import 'dart:async';
import 'dart:convert';
import 'dart:html' as html;
import 'dart:js' as js;
import 'dart:js_util' as js_util;
import 'dart:typed_data';

import 'veilid.dart';

//////////////////////////////////////////////////////////

Veilid getVeilid() => VeilidJS();

Object wasm = js_util.getProperty(html.window, 'veilid_wasm');

Future<T> _wrapApiPromise<T>(Object p) => js_util.promiseToFuture(p).then((value) => value as T).catchError(
      (error) => Future<T>.error(
          VeilidAPIException.fromJson(jsonDecode(error as String))));

class _Ctx {
  _Ctx(int this.id, this.js);
  int? id;
  final VeilidJS js;
  void ensureValid() {
    if (id == null) {
      throw VeilidAPIExceptionNotInitialized();
    }
  }

  void close() {
    if (id != null) {
      js_util.callMethod(wasm, 'release_routing_context', [id!]);
      id = null;
    }
  }
}

// JS implementation of VeilidRoutingContext
class VeilidRoutingContextJS extends VeilidRoutingContext {

  VeilidRoutingContextJS._(this._ctx) {
    _finalizer.attach(this, _ctx, detach: this);
  }
  final _Ctx _ctx;
  static final Finalizer<_Ctx> _finalizer = Finalizer((ctx) => ctx.close());

  @override
  void close() {
    _ctx.close();
  }

  @override
  VeilidRoutingContextJS withPrivacy() {
    _ctx.ensureValid();
    final int newId =
        js_util.callMethod(wasm, 'routing_context_with_privacy', [_ctx.id!]);
    return VeilidRoutingContextJS._(_Ctx(newId, _ctx.js));
  }

  @override
  VeilidRoutingContextJS withCustomPrivacy(SafetySelection safetySelection) {
    _ctx.ensureValid();
    final newId = js_util.callMethod(
        wasm,
        'routing_context_with_custom_privacy',
        [_ctx.id!, jsonEncode(safetySelection)]);

    return VeilidRoutingContextJS._(_Ctx(newId, _ctx.js));
  }

  @override
  VeilidRoutingContextJS withSequencing(Sequencing sequencing) {
    _ctx.ensureValid();
    final newId = js_util.callMethod(wasm, 'routing_context_with_sequencing',
        [_ctx.id!, jsonEncode(sequencing)]);
    return VeilidRoutingContextJS._(_Ctx(newId, _ctx.js));
  }

  @override
  Future<Uint8List> appCall(String target, Uint8List request) async {
    _ctx.ensureValid();
    final encodedRequest = base64UrlNoPadEncode(request);

    return base64UrlNoPadDecode(await _wrapApiPromise(js_util.callMethod(
        wasm, 'routing_context_app_call', [_ctx.id!, target, encodedRequest])));
  }

  @override
  Future<void> appMessage(String target, Uint8List message) {
    _ctx.ensureValid();
    final encodedMessage = base64UrlNoPadEncode(message);

    return _wrapApiPromise(js_util.callMethod(wasm,
        'routing_context_app_message', [_ctx.id!, target, encodedMessage]));
  }

  @override
  Future<DHTRecordDescriptor> createDHTRecord(DHTSchema schema,
      {CryptoKind kind = 0}) async {
    _ctx.ensureValid();
    return DHTRecordDescriptor.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'routing_context_create_dht_record',
            [_ctx.id!, jsonEncode(schema), kind]))));
  }

  @override
  Future<DHTRecordDescriptor> openDHTRecord(
      TypedKey key, KeyPair? writer) async {
    _ctx.ensureValid();
    return DHTRecordDescriptor.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'routing_context_open_dht_record', [
      _ctx.id!,
      jsonEncode(key),
      if (writer != null) jsonEncode(writer) else null
    ]))));
  }

  @override
  Future<void> closeDHTRecord(TypedKey key) {
    _ctx.ensureValid();
    return _wrapApiPromise(js_util.callMethod(
        wasm, 'routing_context_close_dht_record', [_ctx.id!, jsonEncode(key)]));
  }

  @override
  Future<void> deleteDHTRecord(TypedKey key) {
    _ctx.ensureValid();
    return _wrapApiPromise(js_util.callMethod(wasm,
        'routing_context_delete_dht_record', [_ctx.id!, jsonEncode(key)]));
  }

  @override
  Future<ValueData?> getDHTValue(
      TypedKey key, int subkey, bool forceRefresh) async {
    _ctx.ensureValid();
    final opt = await _wrapApiPromise(js_util.callMethod(
        wasm,
        'routing_context_get_dht_value',
        [_ctx.id!, jsonEncode(key), subkey, forceRefresh]));
    return opt == null ? null : ValueData.fromJson(jsonDecode(opt));
  }

