Removal of api key

Network calls,
integration of retrofit api
added backup api

lib/data/network/backupCurrencyApi.dart

@@ -0,0 +1,35 @@
+import 'package:dio/dio.dart';
+import 'package:json_annotation/json_annotation.dart';
+import 'package:retrofit/retrofit.dart';
+
+import '../model/Currency.dart';
+
+part 'backupCurrencyApi.g.dart';
+
+@RestApi(baseUrl: "https://api.frankfurter.app/")
+abstract class BackupCurrencyApi {
+  factory BackupCurrencyApi(Dio dio, {String baseUrl}) = _BackupCurrencyApi;
+
+  @GET("latest?")
+  Future<HttpResponse<CurrencyResponse>> getCurrencyRate(@Query("from") String currencyFrom,
+      @Query("to") String currencyTo);
+}
+
+@JsonSerializable()
+class CurrencyResponse implements Mapper{
+  String? data;
+  double amount;
+  Map<String, double>? rates;
+  String? base;
+
+  CurrencyResponse(this.data, this.amount, this.rates, this.base);
+
+  factory CurrencyResponse.fromJson(Map<String, dynamic> json) => _$CurrencyResponseFromJson(json);
+  Map<String, dynamic> toJson() => _$CurrencyResponseToJson(this);
+
+  @override
+  Currency convert() {
+    MapEntry<String, double>? entry = rates?.entries.elementAt(0);
+    return Currency(base, entry?.key, entry?.value);
+  }
+}

lib/data/network/currencyApi.dart

@@ -0,0 +1,54 @@
+import 'package:dio/dio.dart';
+import 'package:json_annotation/json_annotation.dart';
+import 'package:retrofit/retrofit.dart';
+
+import '../model/Currency.dart';
+
+part 'currencyApi.g.dart';
+
+@RestApi(baseUrl: "https://free.currencyconverterapi.com/api/v3/")
+abstract class CurrencyApi {
+  factory CurrencyApi(Dio dio, {String baseUrl}) = _CurrencyApi;
+
+  @GET("/convert?")
+  Future<HttpResponse<ResponseObject>> getConversion(@Query("apiKey") String apiKey, @Query("q") String currency);
+}
+
+@JsonSerializable()
+class ResponseObject implements Mapper{
+  dynamic query;
+  Map<String, CurrencyObject>? results;
+
+  ResponseObject({
+    this.query,
+    this.results
+  });
+
+  factory ResponseObject.fromJson(Map<String, dynamic> json) => _$ResponseObjectFromJson(json);
+  Map<String, dynamic> toJson() => _$ResponseObjectToJson(this);
+
+  @override
+  Currency convert() {
+    CurrencyObject? cur = results?.entries.elementAt(0).value;
+    return Currency(cur?.fr, cur?.to, cur?.val);
+  }
+  
+}
+
+@JsonSerializable()
+class CurrencyObject{
+  String? id;
+  String? fr;
+  String? to;
+  double? val;
+
+  CurrencyObject({
+    this.id,
+    this.fr,
+    this.to,
+    this.val
+  });
+
+  factory CurrencyObject.fromJson(Map<String, dynamic> json) => _$CurrencyObjectFromJson(json);
+  Map<String, dynamic> toJson() => _$CurrencyObjectToJson(this);
+}

lib/data/network/safeApiCall.dart

@@ -0,0 +1,30 @@
+import 'dart:io';
+
+import 'package:dio/dio.dart';
+import 'package:retrofit/retrofit.dart';
+
+import '../../main.dart';
+
+mixin SafeApiCall {
+  Future<T> getDataFromApiCall<T>(Future<HttpResponse<T>> apiCall) async {
+    try {
+      HttpResponse<T> httpResponse = await apiCall;
+      return httpResponse.data;
+    } on DioError catch(dioError) {
+      Map<String, dynamic>? errorResponse = dioError.response?.data;
+      String error;
+
+      if (errorResponse?["error"] != null){
+        error = errorResponse!["error"];
+      } else if (dioError.error != null){
+        error = dioError.error;
+      } else {
+        error = "Failed to retrieve data from api";
+      }
+
+      logger.e(dioError.error);
+
+      throw HttpException(error);
+    }
+  }
+}