Add basic UI to download a file

storage-api/src/main/java/com/omh/android/storage/api/async/OmhStorageTaskImpl.kt

@@ -31,7 +31,7 @@ internal class OmhStorageTaskImpl<T>(private val task: suspend () -> OmhResult<T
     }
 
     private suspend fun executeFailure(e: Exception) = withContext(Dispatchers.Main) {
-        onFailure?.invoke(e)
+        onFailure?.invoke(e).also { e.printStackTrace() }
     }
 
     private suspend fun executeSuccess(data: T) {

storage-sample/src/main/AndroidManifest.xml

@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+
     <application
         android:name=".AndroidApplication"
         android:allowBackup="true"

storage-sample/src/main/java/com/omh/android/storage/sample/presentation/file_viewer/FileViewerActivity.kt

@@ -1,8 +1,10 @@
 package com.omh.android.storage.sample.presentation.file_viewer
 
+import android.Manifest
 import android.content.Context
 import android.content.DialogInterface
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.net.Uri
 import android.os.Bundle
 import android.view.Menu
@@ -15,6 +17,7 @@ import androidx.activity.result.ActivityResultLauncher
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.activity.viewModels
 import androidx.appcompat.app.AlertDialog
+import androidx.core.content.ContextCompat
 import androidx.documentfile.provider.DocumentFile
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.LinearLayoutManager
@@ -43,6 +46,7 @@ class FileViewerActivity :
     private var filesAdapter: FileAdapter? = null
     private lateinit var onBackPressedCallback: OnBackPressedCallback
     private lateinit var filePicker: ActivityResultLauncher<String>
+    private lateinit var requestPermissionLauncher: ActivityResultLauncher<Array<String>>
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -63,6 +67,25 @@ class FileViewerActivity :
                 showUploadFileDialog(validUri)
             }
         }
+
+        requestPermissionLauncher = registerForActivityResult(
+            ActivityResultContracts.RequestMultiplePermissions()
+        ) { permissions: Map<String, Boolean> ->
+            val deniedPermissions = mutableListOf<String>()
+
+            permissions.entries.forEach { entry: Map.Entry<String, Boolean> ->
+                val permission = entry.key
+                val isGranted = entry.value
+
+                if (!isGranted) {
+                    deniedPermissions.add(permission)
+                }
+            }
+
+            if (deniedPermissions.isNotEmpty()) {
+                requestPermissions()
+            }
+        }
     }
 
     override fun onResume() {
@@ -104,6 +127,7 @@ class FileViewerActivity :
         is FileViewerViewState.Content -> buildContentState(state)
         is FileViewerViewState.SwapLayoutManager -> buildSwapLayoutManagerState()
         FileViewerViewState.Finish -> buildFinishState()
+        FileViewerViewState.CheckPermissions -> requestPermissions()
     }
 
     private fun buildInitialState() {
@@ -276,4 +300,21 @@ class FileViewerActivity :
 
         dialog.dismiss()
     }
+
+    private fun requestPermissions() {
+        val permissionsToRequest: Array<String> = arrayOf(
+            Manifest.permission.READ_EXTERNAL_STORAGE,
+            Manifest.permission.WRITE_EXTERNAL_STORAGE
+        )
+
+        val permissionsToAsk: Array<String> = permissionsToRequest.filter { permission: String ->
+            ContextCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED
+        }.toTypedArray()
+
+        if (permissionsToAsk.isNotEmpty()) {
+            requestPermissionLauncher.launch(permissionsToAsk)
+        } else {
+            dispatchEvent(FileViewerViewEvent.DownloadFile)
+        }
+    }
 }

storage-sample/src/main/java/com/omh/android/storage/sample/presentation/file_viewer/FileViewerViewEvent.kt

@@ -27,6 +27,11 @@ sealed class FileViewerViewEvent : ViewEvent {
         override fun getEventName() = "FileViewerViewEvent.FileClicked"
     }
 
+    object DownloadFile : FileViewerViewEvent() {
+
+        override fun getEventName() = "FileViewerViewEvent.DownloadFile"
+    }
+
     object BackPressed : FileViewerViewEvent() {
 
         override fun getEventName() = "FileViewerViewEvent.BackPressed"

storage-sample/src/main/java/com/omh/android/storage/sample/presentation/file_viewer/FileViewerViewModel.kt

