import { migrateOwnLegacyBundles } from '@chat-app/shared/chat';
import {
  fetchUserKeyBlob,
  listOwnDevices,
  recordPinAttempt,
  resetUserKey,
  tryUnlockUserKey,
  uploadUserKeyBlob,
} from '@chat-app/shared/auth';
import {
  generateRecoveryCode,
  generateUserKeyPair,
  getCryptoBackend,
  normalizeRecoveryCode,
  openUserKey,
  sealUserKey,
} from '@chat-app/shared/crypto';

import { legacyDeviceKey } from './legacyDeviceVault';
import { secretStore } from './secretStore';
import { supabase } from './supabase';

const cacheKey = (userId: string) => 'chatapp.userpriv.' + userId;

export interface SetupParams {
  userId: string;
  pin: string;
  withRecovery: boolean;
}
export interface SetupResult {
  publicKey: Uint8Array;
  recoveryCode: string | null;
}

export async function setupNewUserIdentity(p: SetupParams): Promise<SetupResult> {
  const kp = await generateUserKeyPair();
  const sealed = await sealUserKey({ privateKey: kp.privateKey, pin: p.pin });
  let recoveryCode: string | null = null;
  let recoverySealed: { sealedPrivateKey: Uint8Array; salt: Uint8Array } | null = null;
  if (p.withRecovery) {
    recoveryCode = await generateRecoveryCode();
    const r = await sealUserKey({
      privateKey: kp.privateKey,
      pin: normalizeRecoveryCode(recoveryCode),
    });
    recoverySealed = { sealedPrivateKey: r.sealedPrivateKey, salt: r.salt };
  }
  await uploadUserKeyBlob(supabase, {
    userId: p.userId,
    publicKey: kp.publicKey,
    sealedPrivateKey: sealed.sealedPrivateKey,
    salt: sealed.salt,
    kdfParams: sealed.kdfParams,
    recoverySealedPrivateKey: recoverySealed?.sealedPrivateKey ?? null,
    recoverySalt: recoverySealed?.salt ?? null,
  });
  await secretStore.setSecret(cacheKey(p.userId), kp.privateKey);
  void ensureLegacyMigrated(p.userId).catch((err) => {
    console.warn('legacy conv-key migration failed', err);
  });
  return { publicKey: kp.publicKey, recoveryCode };
}

export interface UnlockParams {
  userId: string;
  pin: string;
  isRecoveryCode?: boolean;
}

export type UnlockOutcome =
  | { kind: 'unlocked' }
  | { kind: 'locked'; lockedUntil: string }
  | { kind: 'missing' };

export async function loadOrUnlockUserKey(p: UnlockParams): Promise<UnlockOutcome> {
  const remote = await tryUnlockUserKey(supabase, p.userId);
  if (!remote.exists) return { kind: 'missing' };
  if (remote.locked) return { kind: 'locked', lockedUntil: remote.lockedUntil };
  const secret = p.isRecoveryCode ? normalizeRecoveryCode(p.pin) : p.pin;
  const sealed = p.isRecoveryCode ? remote.recoverySealedPrivateKey : remote.sealedPrivateKey;
  const salt = p.isRecoveryCode ? remote.recoverySalt : remote.salt;
  if (!sealed || !salt) throw new Error('no recovery blob configured');
  let priv: Uint8Array;
  try {
    priv = await openUserKey({ sealed, pin: secret, salt, kdfParams: remote.kdfParams });
  } catch (err) {
    await recordPinAttempt(supabase, p.userId, false, p.isRecoveryCode === true).catch(() => {});
    throw err;
  }
  await recordPinAttempt(supabase, p.userId, true, p.isRecoveryCode === true).catch(() => {});
  await secretStore.setSecret(cacheKey(p.userId), priv);
  void ensureLegacyMigrated(p.userId).catch((err) => {
    console.warn('legacy conv-key migration failed', err);
  });
  return { kind: 'unlocked' };
}

export async function cachedUserKey(userId: string): Promise<Uint8Array | null> {
  return secretStore.getSecret(cacheKey(userId));
}

export async function clearUserKeyCache(userId: string): Promise<void> {
  await secretStore.removeSecret(cacheKey(userId));
}

export async function userKeyExistsRemotely(userId: string): Promise<boolean> {
  const blob = await fetchUserKeyBlob(supabase, userId);
  return blob !== null;
}

export async function changePin(params: {
  userId: string;
  oldPin: string;
  newPin: string;
}): Promise<void> {
  const cached = await cachedUserKey(params.userId);
  if (!cached) throw new Error('user key not cached locally — re-login required');
  const fresh = await sealUserKey({ privateKey: cached, pin: params.newPin });
  await uploadUserKeyBlob(supabase, {
    userId: params.userId,
    publicKey: getCryptoBackend().scalarMultBase(cached),
    sealedPrivateKey: fresh.sealedPrivateKey,
    salt: fresh.salt,
    kdfParams: fresh.kdfParams,
  });
  void params.oldPin; // cached key already proves old PIN was correct
}

