feature: Extend Resource to have an Error Payload and separate the Er…

app/src/main/java/com/nagpal/shivam/vtucslab/core/ErrorType.kt

@@ -1,6 +1,6 @@
 package com.nagpal.shivam.vtucslab.core
 
-sealed class ErrorType {
-    object NoActiveInternetConnection : ErrorType()
-    object SomeErrorOccurred : ErrorType()
+enum class ErrorType {
+    NoActiveInternetConnection,
+    SomeErrorOccurred,
 }

app/src/main/java/com/nagpal/shivam/vtucslab/core/Resource.kt

@@ -1,7 +1,7 @@
 package com.nagpal.shivam.vtucslab.core
 
-sealed class Resource<T> {
-    class Loading<T>(val data: T? = null) : Resource<T>()
-    class Success<T>(val data: T?) : Resource<T>()
-    class Error<T>(val errorType: ErrorType? = null) : Resource<T>()
+sealed class Resource<D, E> {
+    class Loading<D, E>(val data: D? = null) : Resource<D, E>()
+    class Success<D, E>(val data: D?) : Resource<D, E>()
+    class Error<D, E>(val error: E) : Resource<D, E>()
 }

app/src/main/java/com/nagpal/shivam/vtucslab/core/UIMessage.kt

@@ -0,0 +1,3 @@
+package com.nagpal.shivam.vtucslab.core
+
+data class UIMessage(val messageType: UIMessageType, val args: List<Any> = emptyList())

app/src/main/java/com/nagpal/shivam/vtucslab/core/UIMessageType.kt

@@ -0,0 +1,6 @@
+package com.nagpal.shivam.vtucslab.core
+
+enum class UIMessageType {
+    NoActiveInternetConnection,
+    SomeErrorOccurred,
+}

app/src/main/java/com/nagpal/shivam/vtucslab/repositories/VtuCsLabRepository.kt

@@ -1,14 +1,15 @@
 package com.nagpal.shivam.vtucslab.repositories
 
+import com.nagpal.shivam.vtucslab.core.ErrorType
 import com.nagpal.shivam.vtucslab.core.Resource
 import com.nagpal.shivam.vtucslab.models.LaboratoryExperimentResponse
 import com.nagpal.shivam.vtucslab.models.LaboratoryResponse
 import kotlinx.coroutines.flow.Flow
 
 interface VtuCsLabRepository {
-    fun fetchLaboratories(url: String): Flow<Resource<LaboratoryResponse>>
+    fun fetchLaboratories(url: String): Flow<Resource<LaboratoryResponse, ErrorType>>
 
-    fun fetchExperiments(url: String): Flow<Resource<LaboratoryExperimentResponse>>
+    fun fetchExperiments(url: String): Flow<Resource<LaboratoryExperimentResponse, ErrorType>>
 
-    fun fetchContent(url: String): Flow<Resource<String>>
+    fun fetchContent(url: String): Flow<Resource<String, ErrorType>>
 }

app/src/main/java/com/nagpal/shivam/vtucslab/repositories/VtuCsLabRepositoryImpl.kt

@@ -16,31 +16,32 @@ import kotlinx.coroutines.flow.flow
 private val LOG_TAG: String = VtuCsLabRepositoryImpl::class.java.name
 
 class VtuCsLabRepositoryImpl(
-    val application: Application,
+    private val application: Application,
     private val vtuCsLabService: VtuCsLabService
 ) : VtuCsLabRepository {
-    override fun fetchLaboratories(url: String): Flow<Resource<LaboratoryResponse>> = flow {
-        fetch(url) {
-            vtuCsLabService.getLaboratoryResponse(it)
+    override fun fetchLaboratories(url: String): Flow<Resource<LaboratoryResponse, ErrorType>> =
+        flow {
+            fetch(url) {
+                vtuCsLabService.getLaboratoryResponse(it)
+            }
         }
-    }
 
