Send attachments

- Compose gains an "Attach file" picker (OpenMultipleDocuments) and shows each pick as
  a removable chip; OutgoingMessage carries the picked URIs.
- On send the repository copies the picked files into the outbox message's own cache
  directory; SendWorker passes them to SmtpSender, which builds a multipart message
  (text body + a part per file via attachFile). Files are cleaned up on success/cancel.
- assemble/test/lint green, including a new SmtpSender test that sends an attachment and
  asserts GreenMail received a multipart message containing it; the compose "Attach file"
  affordance verified on the Android 17 emulator.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/kotlin/org/libremail/data/repository/MailRepositoryImpl.kt

@@ -2,6 +2,7 @@
 package org.libremail.data.repository
 
 import android.content.Context
+import android.net.Uri
 import dagger.hilt.android.qualifiers.ApplicationContext
 import jakarta.mail.Flags
 import java.io.File
@@ -25,6 +26,7 @@ import org.libremail.domain.model.Attachment
 import org.libremail.domain.model.Draft
 import org.libremail.domain.model.Message
 import org.libremail.domain.model.OutboxMessage
+import org.libremail.domain.model.OutgoingAttachment
 import org.libremail.domain.model.OutgoingMessage
 import org.libremail.domain.repository.MailRepository
 import org.libremail.mail.DownloadedAttachment
@@ -94,9 +96,11 @@ class MailRepositoryImpl @Inject constructor(
     /** Queues the message in the outbox and triggers the send worker; delivery happens in the background. */
     override suspend fun sendMessage(outgoing: OutgoingMessage): Result<Unit> = runCatching {
         requireNotNull(accountDao.getById(outgoing.accountId)) { "Account not found" }
+        val outboxId = UUID.randomUUID().toString()
+        copyAttachments(outboxId, outgoing.attachments)
         outboxDao.insert(
             OutboxEntity(
-                id = UUID.randomUUID().toString(),
+                id = outboxId,
                 accountId = outgoing.accountId,
                 toAddresses = outgoing.to,
                 ccAddresses = outgoing.cc,
@@ -108,6 +112,20 @@ class MailRepositoryImpl @Inject constructor(
         sendScheduler.sendNow()
     }
 
+    /** Copies the picked attachment URIs into the outbox message's own directory for the worker. */
+    private fun copyAttachments(outboxId: String, attachments: List<OutgoingAttachment>) {
+        if (attachments.isEmpty()) return
+        val dir = File(context.cacheDir, "outbox/$outboxId").apply { mkdirs() }
+        attachments.forEach { attachment ->
+            val safeName = attachment.name.substringAfterLast('/').substringAfterLast('\\').ifBlank { "attachment" }
+            runCatching {
+                context.contentResolver.openInputStream(Uri.parse(attachment.uri))?.use { input ->
+                    File(dir, safeName).outputStream().use { output -> input.copyTo(output) }
+                }
+            }
+        }
+    }
+
     override fun observeDrafts(): Flow<List<Draft>> =
         draftDao.observeAll().map { rows -> rows.map { it.toDomain() } }
 
@@ -120,7 +138,10 @@ class MailRepositoryImpl @Inject constructor(
     override fun observeOutbox(): Flow<List<OutboxMessage>> =
         outboxDao.observeAll().map { rows -> rows.map { it.toDomain() } }
 
