Added Currency converter API

app/src/main/java/com/example/jetpack_compose_all_in_one/demos/currency_converter/data/dto/CurrencyResponse.kt

@@ -1,6 +1,12 @@
 package com.example.jetpack_compose_all_in_one.demos.currency_converter.data.dto
 
+/**
+ * Represents a response containing currency data.
+ *
+ * @property date The date of the response.
+ * @property jpy The Japanese Yen value in the response.
+ */
 data class CurrencyResponse(
-    val date: String,
-    val jpy: Double
-)
+    val date: String, // Date of the response
+    val jpy: Double   // Japanese Yen value in the response
+)

app/src/main/java/com/example/jetpack_compose_all_in_one/demos/currency_converter/data/repository/CurrencyRepository.kt

@@ -2,6 +2,16 @@ package com.example.jetpack_compose_all_in_one.demos.currency_converter.data.rep
 
 import com.example.jetpack_compose_all_in_one.demos.currency_converter.data.dto.CurrencyResponse
 
+/**
+ * Interface representing a currency repository.
+ * Implementations of this interface provide methods to fetch currency exchange rates.
+ */
 interface CurrencyRepository {
+    /**
+     * Asynchronously retrieves the exchange rate from Euro (EUR) to Japanese Yen (JPY).
+     *
+     * @return [Result] object containing the [CurrencyResponse] if the operation is successful,
+     *         or an error if the operation fails.
+     */
     suspend fun getEURToJPY(): Result<CurrencyResponse>
-}
+}

app/src/main/java/com/example/jetpack_compose_all_in_one/demos/currency_converter/data/repository/CurrencyRepositoryImpl.kt

@@ -4,17 +4,37 @@ import com.example.jetpack_compose_all_in_one.demos.currency_converter.data.api.
 import com.example.jetpack_compose_all_in_one.demos.currency_converter.data.dto.CurrencyResponse
 import javax.inject.Inject
 
-class CurrencyRepositoryImpl @Inject constructor(private val apiService: CurrencyApiService) : CurrencyRepository {
+
+/**
+ * Implementation of [CurrencyRepository] interface.
+ * This class is responsible for fetching currency exchange rates.
+ *
+ * @param apiService The API service used to make network calls for currency data.
+ */
+class CurrencyRepositoryImpl @Inject constructor(private val apiService: CurrencyApiService) :
+    CurrencyRepository {
+
+    /**
+     * Asynchronously retrieves the exchange rate from Euro (EUR) to Japanese Yen (JPY).
+     *
+     * @return [Result] object containing the [CurrencyResponse] if the operation is successful,
+     *         or an error if the operation fails.
+     */
     override suspend fun getEURToJPY(): Result<CurrencyResponse> {
         return try {
+            // Make the network call to fetch EUR to JPY exchange rate
             val response = apiService.getEURToJPY()
+            // Check if the response is successful and contains data
             if (response.isSuccessful && response.body() != null) {
+                // If successful, return the currency response wrapped in a success Result
                 Result.success(response.body()!!)
             } else {
+                // If response is not successful or does not contain data, return a failure Result
                 Result.failure(RuntimeException("Failed to fetch data"))
             }
         } catch (e: Exception) {
+            // If an exception occurs during the operation, return a failure Result with the exception
             Result.failure(e)
         }
     }
-}
+}

app/src/main/java/com/example/jetpack_compose_all_in_one/demos/currency_converter/di/NetworkModule.kt

@@ -8,17 +8,26 @@ import dagger.hilt.components.SingletonComponent
 import retrofit2.Retrofit
 import retrofit2.converter.gson.GsonConverterFactory
 
+/**
+ * Dagger Hilt module for providing network-related dependencies.
+ * This module provides the implementation of the [CurrencyApiService].
+ */
 @InstallIn(SingletonComponent::class)
 @Module
 object NetworkModule {
 
+    /**
+     * Provides an instance of [CurrencyApiService] for making network calls related to currency data.
+     *
+     * @return An instance of [CurrencyApiService].
+     */
     @Provides
-    fun provideApiService() : CurrencyApiService {
+    fun provideApiService(): CurrencyApiService {
+        // Configure and build Retrofit instance
         return Retrofit.Builder()
-            .baseUrl("https://cdn.jsdelivr.net")
-            .addConverterFactory(GsonConverterFactory.create())
+            .baseUrl("https://cdn.jsdelivr.net") // Base URL for the API
+            .addConverterFactory(GsonConverterFactory.create()) // Gson converter factory for JSON serialization
             .build()
-            .create(CurrencyApiService::class.java)
-
+            .create(CurrencyApiService::class.java) // Create an instance of CurrencyApiService interface
     }
-}
+}