Improve search suggestions

app/src/main/kotlin/org/koitharu/kotatsu/search/domain/MangaSearchRepository.kt

@@ -73,6 +73,20 @@ class MangaSearchRepository @Inject constructor(
 		}.orEmpty()
 	}
 
+	suspend fun getQueryHintSuggestion(
+		query: String,
+		limit: Int,
+	): List<String> {
+		if (query.isEmpty()) {
+			return emptyList()
+		}
+		val titles = db.suggestionDao.getTitles("$query%")
+		if (titles.isEmpty()) {
+			return emptyList()
+		}
+		return titles.shuffled().take(limit)
+	}
+
 	suspend fun getTagsSuggestion(query: String, limit: Int, source: MangaSource?): List<MangaTag> {
 		return when {
 			query.isNotEmpty() && source != null -> db.tagsDao.findTags(source.name, "%$query%", limit)

app/src/main/kotlin/org/koitharu/kotatsu/search/ui/suggestion/SearchSuggestionFragment.kt

@@ -69,6 +69,11 @@ class SearchSuggestionFragment :
 		viewModel.deleteQuery(query)
 	}
 
+	override fun onResume() {
+		super.onResume()
+		viewModel.onResume()
+	}
+
 	companion object {
 
 		fun newInstance() = SearchSuggestionFragment()

app/src/main/kotlin/org/koitharu/kotatsu/search/ui/suggestion/SearchSuggestionViewModel.kt

@@ -30,6 +30,7 @@ import javax.inject.Inject
 private const val DEBOUNCE_TIMEOUT = 500L
 private const val MAX_MANGA_ITEMS = 6
 private const val MAX_QUERY_ITEMS = 16
+private const val MAX_HINTS_ITEMS = 3
 private const val MAX_TAGS_ITEMS = 8
 private const val MAX_SOURCES_ITEMS = 6
 
@@ -42,6 +43,7 @@ class SearchSuggestionViewModel @Inject constructor(
 
 	private val query = MutableStateFlow("")
 	private var suggestionJob: Job? = null
+	private var invalidateOnResume = false
 
 	val isIncognitoModeEnabled = settings.observeAsStateFlow(
 		scope = viewModelScope + Dispatchers.Default,
@@ -60,11 +62,10 @@ class SearchSuggestionViewModel @Inject constructor(
 	}
 
 	fun saveQuery(query: String) {
-		launchJob(Dispatchers.Default) {
-			if (!settings.isIncognitoModeEnabled) {
-				repository.saveSearchQuery(query)
-			}
+		if (!settings.isIncognitoModeEnabled) {
+			repository.saveSearchQuery(query)
 		}
+		invalidateOnResume = true
 	}
 
 	fun clearSearchHistory() {
@@ -80,6 +81,13 @@ class SearchSuggestionViewModel @Inject constructor(
 		}
 	}
 
+	fun onResume() {
+		if (invalidateOnResume) {
+			invalidateOnResume = false
+			setupSuggestion()
+		}
+	}
+
 	fun deleteQuery(query: String) {
 		launchJob {
 			repository.deleteSearchQuery(query)
@@ -108,6 +116,9 @@ class SearchSuggestionViewModel @Inject constructor(
 		val queriesDeferred = async {
 			repository.getQuerySuggestion(searchQuery, MAX_QUERY_ITEMS)
 		}
+		val hintsDeferred = async {
+			repository.getQueryHintSuggestion(searchQuery, MAX_HINTS_ITEMS)
+		}
 		val tagsDeferred = async {
 			repository.getTagsSuggestion(searchQuery, MAX_TAGS_ITEMS, null)
 		}
@@ -119,16 +130,18 @@ class SearchSuggestionViewModel @Inject constructor(
 		val tags = tagsDeferred.await()
 		val mangaList = mangaDeferred.await()
 		val queries = queriesDeferred.await()
+		val hints = hintsDeferred.await()
 
-		buildList(queries.size + sources.size + 2) {
+		buildList(queries.size + sources.size + hints.size + 2) {
 			if (tags.isNotEmpty()) {
 				add(SearchSuggestionItem.Tags(mapTags(tags)))
 			}
 			if (mangaList.isNotEmpty()) {
 				add(SearchSuggestionItem.MangaList(mangaList))
 			}
-			queries.mapTo(this) { SearchSuggestionItem.RecentQuery(it) }
 			sources.mapTo(this) { SearchSuggestionItem.Source(it, it in enabledSources) }
+			queries.mapTo(this) { SearchSuggestionItem.RecentQuery(it) }
+			hints.mapTo(this) { SearchSuggestionItem.Hint(it) }
 		}
 	}
 

app/src/main/kotlin/org/koitharu/kotatsu/search/ui/suggestion/adapter/SearchSuggestionAdapter.kt

@@ -20,5 +20,6 @@ class SearchSuggestionAdapter(
 			.addDelegate(searchSuggestionSourceAD(coil, lifecycleOwner, listener))
 			.addDelegate(searchSuggestionTagsAD(listener))
 			.addDelegate(searchSuggestionMangaListAD(coil, lifecycleOwner, listener))
+			.addDelegate(searchSuggestionQueryHintAD(listener))
 	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/search/ui/suggestion/adapter/SearchSuggestionQueryHintAD.kt

@@ -0,0 +1,24 @@
+package org.koitharu.kotatsu.search.ui.suggestion.adapter
+
+import android.view.View
+import com.hannesdorfmann.adapterdelegates4.dsl.adapterDelegateViewBinding
+import org.koitharu.kotatsu.databinding.ItemSearchSuggestionQueryHintBinding
+import org.koitharu.kotatsu.search.ui.suggestion.SearchSuggestionListener
+import org.koitharu.kotatsu.search.ui.suggestion.model.SearchSuggestionItem
+
+fun searchSuggestionQueryHintAD(
+	listener: SearchSuggestionListener,
+) = adapterDelegateViewBinding<SearchSuggestionItem.Hint, SearchSuggestionItem, ItemSearchSuggestionQueryHintBinding>(
+	{ inflater, parent -> ItemSearchSuggestionQueryHintBinding.inflate(inflater, parent, false) },
+) {
+
+	val viewClickListener = View.OnClickListener { v ->
+		listener.onQueryClick(item.query, true)
+	}
+
+	binding.root.setOnClickListener(viewClickListener)
+
+	bind {
+		binding.root.text = item.query
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/search/ui/suggestion/model/SearchSuggestionItem.kt

@@ -27,6 +27,15 @@ sealed interface SearchSuggestionItem : ListModel {
 		}
 	}
 
+	data class Hint(
+		val query: String,
+	) : SearchSuggestionItem {
+
+		override fun areItemsTheSame(other: ListModel): Boolean {
+			return other is Hint && query == other.query
+		}
+	}
+
 	data class Source(
 		val source: MangaSource,
 		val isEnabled: Boolean,

app/src/main/kotlin/org/koitharu/kotatsu/suggestions/data/SuggestionDao.kt

@@ -26,6 +26,9 @@ abstract class SuggestionDao {
 	@Query("SELECT COUNT(*) FROM suggestions")
 	abstract suspend fun count(): Int
 
+	@Query("SELECT manga.title FROM suggestions LEFT JOIN manga ON suggestions.manga_id = manga.manga_id WHERE manga.title LIKE :query")
+	abstract suspend fun getTitles(query: String): List<String>
+
 	@Insert(onConflict = OnConflictStrategy.IGNORE)
 	abstract suspend fun insert(entity: SuggestionEntity): Long