wip precompute ranks fully

lib/model/autocomplete.dart

@@ -758,12 +758,12 @@ sealed class ComposeAutocompleteResult extends AutocompleteResult {}
 
 /// An emoji chosen in an autocomplete interaction, via [EmojiAutocompleteView].
 class EmojiAutocompleteResult extends ComposeAutocompleteResult {
-  EmojiAutocompleteResult(this.matchQuality, this.candidate);
+  EmojiAutocompleteResult(this.rank, this.candidate);
 
-  /// The quality of the emoji's match to the query.
+  /// A measure of the result's quality in the context of the query.
   ///
   /// Used internally by [EmojiAutocompleteView] for ranking the results.
-  final EmojiMatchQuality matchQuality;
+  final int rank;
 
   final EmojiCandidate candidate;
 }

lib/model/emoji.dart

@@ -379,12 +379,13 @@ class EmojiAutocompleteView extends AutocompleteView<EmojiAutocompleteQuery, Emo
           candidates: store.allEmojiCandidates(), results: unsorted)) {
       return null;
     }
-    return bucketSort(unsorted, _rankResult, numBuckets: _numResultRanks);
+    return bucketSort(unsorted, (r) => r.rank, numBuckets: _numResultRanks);
   }
 
   EmojiAutocompleteResult? _testCandidate(EmojiAutocompleteQuery query, EmojiCandidate candidate) {
     final match = query.match(candidate);
-    return match == null ? null : EmojiAutocompleteResult(match, candidate);
+    if (match == null) return null;
+    return EmojiAutocompleteResult(_rankResult(match, candidate), candidate);
   }
 
   static const _numResultRanks = 9;
@@ -411,11 +412,10 @@ class EmojiAutocompleteView extends AutocompleteView<EmojiAutocompleteQuery, Emo
   //    only if the latter is also a match for the query.  That mostly works,
   //    because emoji with the same name will mostly both match or both not;
   //    but it breaks if the Unicode emoji was a literal match.
-  static int _rankResult(EmojiAutocompleteResult result) {
-    if (result.matchQuality == EmojiMatchQuality.exact) {
+  static int _rankResult(EmojiMatchQuality matchQuality, EmojiCandidate candidate) {
+    if (matchQuality == EmojiMatchQuality.exact) {
       return 0;
     }
-    final candidate = result.candidate;
     final isPopular = _isPopularEmoji(candidate);
     final isCustomEmoji = switch (candidate.emojiType) {
       // The web implementation calls this condition `is_realm_emoji`,
@@ -424,7 +424,7 @@ class EmojiAutocompleteView extends AutocompleteView<EmojiAutocompleteQuery, Emo
       ReactionType.realmEmoji || ReactionType.zulipExtraEmoji => true,
       ReactionType.unicodeEmoji => false,
     };
-    return switch (result.matchQuality) {
+    return switch (matchQuality) {
       EmojiMatchQuality.exact       => throw Error(), // handled above
       EmojiMatchQuality.prefix      => isPopular ? 1 : isCustomEmoji ? 3 : 5,
       EmojiMatchQuality.wordAligned => isPopular ? 2 : isCustomEmoji ? 4 : 6,