add file drag and drop to external app

desktop/app/src/main/kotlin/com/abdownloadmanager/desktop/pages/home/DownloadItemListDataFlavor.kt

@@ -0,0 +1,47 @@
+package com.abdownloadmanager.desktop.pages.home
+
+import ir.amirab.downloader.monitor.IDownloadItemState
+import java.awt.datatransfer.DataFlavor
+import java.awt.datatransfer.Transferable
+import java.awt.datatransfer.UnsupportedFlavorException
+import java.io.File
+
+val DownloadItemListDataFlavor = DataFlavor(
+    IDownloadItemState::class.java,
+    "Download Item"
+)
+
+class DownloadItemTransferable(
+    val items: List<IDownloadItemState>,
+) : Transferable {
+    override fun getTransferDataFlavors(): Array<DataFlavor> {
+        return arrayOf(
+            DataFlavor.javaFileListFlavor,
+            DataFlavor.stringFlavor,
+            DownloadItemListDataFlavor,
+        )
+    }
+
+    override fun isDataFlavorSupported(flavor: DataFlavor?): Boolean {
+        return (flavor in arrayOf(
+            DataFlavor.javaFileListFlavor,
+            DataFlavor.stringFlavor,
+            DownloadItemListDataFlavor,
+        ))
+    }
+
+    override fun getTransferData(flavor: DataFlavor?): Any {
+        return when (flavor) {
+            DataFlavor.javaFileListFlavor -> items.map {
+                File(it.folder, it.name)
+            }
+
+            DataFlavor.stringFlavor -> items.map {
+                it.downloadLink
+            }.joinToString("\n")
+
+            DownloadItemListDataFlavor -> items
+            else -> throw UnsupportedFlavorException(flavor)
+        }
+    }
+}

desktop/app/src/main/kotlin/com/abdownloadmanager/desktop/pages/home/HomePage.kt

@@ -168,7 +168,10 @@ fun HomePage(component: HomeComponent) {
             .fillMaxSize()
             .dragAndDropTarget(
                 shouldStartDragAndDrop = {
-                    it.awtTransferable.isDataFlavorSupported(DataFlavor.javaFileListFlavor) ||
+                    if (it.awtTransferable.isDataFlavorSupported(DownloadItemListDataFlavor)) {
+                        // this item is ours we don't want to use our download item for import list usage
+                        return@dragAndDropTarget false
+                    } else it.awtTransferable.isDataFlavorSupported(DataFlavor.javaFileListFlavor) ||
                             it.awtTransferable.isDataFlavorSupported(DataFlavor.stringFlavor)
                 },
                 target = remember {

desktop/app/src/main/kotlin/com/abdownloadmanager/desktop/pages/home/sections/DownloadList.kt

@@ -13,18 +13,24 @@ import com.abdownloadmanager.desktop.ui.widget.menu.MenuDisabledItemBehavior
 import com.abdownloadmanager.desktop.ui.widget.menu.ShowOptionsInDropDown
 import ir.amirab.util.compose.action.MenuItem
 import androidx.compose.foundation.*
+import androidx.compose.foundation.draganddrop.dragAndDropSource
+import androidx.compose.foundation.gestures.detectDragGestures
 import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draganddrop.DragAndDropTransferAction
+import androidx.compose.ui.draganddrop.DragAndDropTransferData
+import androidx.compose.ui.draganddrop.DragAndDropTransferable
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.key.*
 import androidx.compose.ui.input.pointer.*
 import androidx.compose.ui.unit.dp
+import com.abdownloadmanager.desktop.pages.home.DownloadItemTransferable
 import com.abdownloadmanager.utils.FileIconProvider
 import com.abdownloadmanager.utils.category.CategoryManager
 import com.abdownloadmanager.utils.category.rememberCategoryOf
@@ -82,8 +88,12 @@ fun DownloadList(
                 it in selectionList
             }
         }
-
     }
+
+    val listToBeDragged by rememberUpdatedState(
+        downloadList.filter { it.id in selectionList }
+    )
+
     val tableInteractionSource = remember { MutableInteractionSource() }
 
     fun newSelection(ids: List<Long>, isSelected: Boolean) {
@@ -110,6 +120,31 @@ fun DownloadList(
             key = { it.id },
             list = downloadList,
             modifier = modifier
+                .dragAndDropSource(
+                    drawDragDecoration = {
+                    },
+                    block = {
+                        detectDragGestures(
+                            onDrag = { _ ->
+                                val selectedDownloads = listToBeDragged
+                                if (selectedDownloads.isEmpty()) {
+                                    return@detectDragGestures
+                                }
+                                startTransfer(
+                                    DragAndDropTransferData(
+                                        transferable = DragAndDropTransferable(
+                                            DownloadItemTransferable(selectedDownloads)
+                                        ),
+                                        supportedActions = listOf(
+                                            // TODO it doesn't work!
+                                            DragAndDropTransferAction.Copy,
+                                        ),
+                                    )
+                                )
+                            }
+                        )
+                    }
+                )
                 .onKeyEvent {
                     val ctrlPressed = it.isCtrlPressed
                     val shiftPressed = it.isShiftPressed
@@ -366,5 +401,4 @@ fun ShowDownloadOptions(
         }
     }
 
-}
-
+}