  @override
  Future<ValueData?> setDHTValue(
      TypedKey key, int subkey, Uint8List data) async {
    _ctx.ensureValid();
    final opt = await _wrapApiPromise(js_util.callMethod(
        wasm,
        'routing_context_set_dht_value',
        [_ctx.id!, jsonEncode(key), subkey, base64UrlNoPadEncode(data)]));
    return opt == null ? null : ValueData.fromJson(jsonDecode(opt));
  }

  @override
  Future<Timestamp> watchDHTValues(TypedKey key, List<ValueSubkeyRange> subkeys,
      Timestamp expiration, int count) async {
    _ctx.ensureValid();
    final ts = await _wrapApiPromise(js_util.callMethod(
        wasm, 'routing_context_watch_dht_values', [
      _ctx.id!,
      jsonEncode(key),
      jsonEncode(subkeys),
      expiration.toString(),
      count
    ]));
    return Timestamp.fromString(ts);
  }

  @override
  Future<bool> cancelDHTWatch(TypedKey key, List<ValueSubkeyRange> subkeys) {
    _ctx.ensureValid();
    return _wrapApiPromise(js_util.callMethod(
        wasm,
        'routing_context_cancel_dht_watch',
        [_ctx.id!, jsonEncode(key), jsonEncode(subkeys)]));
  }
}

// JS implementation of VeilidCryptoSystem
class VeilidCryptoSystemJS extends VeilidCryptoSystem {

  VeilidCryptoSystemJS._(this._js, this._kind) {
    // Keep the reference
    _js;
  }
  final CryptoKind _kind;
  final VeilidJS _js;

  @override
  CryptoKind kind() => _kind;

  @override
  Future<SharedSecret> cachedDH(PublicKey key, SecretKey secret) async => SharedSecret.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'crypto_cached_dh',
            [_kind, jsonEncode(key), jsonEncode(secret)]))));

  @override
  Future<SharedSecret> computeDH(PublicKey key, SecretKey secret) async => SharedSecret.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'crypto_compute_dh',
            [_kind, jsonEncode(key), jsonEncode(secret)]))));

  @override
  Future<Uint8List> randomBytes(int len) async => base64UrlNoPadDecode(await _wrapApiPromise(
        js_util.callMethod(wasm, 'crypto_random_bytes', [_kind, len])));

  @override
  Future<int> defaultSaltLength() => _wrapApiPromise(
        js_util.callMethod(wasm, 'crypto_default_salt_length', [_kind]));

  @override
  Future<String> hashPassword(Uint8List password, Uint8List salt) => _wrapApiPromise(js_util.callMethod(wasm, 'crypto_hash_password',
        [_kind, base64UrlNoPadEncode(password), base64UrlNoPadEncode(salt)]));

  @override
  Future<bool> verifyPassword(Uint8List password, String passwordHash) => _wrapApiPromise(js_util.callMethod(wasm, 'crypto_verify_password',
        [_kind, base64UrlNoPadEncode(password), passwordHash]));

  @override
  Future<SharedSecret> deriveSharedSecret(
      Uint8List password, Uint8List salt) async => SharedSecret.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'crypto_derive_shared_secret', [
      _kind,
      base64UrlNoPadEncode(password),
      base64UrlNoPadEncode(salt)
    ]))));

  @override
  Future<Nonce> randomNonce() async => Nonce.fromJson(jsonDecode(await _wrapApiPromise(
        js_util.callMethod(wasm, 'crypto_random_nonce', [_kind]))));

  @override
  Future<SharedSecret> randomSharedSecret() async => SharedSecret.fromJson(jsonDecode(await _wrapApiPromise(
        js_util.callMethod(wasm, 'crypto_random_shared_secret', [_kind]))));

  @override
  Future<KeyPair> generateKeyPair() async => KeyPair.fromJson(jsonDecode(await _wrapApiPromise(
        js_util.callMethod(wasm, 'crypto_generate_key_pair', [_kind]))));

  @override
  Future<HashDigest> generateHash(Uint8List data) async => HashDigest.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'crypto_generate_hash',
            [_kind, base64UrlNoPadEncode(data)]))));

  @override
  Future<bool> validateKeyPair(PublicKey key, SecretKey secret) => _wrapApiPromise(js_util.callMethod(wasm, 'crypto_validate_key_pair',
        [_kind, jsonEncode(key), jsonEncode(secret)]));

