath: model1Paths.evalPath,
		model2EvalPath: model2Paths.evalPath,
		boardShape,
		numGames,
		temperature,
		maxMoves,
		useMCTS,
		mctsSimulations,
		mctsCPuct,
		mctsDirichletAlpha,
		mctsDirichletEpsilon,
		outputDir,
		verbose,
		vocabSize: DEFAULT_VOCAB_SIZE,
		seqLen: DEFAULT_SEQ_LEN
	};
}


// ============================================================================
// Agent Initialization
// ============================================================================

async function createAgent(
	treeModelPath: string,
	evalModelPath: string | undefined,
	config: BattleConfig,
	name: string
): Promise<Agent> {
	console.log(`  Loading ${name}...`);

	const sessionOptions = getOnnxSessionOptions();

	// Load tree model
	const treeSession = await ort.InferenceSession.create(treeModelPath, sessionOptions);
	const treeInferencer = new ModelInferencer(ort.Tensor as any, {
		vocabSize: config.vocabSize,
		seqLen: config.seqLen,
		modelPath: treeModelPath
	});
	treeInferencer.setSession(treeSession as any);
	const treeAgent = new TrigoTreeAgent(treeInferencer);

	if (!config.useMCTS) {
		return treeAgent;
	}

	// MCTS mode requires evaluation model
	if (!evalModelPath) {
		throw new Error(`MCTS enabled but evaluation model path is missing for ${name}`);
	}

	// Load evaluation model for MCTS
	const evalSession = await ort.InferenceSession.create(evalModelPath, sessionOptions);
	const evalInferencer = new ModelInferencer(ort.Tensor as any, {
		vocabSize: config.vocabSize,
		seqLen: config.seqLen,
		modelPath: evalModelPath
	});
	evalInferencer.setSession(evalSession as any);
	const evalAgent = new TrigoEvaluationAgent(evalInferencer);

	const mctsConfig: MCTSConfig = {
		numSimulations: config.mctsSimulations,
		cPuct: config.mctsCPuct,
		temperature: config.temperature,
		dirichletAlpha: config.mctsDirichletAlpha,
		dirichletEpsilon: config.mctsDirichletEpsilon
	};

	return new MCTSAgent(treeAgent, evalAgent, mctsConfig);
}


async function initializeAgents(config: BattleConfig): Promise<{ agent1: Agent; agent2: Agent }> {
	console.log("\nInitializing agents...");

	const agent1 = await createAgent(
		config.model1TreePath,
		config.model1EvalPath,
		config,
		"Model 1"
	);
	console.log(`  ✓ Model 1 ready`);

	const agent2 = await createAgent(
		config.model2TreePath,
		config.model2EvalPath,
		config,
		"Model 2"
	);
	console.log(`  ✓ Model 2 ready`);

	return { agent1, agent2 };
}


// ============================================================================
// Game Playing
// ============================================================================

async function playBattleGame(
	agent1: Agent,
	agent2: Agent,
	gameId: number,
	config: BattleConfig,
	model1AsBlack: boolean
): Promise<BattleResult> {
	const startTime = Date.now();
	const game = new TrigoGame(config.boardShape, {});

	// Determine which agent plays which color
	const blackAgent = model1AsBlack ? agent1 : agent2;
	const whiteAgent = model1AsBlack ? agent2 : agent1;

	let moveCount = 0;
	let consecutivePasses = 0;
	const totalPositions = config.boardShape.x * config.boardShape.y * config.boardShape.z;
	const coverageThreshold = Math.floor(totalPositions * 0.5);
	let territoryCheckStarted = false;

	while (moveCount < config.maxMoves) {
		const currentPlayer = game.getCurrentPlayer();
		const playerStr = currentPlayer === StoneType.BLACK ? "black" : "white";
		const currentAgent = currentPlayer === StoneType.BLACK ? blackAgent : whiteAgent;

