better fuzzy search

app/src/main/java/com/github/droidworksstudio/fuzzywuzzy/FuzzyFinder.kt

@@ -2,65 +2,133 @@ package com.github.droidworksstudio.fuzzywuzzy
 
 import com.github.droidworksstudio.launcher.data.entities.AppInfo
 import java.text.Normalizer
-import java.util.*
 
+/**
+ * Fast in-memory fuzzy search index for app names.
+ *
+ * Matching runs on a normalized form of the app name: uppercase, without
+ * diacritical marks and without separators, so "fdroid" finds "F-Droid".
+ * A query matches when all of its characters appear in the name in order
+ * (a subsequence match), but not necessarily consecutively: "fro" finds
+ * "F-Droid" too.
+ *
+ * The normalized names and word boundaries are precomputed once per app list
+ * ([buildIndex]), so scoring one keystroke is a plain scan over plain strings
+ * — no regex, no allocations per app, no database query. A few hundred apps
+ * score in well under a millisecond.
+ */
 object FuzzyFinder {
-    fun scoreApp(app: AppInfo, searchChars: String, topScore: Int): Int {
-        val appChars = app.appName
 
-        val fuzzyScore = calculateFuzzyScore(
+    /** One app with its precomputed search data. */
-            normalizeString(appChars),
+    class IndexedApp(val app: AppInfo) {
-            normalizeString(searchChars)
+        /** App name, uppercased, without diacritics and separators. */
-        )
+        val normalizedName: String = normalize(app.appName)
 
-        return (fuzzyScore * topScore).toInt()
+        /** True at positions in [normalizedName] that begin a word. */
+        val wordStarts: BooleanArray = wordStartsOf(app.appName, normalizedName)
     }
 
-    fun normalizeString(appLabel: String, searchChars: String): Boolean {
+    /** Precomputes search data for a list of apps. Call once per app list change. */
-        return (appLabel.contains(searchChars, true) or
+    fun buildIndex(apps: List<AppInfo>): List<IndexedApp> = apps.map(::IndexedApp)
-                Normalizer.normalize(appLabel, Normalizer.Form.NFD)
+
-                    .replace(Regex("\\p{InCombiningDiacriticalMarks}+"), "")
+    /** Normalizes a name or a query: uppercase, no diacritics, no separators. */
-                    .replace(Regex("[-_+,. ]"), "")
+    fun normalize(input: String): String {
-                    .contains(searchChars, true))
+        val nfd = Normalizer.normalize(input, Normalizer.Form.NFD)
+        val sb = StringBuilder(nfd.length)
+        for (ch in nfd) {
+            if (ch.isLetterOrDigit()) {
+                sb.append(ch.uppercaseChar())
+            }
+        }
+        return sb.toString()
     }
 
-    private fun normalizeString(input: String): String {
+    private fun wordStartsOf(original: String, normalized: String): BooleanArray {
-        // Remove diacritical marks and special characters, and convert to uppercase
+        val nfd = Normalizer.normalize(original, Normalizer.Form.NFD)
-        return input
+        val starts = BooleanArray(normalized.length)
-            .uppercase(Locale.getDefault())
+        var atWordStart = true
-            .replace(Regex("[\\p{InCombiningDiacriticalMarks}-_+,.]"), "")
+        var prevWasLower = false
-    }
+        var normalizedIndex = 0
+        for (ch in nfd) {
+            when {
+                ch.isLetterOrDigit() -> {
+                    // Camel case: "easyLauncher" starts a word at the uppercase letter.
+                    starts[normalizedIndex] = atWordStart || (prevWasLower && ch.isUpperCase())
+                    atWordStart = false
+                    prevWasLower = ch.isLowerCase()
+                    normalizedIndex++
+                }
 
-    private fun calculateFuzzyScore(s1: String, s2: String): Float {
+                Character.getType(ch) == Character.NON_SPACING_MARK.toInt() -> {
-        val m = s1.length
+                    // Combining mark left over from NFD (the accent of "é") — ignore.
-        val n = s2.length
+                }
-        var matchCount = 0
-        var s1Index = 0
 
