Implement search state, action and view events.

vector/src/main/java/im/vector/app/features/home/room/detail/search/SearchAction.kt

@@ -18,4 +18,8 @@ package im.vector.app.features.home.room.detail.search
 
 import im.vector.app.core.platform.VectorViewModelAction
 
-sealed class SearchAction : VectorViewModelAction
+sealed class SearchAction : VectorViewModelAction {
+    data class SearchWith(val roomId: String, val searchTerm: String) : SearchAction()
+    object ScrolledToTop : SearchAction()
+    object Retry : SearchAction()
+}

vector/src/main/java/im/vector/app/features/home/room/detail/search/SearchViewEvents.kt

@@ -18,4 +18,7 @@ package im.vector.app.features.home.room.detail.search
 
 import im.vector.app.core.platform.VectorViewEvents
 
-sealed class SearchViewEvents : VectorViewEvents
+sealed class SearchViewEvents : VectorViewEvents {
+    data class Failure(val throwable: Throwable) : SearchViewEvents()
+    data class Loading(val message: CharSequence? = null) : SearchViewEvents()
+}

vector/src/main/java/im/vector/app/features/home/room/detail/search/SearchViewState.kt

@@ -17,7 +17,14 @@
 package im.vector.app.features.home.room.detail.search
 
 import com.airbnb.mvrx.MvRxState
+import org.matrix.android.sdk.api.session.search.SearchResult
 
 data class SearchViewState(
-        val searchTerm: String = ""
+        // Accumulated search result
+        val searchResult: SearchResult? = null,
+        // Last batch result will help RecyclerView to position itself
+        val lastBatch: SearchResult? = null,
+        val searchTerm: String? = null,
+        val roomId: String? = null,
+        val isNextBatch: Boolean = false
 ) : MvRxState