// Persistence for the desktop shell.
//
// Two tiers, both different from the mobile client:
//   * KeyFile lives in the OS keychain (via Electron safeStorage in main.ts,
//     exposed as `window.dchain.keyfile`). We never touch it here from
//     renderer code except through that IPC.
//   * Everything else — settings, contacts, chat cache, "this device was
//     registered" marker — lives in localStorage. It's synchronous,
//     origin-isolated inside the renderer, and plenty durable for
//     per-install state. A future polish could move chats to IndexedDB
//     for streaming writes, but localStorage is fine for v2.2.0.

import type { KeyFile, NodeSettings, Contact, Message } from './types';
import type { DChainAPI } from '../../electron/preload';

declare global {
  interface Window {
    dchain: DChainAPI;
  }
}

// ─── KeyFile (safeStorage-backed via IPC) ────────────────────────────────
//
// All keyfile operations go through window.dchain.keyfile — the preload
// script bridges them to Electron's safeStorage. If preload failed to
// load (dev misconfig, broken build), we surface a loud error rather
// than silently failing, since a missing keyfile layer means nothing
// else in the app can work.

function requireDchain() {
  if (typeof window === 'undefined' || !window.dchain) {
    throw new Error(
      'window.dchain is not available — the Electron preload failed to ' +
      'load. Check dist-electron/preload.js exists and that main.ts is ' +
      'pointing at it.',
    );
  }
  return window.dchain;
}

export async function loadKeyFile(): Promise<KeyFile | null> {
  const raw = await requireDchain().keyfile.load();
  if (!raw) return null;
  try {
    return JSON.parse(raw) as KeyFile;
  } catch {
    return null;
  }
}

export async function saveKeyFile(kf: KeyFile): Promise<void> {
  await requireDchain().keyfile.save(JSON.stringify(kf));
}

export async function deleteKeyFile(): Promise<void> {
  await requireDchain().keyfile.delete();
}

// ─── Settings ─────────────────────────────────────────────────────────────

const SETTINGS_KEY = 'dchain_settings';

const DEFAULT_SETTINGS: NodeSettings = {
  nodeUrl:    'http://localhost:8080',
  contractId: '',
};

export function loadSettings(): NodeSettings {
  const raw = localStorage.getItem(SETTINGS_KEY);
  if (!raw) return DEFAULT_SETTINGS;
  try {
    return { ...DEFAULT_SETTINGS, ...JSON.parse(raw) };
  } catch {
    return DEFAULT_SETTINGS;
  }
}

export function saveSettings(s: Partial<NodeSettings>): void {
  const cur = loadSettings();
  localStorage.setItem(SETTINGS_KEY, JSON.stringify({ ...cur, ...s }));
}

// ─── Contacts ─────────────────────────────────────────────────────────────

const CONTACTS_KEY = 'dchain_contacts';

export function loadContacts(): Contact[] {
  const raw = localStorage.getItem(CONTACTS_KEY);
  if (!raw) return [];
  try {
    return JSON.parse(raw) as Contact[];
  } catch {
    return [];
  }
}

export function saveContacts(list: Contact[]): void {
  localStorage.setItem(CONTACTS_KEY, JSON.stringify(list));
}

export function upsertContact(c: Contact): void {
  const cs = loadContacts();
  const i = cs.findIndex(x => x.address === c.address);
  if (i >= 0) cs[i] = c; else cs.push(c);
  saveContacts(cs);
}

// ─── Chat cache (per-conversation, capped) ───────────────────────────────

const CHATS_PREFIX = 'dchain_chats_';
const CHAT_CAP = 500;

export function loadMessages(chatAddr: string): Message[] {
  const raw = localStorage.getItem(CHATS_PREFIX + chatAddr);
  if (!raw) return [];
  try {
    return JSON.parse(raw) as Message[];
  } catch {
    return [];
  }
}

/**
 * Append + persist. Deduplicates by id, trims to CHAT_CAP newest. Callers
 * in the UI should prefer zustand's store.appendMessage for reactivity
 * and call this from effects to flush to disk.
 */
export function appendMessage(chatAddr: string, m: Message): void {
  const cur = loadMessages(chatAddr);
  if (cur.some(x => x.id === m.id)) return;
  cur.push(m);
  const trimmed = cur.slice(-CHAT_CAP);
  localStorage.setItem(CHATS_PREFIX + chatAddr, JSON.stringify(trimmed));
}

// ─── Multi-device bookkeeping (shared semantic with mobile client) ───────

const DEVICE_REGISTERED_KEY = 'dchain_device_registered';

export function isDeviceRegistered(): boolean {
  return localStorage.getItem(DEVICE_REGISTERED_KEY) === '1';
}

export function markDeviceRegistered(): void {
  localStorage.setItem(DEVICE_REGISTERED_KEY, '1');
}

export async function wipeAllLocalState(): Promise<void> {
  await deleteKeyFile();
  // Everything else in localStorage we control; iterate + clear our prefix.
  const ours = [
    SETTINGS_KEY, CONTACTS_KEY, DEVICE_REGISTERED_KEY,
  ];
  for (const key of Object.keys(localStorage)) {
    if (ours.includes(key) || key.startsWith('dchain_chats_')) {
      localStorage.removeItem(key);
    }
  }
}