-        // Iterate over each character in s2 and check if it exists in s1
+                else -> {
-        for (c2 in s2) {
+                    // Separator: the next letter begins a new word.
-            var found = false
+                    atWordStart = true
-
+                    prevWasLower = false
-            // Start searching for c2 from the current s1Index
-            for (j in s1Index until m) {
-                if (s1[j] == c2) {
-                    found = true
-                    // Update s1Index to the next position for the next iteration
-                    s1Index = j + 1
-                    break
                 }
             }
+        }
+        return starts
+    }
 
-            // If the current character in s2 is not found in s1, return a score of 0
+    /**
-            if (!found) {
+     * Scores [entry] against an already normalized [query] (see [normalize]).
-                return 0f
+     *
-            }
+     * Returns 0 when the query is not a subsequence of the app name, otherwise
+     * a score from 1 to 100. Matches at the start of the name, consecutive
+     * runs and word boundaries score higher, so the best match ranks on top.
+     * An exact match always scores 100.
+     */
+    fun score(entry: IndexedApp, query: String): Int {
+        val name = entry.normalizedName
+        val qLen = query.length
+        val nLen = name.length
+        if (qLen == 0) return 100
+        if (qLen > nLen) return 0
 
-            // Increment the match count
+        var nameIndex = 0
-            matchCount++
+        var prevMatch = -2
+        var run = 0
+        var runPoints = 0
+        var boundaryHits = 0
+        var firstMatch = -1
+
+        for (i in 0 until qLen) {
+            val c = query[i]
+            while (nameIndex < nLen && name[nameIndex] != c) nameIndex++
+            if (nameIndex == nLen) return 0
+            if (firstMatch < 0) firstMatch = nameIndex
+            run = if (nameIndex == prevMatch + 1) run + 1 else 1
+            runPoints += run
+            if (entry.wordStarts[nameIndex]) boundaryHits++
+            prevMatch = nameIndex
+            nameIndex++
         }
 
-        // Calculate the score as the ratio of matched characters to the longer string length
+        if (firstMatch == 0 && qLen == nLen) return 100 // exact match
-        return matchCount.toFloat() / maxOf(m, n)
+
+        // Where does the match start? 40 points at the start, falling off quickly.
+        val startScore = when {
+            firstMatch == 0 -> 40
+            firstMatch == 1 -> 30
+            else -> (20 - firstMatch).coerceAtLeast(0)
+        }
+
+        // Are the query characters consecutive? Up to 30 points. runPoints is
+        // the sum of run lengths: 1 + 2 + ... + qLen for a perfectly
+        // consecutive match, qLen for a fully scattered one.
+        val consecutiveScore = if (qLen > 1) {
+            val scattered = runPoints.toDouble() / qLen
+            ((scattered - 1.0) / ((qLen + 1.0) / 2.0 - 1.0)).coerceIn(0.0, 1.0)
+        } else {
+            0.0
+        }
+
+        // Do matches hit word starts? Up to 30 points.
+        val boundaryScore = boundaryHits.toDouble() / qLen
+
+        return (startScore + 30 * consecutiveScore + 30 * boundaryScore).toInt()
     }
 }

app/src/main/java/com/github/droidworksstudio/launcher/adapter/drawer/DrawAdapter.kt

@@ -1,6 +1,5 @@
 package com.github.droidworksstudio.launcher.adapter.drawer
 
-import android.annotation.SuppressLint
 import android.view.LayoutInflater
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListAdapter
@@ -49,10 +48,4 @@ class DrawAdapter(
         override fun areContentsTheSame(oldItem: AppInfo, newItem: AppInfo) =
             oldItem == newItem
     }
-
-    @SuppressLint("NotifyDataSetChanged")
-    fun updateDataWithStateFlow(newData: List<AppInfo>) {
-        submitList(newData.toMutableList())
-        notifyDataSetChanged()
-    }
 }

app/src/main/java/com/github/droidworksstudio/launcher/data/dao/AppInfoDAO.kt

@@ -49,9 +49,6 @@ interface AppInfoDAO {
     @Query("SELECT * FROM app WHERE is_lock = 1 ORDER BY app_order ASC")
     fun getLockAppsFlow(): Flow<List<AppInfo>>
 
-    @Query("SELECT * FROM app WHERE is_hidden = 0 ORDER BY app_name COLLATE NOCASE ASC")
-    fun searchApps(): Flow<List<AppInfo>>
-
     @Update
     suspend fun updateAppInfo(appInfo: AppInfo)
 

app/src/main/java/com/github/droidworksstudio/launcher/repository/AppInfoRepository.kt