-    override suspend fun cancelOutboxMessage(id: String) = outboxDao.delete(id)
+    override suspend fun cancelOutboxMessage(id: String) {
+        outboxDao.delete(id)
+        File(context.cacheDir, "outbox/$id").deleteRecursively()
+    }
 
     override suspend fun retryOutbox() = sendScheduler.sendNow()
 

app/src/main/kotlin/org/libremail/data/sync/SendWorker.kt

@@ -7,6 +7,7 @@ import androidx.work.CoroutineWorker
 import androidx.work.WorkerParameters
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedInject
+import java.io.File
 import org.libremail.data.local.dao.AccountDao
 import org.libremail.data.local.dao.OutboxDao
 import org.libremail.data.local.toDomain
@@ -30,9 +31,11 @@ class SendWorker @AssistedInject constructor(
 
         var anyFailed = false
         for (entity in pending) {
+            val attachmentDir = File(applicationContext.cacheDir, "outbox/${entity.id}")
             val account = accountDao.getById(entity.accountId)?.toDomain()
             if (account == null) {
                 outboxDao.delete(entity.id) // account removed — drop the queued message
+                attachmentDir.deleteRecursively()
                 continue
             }
             runCatching {
@@ -46,9 +49,13 @@ class SendWorker @AssistedInject constructor(
                         subject = entity.subject,
                         body = entity.body,
                     ),
+                    attachments = attachmentDir.listFiles()?.toList().orEmpty(),
                 )
             }.fold(
-                onSuccess = { outboxDao.delete(entity.id) },
+                onSuccess = {
+                    outboxDao.delete(entity.id)
+                    attachmentDir.deleteRecursively()
+                },
                 onFailure = { e ->
                     outboxDao.setError(entity.id, e.message)
                     anyFailed = true

app/src/main/kotlin/org/libremail/domain/model/OutgoingMessage.kt

@@ -8,4 +8,11 @@ data class OutgoingMessage(
     val cc: String = "",
     val subject: String,
     val body: String,
+    val attachments: List<OutgoingAttachment> = emptyList(),
+)
+
+/** A file the user attached, referenced by its content-URI string until it is sent. */
+data class OutgoingAttachment(
+    val uri: String,
+    val name: String,
 )

app/src/main/kotlin/org/libremail/mail/SmtpSender.kt

@@ -4,7 +4,10 @@ package org.libremail.mail
 import jakarta.mail.Message
 import jakarta.mail.Session
 import jakarta.mail.internet.InternetAddress
+import jakarta.mail.internet.MimeBodyPart
 import jakarta.mail.internet.MimeMessage
+import jakarta.mail.internet.MimeMultipart
+import java.io.File
 import java.util.Date
 import java.util.Properties
 import javax.inject.Inject
@@ -19,7 +22,12 @@ import org.libremail.domain.model.SmtpParams
 @Singleton
 class SmtpSender @Inject constructor() {
 
-    suspend fun send(params: SmtpParams, from: String, message: OutgoingMessage) =
+    suspend fun send(
+        params: SmtpParams,
+        from: String,
+        message: OutgoingMessage,
+        attachments: List<File> = emptyList(),
+    ) =
         withContext(Dispatchers.IO) {
             val protocol = if (params.security == MailSecurity.SSL_TLS) "smtps" else "smtp"
             val props = Properties().apply {
@@ -50,9 +58,18 @@ class SmtpSender @Inject constructor() {
                     setRecipients(Message.RecipientType.CC, InternetAddress.parse(message.cc))
                 }
                 subject = message.subject
-                setText(message.body, "UTF-8")
                 sentDate = Date()
             }
+            if (attachments.isEmpty()) {
+                mime.setText(message.body, "UTF-8")
+            } else {
+                val multipart = MimeMultipart()
+                multipart.addBodyPart(MimeBodyPart().apply { setText(message.body, "UTF-8") })
+                attachments.forEach { file ->
+                    multipart.addBodyPart(MimeBodyPart().apply { attachFile(file) })
+                }
+                mime.setContent(multipart)
+            }
 
             val transport = session.getTransport(protocol)
             transport.connect(params.host, params.port, params.username, params.secret)