  @override
  Future<bool> validateHash(Uint8List data, HashDigest hash) => _wrapApiPromise(js_util.callMethod(wasm, 'crypto_validate_hash',
        [_kind, base64UrlNoPadEncode(data), jsonEncode(hash)]));

  @override
  Future<CryptoKeyDistance> distance(CryptoKey key1, CryptoKey key2) async => CryptoKeyDistance.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'crypto_distance',
            [_kind, jsonEncode(key1), jsonEncode(key2)]))));

  @override
  Future<Signature> sign(
      PublicKey key, SecretKey secret, Uint8List data) async => Signature.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(wasm, 'crypto_sign', [
      _kind,
      jsonEncode(key),
      jsonEncode(secret),
      base64UrlNoPadEncode(data)
    ]))));

  @override
  Future<void> verify(PublicKey key, Uint8List data, Signature signature) => _wrapApiPromise(js_util.callMethod(wasm, 'crypto_verify', [
      _kind,
      jsonEncode(key),
      base64UrlNoPadEncode(data),
      jsonEncode(signature),
    ]));

  @override
  Future<int> aeadOverhead() => _wrapApiPromise(
        js_util.callMethod(wasm, 'crypto_aead_overhead', [_kind]));

  @override
  Future<Uint8List> decryptAead(Uint8List body, Nonce nonce,
      SharedSecret sharedSecret, Uint8List? associatedData) async => base64UrlNoPadDecode(
        await _wrapApiPromise(js_util.callMethod(wasm, 'crypto_decrypt_aead', [
      _kind,
      base64UrlNoPadEncode(body),
      jsonEncode(nonce),
      jsonEncode(sharedSecret),
      if (associatedData != null) base64UrlNoPadEncode(associatedData) else null
    ])));

  @override
  Future<Uint8List> encryptAead(Uint8List body, Nonce nonce,
      SharedSecret sharedSecret, Uint8List? associatedData) async => base64UrlNoPadDecode(
        await _wrapApiPromise(js_util.callMethod(wasm, 'crypto_encrypt_aead', [
      _kind,
      base64UrlNoPadEncode(body),
      jsonEncode(nonce),
      jsonEncode(sharedSecret),
      if (associatedData != null) base64UrlNoPadEncode(associatedData) else null
    ])));

  @override
  Future<Uint8List> cryptNoAuth(
      Uint8List body, Nonce nonce, SharedSecret sharedSecret) async => base64UrlNoPadDecode(await _wrapApiPromise(js_util.callMethod(
        wasm, 'crypto_crypt_no_auth', [
      _kind,
      base64UrlNoPadEncode(body),
      jsonEncode(nonce),
      jsonEncode(sharedSecret)
    ])));
}

class _TDBT {

  _TDBT(this.id, this.tdbjs, this.js);
  int? id;
  final VeilidTableDBJS tdbjs;
  final VeilidJS js;
  void ensureValid() {
    if (id == null) {
      throw VeilidAPIExceptionNotInitialized();
    }
  }

  void close() {
    if (id != null) {
      js_util.callMethod(wasm, 'release_table_db_transaction', [id!]);
      id = null;
    }
  }
}

// JS implementation of VeilidTableDBTransaction
class VeilidTableDBTransactionJS extends VeilidTableDBTransaction {

  VeilidTableDBTransactionJS._(this._tdbt) {
    _finalizer.attach(this, _tdbt, detach: this);
  }
  final _TDBT _tdbt;
  static final Finalizer<_TDBT> _finalizer = Finalizer((tdbt) => tdbt.close());

  @override
  bool isDone() => _tdbt.id == null;

  @override
  Future<void> commit() async {
    _tdbt.ensureValid();
    await _wrapApiPromise(
        js_util.callMethod(wasm, 'table_db_transaction_commit', [_tdbt.id!]));
    _tdbt.close();
  }

  @override
  Future<void> rollback() async {
    _tdbt.ensureValid();
    await _wrapApiPromise(
        js_util.callMethod(wasm, 'table_db_transaction_rollback', [_tdbt.id!]));
    _tdbt.close();
  }

  @override
  Future<void> store(int col, Uint8List key, Uint8List value) async {
    _tdbt.ensureValid();
    final encodedKey = base64UrlNoPadEncode(key);
    final encodedValue = base64UrlNoPadEncode(value);

    await _wrapApiPromise(js_util.callMethod(wasm, 'table_db_transaction_store',
        [_tdbt.id!, col, encodedKey, encodedValue]));
  }