@@ -53,10 +53,6 @@ class AppInfoRepository @Inject constructor(
         }
     }
 
-    fun searchNote(): Flow<List<AppInfo>> {
-        return appDao.searchApps()
-    }
-
     suspend fun updateFavoriteAppInfo(appInfo: AppInfo) = withContext(Dispatchers.IO) {
 
         if (appInfo.favorite) {

app/src/main/java/com/github/droidworksstudio/launcher/ui/drawer/DrawFragment.kt

@@ -81,6 +81,12 @@ class DrawFragment : Fragment(),
         )
     }
 
+    /**
+     * In-memory search index, rebuilt whenever the app list changes. Searching
+     * reads only from this index — no database query per keystroke.
+     */
+    private var searchIndex: List<FuzzyFinder.IndexedApp> = emptyList()
+
     private lateinit var context: Context
     override fun onCreateView(
         inflater: LayoutInflater, container: ViewGroup?,
@@ -165,10 +171,15 @@ class DrawFragment : Fragment(),
             repeatOnLifecycle(Lifecycle.State.CREATED) {
                 // Collect the drawer apps from the ViewModel
                 viewModel.drawApps.collect { apps ->
-                    // Update the adapter with the new list of apps
+                    // Rebuild the search index from the fresh app list
-                    drawAdapter.submitList(apps)
+                    searchIndex = FuzzyFinder.buildIndex(apps)
-                    // Update the adapter's data with the new state flow
+                    // Keep whatever search results are currently shown, or show the full list
-                    drawAdapter.updateDataWithStateFlow(apps)
+                    val query = binding.searchViewText.query?.toString().orEmpty()
+                    if (query.isBlank()) {
+                        drawAdapter.submitList(apps)
+                    } else {
+                        drawAdapter.submitList(performSearch(query))
+                    }
                 }
             }
         }
@@ -185,8 +196,15 @@ class DrawFragment : Fragment(),
                             val searchQuery = trimmedQuery.substringAfter("!")
                             requireContext().searchCustomSearchEngine(preferenceHelper, searchQuery)
                         } else {
-                            searchApp(trimmedQuery, false)
+                            val results = performSearch(trimmedQuery)
-                            return true // Exit the function
+                            if (results.isEmpty()) {
+                                if (!requireContext().searchOnPlayStore(trimmedQuery)) {
+                                    requireContext().openSearch(trimmedQuery)
+                                }
+                            } else {
+                                observeBioAuthCheck(results.first())
+                                drawAdapter.submitList(results)
+                            }
                         }
                     }
                 }
@@ -194,7 +212,13 @@ class DrawFragment : Fragment(),
             }
 
             override fun onQueryTextChange(newText: String?): Boolean {
-                searchApp(newText.toString(), true)
+                val query = newText.orEmpty()
+                val results = performSearch(query)
+                // Auto-open when exactly one app matches the query
+                if (query.isNotBlank() && results.size == 1 && preferenceHelper.automaticOpenApp) {
+                    observeBioAuthCheck(results.first())
+                }
+                drawAdapter.submitList(results)
                 return true
             }
         })
@@ -308,91 +332,41 @@ class DrawFragment : Fragment(),
         }
     }
 
-    private fun searchApp(query: String, isSearching: Boolean) {
+    /**
-        // Launch a coroutine tied to the lifecycle of the view
+     * Runs the fuzzy search synchronously over the in-memory index.
-        viewLifecycleOwner.lifecycleScope.launch {
+     *
-            // Repeat the block when the lifecycle is at least CREATED
+     * Called on every keystroke, including the very first character. This is
-            repeatOnLifecycle(Lifecycle.State.CREATED) {
+     * fast enough to run on the main thread — the index holds plain strings
-                val trimmedQuery = query.trim()
+     * and a few hundred apps score in well under a millisecond — so results
+     * appear in the same frame the character is typed.
+     */
+    private fun performSearch(query: String): List<AppInfo> {
+        val index = searchIndex
+        val trimmedQuery = query.trim()
+        if (trimmedQuery.isEmpty()) return index.map { it.app }
 
