feat(mobile): Android. Immich as a gallery / image viewer app

mobile/android/app/src/main/AndroidManifest.xml

@@ -89,6 +89,22 @@
         <data android:mimeType="video/*" />
       </intent-filter>
 
+      <!-- Allow Immich to act as an image viewer -->
+      <intent-filter android:label="View in Immich">
+        <action android:name="android.intent.action.VIEW" />
+        <category android:name="android.intent.category.DEFAULT" />
+        <data android:scheme="content" android:mimeType="image/*" />
+        <data android:scheme="file" android:mimeType="image/*" />
+      </intent-filter>
+
+      <!-- Allow Immich to act as a video viewer -->
+      <intent-filter android:label="View in Immich">
+        <action android:name="android.intent.action.VIEW" />
+        <category android:name="android.intent.category.DEFAULT" />
+        <data android:scheme="content" android:mimeType="video/*" />
+        <data android:scheme="file" android:mimeType="video/*" />
+      </intent-filter>
+
       <!-- immich:// URL scheme handling -->
       <intent-filter>
         <action android:name="android.intent.action.VIEW" />

mobile/android/app/src/main/kotlin/app/alextran/immich/MainActivity.kt

@@ -1,6 +1,7 @@
 package app.alextran.immich
 
 import android.content.Context
+import android.content.Intent
 import android.os.Build
 import android.os.ext.SdkExtensions
 import app.alextran.immich.background.BackgroundEngineLock
@@ -20,6 +21,7 @@ import app.alextran.immich.images.RemoteImagesImpl
 import app.alextran.immich.sync.NativeSyncApi
 import app.alextran.immich.sync.NativeSyncApiImpl26
 import app.alextran.immich.sync.NativeSyncApiImpl30
+import app.alextran.immich.viewintent.ViewIntentPlugin
 import io.flutter.embedding.android.FlutterFragmentActivity
 import io.flutter.embedding.engine.FlutterEngine
 
@@ -29,6 +31,11 @@ class MainActivity : FlutterFragmentActivity() {
     registerPlugins(this, flutterEngine)
   }
 
+  override fun onNewIntent(intent: Intent) {
+    super.onNewIntent(intent)
+    setIntent(intent)
+  }
+
   companion object {
     fun registerPlugins(ctx: Context, flutterEngine: FlutterEngine) {
       HttpClientManager.initialize(ctx)
@@ -51,6 +58,7 @@ class MainActivity : FlutterFragmentActivity() {
       BackgroundWorkerFgHostApi.setUp(messenger, BackgroundWorkerApiImpl(ctx))
       ConnectivityApi.setUp(messenger, ConnectivityApiImpl(ctx))
 
+      flutterEngine.plugins.add(ViewIntentPlugin())
       flutterEngine.plugins.add(backgroundEngineLockImpl)
       flutterEngine.plugins.add(nativeSyncApiImpl)
     }