  @override
  Future<void> delete(int col, Uint8List key) async {
    _tdbt.ensureValid();
    final encodedKey = base64UrlNoPadEncode(key);

    await _wrapApiPromise(js_util.callMethod(
        wasm, 'table_db_transaction_delete', [_tdbt.id!, col, encodedKey]));
  }
}

class _TDB {

  _TDB(int this.id, this.js);
  int? id;
  final VeilidJS js;
  void ensureValid() {
    if (id == null) {
      throw VeilidAPIExceptionNotInitialized();
    }
  }

  void close() {
    if (id != null) {
      js_util.callMethod(wasm, 'release_table_db', [id!]);
      id = null;
    }
  }
}

// JS implementation of VeilidTableDB
class VeilidTableDBJS extends VeilidTableDB {

  VeilidTableDBJS._(this._tdb) {
    _finalizer.attach(this, _tdb, detach: this);
  }
  final _TDB _tdb;
  static final Finalizer<_TDB> _finalizer = Finalizer((tdb) => tdb.close());

  @override
  void close() {
    _tdb.close();
  }

  @override
  int getColumnCount() {
    _tdb.ensureValid();
    return js_util.callMethod(wasm, 'table_db_get_column_count', [_tdb.id!]);
  }

  @override
  Future<List<Uint8List>> getKeys(int col) async {
    _tdb.ensureValid();
    return jsonListConstructor(base64UrlNoPadDecodeDynamic)(jsonDecode(
        await js_util.callMethod(wasm, 'table_db_get_keys', [_tdb.id!, col])));
  }

  @override
  VeilidTableDBTransaction transact() {
    _tdb.ensureValid();
    final id = js_util.callMethod(wasm, 'table_db_transact', [_tdb.id!]);

    return VeilidTableDBTransactionJS._(_TDBT(id, this, _tdb.js));
  }

  @override
  Future<void> store(int col, Uint8List key, Uint8List value) {
    _tdb.ensureValid();
    final encodedKey = base64UrlNoPadEncode(key);
    final encodedValue = base64UrlNoPadEncode(value);

    return _wrapApiPromise(js_util.callMethod(
        wasm, 'table_db_store', [_tdb.id!, col, encodedKey, encodedValue]));
  }

  @override
  Future<Uint8List?> load(int col, Uint8List key) async {
    _tdb.ensureValid();
    final encodedKey = base64UrlNoPadEncode(key);

    final out = await _wrapApiPromise(
        js_util.callMethod(wasm, 'table_db_load', [_tdb.id!, col, encodedKey]));
    if (out == null) {
      return null;
    }
    return base64UrlNoPadDecode(out);
  }

  @override
  Future<Uint8List?> delete(int col, Uint8List key) {
    _tdb.ensureValid();
    final encodedKey = base64UrlNoPadEncode(key);

    return _wrapApiPromise(js_util
        .callMethod(wasm, 'table_db_delete', [_tdb.id!, col, encodedKey]));
  }
}

// JS implementation of high level Veilid API

class VeilidJS extends Veilid {
  @override
  void initializeVeilidCore(Map<String, dynamic> platformConfigJson) {
    final platformConfigJsonString = jsonEncode(platformConfigJson);
    js_util
        .callMethod(wasm, 'initialize_veilid_core', [platformConfigJsonString]);
  }

  @override
  void changeLogLevel(String layer, VeilidConfigLogLevel logLevel) {
    final logLevelJsonString = jsonEncode(logLevel);
    js_util.callMethod(wasm, 'change_log_level', [layer, logLevelJsonString]);
  }

  @override
  Future<Stream<VeilidUpdate>> startupVeilidCore(VeilidConfig config) async {
    final streamController = StreamController<VeilidUpdate>();
    updateCallback(String update) {
      final updateJson = jsonDecode(update);
      if (updateJson['kind'] == 'Shutdown') {
        streamController.close();
      } else {
        final update = VeilidUpdate.fromJson(updateJson);
        streamController.add(update);
      }
    }

    await _wrapApiPromise(js_util.callMethod(wasm, 'startup_veilid_core',
        [js.allowInterop(updateCallback), jsonEncode(config)]));

    return streamController.stream;
  }

  @override
  Future<VeilidState> getVeilidState() async => VeilidState.fromJson(jsonDecode(await _wrapApiPromise(
        js_util.callMethod(wasm, 'get_veilid_state', []))));

  @override
  Future<void> attach() => _wrapApiPromise(js_util.callMethod(wasm, 'attach', []));

  @override
  Future<void> detach() => _wrapApiPromise(js_util.callMethod(wasm, 'detach', []));

