import { getAccessToken } from './api.js';

const API_BASE = '/api/v1/sync';
const SYNC_INTERVAL = 30000; // 30 seconds

let _syncTimer = null;

async function apiFetch(method, path, body = null) {
  const token = getAccessToken();
  if (!token) return null;

  const res = await fetch(`${API_BASE}${path}`, {
    method,
    headers: {
      'Content-Type': 'application/json',
      'Authorization': `Bearer ${token}`,
    },
    credentials: 'include',
    body: body ? JSON.stringify(body) : null,
  });

  if (!res.ok) return null;
  return res.json();
}

// ==================== Preset Sync ====================

export async function syncPresets() {
  if (!getAccessToken()) return;

  try {
    // Get local presets
    const localRaw = localStorage.getItem('reaktor_presets');
    const localPresets = localRaw ? JSON.parse(localRaw) : [];

    // Get server presets
    const serverData = await apiFetch('GET', '/presets');
    if (!serverData) return;

    // Push local presets to server
    if (localPresets.length > 0) {
      await apiFetch('PUT', '/presets', {
        presets: localPresets.map(p => ({
          name: p.name,
          data: p.data,
          updatedAt: p.savedAt || new Date().toISOString(),
        })),
      });
    }

    // Merge server presets into local (add any missing)
    const serverPresets = serverData.presets || [];
    const localNames = new Set(localPresets.map(p => p.name));
    let merged = [...localPresets];

    for (const sp of serverPresets) {
      if (!localNames.has(sp.name)) {
        merged.push({
          name: sp.name,
          data: sp.data,
          savedAt: sp.updatedAt,
        });
      }
    }

    localStorage.setItem('reaktor_presets', JSON.stringify(merged));
  } catch (err) {
    console.warn('[sync] preset sync failed:', err.message);
  }
}

// ==================== Game Progress Sync ====================

export async function syncProgress() {
  if (!getAccessToken()) return;

  try {
    const localRaw = localStorage.getItem('synthquest-progress');
    const localProgress = localRaw ? JSON.parse(localRaw) : null;

    // Get server progress
    const serverData = await apiFetch('GET', '/progress');

    if (localProgress) {
      // Push local to server
      await apiFetch('PUT', '/progress', {
        data: localProgress,
        updatedAt: new Date().toISOString(),
      });
    }

    // If server has progress and local doesn't, pull it
    if (serverData?.progress && !localProgress) {
      localStorage.setItem('synthquest-progress', JSON.stringify(serverData.progress));
    }

    // Also sync hint data
    const hintsRaw = localStorage.getItem('synthquest-hints');
    // Hints are local-only for now (anti-cheat integrity)
  } catch (err) {
    console.warn('[sync] progress sync failed:', err.message);
  }
}

// ==================== Auto Sync ====================

export function startAutoSync() {
  if (_syncTimer) return;

  // Initial sync
  syncPresets();
  syncProgress();

  // Periodic sync
  _syncTimer = setInterval(() => {
    syncPresets();
    syncProgress();
  }, SYNC_INTERVAL);

  // Sync on tab focus
  document.addEventListener('visibilitychange', () => {
    if (document.visibilityState === 'visible') {
      syncPresets();
      syncProgress();
    }
  });
}

export function stopAutoSync() {
  if (_syncTimer) {
    clearInterval(_syncTimer);
    _syncTimer = null;
  }
}