mobile/android/app/src/main/kotlin/app/alextran/immich/media/MediaStoreUtils.kt

@@ -0,0 +1,103 @@
+package app.alextran.immich.media
+
+import android.content.Context
+import android.net.Uri
+import android.os.Build
+import android.provider.MediaStore
+import android.provider.OpenableColumns
+
+object MediaStoreUtils {
+  private fun externalFilesUri(): Uri =
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+      MediaStore.Files.getContentUri(MediaStore.VOLUME_EXTERNAL)
+    } else {
+      MediaStore.Files.getContentUri("external")
+    }
+
+  fun contentUriForMimeType(mimeType: String): Uri =
+    when {
+      mimeType.startsWith("image/") -> MediaStore.Images.Media.EXTERNAL_CONTENT_URI
+      mimeType.startsWith("video/") -> MediaStore.Video.Media.EXTERNAL_CONTENT_URI
+      mimeType.startsWith("audio/") -> MediaStore.Audio.Media.EXTERNAL_CONTENT_URI
+      else -> externalFilesUri()
+    }
+
+  fun contentUriForAssetType(type: Int): Uri =
+    when (type) {
+      // same order as AssetType from dart
+      1 -> MediaStore.Images.Media.EXTERNAL_CONTENT_URI
+      2 -> MediaStore.Video.Media.EXTERNAL_CONTENT_URI
+      3 -> MediaStore.Audio.Media.EXTERNAL_CONTENT_URI
+      else -> externalFilesUri()
+    }
+
+  fun resolveLocalIdByRelativePath(context: Context, path: String, mimeType: String): String? {
+    val fileName = path.substringAfterLast('/', missingDelimiterValue = path)
+    val parent = path.substringBeforeLast('/', "").let { if (it.isEmpty()) "" else "$it/" }
+    if (fileName.isBlank()) return null
+
+    val (selection, args) =
+      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+        "${MediaStore.MediaColumns.DISPLAY_NAME}=? AND ${MediaStore.MediaColumns.RELATIVE_PATH}=?" to arrayOf(fileName, parent)
+      } else {
+        "${MediaStore.MediaColumns.DISPLAY_NAME}=?" to arrayOf(fileName)
+      }
+
+    return queryLatestId(
+      context = context,
+      tableUri = contentUriForMimeType(mimeType),
+      selection = selection,
+      selectionArgs = args,
+    )
+  }
+
+  fun resolveLocalIdByNameAndSize(context: Context, uri: Uri, mimeType: String): String? {
+    val metaProjection = arrayOf(OpenableColumns.DISPLAY_NAME, OpenableColumns.SIZE)
+    val (displayName, size) =
+      try {
+        context.contentResolver.query(uri, metaProjection, null, null, null)?.use { cursor ->
+          if (!cursor.moveToFirst()) return null
+          val nameIdx = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
+          val sizeIdx = cursor.getColumnIndex(OpenableColumns.SIZE)
+          val name = if (nameIdx >= 0) cursor.getString(nameIdx) else null
+          val bytes = if (sizeIdx >= 0) cursor.getLong(sizeIdx) else -1L
+          if (name.isNullOrBlank() || bytes < 0) return null
+          name to bytes
+        } ?: return null
+      } catch (_: Exception) {
+        return null
+      }
+
+    return queryLatestId(
+      context = context,
+      tableUri = contentUriForMimeType(mimeType),
+      selection = "${MediaStore.MediaColumns.DISPLAY_NAME}=? AND ${MediaStore.MediaColumns.SIZE}=?",
+      selectionArgs = arrayOf(displayName, size.toString()),
+    )
+  }
+
+  private fun queryLatestId(
+    context: Context,
+    tableUri: Uri,
+    selection: String,
+    selectionArgs: Array<String>,
+  ): String? {
+    return try {
+      context.contentResolver
+        .query(
+          tableUri,
+          arrayOf(MediaStore.MediaColumns._ID),
+          selection,
+          selectionArgs,
+          "${MediaStore.MediaColumns.DATE_MODIFIED} DESC",
+        )?.use { cursor ->
+          if (!cursor.moveToFirst()) return null
+          val idIndex = cursor.getColumnIndex(MediaStore.MediaColumns._ID)
+          if (idIndex < 0) return null
+          cursor.getLong(idIndex).toString()
+        }
+    } catch (_: Exception) {
+      null
+    }
+  }
+}

mobile/android/app/src/main/kotlin/app/alextran/immich/sync/Messages.g.kt

@@ -383,6 +383,7 @@ interface NativeSyncApi {
   fun getAssetsCountSince(albumId: String, timestamp: Long): Long
   fun getAssetsForAlbum(albumId: String, updatedTimeCond: Long?): List<PlatformAsset>
   fun hashAssets(assetIds: List<String>, allowNetworkAccess: Boolean, callback: (Result<List<HashResult>>) -> Unit)
+  fun hashFiles(paths: List<String>, callback: (Result<List<HashResult>>) -> Unit)
   fun cancelHashing()
   fun getTrashedAssets(): Map<String, List<PlatformAsset>>
   fun getCloudIdForAssetIds(assetIds: List<String>): List<CloudIdResult>
@@ -548,6 +549,26 @@ interface NativeSyncApi {
           channel.setMessageHandler(null)
         }
       }
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashFiles$separatedMessageChannelSuffix", codec, taskQueue)
+        if (api != null) {
+          channel.setMessageHandler { message, reply ->
+            val args = message as List<Any?>
+            val pathsArg = args[0] as List<String>
+            api.hashFiles(pathsArg) { result: Result<List<HashResult>> ->
+              val error = result.exceptionOrNull()
+              if (error != null) {
+                reply.reply(MessagesPigeonUtils.wrapError(error))
+              } else {
+                val data = result.getOrNull()
+                reply.reply(MessagesPigeonUtils.wrapResult(data))
+              }
+            }
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
       run {
         val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.NativeSyncApi.cancelHashing$separatedMessageChannelSuffix", codec)
         if (api != null) {