-    override fun fetchExperiments(url: String): Flow<Resource<LaboratoryExperimentResponse>> =
+    override fun fetchExperiments(url: String): Flow<Resource<LaboratoryExperimentResponse, ErrorType>> =
         flow {
             fetch(url) {
                 vtuCsLabService.getLaboratoryExperimentsResponse(it)
             }
         }
 
-    override fun fetchContent(url: String): Flow<Resource<String>> = flow {
+    override fun fetchContent(url: String): Flow<Resource<String, ErrorType>> = flow {
         fetch(url) {
             vtuCsLabService.fetchRawResponse(it)
         }
     }
 
-    private suspend fun <T : Any> FlowCollector<Resource<T>>.fetch(
+    private suspend fun <D : Any> FlowCollector<Resource<D, ErrorType>>.fetch(
         url: String,
-        executable: suspend (String) -> ApiResult<T>
+        executable: suspend (String) -> ApiResult<D>
     ) {
         emit(Resource.Loading())
         if (!NetworkUtils.isNetworkConnected(application)) {
@@ -53,11 +54,11 @@ class VtuCsLabRepositoryImpl(
             }
             is ApiResult.ApiError -> {
                 StaticMethods.logNetworkResultError(LOG_TAG, url, apiResult.code, apiResult.message)
-                emit(Resource.Error())
+                emit(Resource.Error(ErrorType.SomeErrorOccurred))
             }
             is ApiResult.ApiException -> {
                 StaticMethods.logNetworkResultException(LOG_TAG, url, apiResult.throwable)
-                emit(Resource.Error())
+                emit(Resource.Error(ErrorType.SomeErrorOccurred))
             }
         }
     }

app/src/main/java/com/nagpal/shivam/vtucslab/screens/ContentState.kt

@@ -1,10 +1,10 @@
 package com.nagpal.shivam.vtucslab.screens
 
-import com.nagpal.shivam.vtucslab.core.ErrorType
+import com.nagpal.shivam.vtucslab.core.UIMessage
 
 data class ContentState<T>(
     val stage: String,
     val data: T? = null,
-    val errorType: ErrorType? = null,
+    val errorMessage: UIMessage? = null,
     val baseUrl: String? = null,
 )

app/src/main/java/com/nagpal/shivam/vtucslab/screens/Utils.kt

@@ -4,6 +4,8 @@ import android.content.Context
 import com.nagpal.shivam.vtucslab.R
 import com.nagpal.shivam.vtucslab.core.ErrorType
 import com.nagpal.shivam.vtucslab.core.Resource
+import com.nagpal.shivam.vtucslab.core.UIMessage
+import com.nagpal.shivam.vtucslab.core.UIMessageType
 import com.nagpal.shivam.vtucslab.utilities.Stages
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -16,7 +18,7 @@ object Utils {
         uiStateFlow: MutableStateFlow<ContentState<T>>,
         fetchJob: Job?,
         viewModelScope: CoroutineScope,
-        fetchExecutable: (String) -> Flow<Resource<T>>,
+        fetchExecutable: (String) -> Flow<Resource<T, ErrorType>>,
         getBaseUrl: (T) -> String?,
         url: String
     ): Job? {
@@ -43,9 +45,13 @@ object Utils {
                         }
                         is Resource.Error -> {
                             uiStateFlow.update {
+                                val uiMessage: UIMessage = when (resource.error) {
+                                    ErrorType.NoActiveInternetConnection -> UIMessage(UIMessageType.NoActiveInternetConnection)
+                                    ErrorType.SomeErrorOccurred -> UIMessage(UIMessageType.SomeErrorOccurred)
+                                }
                                 ContentState(
                                     Stages.FAILED,
-                                    errorType = resource.errorType,
+                                    errorMessage = uiMessage,
                                 )
                             }
                         }
@@ -61,10 +67,11 @@ object Utils {
         uiStateFlow.update { initialState }
     }
 