app/src/main/kotlin/org/libremail/ui/compose/ComposeScreen.kt

@@ -2,7 +2,11 @@
 package org.libremail.ui.compose
 
 import android.Manifest
+import android.content.Context
+import android.content.Intent
 import android.content.pm.PackageManager
+import android.net.Uri
+import android.provider.OpenableColumns
 import androidx.activity.compose.BackHandler
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
@@ -20,7 +24,9 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
 import androidx.compose.material.icons.automirrored.filled.Send
+import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.ArrowDropDown
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
@@ -28,6 +34,7 @@ import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.InputChip
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Scaffold
@@ -56,6 +63,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import kotlinx.coroutines.flow.collect
 import org.libremail.R
 import org.libremail.domain.model.Account
+import org.libremail.domain.model.OutgoingAttachment
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -72,6 +80,19 @@ fun ComposeScreen(
         ActivityResultContracts.RequestPermission(),
     ) { granted -> viewModel.onContactsPermission(granted) }
 
+    val attachmentPicker = rememberLauncherForActivityResult(
+        ActivityResultContracts.OpenMultipleDocuments(),
+    ) { uris ->
+        viewModel.addAttachments(
+            uris.map { uri ->
+                runCatching {
+                    context.contentResolver.takePersistableUriPermission(uri, Intent.FLAG_GRANT_READ_URI_PERMISSION)
+                }
+                OutgoingAttachment(uri.toString(), queryFileName(context, uri))
+            },
+        )
+    }
+
     LaunchedEffect(Unit) {
         val granted = ContextCompat.checkSelfPermission(context, Manifest.permission.READ_CONTACTS) ==
             PackageManager.PERMISSION_GRANTED
@@ -141,6 +162,11 @@ fun ComposeScreen(
                     singleLine = true,
                     modifier = Modifier.fillMaxWidth(),
                 )
+                AttachmentsSection(
+                    attachments = state.attachments,
+                    onAttach = { attachmentPicker.launch(arrayOf("*/*")) },
+                    onRemove = viewModel::removeAttachment,
+                )
                 Spacer(Modifier.height(8.dp))
                 OutlinedTextField(
                     value = state.body,
@@ -197,6 +223,39 @@ private fun FromRow(accounts: List<Account>, selectedId: String?, onSelect: (Str
     }
 }
 
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun AttachmentsSection(
+    attachments: List<OutgoingAttachment>,
+    onAttach: () -> Unit,
+    onRemove: (String) -> Unit,
+) {
+    Column(Modifier.fillMaxWidth()) {
+        TextButton(onClick = onAttach) {
+            Icon(Icons.Filled.Add, contentDescription = null)
+            Spacer(Modifier.width(4.dp))
+            Text(stringResource(R.string.compose_attach))
+        }
+        attachments.forEach { attachment ->
+            InputChip(
+                selected = false,
+                onClick = { onRemove(attachment.uri) },
+                label = { Text(attachment.name, maxLines = 1) },
+                trailingIcon = {
+                    Icon(Icons.Filled.Close, contentDescription = stringResource(R.string.compose_attachment_remove))
+                },
+            )
+        }
+    }
+}
+
+private fun queryFileName(context: Context, uri: Uri): String {
+    val name = context.contentResolver
+        .query(uri, arrayOf(OpenableColumns.DISPLAY_NAME), null, null, null)
+        ?.use { cursor -> if (cursor.moveToFirst()) cursor.getString(0) else null }
+    return name ?: uri.lastPathSegment?.substringAfterLast('/') ?: "attachment"
+}
+
 @Composable
 private fun SuggestionList(
     suggestions: List<org.libremail.contacts.ContactSuggestion>,