@@ -3,13 +3,16 @@ package com.omh.android.storage.sample.presentation.file_viewer
 import android.content.Context
 import android.net.Uri
 import com.omh.android.auth.api.OmhAuthClient
+import android.os.Environment
 import com.omh.android.storage.api.OmhStorageClient
 import com.omh.android.storage.api.domain.model.OmhFile
 import com.omh.android.storage.api.domain.model.OmhFileType
+import com.omh.android.storage.api.domain.usecase.DownloadFileUseCaseResult
 import com.omh.android.storage.sample.domain.model.FileType
 import com.omh.android.storage.sample.presentation.BaseViewModel
 import dagger.hilt.android.lifecycle.HiltViewModel
 import java.io.File
+import java.io.FileOutputStream
 import java.util.Stack
 import javax.inject.Inject
 
@@ -36,6 +39,7 @@ class FileViewerViewModel @Inject constructor(
     var isGridLayoutManager = true
     var createFileSelectedType: OmhFileType? = null
     private val parentIdStack = Stack<String>().apply { push(ID_ROOT) }
+    private var lastFileClicked: OmhFile? = null
 
     override fun getInitialState(): FileViewerViewState = FileViewerViewState.Initial
 
@@ -50,6 +54,7 @@ class FileViewerViewModel @Inject constructor(
             is FileViewerViewEvent.DeleteFile -> deleteFileEvent(event)
             is FileViewerViewEvent.UploadFile -> uploadFile(event)
             FileViewerViewEvent.SignOut -> signOut()
+            FileViewerViewEvent.DownloadFile -> downloadFileEvent()
         }
     }
 
@@ -88,7 +93,8 @@ class FileViewerViewModel @Inject constructor(
             parentIdStack.push(fileId)
             refreshFileListEvent()
         } else {
-            // TODO: Implement download file
+            lastFileClicked = file
+            setState(FileViewerViewState.CheckPermissions)
         }
     }
 
@@ -101,6 +107,28 @@ class FileViewerViewModel @Inject constructor(
         }
     }
 
+    private fun downloadFileEvent() {
+        setState(FileViewerViewState.Loading)
+
+        lastFileClicked?.let { file ->
+            val cancellable = omhStorageClient.downloadFile(file.id)
+                .addOnSuccess { data ->
+                    handleDownloadSuccess(data, file)
+                    toastMessage.postValue("${file.name} was successfully downloaded")
+                    refreshFileListEvent()
+                }
+                .addOnFailure {
+                    toastMessage.postValue("ERROR: ${file.name} was NOT downloaded")
+                    refreshFileListEvent()
+                }
+                .execute()
+            cancellableCollector.addCancellable(cancellable)
+        } ?: run {
+            toastMessage.postValue("The file was NOT downloaded")
+            refreshFileListEvent()
+        }
+    }
+
     private fun createFileEvent(event: FileViewerViewEvent.CreateFile) {
         setState(FileViewerViewState.Loading)
         val parentId = parentIdStack.peek()
@@ -196,4 +224,19 @@ class FileViewerViewModel @Inject constructor(
 
         cancellableCollector.addCancellable(cancellable)
     }
+
+    private fun handleDownloadSuccess(
+        result: DownloadFileUseCaseResult,
+        file: OmhFile
+    ) {
+        val bytes = result.outputStream
+        val downloadFolder = Environment
+            .getExternalStoragePublicDirectory(
+                Environment.DIRECTORY_DOWNLOADS
+            )
+        val fileToSave = File(downloadFolder, file.name)
+        val fileOutputStream = FileOutputStream(fileToSave)
+
+        bytes.writeTo(fileOutputStream)
+    }
 }

storage-sample/src/main/java/com/omh/android/storage/sample/presentation/file_viewer/FileViewerViewState.kt

@@ -27,6 +27,11 @@ sealed class FileViewerViewState : ViewState {
 
     object Finish : FileViewerViewState() {
 
-        override fun getName() = "Finish.SwapLayoutManager"
+        override fun getName() = "FileViewerViewState.Finish"
+    }
+
+    object CheckPermissions : FileViewerViewState() {
+
+        override fun getName() = "FileViewerViewState.CheckPermissions"
     }
 }