  @override
  Future<void> shutdownVeilidCore() => _wrapApiPromise(
        js_util.callMethod(wasm, 'shutdown_veilid_core', []));

  @override
  List<CryptoKind> validCryptoKinds() {
    final vck = jsonDecode(js_util.callMethod(wasm, 'valid_crypto_kinds', []))
        as List<dynamic>;
    return vck.map((v) => v as CryptoKind).toList();
  }

  @override
  Future<VeilidCryptoSystem> getCryptoSystem(CryptoKind kind) async {
    if (!validCryptoKinds().contains(kind)) {
      throw const VeilidAPIExceptionGeneric('unsupported cryptosystem');
    }
    return VeilidCryptoSystemJS._(this, kind);
  }

  @override
  Future<VeilidCryptoSystem> bestCryptoSystem() async => VeilidCryptoSystemJS._(
        this, js_util.callMethod(wasm, 'best_crypto_kind', []));

  @override
  Future<List<TypedKey>> verifySignatures(List<TypedKey> nodeIds,
      Uint8List data, List<TypedSignature> signatures) async => jsonListConstructor(TypedKey.fromJson)(jsonDecode(
        await _wrapApiPromise(js_util.callMethod(wasm, 'verify_signatures', [
      jsonEncode(nodeIds),
      base64UrlNoPadEncode(data),
      jsonEncode(signatures)
    ]))));

  @override
  Future<List<TypedSignature>> generateSignatures(
      Uint8List data, List<TypedKeyPair> keyPairs) async => jsonListConstructor(TypedSignature.fromJson)(jsonDecode(
        await _wrapApiPromise(js_util.callMethod(wasm, 'generate_signatures',
            [base64UrlNoPadEncode(data), jsonEncode(keyPairs)]))));

  @override
  Future<TypedKeyPair> generateKeyPair(CryptoKind kind) async => TypedKeyPair.fromJson(jsonDecode(await _wrapApiPromise(
        js_util.callMethod(wasm, 'generate_key_pair', [kind]))));

  @override
  Future<VeilidRoutingContext> routingContext() async {
    final var id =
        await _wrapApiPromise(js_util.callMethod(wasm, 'routing_context', []));
    return VeilidRoutingContextJS._(_Ctx(id, this));
  }

  @override
  Future<RouteBlob> newPrivateRoute() async => RouteBlob.fromJson(jsonDecode(await _wrapApiPromise(
        js_util.callMethod(wasm, 'new_private_route', []))));

  @override
  Future<RouteBlob> newCustomPrivateRoute(
      Stability stability, Sequencing sequencing) async {
    final stabilityString = jsonEncode(stability);
    final sequencingString = jsonEncode(sequencing);

    return RouteBlob.fromJson(jsonDecode(await _wrapApiPromise(js_util
        .callMethod(
            wasm, 'new_private_route', [stabilityString, sequencingString]))));
  }

  @override
  Future<String> importRemotePrivateRoute(Uint8List blob) {
    final encodedBlob = base64UrlNoPadEncode(blob);
    return _wrapApiPromise(
        js_util.callMethod(wasm, 'import_remote_private_route', [encodedBlob]));
  }

  @override
  Future<void> releasePrivateRoute(String key) => _wrapApiPromise(
        js_util.callMethod(wasm, 'release_private_route', [key]));

  @override
  Future<void> appCallReply(String callId, Uint8List message) {
    final encodedMessage = base64UrlNoPadEncode(message);
    return _wrapApiPromise(
        js_util.callMethod(wasm, 'app_call_reply', [callId, encodedMessage]));
  }

  @override
  Future<VeilidTableDB> openTableDB(String name, int columnCount) async {
    final id = await _wrapApiPromise(
        js_util.callMethod(wasm, 'open_table_db', [name, columnCount]));
    return VeilidTableDBJS._(_TDB(id, this));
  }

  @override
  Future<bool> deleteTableDB(String name) => _wrapApiPromise(js_util.callMethod(wasm, 'delete_table_db', [name]));

  @override
  Timestamp now() => Timestamp.fromString(js_util.callMethod(wasm, 'now', []));

  @override
  Future<String> debug(String command) async => await _wrapApiPromise(js_util.callMethod(wasm, 'debug', [command]));

  @override
  String veilidVersionString() => js_util.callMethod(wasm, 'veilid_version_string', []);

  @override
  VeilidVersion veilidVersion() {
    Map<String, dynamic> jsonVersion =
        jsonDecode(js_util.callMethod(wasm, 'veilid_version', []));
    return VeilidVersion(
        jsonVersion['major'], jsonVersion['minor'], jsonVersion['patch']);
  }
}