import 'dart:convert';
import 'dart:typed_data';

import 'package:dio/dio.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:uuid/uuid.dart';

import '../../../common/network/dio_provider.dart';

const splashAdPlacement = 'splash';
const homeBannerAdPlacement = 'home_banner';

enum AdMediaType { image, gif, video, unsupported }

enum AdOpenMode { external, inApp }

class AdCreative {
  const AdCreative({
    required this.adId,
    required this.placement,
    required this.targetApp,
    required this.title,
    required this.imageUrl,
    required this.mediaType,
    required this.h5Url,
    required this.trackingId,
    required this.countdownSeconds,
    required this.endAtMs,
    required this.trackedUrl,
    required this.openMode,
  });
  final String adId,
      placement,
      targetApp,
      title,
      imageUrl,
      h5Url,
      trackingId,
      trackedUrl;
  final AdMediaType mediaType;
  final int countdownSeconds, endAtMs;
  final AdOpenMode openMode;
  Uri? get mediaUri => _http(imageUrl);
  Uri? get targetUri => _http(trackedUrl) ?? _http(h5Url);
  bool get isRenderable =>
      adId.isNotEmpty &&
      mediaUri != null &&
      targetUri != null &&
      mediaType != AdMediaType.unsupported &&
      (endAtMs <= 0 || endAtMs > DateTime.now().millisecondsSinceEpoch);
  Uri? clickUri(String clickId) {
    final uri = targetUri;
    if (uri == null) return null;
    return uri.replace(
      queryParameters: {
        ...uri.queryParameters,
        'ad_id': adId,
        'placement': placement,
        'tracking_id': trackingId,
        'click_id': clickId,
        'target_app': targetApp,
        'hook_type': placement,
        'ts': DateTime.now().millisecondsSinceEpoch.toString(),
      },
    );
  }

  Map<String, dynamic> toJson() => {
    'adId': adId,
    'placement': placement,
    'targetApp': targetApp,
    'title': title,
    'imageUrl': imageUrl,
    'mediaType': mediaType.index,
    'h5Url': h5Url,
    'trackingId': trackingId,
    'countdownSeconds': countdownSeconds,
    'endAtMs': endAtMs,
    'trackedUrl': trackedUrl,
    'openMode': openMode.index,
  };
  factory AdCreative.fromJson(Map<String, dynamic> value) => AdCreative(
    adId: '${value['adId'] ?? ''}',
    placement: '${value['placement'] ?? ''}',
    targetApp: '${value['targetApp'] ?? ''}',
    title: '${value['title'] ?? ''}',
    imageUrl: '${value['imageUrl'] ?? ''}',
    mediaType:
        AdMediaType.values[(value['mediaType'] as num?)?.toInt().clamp(
              0,
              AdMediaType.values.length - 1,
            ) ??
            AdMediaType.unsupported.index],
    h5Url: '${value['h5Url'] ?? ''}',
    trackingId: '${value['trackingId'] ?? ''}',
    countdownSeconds: (value['countdownSeconds'] as num?)?.toInt() ?? 0,
    endAtMs: (value['endAtMs'] as num?)?.toInt() ?? 0,
    trackedUrl: '${value['trackedUrl'] ?? ''}',
    openMode: (value['openMode'] as num?)?.toInt() == AdOpenMode.inApp.index
        ? AdOpenMode.inApp
        : AdOpenMode.external,
  );
  factory AdCreative.fromProto(ProtoMessage fields) => AdCreative(
    adId: fields.string(1),
    placement: fields.string(2),
    targetApp: fields.string(3),
    title: fields.string(4),
    imageUrl: fields.string(6),
    mediaType: switch (fields.integer(7)) {
      1 => AdMediaType.image,
      2 => AdMediaType.gif,
      3 => AdMediaType.video,
      _ => AdMediaType.unsupported,
    },
    h5Url: fields.string(9),
    trackingId: fields.string(10),
    countdownSeconds: fields.integer(11),
    endAtMs: fields.integer(13),
    trackedUrl: fields.string(14),
    openMode: fields.integer(15) == 2 ? AdOpenMode.inApp : AdOpenMode.external,
  );
}

class GetAdResult {
  const GetAdResult(this.enabled, this.ad, this.dailyCap);
  final bool enabled;
  final AdCreative? ad;
  final int dailyCap;
}

class FeaturedAdsState {
  const FeaturedAdsState(this.enabled, this.ads, {this.trackingId});
  final bool enabled;
  final List<AdCreative> ads;
  final String? trackingId;
  bool get hasAds => enabled && ads.isNotEmpty;
}

class AdsApiClient {
  AdsApiClient(this._dio);
  final Dio _dio;
  Future<GetAdResult> getAdResult(String placement) async {
    final response = await _dio.get<List<int>>(
      '/api/v1/ads',
      queryParameters: {'placement': placement},
      options: protobufOptions(),
    );
    final root = ProtoMessage(response.data ?? const []);
    final creative = root.message(2);
    final ad = AdCreative.fromProto(creative);
    return GetAdResult(
      root.integer(1) != 0,
      ad.isRenderable ? ad : null,
      root.integer(3),
    );
  }

