import 'dart:async';
import 'dart:convert';
import 'package:angel_framework/angel_framework.dart';
import 'package:resp_client/resp_client.dart';
import 'package:resp_client/resp_commands.dart';

/// An Angel service that reads and writes JSON within a Redis store.
class RedisService extends Service<String, Map<String, dynamic>> {
  final RespCommandsTier2 respCommands;

  /// An optional string prefixed to keys before they are inserted into Redis.
  ///
  /// Consider using this if you are using several different Redis collections
  /// within a single application.
  final String? prefix;

  RedisService(this.respCommands, {this.prefix});

  String? _applyPrefix(String? id) => prefix == null ? id : '$prefix:$id';

  @override
  Future<List<Map<String, dynamic>>> index(
      [Map<String, dynamic>? params]) async {
    var result =
        //await respCommands.client.writeArrayOfBulk(['KEYS', _applyPrefix('*')]);
        await respCommands.tier1.tier0.execute(['KEYS', _applyPrefix('*')]);
    var keys = result.payload.map((RespType s) => s.payload) as Iterable;
    if (keys.isEmpty) return [];
    //result = await respCommands.client.writeArrayOfBulk(['MGET']..addAll(keys));
    result = await respCommands.tier1.tier0.execute(['MGET', ...keys]);

    if (result.isArray) {
      return (result as List<RespType>)
          .map<Map<String, dynamic>>((RespType s) =>
              json.decode(s.payload as String) as Map<String, dynamic>)
          .toList();
    } else {
      // TODO: To be reviewed for handling none array objects
      return [json.decode(result.payload as String) as Map<String, dynamic>];
    }
  }

  @override
  Future<Map<String, dynamic>> read(String id,
      [Map<String, dynamic>? params]) async {
    var value = await respCommands.get(_applyPrefix(id)!);

    if (value == null) {
      throw AngelHttpException.notFound(message: 'No record found for ID $id');
    } else {
      return json.decode(value) as Map<String, dynamic>;
    }
  }

  @override
  Future<Map<String, dynamic>> create(Map<String, dynamic>? data,
      [Map<String, dynamic>? params]) async {
    String? id;
    if (data!['id'] != null) {
      id = data['id'] as String?;
    } else {
      var keyVar = await respCommands.tier1.tier0
          .execute(['INCR', _applyPrefix('angel_redis:id')]);
      id = keyVar.payload.toString();
      data = Map<String, dynamic>.from(data)..['id'] = id;
    }

    await respCommands.set(_applyPrefix(id)!, json.encode(data));
    return data;
  }

  @override
  Future<Map<String, dynamic>> modify(String id, Map<String, dynamic>? data,
      [Map<String, dynamic>? params]) async {
    var input = await (read(id));
    input.addAll(data!);
    return await update(id, input, params);
  }

  @override
  Future<Map<String, dynamic>> update(String id, Map<String, dynamic>? data,
      [Map<String, dynamic>? params]) async {
    data = Map<String, dynamic>.from(data!)..['id'] = id;
    await respCommands.set(_applyPrefix(id)!, json.encode(data));
    return data;
  }

  @override
  Future<Map<String, dynamic>> remove(String id,
      [Map<String, dynamic>? params]) async {
    var client = respCommands.tier1.tier0;
    await client.execute(['MULTI']);
    await client.execute(['GET', _applyPrefix(id)]);
    await client.execute(['DEL', _applyPrefix(id)]);
    var result = await client.execute(['EXEC']);
    var str = result.payload[0] as RespBulkString;

    if (str.payload == null) {
      throw AngelHttpException.notFound(message: 'No record found for ID $id');
    } else {
      return json.decode(str.payload!) as Map<String, dynamic>;
    }
  }
}