-    fun mapErrorTypeToString(context: Context, errorType: ErrorType?): String {
-        return when (errorType) {
-            ErrorType.NoActiveInternetConnection -> context.getString(R.string.no_internet_connection)
-            else -> context.getString(R.string.error_occurred)
+    fun UIMessage?.asString(context: Context): String {
+        return when (this?.messageType) {
+            UIMessageType.NoActiveInternetConnection -> context.getString(R.string.no_internet_connection)
+            UIMessageType.SomeErrorOccurred -> context.getString(R.string.error_occurred)
+            null -> context.getString(R.string.error_occurred)
         }
     }
 }

app/src/main/java/com/nagpal/shivam/vtucslab/screens/display/DisplayFragment.kt

@@ -18,7 +18,7 @@ import androidx.navigation.fragment.navArgs
 import com.nagpal.shivam.vtucslab.R
 import com.nagpal.shivam.vtucslab.databinding.FragmentDisplayBinding
 import com.nagpal.shivam.vtucslab.screens.UiEvent
-import com.nagpal.shivam.vtucslab.screens.Utils
+import com.nagpal.shivam.vtucslab.screens.Utils.asString
 import com.nagpal.shivam.vtucslab.utilities.Constants
 import com.nagpal.shivam.vtucslab.utilities.Stages
 import kotlinx.coroutines.launch
@@ -59,8 +59,7 @@ class DisplayFragment : Fragment() {
                             }, 500)
                         }
                         Stages.FAILED -> {
-                            val message: String =
-                                Utils.mapErrorTypeToString(requireContext(), it.errorType)
+                            val message: String = it.errorMessage.asString(requireContext())
                             showErrorMessage(message)
                         }
                     }

app/src/main/java/com/nagpal/shivam/vtucslab/screens/programs/ProgramFragment.kt

@@ -16,7 +16,7 @@ import com.nagpal.shivam.vtucslab.adapters.ContentAdapter
 import com.nagpal.shivam.vtucslab.databinding.FragmentProgramBinding
 import com.nagpal.shivam.vtucslab.models.ContentFile
 import com.nagpal.shivam.vtucslab.screens.UiEvent
-import com.nagpal.shivam.vtucslab.screens.Utils
+import com.nagpal.shivam.vtucslab.screens.Utils.asString
 import com.nagpal.shivam.vtucslab.utilities.Stages
 import kotlinx.coroutines.launch
 
@@ -57,8 +57,7 @@ class ProgramFragment : Fragment() {
                             }
                         }
                         Stages.FAILED -> {
-                            val message: String =
-                                Utils.mapErrorTypeToString(requireContext(), it.errorType)
+                            val message: String = it.errorMessage.asString(requireContext())
                             showErrorMessage(message)
                         }
                     }

app/src/main/java/com/nagpal/shivam/vtucslab/screens/repository/RepositoryFragment.kt

@@ -17,7 +17,7 @@ import com.nagpal.shivam.vtucslab.adapters.NavigationAdapter
 import com.nagpal.shivam.vtucslab.databinding.FragmentRepositoryBinding
 import com.nagpal.shivam.vtucslab.models.Laboratory
 import com.nagpal.shivam.vtucslab.screens.UiEvent
-import com.nagpal.shivam.vtucslab.screens.Utils
+import com.nagpal.shivam.vtucslab.screens.Utils.asString
 import com.nagpal.shivam.vtucslab.utilities.Constants
 import com.nagpal.shivam.vtucslab.utilities.Stages
 import kotlinx.coroutines.launch
@@ -57,8 +57,7 @@ class RepositoryFragment : Fragment() {
                             }
                         }
                         Stages.FAILED -> {
-                            val message: String =
-                                Utils.mapErrorTypeToString(requireContext(), it.errorType)
+                            val message: String = it.errorMessage.asString(requireContext())
                             showErrorMessage(message)
                         }
                     }