  Future<FeaturedAdsState> listAds(String placement) async {
    final response = await _dio.get<List<int>>(
      '/api/v1/ads/list',
      queryParameters: {'placement': placement},
      options: protobufOptions(),
    );
    final root = ProtoMessage(response.data ?? const []);
    final ads = root
        .messages(2)
        .map(AdCreative.fromProto)
        .where((ad) => ad.isRenderable)
        .toList(growable: false);
    return FeaturedAdsState(
      root.integer(1) != 0,
      ads,
      trackingId: root.string(3).isEmpty ? null : root.string(3),
    );
  }

  Future<void> report(
    AdCreative ad,
    String event, {
    String? clickId,
    String? trackingId,
  }) => _dio.post<List<int>>(
    '/api/v1/ads/events',
    data: _Writer()
        .string(1, event)
        .string(2, ad.placement)
        .string(3, ad.adId)
        .string(4, trackingId ?? ad.trackingId)
        .string(5, clickId ?? '')
        .integer(6, DateTime.now().millisecondsSinceEpoch)
        .toBytes(),
    options: protobufOptions(),
  );
  String newClickId() => const Uuid().v4();
}

final adsApiClientProvider = Provider(
  (ref) => AdsApiClient(ref.watch(dioProvider)),
);
final featuredAdsProvider = FutureProvider.autoDispose
    .family<FeaturedAdsState, String>(
      (ref, placement) => ref.watch(adsApiClientProvider).listAds(placement),
    );

Uri? _http(String raw) {
  final uri = Uri.tryParse(raw.trim());
  return uri != null &&
          uri.host.isNotEmpty &&
          (uri.scheme == 'https' || uri.scheme == 'http')
      ? uri
      : null;
}

class ProtoMessage {
  ProtoMessage(this.bytes);
  final List<int> bytes;
  Map<int, List<Object>>? _cache;
  Map<int, List<Object>> get _fields => _cache ??= _read();
  int integer(int tag) => (_fields[tag]?.lastOrNull as int?) ?? 0;
  String string(int tag) {
    final value = _fields[tag]?.lastOrNull;
    return value is List<int> ? utf8.decode(value, allowMalformed: true) : '';
  }

  ProtoMessage message(int tag) {
    final value = _fields[tag]?.lastOrNull;
    return ProtoMessage(value is List<int> ? value : const []);
  }

  List<ProtoMessage> messages(int tag) => (_fields[tag] ?? const [])
      .whereType<List<int>>()
      .map(ProtoMessage.new)
      .toList();
  Map<int, List<Object>> _read() {
    final out = <int, List<Object>>{};
    var i = 0;
    int v() {
      var n = 0, s = 0;
      while (i < bytes.length) {
        final b = bytes[i++];
        n |= (b & 127) << s;
        if (b < 128) return n;
        s += 7;
      }
      throw const FormatException('Invalid protobuf');
    }

    while (i < bytes.length) {
      final key = v(), tag = key >> 3;
      Object value;
      if ((key & 7) == 0) {
        value = v();
      } else if ((key & 7) == 2) {
        final l = v(), end = i + l;
        if (end > bytes.length) throw const FormatException('Invalid protobuf');
        value = bytes.sublist(i, end);
        i = end;
      } else {
        throw const FormatException('Unsupported protobuf');
      }
      (out[tag] ??= []).add(value);
    }
    return out;
  }
}

extension on List<Object> {
  Object? get lastOrNull => isEmpty ? null : last;
}

class _Writer {
  final b = BytesBuilder(copy: false);
  _Writer string(int t, String value) {
    final d = value.codeUnits;
    v((t << 3) | 2);
    v(d.length);
    b.add(d);
    return this;
  }

  _Writer integer(int t, int value) {
    v(t << 3);
    v(value);
    return this;
  }

  Uint8List toBytes() => b.toBytes();
  void v(int n) {
    while (n > 127) {
      b.addByte((n & 127) | 128);
      n >>= 7;
    }
    b.addByte(n);
  }
}