feat: full local assets / album sync

mobile-v2/lib/utils/collection_util.dart

@@ -1,5 +1,7 @@
 // ignore_for_file: avoid-unsafe-collection-methods
 
+import 'dart:async';
+
 class CollectionUtil {
   const CollectionUtil();
 
@@ -13,28 +15,33 @@ class CollectionUtil {
     return a.compareTo(b);
   }
 
-  /// Find the difference between the two sorted lists [first] and [second]
+  /// Find the difference between the two lists [first] and [second]
   /// Results are passed as callbacks back to the caller during the comparison
-  static bool diffSortedLists<T>(
+  static FutureOr<bool> diffLists<T>(
     List<T> first,
     List<T> second, {
-    required Comparator<T> compare,
-    required bool Function(T a, T b) both,
-    required void Function(T a) onlyFirst,
-    required void Function(T b) onlySecond,
-  }) {
+    required int Function(T a, T b) compare,
+    required FutureOr<bool> Function(T a, T b) both,
+    required FutureOr<void> Function(T a) onlyFirst,
+    required FutureOr<void> Function(T b) onlySecond,
+  }) async {
+    first.sort(compare);
+    first.uniqueConsecutive(compare);
+    second.sort(compare);
+    second.uniqueConsecutive(compare);
+
     bool diff = false;
     int i = 0, j = 0;
 
     for (; i < first.length && j < second.length;) {
       final int order = compare(first[i], second[j]);
       if (order == 0) {
-        diff |= both(first[i++], second[j++]);
+        diff |= await both(first[i++], second[j++]);
       } else if (order < 0) {
-        onlyFirst(first[i++]);
+        await onlyFirst(first[i++]);
         diff = true;
       } else if (order > 0) {
-        onlySecond(second[j++]);
+        await onlySecond(second[j++]);
         diff = true;
       }
     }
@@ -50,3 +57,19 @@ class CollectionUtil {
     return diff;
   }
 }
+
+extension _ListExtension<T> on List<T> {
+  List<T> uniqueConsecutive(int Function(T a, T b) compare) {
+    int i = 1, j = 1;
+    for (; i < length; i++) {
+      if (compare(this[i - 1], this[i]) != 0) {
+        if (i != j) {
+          this[j] = this[i];
+        }
+        j++;
+      }
+    }
+    length = length == 0 ? 0 : j;
+    return this;
+  }
+}