export async function regenerateRecoveryCode(params: { userId: string }): Promise<string> {
  const cached = await cachedUserKey(params.userId);
  if (!cached) throw new Error('user key not cached locally');
  const blob = await fetchUserKeyBlob(supabase, params.userId);
  if (!blob || !blob.exists || blob.locked) {
    throw new Error('cannot regenerate recovery while locked');
  }
  const recoveryCode = await generateRecoveryCode();
  const sealed = await sealUserKey({
    privateKey: cached,
    pin: normalizeRecoveryCode(recoveryCode),
  });
  await uploadUserKeyBlob(supabase, {
    userId: params.userId,
    publicKey: getCryptoBackend().scalarMultBase(cached),
    sealedPrivateKey: blob.sealedPrivateKey,
    salt: blob.salt,
    kdfParams: blob.kdfParams,
    recoverySealedPrivateKey: sealed.sealedPrivateKey,
    recoverySalt: sealed.salt,
  });
  return recoveryCode;
}

export async function resetIdentity(params: {
  userId: string;
  pin: string;
}): Promise<string> {
  await clearUserKeyCache(params.userId);
  await resetUserKey(supabase, {
    userId: params.userId,
    publicKey: new Uint8Array(32),
    sealedPrivateKey: new Uint8Array(40),
    salt: new Uint8Array(16),
    kdfParams: { algo: 'argon2id', preset: 'moderate', opslimit: 1, memlimit: 1 },
  });
  const setup = await setupNewUserIdentity({
    userId: params.userId,
    pin: params.pin,
    withRecovery: true,
  });
  return setup.recoveryCode ?? '';
}

export interface LegacyMigrationReport {
  serverDevices: number;
  strongholdKeysFromServerDevices: number;
  strongholdKeysFromBundleScan: number;
  attempted: number;
  migrated: number;
  noStrongholdKey: number;
  decryptFailed: number;
  rpcFailed: number;
}

export async function ensureLegacyMigrated(userId: string): Promise<LegacyMigrationReport | null> {
  const priv = await cachedUserKey(userId);
  if (!priv) return null;
  const pub = getCryptoBackend().scalarMultBase(priv);
  return runLegacyMigration(userId, priv, pub);
}

export async function retryLegacyMigration(userId: string): Promise<LegacyMigrationReport> {
  const priv = await cachedUserKey(userId);
  if (!priv) throw new Error('user key not cached locally — re-login required');
  const pub = getCryptoBackend().scalarMultBase(priv);
  return runLegacyMigration(userId, priv, pub);
}

async function runLegacyMigration(
  userId: string,
  ownNewPriv: Uint8Array,
  ownNewPub: Uint8Array,
): Promise<LegacyMigrationReport> {
  const report: LegacyMigrationReport = {
    serverDevices: 0,
    strongholdKeysFromServerDevices: 0,
    strongholdKeysFromBundleScan: 0,
    attempted: 0,
    migrated: 0,
    noStrongholdKey: 0,
    decryptFailed: 0,
    rpcFailed: 0,
  };

  const devices = await listOwnDevices(supabase);
  report.serverDevices = devices.length;
  const ownLegacyDevicePrivateKeys: Record<string, Uint8Array> = {};

  for (const d of devices) {
    const k = await legacyDeviceKey(userId, d.id);
    if (k) ownLegacyDevicePrivateKeys[d.id] = k;
  }
  report.strongholdKeysFromServerDevices = Object.keys(ownLegacyDevicePrivateKeys).length;

  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const { data: scanRowsRaw } = await (supabase as any)
    .from('conversation_keys')
    .select('recipient_device_id')
    .is('recipient_user_id', null)
    .not('recipient_device_id', 'is', null);
  const scanIds = Array.from(
    new Set(
      ((scanRowsRaw ?? []) as { recipient_device_id: string }[])
        .map((r) => r.recipient_device_id)
        .filter((id): id is string => Boolean(id)),
    ),
  );
  for (const id of scanIds) {
    if (ownLegacyDevicePrivateKeys[id]) continue;
    const k = await legacyDeviceKey(userId, id);
    if (k) {
      ownLegacyDevicePrivateKeys[id] = k;
      report.strongholdKeysFromBundleScan += 1;
    }
  }

  const ids = Object.keys(ownLegacyDevicePrivateKeys);
  if (ids.length === 0) {
    console.warn('[crypto-migration] no legacy private keys in vault — nothing to migrate');
    return report;
  }

  const result = await migrateOwnLegacyBundles({
    client: supabase,
    ownUserId: userId,
    ownNewPublicKey: ownNewPub,
    ownNewPrivateKey: ownNewPriv,
    ownLegacyDeviceIds: ids,
    ownLegacyDevicePrivateKeys,
  });
  report.attempted = result.attempted;
  report.migrated = result.migratedConversations;
  report.noStrongholdKey = result.noStrongholdKey;
  report.decryptFailed = result.decryptFailed;
  report.rpcFailed = result.rpcFailed;
  return report;
}