FolderPickerActivity: disable copy/move to the same folder

It's a no-op anyways, right now, and causes bad UX

Signed-off-by: Álvaro Brey <alvaro.brey@nextcloud.com>

app/src/main/java/com/owncloud/android/ui/activity/FolderPickerActivity.kt

@@ -74,6 +74,9 @@ open class FolderPickerActivity :
     private var mChooseBtn: MaterialButton? = null
     private var caption: String? = null
 
+    private var mAction: String? = null
+    private var mTargetFilePaths: ArrayList<String>? = null
+
     @Inject
     lateinit var localBroadcastManager: LocalBroadcastManager
 
@@ -95,8 +98,9 @@ open class FolderPickerActivity :
             View.VISIBLE
         findViewById<View>(R.id.switch_grid_view_button).visibility =
             View.GONE
-        if (intent.getStringExtra(EXTRA_ACTION) != null) {
-            when (intent.getStringExtra(EXTRA_ACTION)) {
+        mAction = intent.getStringExtra(EXTRA_ACTION)
+        if (mAction != null) {
+            when (mAction) {
                 MOVE -> {
                     caption = resources.getText(R.string.move_to).toString()
                     mSearchOnlyFolders = true
@@ -118,6 +122,7 @@ open class FolderPickerActivity :
         } else {
             caption = themeUtils.getDefaultDisplayNameForRootFolder(this)
         }
+        mTargetFilePaths = intent.getStringArrayListExtra(EXTRA_FILE_PATHS)
         if (intent.getParcelableExtra<Parcelable?>(EXTRA_CURRENT_FOLDER) != null) {
             file = intent.getParcelableExtra(EXTRA_CURRENT_FOLDER)
         }
@@ -146,7 +151,7 @@ open class FolderPickerActivity :
             val listOfFolders = listOfFilesFragment
             listOfFolders!!.listDirectory(folder, false, false)
             startSyncFolderOperation(folder, false)
-            updateNavigationElementsInActionBar()
+            updateUiElements()
         }
     }
 
@@ -205,7 +210,7 @@ open class FolderPickerActivity :
      */
     override fun onBrowsedDownTo(directory: OCFile) {
         file = directory
-        updateNavigationElementsInActionBar()
+        updateUiElements()
         // Sync Folder
         startSyncFolderOperation(directory, false)
     }
@@ -241,6 +246,8 @@ open class FolderPickerActivity :
         // refresh list of files
         refreshListOfFilesFragment(false)
 
+        updateUiElements()
+
         // Listen for sync messages
         val syncIntentFilter = IntentFilter(FileSyncAdapter.EVENT_FULL_SYNC_START)
         syncIntentFilter.addAction(FileSyncAdapter.EVENT_FULL_SYNC_END)
@@ -317,7 +324,7 @@ open class FolderPickerActivity :
             val root = storageManager.getFileByPath(OCFile.ROOT_PATH)
             listOfFiles.listDirectory(root, false, false)
             file = listOfFiles.currentFile
-            updateNavigationElementsInActionBar()
+            updateUiElements()
             startSyncFolderOperation(root, false)
         }
     }
@@ -331,10 +338,34 @@ open class FolderPickerActivity :
                 return
             }
             file = listOfFiles.currentFile
-            updateNavigationElementsInActionBar()
+            updateUiElements()
         }
     }
 
+    private fun updateUiElements() {
+        toggleChooseEnabled()
+        updateNavigationElementsInActionBar()
+    }
+
+    private fun toggleChooseEnabled() {
+        mChooseBtn?.isEnabled = checkFolderSelectable()
+    }
+
+    // for copy and move, disable selecting parent folder of target files
+    private fun checkFolderSelectable(): Boolean {
+        return when {
+            mAction != COPY && mAction != MOVE -> true
+            mTargetFilePaths.isNullOrEmpty() -> true
+            file?.isFolder != true -> true
+            // only disable if ALL target files are in selected folder
+            else -> mTargetFilePaths!!.any { !isParentFolder(file.remotePath, it) }
+        }
+    }
+
+    private fun isParentFolder(folderPath: String, filePath: String): Boolean {
+        return folderPath == File(filePath).parent
+    }
+
     private fun updateNavigationElementsInActionBar() {
         val currentDir = currentFolder
         val actionBar = supportActionBar
@@ -378,9 +409,8 @@ open class FolderPickerActivity :
             if (targetFiles != null) {
                 resultData.putParcelableArrayListExtra(EXTRA_FILES, targetFiles)
             }
-            val targetFilePaths = i.getStringArrayListExtra(EXTRA_FILE_PATHS)
-            if (targetFilePaths != null) {
-                resultData.putStringArrayListExtra(EXTRA_FILE_PATHS, targetFilePaths)
+            mTargetFilePaths.let {
+                resultData.putStringArrayListExtra(EXTRA_FILE_PATHS, it)
             }
             setResult(RESULT_OK, resultData)
             finish()