		// Check if we should start territory checking
		if (!territoryCheckStarted && moveCount >= coverageThreshold) {
			territoryCheckStarted = true;
		}

		let selectedMove: Move;

		try {
			if (currentAgent instanceof MCTSAgent) {
				const result = await currentAgent.selectMove(game, moveCount);
				selectedMove = result.move;
			} else {
				// Tree agent mode - use selectMove with temperature
				selectedMove = await currentAgent.selectMove(game, config.temperature);
			}
		} catch (err) {
			if (config.verbose) {
				console.error(`Error getting move: ${err}`);
			}
			// Pass on error
			game.pass();
			consecutivePasses++;
			if (consecutivePasses >= 2) break;
			moveCount++;
			continue;
		}

		// Apply move
		let success: boolean;
		if (selectedMove.isPass) {
			success = game.pass();
			consecutivePasses++;
		} else if (selectedMove.x !== undefined && selectedMove.y !== undefined && selectedMove.z !== undefined) {
			success = game.drop({
				x: selectedMove.x,
				y: selectedMove.y,
				z: selectedMove.z
			});
			consecutivePasses = 0;
		} else {
			success = game.pass();
			consecutivePasses++;
		}

		if (!success) {
			if (config.verbose) {
				console.warn(`Move failed, passing instead`);
			}
			game.pass();
			consecutivePasses++;
		}

		moveCount++;

		// Check game end conditions
		if (consecutivePasses >= 2) break;

		// Check for natural termination (all territory claimed, no capturing moves)
		if (territoryCheckStarted && !selectedMove.isPass) {
			if (game.isNaturallyTerminal()) {
				break;
			}
		}
	}

	// Calculate final scores with komi (Black compensates White)
	const territory = game.getTerritory();
	const blackScore = territory.black;
	const whiteScore = territory.white + DEFAULT_KOMI;  // White gets komi
	const scoreDiff = blackScore - whiteScore;  // Positive = Black wins by X

	// Determine winner (with komi applied to White)
	let winner: "model1" | "model2" | "draw";
	if (blackScore > whiteScore) {
		winner = model1AsBlack ? "model1" : "model2";
	} else if (whiteScore > blackScore) {
		winner = model1AsBlack ? "model2" : "model1";
	} else {
		winner = "draw";
	}

	const duration = Date.now() - startTime;

	// Generate TGN record if output is enabled
	let tgn: string | undefined;
	if (config.outputDir) {
		// Format: parentDir/modelName (without _tree.onnx suffix)
		const formatModelName = (treePath: string) => {
			const dir = path.basename(path.dirname(treePath));
			const filename = path.basename(treePath).replace(/_tree\.onnx$/, "");
			return `${dir}/${filename}`;
		};
		const blackModel = model1AsBlack ? formatModelName(config.model1TreePath) : formatModelName(config.model2TreePath);
		const whiteModel = model1AsBlack ? formatModelName(config.model2TreePath) : formatModelName(config.model1TreePath);
		tgn = game.toTGN({
			black: blackModel,
			white: whiteModel,
			event: "Model Battle",
			date: new Date().toISOString().split("T")[0].replace(/-/g, ".")
		}, { markResult: true });
	}

	return {
		gameId,
		model1AsBlack,
		winner,
		model1Score: model1AsBlack ? blackScore : whiteScore,
		model2Score: model1AsBlack ? whiteScore : blackScore,
		scoreDiff,
		moveCount,
		duration,
		tgn
	};
}


// ============================================================================
// Battle Execution
// ============================================================================

async function runBattle(
	agent1: Agent,
	agent2: Agent,
	config: BattleConfig,
	gamesDir?: string
): Promise<BattleStatistics> {
	const results: BattleResult[] = [];
	const startTime = Date.now();

	console.log(`\nStarting battle: ${config.numGames} games`);
	console.log("=".repeat(80));

	// Alternating colors for fairness
	for (let i = 0; i < config.numGames; i++) {
		const gameId = i + 1;
		const model1AsBlack = i % 2 === 0;  // Odd games: M1=Black, Even games: M1=White
		const colorStr = model1AsBlack ? "M1=Black" : "M1=White";
		process.stdout.write(`Game ${gameId}/${config.numGames} (${colorStr}): `);

		const result = await playBattleGame(agent1, agent2, gameId, config, model1AsBlack);
		results.push(result);

