// User statistics tracking and persistence

import { join } from "@std/path";
import { ensureDir } from "@std/fs";

export interface GameStats {
  totalGames: number;
  totalRounds: number;
  correctAnswers: number;
  incorrectAnswers: number;
  averageTimePerRound: number;
  bestStreak: number;
  modeStats: {
    letters: ModeStats;
    alphanumeric: ModeStats;
    full: ModeStats;
    words: ModeStats;
    phrases: ModeStats;
  };
  lastPlayed?: string;
}

export interface ModeStats {
  gamesPlayed: number;
  correctAnswers: number;
  incorrectAnswers: number;
  averageAccuracy: number;
}

export interface GameResult {
  mode: "letters" | "alphanumeric" | "full" | "words" | "phrases";
  rounds: number;
  correct: number;
  incorrect: number;
  averageTime: number;
  streak: number;
}

const DEFAULT_STATS: GameStats = {
  totalGames: 0,
  totalRounds: 0,
  correctAnswers: 0,
  incorrectAnswers: 0,
  averageTimePerRound: 0,
  bestStreak: 0,
  modeStats: {
    letters: {
      gamesPlayed: 0,
      correctAnswers: 0,
      incorrectAnswers: 0,
      averageAccuracy: 0,
    },
    alphanumeric: {
      gamesPlayed: 0,
      correctAnswers: 0,
      incorrectAnswers: 0,
      averageAccuracy: 0,
    },
    full: {
      gamesPlayed: 0,
      correctAnswers: 0,
      incorrectAnswers: 0,
      averageAccuracy: 0,
    },
    words: {
      gamesPlayed: 0,
      correctAnswers: 0,
      incorrectAnswers: 0,
      averageAccuracy: 0,
    },
    phrases: {
      gamesPlayed: 0,
      correctAnswers: 0,
      incorrectAnswers: 0,
      averageAccuracy: 0,
    },
  },
};

function getStatsPath(): string {
  return join(Deno.cwd(), "data", "stats.json");
}

/**
 * Load stats from JSON file
 */
export async function loadStats(): Promise<GameStats> {
  try {
    const statsPath = getStatsPath();
    const content = await Deno.readTextFile(statsPath);
    return JSON.parse(content);
  } catch {
    return { ...DEFAULT_STATS };
  }
}

/**
 * Save stats to JSON file
 */
export async function saveStats(stats: GameStats): Promise<void> {
  try {
    const statsPath = getStatsPath();
    const dataDir = join(Deno.cwd(), "data");

    await ensureDir(dataDir);
    await Deno.writeTextFile(statsPath, JSON.stringify(stats, null, 2));
  } catch (error) {
    throw new Error(
      `Failed to save statistics: ${error instanceof Error ? error.message : "Unknown error"}`
    );
  }
}

/**
 * Update stats with a new game result
 */
export async function updateStats(result: GameResult): Promise<GameStats> {
  const stats = await loadStats();

  // Update overall stats
  stats.totalGames++;
  stats.totalRounds += result.rounds;
  stats.correctAnswers += result.correct;
  stats.incorrectAnswers += result.incorrect;
  stats.averageTimePerRound =
    (stats.averageTimePerRound * (stats.totalRounds - result.rounds) +
      result.averageTime * result.rounds) /
    stats.totalRounds;
  stats.bestStreak = Math.max(stats.bestStreak, result.streak);
  stats.lastPlayed = new Date().toISOString();

  // Update mode-specific stats
  const modeStats = stats.modeStats[result.mode];
  modeStats.gamesPlayed++;
  modeStats.correctAnswers += result.correct;
  modeStats.incorrectAnswers += result.incorrect;
  const totalAnswers = modeStats.correctAnswers + modeStats.incorrectAnswers;
  modeStats.averageAccuracy =
    totalAnswers > 0 ? (modeStats.correctAnswers / totalAnswers) * 100 : 0;

  await saveStats(stats);
  return stats;
}

/**
 * Reset all stats
 */
export async function resetStats(): Promise<void> {
  await saveStats({ ...DEFAULT_STATS });
}

/**
 * Get formatted accuracy percentage
 */
export function getAccuracy(stats: GameStats): number {
  const total = stats.correctAnswers + stats.incorrectAnswers;
  return total > 0 ? (stats.correctAnswers / total) * 100 : 0;
}