app/src/main/kotlin/org/libremail/ui/compose/ComposeViewModel.kt

@@ -21,6 +21,7 @@ import org.libremail.contacts.ContactSuggestion
 import org.libremail.contacts.ContactsRepository
 import org.libremail.domain.model.Account
 import org.libremail.domain.model.Draft
+import org.libremail.domain.model.OutgoingAttachment
 import org.libremail.domain.model.OutgoingMessage
 import org.libremail.domain.repository.AccountRepository
 import org.libremail.domain.repository.MailRepository
@@ -32,6 +33,7 @@ data class ComposeUiState(
     val subject: String = "",
     val body: String = "",
     val fromAccountId: String? = null,
+    val attachments: List<OutgoingAttachment> = emptyList(),
     val suggestions: List<ContactSuggestion> = emptyList(),
     val contactsAllowed: Boolean = false,
     val sending: Boolean = false,
@@ -94,6 +96,10 @@ class ComposeViewModel @Inject constructor(
     fun onSubjectChange(value: String) = _state.update { it.copy(subject = value) }
     fun onBodyChange(value: String) = _state.update { it.copy(body = value) }
     fun selectFrom(accountId: String) = _state.update { it.copy(fromAccountId = accountId) }
+    fun addAttachments(items: List<OutgoingAttachment>) =
+        _state.update { it.copy(attachments = it.attachments + items) }
+    fun removeAttachment(uri: String) =
+        _state.update { it.copy(attachments = it.attachments.filterNot { a -> a.uri == uri }) }
     fun consumeError() = _state.update { it.copy(error = null) }
     fun onContactsPermission(granted: Boolean) = _state.update { it.copy(contactsAllowed = granted) }
 
@@ -153,7 +159,7 @@ class ComposeViewModel @Inject constructor(
             else -> viewModelScope.launch {
                 _state.update { it.copy(sending = true, error = null) }
                 mailRepository.sendMessage(
-                    OutgoingMessage(account.id, s.to, s.cc, s.subject, s.body),
+                    OutgoingMessage(account.id, s.to, s.cc, s.subject, s.body, s.attachments),
                 ).fold(
                     onSuccess = {
                         draftId?.let { mailRepository.deleteDraft(it) }

app/src/main/res/values/strings.xml

@@ -40,6 +40,8 @@
     <string name="compose_subject">Subject</string>
     <string name="compose_body">Message</string>
     <string name="compose_no_account">Add an account before composing</string>
+    <string name="compose_attach">Attach file</string>
+    <string name="compose_attachment_remove">Remove attachment</string>
 
     <!-- Drafts -->
     <string name="drafts_title">Drafts</string>

app/src/test/kotlin/org/libremail/mail/SmtpSenderTest.kt

@@ -4,6 +4,7 @@ package org.libremail.mail
 import com.icegreen.greenmail.util.GreenMail
 import com.icegreen.greenmail.util.GreenMailUtil
 import com.icegreen.greenmail.util.ServerSetupTest
+import java.io.File
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 import kotlinx.coroutines.test.runTest
@@ -59,4 +60,37 @@ class SmtpSenderTest {
         assertEquals("Hi Bob", received[0].subject)
         assertTrue(GreenMailUtil.getBody(received[0]).contains("Hello there"))
     }
+
+    @Test
+    fun `send delivers a message with an attachment`() = runTest {
+        val file = File.createTempFile("libremail-report", ".txt").apply { writeText("quarterly numbers") }
+        val params = SmtpParams(
+            host = "127.0.0.1",
+            port = greenMail.smtp.port,
+            security = MailSecurity.NONE,
+            username = "sender@example.org",
+            secret = "secret",
+            useXoauth2 = false,
+        )
+
+        sender.send(
+            params = params,
+            from = "sender@example.org",
+            message = OutgoingMessage(
+                accountId = "x",
+                to = "bob@example.org",
+                subject = "With file",
+                body = "See the attached report.",
+            ),
+            attachments = listOf(file),
+        )
+
+        greenMail.waitForIncomingEmail(1)
+        val received = greenMail.receivedMessages.single()
+        assertTrue(received.contentType.contains("multipart", ignoreCase = true))
+        val raw = GreenMailUtil.getWholeMessage(received)
+        assertTrue(raw.contains("See the attached report."))
+        assertTrue(raw.contains(file.name))
+        file.delete()
+    }
 }