		// Save TGN immediately after each game
		if (gamesDir && result.tgn) {
			const colorSuffix = model1AsBlack ? "M1B" : "M1W";
			const winnerSuffix = result.winner === "model1" ? "M1" : result.winner === "model2" ? "M2" : "Draw";
			const tgnFilename = `game_${String(gameId).padStart(3, "0")}_${colorSuffix}_${winnerSuffix}.tgn`;
			const tgnPath = path.join(gamesDir, tgnFilename);
			fs.writeFileSync(tgnPath, result.tgn);
		}

		const winnerStr = result.winner === "model1" ? "M1" : result.winner === "model2" ? "M2" : "Draw";
		const scoreDiffStr = result.scoreDiff > 0 ? `B+${result.scoreDiff.toFixed(1)}` : `W+${(-result.scoreDiff).toFixed(1)}`;
		console.log(`${result.moveCount} moves, ${winnerStr} wins (${scoreDiffStr}), ${(result.duration / 1000).toFixed(1)}s`);
	}

	const totalTime = Date.now() - startTime;

	// Calculate statistics
	const stats: BattleStatistics = {
		totalGames: config.numGames,
		model1Wins: results.filter((r) => r.winner === "model1").length,
		model2Wins: results.filter((r) => r.winner === "model2").length,
		draws: results.filter((r) => r.winner === "draw").length,
		model1WinRate: 0,
		model2WinRate: 0,
		model1AsBlackWins: results.filter((r) => r.model1AsBlack && r.winner === "model1").length,
		model1AsWhiteWins: results.filter((r) => !r.model1AsBlack && r.winner === "model1").length,
		model2AsBlackWins: results.filter((r) => !r.model1AsBlack && r.winner === "model2").length,
		model2AsWhiteWins: results.filter((r) => r.model1AsBlack && r.winner === "model2").length,
		averageGameLength: results.reduce((sum, r) => sum + r.moveCount, 0) / results.length,
		averageScoreDiff: results.reduce((sum, r) => sum + r.scoreDiff, 0) / results.length,
		totalTime,
		results
	};

	stats.model1WinRate = (stats.model1Wins / stats.totalGames) * 100;
	stats.model2WinRate = (stats.model2Wins / stats.totalGames) * 100;

	return stats;
}


// ============================================================================
// Output and Statistics
// ============================================================================

function printStatistics(stats: BattleStatistics, config: BattleConfig): void {
	console.log("\n" + "=".repeat(80));
	console.log("Battle Results");
	console.log("=".repeat(80));

	console.log(`\nModel 1: ${path.basename(config.model1TreePath)}`);
	console.log(`Model 2: ${path.basename(config.model2TreePath)}`);
	console.log(`Board: ${config.boardShape.x}×${config.boardShape.y}×${config.boardShape.z}`);
	console.log(`Games: ${stats.totalGames} (${stats.totalGames / 2} as each color)`);
	console.log(`Mode: ${config.useMCTS ? `MCTS (${config.mctsSimulations} simulations)` : "Tree Attention"}`);

	console.log("\n" + "-".repeat(80));
	console.log("Win Statistics:");
	console.log("-".repeat(80));

	console.log(`\n  Model 1 Wins: ${stats.model1Wins} (${stats.model1WinRate.toFixed(1)}%)`);
	console.log(`    - As Black: ${stats.model1AsBlackWins}`);
	console.log(`    - As White: ${stats.model1AsWhiteWins}`);

	console.log(`\n  Model 2 Wins: ${stats.model2Wins} (${stats.model2WinRate.toFixed(1)}%)`);
	console.log(`    - As Black: ${stats.model2AsBlackWins}`);
	console.log(`    - As White: ${stats.model2AsWhiteWins}`);

	console.log(`\n  Draws: ${stats.draws}`);

