Convert :source-api and :source-local to android library module (#3636)

- There's really no plan to support other platforms on this code base
- The "KMP" modules only had android target which is rather pointless
- `i18n` involves more work but given it has no actual code keeping it as is

source-local/src/main/kotlin/tachiyomi/source/local/image/LocalCoverManager.kt

@@ -0,0 +1,50 @@
+package tachiyomi.source.local.image
+
+import android.content.Context
+import com.hippo.unifile.UniFile
+import eu.kanade.tachiyomi.source.model.SManga
+import eu.kanade.tachiyomi.util.storage.DiskUtil
+import tachiyomi.core.common.storage.nameWithoutExtension
+import tachiyomi.core.common.util.system.ImageUtil
+import tachiyomi.source.local.io.LocalSourceFileSystem
+import java.io.InputStream
+
+private const val DEFAULT_COVER_NAME = "cover.jpg"
+
+class LocalCoverManager(
+    private val context: Context,
+    private val fileSystem: LocalSourceFileSystem,
+) {
+
+    fun find(mangaUrl: String): UniFile? {
+        return fileSystem.getFilesInMangaDirectory(mangaUrl)
+            // Get all file whose names start with "cover"
+            .filter { it.isFile && it.nameWithoutExtension.equals("cover", ignoreCase = true) }
+            // Get the first actual image
+            .firstOrNull { ImageUtil.isImage(it.name) { it.openInputStream() } }
+    }
+
+    fun update(
+        manga: SManga,
+        inputStream: InputStream,
+    ): UniFile? {
+        val directory = fileSystem.getMangaDirectory(manga.url)
+        if (directory == null) {
+            inputStream.close()
+            return null
+        }
+
+        val targetFile = find(manga.url) ?: directory.createFile(DEFAULT_COVER_NAME)!!
+
+        inputStream.use { input ->
+            targetFile.openOutputStream().use { output ->
+                input.copyTo(output)
+            }
+        }
+
+        DiskUtil.createNoMediaFile(directory, context)
+
+        manga.thumbnail_url = targetFile.uri.toString()
+        return targetFile
+    }
+}