Improving genre search started from the manga page of a popular manga (#4375)

Co-authored-by: E3FxGaming <E3FxGaming@users.noreply.github.com>

app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/BrowseSourceController.kt

@@ -29,6 +29,7 @@ import eu.kanade.tachiyomi.data.preference.asImmediateFlow
 import eu.kanade.tachiyomi.databinding.SourceControllerBinding
 import eu.kanade.tachiyomi.source.CatalogueSource
 import eu.kanade.tachiyomi.source.LocalSource
+import eu.kanade.tachiyomi.source.model.Filter
 import eu.kanade.tachiyomi.source.model.FilterList
 import eu.kanade.tachiyomi.source.online.HttpSource
 import eu.kanade.tachiyomi.ui.base.controller.FabController
@@ -335,6 +336,54 @@ open class BrowseSourceController(bundle: Bundle) :
         presenter.restartPager(newQuery)
     }
 
+    /**
+     * Attempts to restart the request with a new genre-filtered query.
+     * If the genre name can't be found the filters,
+     * the standard searchWithQuery search method is used instead.
+     *
+     * @param genreName the name of the genre
+     */
+    fun searchWithGenre(genreName: String) {
+        presenter.sourceFilters = presenter.source.getFilterList()
+
+        var filterList: FilterList? = null
+
+        filter@ for (sourceFilter in presenter.sourceFilters) {
+            if (sourceFilter is Filter.Group<*>) {
+                for (filter in sourceFilter.state) {
+                    if (filter is Filter<*> && filter.name.equals(genreName, true)) {
+                        when (filter) {
+                            is Filter.TriState -> filter.state = 1
+                            is Filter.CheckBox -> filter.state = true
+                        }
+                        filterList = presenter.sourceFilters
+                        break@filter
+                    }
+                }
+            } else if (sourceFilter is Filter.Select<*>) {
+                val index = sourceFilter.values.filterIsInstance<String>()
+                    .indexOfFirst { it.equals(genreName, true) }
+
+                if (index != -1) {
+                    sourceFilter.state = index
+                    filterList = presenter.sourceFilters
+                    break
+                }
+            }
+        }
+
+        if (filterList != null) {
+            filterSheet?.setFilters(presenter.filterItems)
+
+            showProgressBar()
+
+            adapter?.clear()
+            presenter.restartPager("", filterList)
+        } else {
+            searchWithQuery(genreName)
+        }
+    }
+
     /**
      * Called from the presenter when the network request is received.
      *

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaController.kt

@@ -638,6 +638,29 @@ class MangaController :
         }
     }
 
+    /**
+     * Performs a genre search using the provided genre name.
+     *
+     * @param genreName the search genre to the parent controller
+     */
+    fun performGenreSearch(genreName: String) {
+        if (router.backstackSize < 2) {
+            return
+        }
+
+        val previousController = router.backstack[router.backstackSize - 2].controller
+        val presenterSource = presenter.source
+
+        if (previousController is BrowseSourceController &&
+            presenterSource is HttpSource
+        ) {
+            router.handleBack()
+            previousController.searchWithGenre(genreName)
+        } else {
+            performSearch(genreName)
+        }
+    }
+
     private fun shareCover() {
         try {
             val activity = activity!!

app/src/main/java/eu/kanade/tachiyomi/ui/manga/info/MangaInfoHeaderAdapter.kt

@@ -262,11 +262,11 @@ class MangaInfoHeaderAdapter(
                 if (!manga.genre.isNullOrBlank()) {
                     binding.mangaGenresTagsCompactChips.setChips(
                         manga.getGenres(),
-                        controller::performSearch
+                        controller::performGenreSearch
                     )
                     binding.mangaGenresTagsFullChips.setChips(
                         manga.getGenres(),
-                        controller::performSearch
+                        controller::performGenreSearch
                     )
                 } else {
                     binding.mangaGenresTagsCompactChips.isVisible = false