	console.log("\n" + "-".repeat(80));
	console.log("Game Statistics:");
	console.log("-".repeat(80));
	console.log(`  Average game length: ${stats.averageGameLength.toFixed(1)} moves`);
	console.log(`  Average score diff: ${stats.averageScoreDiff > 0 ? "+" : ""}${stats.averageScoreDiff.toFixed(1)} (White - Black)`);
	console.log(`  Total time: ${(stats.totalTime / 60000).toFixed(1)} minutes`);
	console.log(`  Average time per game: ${(stats.totalTime / stats.totalGames / 1000).toFixed(1)} seconds`);

	console.log("\n" + "=".repeat(80));
	if (stats.model1Wins > stats.model2Wins) {
		console.log(`Winner: Model 1 (${stats.model1WinRate.toFixed(1)}% vs ${stats.model2WinRate.toFixed(1)}%)`);
	} else if (stats.model2Wins > stats.model1Wins) {
		console.log(`Winner: Model 2 (${stats.model2WinRate.toFixed(1)}% vs ${stats.model1WinRate.toFixed(1)}%)`);
	} else {
		console.log(`Result: Tie (${stats.model1WinRate.toFixed(1)}% each)`);
	}
	console.log("=".repeat(80));
}


function saveStatistics(stats: BattleStatistics, config: BattleConfig, gamesDir?: string): void {
	if (!config.outputDir) return;

	// Create output directory
	if (!fs.existsSync(config.outputDir)) {
		fs.mkdirSync(config.outputDir, { recursive: true });
	}

	// Save battle summary JSON (use gamesDir name for consistency)
	const dirName = gamesDir ? path.basename(gamesDir) : `battle_${new Date().toISOString().replace(/[:.]/g, "-")}`;
	const summaryFilename = `${dirName}.json`;
	const summaryFilepath = path.join(config.outputDir, summaryFilename);

	// Remove TGN from results to keep JSON clean
	const resultsWithoutTgn = stats.results.map(({ tgn, ...rest }) => rest);

	const output = {
		config: {
			model1Tree: config.model1TreePath,
			model2Tree: config.model2TreePath,
			model1Eval: config.model1EvalPath,
			model2Eval: config.model2EvalPath,
			boardShape: config.boardShape,
			numGames: config.numGames,
			temperature: config.temperature,
			useMCTS: config.useMCTS,
			mctsSimulations: config.mctsSimulations,
			komi: DEFAULT_KOMI
		},
		statistics: { ...stats, results: resultsWithoutTgn },
		timestamp: new Date().toISOString()
	};

	fs.writeFileSync(summaryFilepath, JSON.stringify(output, null, 2));
	console.log(`\nResults saved to: ${summaryFilepath}`);
	if (gamesDir) {
		console.log(`Game records saved to: ${gamesDir}/`);
	}
}


// ============================================================================
// Main
// ============================================================================

async function main(): Promise<void> {
	// Load environment config
	await loadEnvConfig();

	// Parse arguments
	const config = parseArgs();
	if (!config) {
		process.exit(1);
	}

	console.log("=".repeat(80));
	console.log("Model vs Model Battle");
	console.log("=".repeat(80));
	console.log(`Model 1: ${config.model1TreePath}`);
	console.log(`Model 2: ${config.model2TreePath}`);
	console.log(`Board: ${config.boardShape.x}×${config.boardShape.y}×${config.boardShape.z}`);
	console.log(`Games: ${config.numGames}`);
	console.log(`Mode: ${config.useMCTS ? "MCTS" : "Tree Attention"}`);
	if (config.useMCTS) {
		console.log(`MCTS Simulations: ${config.mctsSimulations}`);
	}

	// Initialize agents
	const { agent1, agent2 } = await initializeAgents(config);

	// Create games directory if output is enabled
	let gamesDir: string | undefined;
	if (config.outputDir) {
		const timestamp = new Date().toISOString().replace(/[:.]/g, "-");
		gamesDir = path.join(config.outputDir, `battle_${timestamp}`);
		fs.mkdirSync(gamesDir, { recursive: true });
	}

	// Run battle
	const stats = await runBattle(agent1, agent2, config, gamesDir);

	// Print results
	printStatistics(stats, config);

	// Save results
	if (config.outputDir) {
		saveStatistics(stats, config, gamesDir);
	}
}


main().catch((err) => {
	console.error("Error:", err);
	process.exit(1);
});