mobile/android/app/src/main/kotlin/app/alextran/immich/sync/MessagesImplBase.kt

@@ -28,6 +28,8 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Semaphore
 import kotlinx.coroutines.sync.withPermit
 import java.io.File
+import java.io.FileInputStream
+import java.io.InputStream
 import java.security.MessageDigest
 import kotlin.coroutines.cancellation.CancellationException
 
@@ -417,24 +419,55 @@ open class NativeSyncApiImplBase(context: Context) : ImmichPlugin() {
     }
   }
 
+  fun hashFiles(
+    paths: List<String>,
+    callback: (Result<List<HashResult>>) -> Unit
+  ) {
+    if (paths.isEmpty()) {
+      completeWhenActive(callback, Result.success(emptyList()))
+      return
+    }
+
+    hashTask?.cancel()
+    hashTask = CoroutineScope(Dispatchers.IO).launch {
+      try {
+        val results = paths.map { path ->
+          async {
+            hashSemaphore.withPermit {
+              ensureActive()
+              hashFile(path)
+            }
+          }
+        }.awaitAll()
+
+        completeWhenActive(callback, Result.success(results))
+      } catch (e: CancellationException) {
+        completeWhenActive(
+          callback, Result.failure(
+            FlutterError(
+              HASHING_CANCELLED_CODE,
+              "Hashing operation was cancelled",
+              null
+            )
+          )
+        )
+      } catch (e: Exception) {
+        completeWhenActive(callback, Result.failure(e))
+      }
+    }
+  }
+
   private suspend fun hashAsset(assetId: String): HashResult {
     return try {
       val assetUri = ContentUris.withAppendedId(
         MediaStore.Files.getContentUri(MediaStore.VOLUME_EXTERNAL),
         assetId.toLong()
       )
 
-      val digest = MessageDigest.getInstance("SHA-1")
-      ctx.contentResolver.openInputStream(assetUri)?.use { inputStream ->
-        var bytesRead: Int
-        val buffer = ByteArray(HASH_BUFFER_SIZE)
-        while (inputStream.read(buffer).also { bytesRead = it } > 0) {
-          currentCoroutineContext().ensureActive()
-          digest.update(buffer, 0, bytesRead)
-        }
+      val hashString = ctx.contentResolver.openInputStream(assetUri)?.use { inputStream ->
+        hashInputStream(inputStream)
       } ?: return HashResult(assetId, "Cannot open input stream for asset", null)
 
-      val hashString = Base64.encodeToString(digest.digest(), Base64.NO_WRAP)
       HashResult(assetId, null, hashString)
     } catch (e: SecurityException) {
       HashResult(assetId, "Permission denied accessing asset: ${e.message}", null)
@@ -443,6 +476,35 @@ open class NativeSyncApiImplBase(context: Context) : ImmichPlugin() {
     }
   }
 
+  private suspend fun hashFile(path: String): HashResult {
+    return try {
+      val file = File(path)
+      if (!file.exists()) {
+        return HashResult(path, "File does not exist", null)
+      }
+
+      val hashString = FileInputStream(file).use { inputStream ->
+        hashInputStream(inputStream)
+      }
+      HashResult(path, null, hashString)
+    } catch (e: SecurityException) {
+      HashResult(path, "Permission denied accessing file: ${e.message}", null)
+    } catch (e: Exception) {
+      HashResult(path, "Failed to hash file: ${e.message}", null)
+    }
+  }
+
+  private suspend fun hashInputStream(inputStream: InputStream): String {
+    val digest = MessageDigest.getInstance("SHA-1")
+    var bytesRead: Int
+    val buffer = ByteArray(HASH_BUFFER_SIZE)
+    while (inputStream.read(buffer).also { bytesRead = it } > 0) {
+      currentCoroutineContext().ensureActive()
+      digest.update(buffer, 0, bytesRead)
+    }
+    return Base64.encodeToString(digest.digest(), Base64.NO_WRAP)
+  }
+
   fun cancelHashing() {
     hashTask?.cancel()
     hashTask = null