first bang implementation

app/lib/features/query/domain/entities/abstract/i_query_builder.dart

@@ -0,0 +1,6 @@
+abstract interface class IQueryBuilder {
+  int get ftsTokenLimit;
+  int get ftsMinTokenLength;
+
+  String buildQuery(String input);
+}

app/lib/features/query/domain/entities/bareword.dart

@@ -0,0 +1,70 @@
+const barewordConcat = ' ';
+
+sealed class Bareword {
+  final String word;
+
+  @override
+  int get hashCode => word.hashCode;
+
+  Bareword(String word) : word = word.replaceAll('"', '""');
+
+  @override
+  bool operator ==(Object other) {
+    if (other is Bareword) {
+      return word == other.word;
+    }
+
+    return false;
+  }
+
+  JoinedBareword join(Bareword other) {
+    return JoinedBareword(other.word, this);
+  }
+}
+
+final class SimpleBareword extends Bareword {
+  SimpleBareword(super.word);
+
+  @override
+  String toString() => word;
+}
+
+final class EnclosedBareword extends Bareword {
+  EnclosedBareword(super.word);
+
+  @override
+  String toString() {
+    return '"$word"';
+  }
+}
+
+final class JoinedBareword extends Bareword {
+  final Bareword parent;
+
+  JoinedBareword(super.bareword, this.parent);
+
+  bool hasDependency(Bareword other) {
+    if (parent is JoinedBareword) {
+      return (parent as JoinedBareword).hasDependency(other);
+    } else {
+      return parent == other;
+    }
+  }
+
+  Iterable<Bareword> get dependencies {
+    final depencies = <Bareword>[parent];
+    while (depencies.last is JoinedBareword) {
+      depencies.add((depencies.last as JoinedBareword).parent);
+    }
+
+    return depencies.reversed;
+  }
+
+  @override
+  String toString() {
+    final deps = dependencies
+        .map((bareword) => bareword.toString())
+        .join(barewordConcat);
+    return '"$deps$barewordConcat$word"';
+  }
+}