-                // Collect search results from the ViewModel
+        // Normalize the query once, not once per app
-                viewModel.searchAppInfo().collect { searchResults ->
+        val normalizedQuery = FuzzyFinder.normalize(trimmedQuery)
-                    // Filter and score results using FuzzyFinder
+        val minScore = preferenceHelper.filterStrength
-                    val filteredResults = searchResults
+        val searchFromStart = preferenceHelper.searchFromStart
-                        .map { appInfo ->
-                            val score = FuzzyFinder.scoreApp(appInfo, trimmedQuery, Constants.FILTER_STRENGTH_MAX)
-                            appInfo to score // Pairing app info with its score
-                        }
-                        .filter { it.second > 25 } // Only keep results with a positive score
-                        .sortedByDescending { it.second } // Sort results by score, descending
 
-                    // Applying additional filtering based on preferences
+        val scored = ArrayList<Pair<FuzzyFinder.IndexedApp, Int>>()
-                    val scoredApps = filteredResults.toMap()
+        for (entry in index) {
-
+            val score = FuzzyFinder.score(entry, normalizedQuery)
-                    val finalResults = if (preferenceHelper.filterStrength >= 1) {
+            // Compare against the normalized name, so "fdroid" matches "F-Droid"
-                        // Filtering based on score strength
+            val matchesFromStart = !searchFromStart ||
-                        if (preferenceHelper.searchFromStart) {
+                    entry.normalizedName.startsWith(normalizedQuery)
-                            // Filter apps that start with the search query and score higher than the filter strength
+            if (score > minScore && matchesFromStart) {
-                            scoredApps.filter { (app, _) ->
+                scored.add(entry to score)
-                                app.appName.startsWith(trimmedQuery, ignoreCase = true)
-                            }
-                                .filter { (_, score) -> score > preferenceHelper.filterStrength }
-                                .map { it.key }
-                                .toMutableList()
-                        } else {
-                            // Filter based on score strength alone
-                            scoredApps.filterValues { it > preferenceHelper.filterStrength }
-                                .keys
-                                .toMutableList()
-                        }
-                    } else {
-                        if (preferenceHelper.searchFromStart) {
-                            // Filter apps that start with the search query and score higher than the filter strength
-                            searchResults.filter { app ->
-                                FuzzyFinder.normalizeString(app.appName, trimmedQuery) ||
-                                        app.appName.startsWith(trimmedQuery, ignoreCase = true)
-                            }.toMutableList()
-                        } else {
-                            // If filter strength is less than 1, normalize app names for both cases
-                            searchResults.filter { app ->
-                                FuzzyFinder.normalizeString(app.appName, trimmedQuery)
-                            }.toMutableList()
-                        }
-                    }
-
-
-                    val numberOfItemsLeft = finalResults.size
-                    val appResults = finalResults.firstOrNull()
-
-                    if (isSearching) {
-                        when (numberOfItemsLeft) {
-                            1 -> {
-                                appResults?.let { appInfo ->
-                                    if (preferenceHelper.automaticOpenApp) observeBioAuthCheck(appInfo)
-                                }
-                                drawAdapter.submitList(finalResults)
-                            }
-
-                            else -> {
-                                drawAdapter.submitList(finalResults)
-                            }
-                        }
-                        if (trimmedQuery.isEmpty()) {
-                            drawAdapter.submitList(searchResults)
-                        }
-                    } else {
-                        if (numberOfItemsLeft == 0 && !requireContext().searchOnPlayStore(trimmedQuery)) {
-                            requireContext().openSearch(trimmedQuery)
-                        } else {
-                            appResults?.let { appInfo ->
-                                observeBioAuthCheck(appInfo)
-                            }
-                            drawAdapter.submitList(searchResults)
-                        }
-                    }
-                }
             }
         }
+
+        // Best score first, alphabetical as a tie breaker
+        scored.sortWith(
+            compareByDescending<Pair<FuzzyFinder.IndexedApp, Int>> { it.second }
+                .thenBy { it.first.app.appName.lowercase() }
+        )
+        return scored.map { it.first.app }
     }
 
     private fun showSelectedApp(appInfo: AppInfo) {

app/src/main/java/com/github/droidworksstudio/launcher/viewmodel/AppViewModel.kt

@@ -76,6 +76,4 @@ class AppViewModel @Inject constructor(
             appInfoRepository.updateInfo(appInfo)
         }
     }
-
-    fun searchAppInfo() = appInfoRepository.searchNote()
 }