"use client";
/**
 * Progress tracking — localStorage-based profile.
 * Structure ready for server-side sync in the future.
 */

import { GAMES, GameId, TOTAL_LEVELS } from "./levels";

const PROFILE_KEY = "pt-profile";
const PROGRESS_KEY = (game: GameId) => `pt-progress-${game}`;

export interface Profile {
  id: string;          // UUID
  createdAt: string;   // ISO date
  name?: string;
}

export interface LevelRecord {
  completedAt: string; // ISO datetime
  bestTime: number;    // seconds
  attempts: number;
}

export type GameProgress = Record<number, LevelRecord>; // level → record

// ── Profile ───────────────────────────────────────────────────────────────────

function uuid(): string {
  return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, (c) => {
    const r = Math.random() * 16 | 0;
    return (c === "x" ? r : (r & 0x3 | 0x8)).toString(16);
  });
}

export function getProfile(): Profile {
  if (typeof window === "undefined") return { id: "ssr", createdAt: new Date().toISOString() };
  const raw = localStorage.getItem(PROFILE_KEY);
  if (raw) try { return JSON.parse(raw) as Profile; } catch { /* corrupted, re-create */ }
  const profile: Profile = { id: uuid(), createdAt: new Date().toISOString() };
  localStorage.setItem(PROFILE_KEY, JSON.stringify(profile));
  return profile;
}

// ── Progress ──────────────────────────────────────────────────────────────────

export function getGameProgress(game: GameId): GameProgress {
  if (typeof window === "undefined") return {};
  const raw = localStorage.getItem(PROGRESS_KEY(game));
  if (!raw) return {};
  try { return JSON.parse(raw); } catch { return {}; }
}

export function recordLevelSolve(game: GameId, level: number, elapsed: number): GameProgress {
  const progress = getGameProgress(game);
  const existing = progress[level];
  progress[level] = {
    completedAt: existing?.completedAt ?? new Date().toISOString(),
    bestTime: existing ? Math.min(existing.bestTime, elapsed) : elapsed,
    attempts: (existing?.attempts ?? 0) + 1,
  };
  localStorage.setItem(PROGRESS_KEY(game), JSON.stringify(progress));
  return progress;
}

/** Returns the next uncompleted level (1-based), or null if all done. */
export function nextLevel(game: GameId): number {
  const progress = getGameProgress(game);
  for (let l = 1; l <= TOTAL_LEVELS; l++) {
    if (!progress[l]) return l;
  }
  return TOTAL_LEVELS; // all done → stay on last
}

/** Summary stats for a game. */
export interface GameStats {
  completed: number;
  total: number;
  pct: number;         // 0–100
  bestTime: number;    // fastest solve (seconds), 0 if none
  nextLevel: number;   // next uncompleted level
}

export function gameStats(game: GameId): GameStats {
  const progress = getGameProgress(game);
  const completed = Object.keys(progress).length;
  const best = Object.values(progress).reduce((m, r) => Math.min(m, r.bestTime), Infinity);
  return {
    completed,
    total: TOTAL_LEVELS,
    pct: Math.round((completed / TOTAL_LEVELS) * 100),
    bestTime: isFinite(best) ? best : 0,
    nextLevel: nextLevel(game),
  };
}

export function allStats(): Record<GameId, GameStats> {
  return Object.fromEntries(GAMES.map(g => [g, gameStats(g)])) as Record<GameId, GameStats>;
}