feat: allow copying multiple messages (#601)

Refs: https://github.com/FossifyOrg/Messages/issues/600

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Ability to select and copy multiple text messages at once ([#600])
 
 ## [1.6.0] - 2025-10-29
 ### Changed
@@ -200,6 +202,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [#561]: https://github.com/FossifyOrg/Messages/issues/561
 [#562]: https://github.com/FossifyOrg/Messages/issues/562
 [#574]: https://github.com/FossifyOrg/Messages/issues/574
+[#600]: https://github.com/FossifyOrg/Messages/issues/600
 
 [Unreleased]: https://github.com/FossifyOrg/Messages/compare/1.6.0...HEAD
 [1.6.0]: https://github.com/FossifyOrg/Messages/compare/1.5.0...1.6.0

app/src/main/kotlin/org/fossify/messages/adapters/ThreadAdapter.kt

@@ -115,14 +115,14 @@ class ThreadAdapter(
 
     override fun prepareActionMode(menu: Menu) {
         val isOneItemSelected = isOneItemSelected()
-        val selectedItem = getSelectedItems().firstOrNull() as? Message
-        val hasText = selectedItem?.body != null && selectedItem.body != ""
+        val selectedMessages = getSelectedItems().filterIsInstance<Message>()
+        val hasText = selectedMessages.any { it.body.isNotEmpty() }
         val showSaveAs = getSelectedItems().all {
             it is Message && (it.attachment?.attachments?.size ?: 0) > 0
         } && getSelectedAttachments().isNotEmpty()
 
         menu.apply {
-            findItem(R.id.cab_copy_to_clipboard).isVisible = isOneItemSelected && hasText
+            findItem(R.id.cab_copy_to_clipboard).isVisible = hasText
             findItem(R.id.cab_save_as).isVisible = showSaveAs
             findItem(R.id.cab_share).isVisible = isOneItemSelected && hasText
             findItem(R.id.cab_forward_message).isVisible = isOneItemSelected
@@ -219,8 +219,14 @@ class ThreadAdapter(
     }
 
     private fun copyToClipboard() {
-        val firstItem = getSelectedItems().firstOrNull() as? Message ?: return
-        activity.copyToClipboard(firstItem.body)
+        val selectedMessages = getSelectedItems().filterIsInstance<Message>()
+        val textToCopy = selectedMessages
+            .mapNotNull { message -> message.body.takeIf { it.isNotEmpty() } }
+            .joinToString("\n\n")
+        
+        if (textToCopy.isNotEmpty()) {
+            activity.copyToClipboard(textToCopy)
+        }
     }
 
     private fun getSelectedAttachments(): List<Attachment> {