// Paired-device registry — v3 chirp-sync.
//
// Per the brief: long-term records live in `chrome.storage.sync` so the
// registry roams across browser profiles signed into Chrome/Firefox sync.
// `lastKnownIp` is network-specific and lives in `chrome.storage.local`
// instead — bringing the IP across networks would do nothing but cause
// the subnet probe to chase a stale address.
//
// `deviceId` is the canonical primary key (UUID v4, stable for the
// lifetime of the installation). `longTermPublicKeyHex` is also unique
// per device but rotates if the user reinstalls before re-pairing, so we
// key on deviceId and update the key in place during re-pair.

import type { PairedDevice } from "../shared/sync-types";

const REGISTRY_KEY = "peach_paired_devices_v3";
const LAST_IP_KEY_PREFIX = "peach_last_known_ip_v3:";
const LAST_SYNC_AT_KEY = "peach_last_sync_at";

// chrome.storage.sync has hard quotas: 100KB total, 8KB per item. A paired
// device record is ~200 bytes (one X25519 hex pubkey + UUIDs + a name);
// 100KB easily holds the realistic ~5-10 devices a user pairs. We store
// the array under a single key to avoid eating the per-key quota.

export async function listPairedDevices(): Promise<PairedDevice[]> {
  try {
    const result = await chrome.storage.sync.get(REGISTRY_KEY);
    const devices = (result as Record<string, unknown>)[REGISTRY_KEY];
    if (!Array.isArray(devices)) return [];
    return devices.filter(isPairedDevice);
  } catch {
    return [];
  }
}

export async function findPairedDeviceById(deviceId: string): Promise<PairedDevice | null> {
  const devices = await listPairedDevices();
  return devices.find((d) => d.deviceId === deviceId) ?? null;
}

export async function findPairedDeviceByPubkey(pubkeyHex: string): Promise<PairedDevice | null> {
  const devices = await listPairedDevices();
  return devices.find((d) => d.longTermPublicKeyHex === pubkeyHex) ?? null;
}

/**
 * Add or update a device by `deviceId`. On re-pair the new pubkey
 * silently replaces the old one; the deviceId is stable across the
 * other device's reinstall.
 */
export async function upsertPairedDevice(device: PairedDevice): Promise<void> {
  if (!device.deviceId) throw new Error("device.deviceId is required");
  if (!device.longTermPublicKeyHex) throw new Error("device.longTermPublicKeyHex is required");
  if (!device.deviceName) throw new Error("device.deviceName is required");
  if (!device.deviceType) throw new Error("device.deviceType is required");

  const devices = await listPairedDevices();
  const idx = devices.findIndex((d) => d.deviceId === device.deviceId);
  if (idx >= 0) {
    devices[idx] = { ...devices[idx], ...device };
  } else {
    devices.push(device);
  }
  await chrome.storage.sync.set({ [REGISTRY_KEY]: devices });
}

export async function removePairedDeviceById(deviceId: string): Promise<void> {
  const devices = await listPairedDevices();
  const filtered = devices.filter((d) => d.deviceId !== deviceId);
  await chrome.storage.sync.set({ [REGISTRY_KEY]: filtered });
  // Also clear the per-network IP cache for this device.
  const device = devices.find((d) => d.deviceId === deviceId);
  if (device?.longTermPublicKeyHex) {
    await chrome.storage.local.remove(LAST_IP_KEY_PREFIX + device.longTermPublicKeyHex);
  }
}

export async function clearPairedDevices(): Promise<void> {
  await chrome.storage.sync.remove(REGISTRY_KEY);
}

export async function markLastSyncedAt(deviceId: string, when: number): Promise<void> {
  const devices = await listPairedDevices();
  const idx = devices.findIndex((d) => d.deviceId === deviceId);
  if (idx < 0) return;
  devices[idx] = { ...devices[idx], lastSyncedAt: when };
  await chrome.storage.sync.set({ [REGISTRY_KEY]: devices });
}

export async function getLastKnownIp(pubkeyHex: string): Promise<string | null> {
  try {
    const key = LAST_IP_KEY_PREFIX + pubkeyHex;
    const result = await chrome.storage.local.get(key);
    const value = (result as Record<string, unknown>)[key];
    return typeof value === "string" ? value : null;
  } catch {
    return null;
  }
}

export async function setLastKnownIp(pubkeyHex: string, ip: string): Promise<void> {
  await chrome.storage.local.set({ [LAST_IP_KEY_PREFIX + pubkeyHex]: ip });
}

export async function clearLastKnownIp(pubkeyHex: string): Promise<void> {
  await chrome.storage.local.remove(LAST_IP_KEY_PREFIX + pubkeyHex);
}

export async function getLastSyncAt(): Promise<number | null> {
  try {
    const result = await chrome.storage.local.get(LAST_SYNC_AT_KEY);
    const value = (result as Record<string, unknown>)[LAST_SYNC_AT_KEY];
    if (typeof value === "number") return value;
    if (typeof value === "string" && value !== "") {
      const n = Number.parseInt(value, 10);
      return Number.isFinite(n) ? n : null;
    }
    return null;
  } catch {
    return null;
  }
}

export async function setLastSyncAt(when: number): Promise<void> {
  await chrome.storage.local.set({ [LAST_SYNC_AT_KEY]: when });
}

function isPairedDevice(x: unknown): x is PairedDevice {
  if (typeof x !== "object" || x === null) return false;
  const r = x as Record<string, unknown>;
  if (typeof r.deviceId !== "string" || !r.deviceId) return false;
  if (typeof r.pairedAt !== "number") return false;
  return true;
}