Add zip export

domain/src/main/kotlin/usecases/export/ExportUseCase.kt

@@ -1,5 +1,8 @@
 package be.simplenotes.domain.usecases.export
 
+import java.io.InputStream
+
 interface ExportUseCase {
-    fun export(userId: Int): String
+    fun exportAsJson(userId: Int): String
+    fun exportAsZip(userId: Int): InputStream
 }

domain/src/main/kotlin/usecases/export/ExportUseCaseImpl.kt

@@ -11,10 +11,15 @@ import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.modules.SerializersModule
+import org.apache.commons.compress.archivers.zip.ZipArchiveEntry
+import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.InputStream
 import java.time.LocalDateTime
 
 internal class ExportUseCaseImpl(private val noteRepository: NoteRepository) : ExportUseCase {
-    override fun export(userId: Int): String {
+    override fun exportAsJson(userId: Int): String {
         val module = SerializersModule {
             contextual(LocalDateTime::class, LocalDateTimeSerializer)
         }
@@ -27,8 +32,41 @@ internal class ExportUseCaseImpl(private val noteRepository: NoteRepository) : E
         val notes = noteRepository.export(userId)
         return json.encodeToString(ListSerializer(ExportedNote.serializer()), notes)
     }
+
+    private fun sanitizeFilename(inputName: String): String = inputName.replace("[^a-zA-Z0-9-_.]".toRegex(), "_")
+
+    override fun exportAsZip(userId: Int): InputStream {
+        val notes = noteRepository.export(userId)
+        val zipOutput = ZipOutput()
+        zipOutput.use { zip ->
+            notes.forEach {
+                val name = sanitizeFilename(it.title)
+                zip.write("notes/$name.md", it.markdown)
+            }
+        }
+        return ByteArrayInputStream(zipOutput.outputStream.toByteArray())
+    }
 }
 
+
+class ZipOutput : AutoCloseable {
+    val outputStream = ByteArrayOutputStream()
+    private val zipOutputStream = ZipArchiveOutputStream(outputStream)
+
+    fun write(path: String, content: String) {
+        val entry = ZipArchiveEntry(path)
+        zipOutputStream.putArchiveEntry(entry)
+        zipOutputStream.write(content.toByteArray())
+        zipOutputStream.closeArchiveEntry()
+    }
+
+    override fun close() {
+        zipOutputStream.finish()
+        zipOutputStream.close()
+    }
+}
+
+
 internal object LocalDateTimeSerializer : KSerializer<LocalDateTime> {
     override val descriptor: SerialDescriptor
         get() = PrimitiveSerialDescriptor("LocalDateTime", PrimitiveKind.STRING)