Add FileSaverLauncher to desktop

calf-file-picker/src/desktopMain/kotlin/com/mohamedrejeb/calf/picker/FileSaverLauncher.desktop.kt

@@ -0,0 +1,50 @@
+package com.mohamedrejeb.calf.picker
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.rememberUpdatedState
+import com.mohamedrejeb.calf.io.KmpFile
+import com.mohamedrejeb.calf.picker.platform.awt.AwtFileSaver
+import kotlinx.coroutines.launch
+
+@Composable
+fun rememberFileSaverLauncher(
+    bytes: ByteArray?,
+    baseName: String,
+    extension: String,
+    initialDirectory: String?,
+    onResult: (KmpFile?) -> Unit,
+): FileSaverLauncher {
+    val scope = rememberCoroutineScope()
+
+    val currentBytes by rememberUpdatedState(bytes)
+    val currentBaseName by rememberUpdatedState(baseName)
+    val currentExtension by rememberUpdatedState(extension)
+    val currentInitialDirectory by rememberUpdatedState(initialDirectory)
+    val currentOnResult by rememberUpdatedState(onResult)
+
+    return FileSaverLauncher(
+        onLaunch = {
+            scope.launch {
+                val file = AwtFileSaver.saveFile(
+                    bytes = currentBytes,
+                    baseName = currentBaseName,
+                    extension = currentExtension,
+                    initialDirectory = currentInitialDirectory,
+                    parentWindow = null,
+                )
+
+                currentOnResult(file)
+            }
+        }
+    )
+}
+
+class FileSaverLauncher(
+    private val onLaunch: () -> Unit,
+) {
+    fun launch() {
+        onLaunch()
+    }
+}

calf-file-picker/src/desktopMain/kotlin/com/mohamedrejeb/calf/picker/platform/awt/AwtFileSaver.kt

@@ -0,0 +1,60 @@
+package com.mohamedrejeb.calf.picker.platform.awt
+
+import com.mohamedrejeb.calf.io.KmpFile
+import kotlinx.coroutines.suspendCancellableCoroutine
+import java.awt.Dialog
+import java.awt.FileDialog
+import java.awt.Frame
+import java.awt.Window
+import java.io.File
+import kotlin.coroutines.resume
+
+internal object AwtFileSaver {
+    suspend fun saveFile(
+        bytes: ByteArray?,
+        baseName: String,
+        extension: String,
+        initialDirectory: String?,
+        parentWindow: Window?,
+    ): KmpFile? = suspendCancellableCoroutine { continuation ->
+        fun handleResult(value: Boolean, files: Array<File>?) {
+            if (value) {
+                val file = files?.firstOrNull()?.let { file ->
+                    // Write bytes to file, or create a new file
+                    bytes?.let { file.writeBytes(bytes) } ?: file.createNewFile()
+                    KmpFile(file)
+                }
+                continuation.resume(file)
+            }
+        }
+
+        // Handle parentWindow: Dialog, Frame, or null
+        val dialog = when (parentWindow) {
+            is Dialog -> object : FileDialog(parentWindow, "Save dialog", SAVE) {
+                override fun setVisible(value: Boolean) {
+                    super.setVisible(value)
+                    handleResult(value, files)
+                }
+            }
+
+            else -> object : FileDialog(parentWindow as? Frame, "Save dialog", SAVE) {
+                override fun setVisible(value: Boolean) {
+                    super.setVisible(value)
+                    handleResult(value, files)
+                }
+            }
+        }
+
+        // Set initial directory
+        dialog.directory = initialDirectory
+
+        // Set file name
+        dialog.file = "$baseName.$extension"
+
+        // Show the dialog
+        dialog.isVisible = true
+
+        // Dispose the dialog when the continuation is cancelled
+        continuation.invokeOnCancellation { dialog.dispose() }
+    }
+}