feat(board_generator_playground): define toPrettyString (#104)

* feat: define toPrettyString

* refactor: removed trim

* refactor: removed unused import

packages/board_generator_playground/lib/src/crossword.dart

@@ -370,4 +370,42 @@ class Crossword {
       constraints: constraints,
     );
   }
+
+  /// A pretty string representation of the board.
+  ///
+  /// For example, a board with the words "ALBUS" and "BEHAN" would be:
+  ///
+  /// ```txt
+  /// ALBUS
+  /// --E--
+  /// --H--
+  /// --A--
+  /// --N--
+  /// ```
+  String toPrettyString() {
+    final stringBuffer = StringBuffer();
+
+    final minX =
+        characterMap.keys.map((e) => e.x).reduce((a, b) => a < b ? a : b);
+    final maxX =
+        characterMap.keys.map((e) => e.x).reduce((a, b) => a > b ? a : b);
+    final minY =
+        characterMap.keys.map((e) => e.y).reduce((a, b) => a < b ? a : b);
+    final maxY =
+        characterMap.keys.map((e) => e.y).reduce((a, b) => a > b ? a : b);
+
+    final width = maxX - minX + 1;
+
+    for (var row = minY; row <= maxY; row++) {
+      final characters = List.generate(width, (column) {
+        final location = Location(x: column + minX, y: row);
+        final character = characterMap[location]?.character ?? '-';
+        return character.toUpperCase();
+      });
+
+      stringBuffer.writeln(characters.join());
+    }
+
+    return stringBuffer.toString();
+  }
 }

packages/board_generator_playground/test/src/crossword_test.dart

@@ -849,5 +849,23 @@ void main() {
         });
       });
     });
+
+    group('toPrettyString', () {
+      test('returns a pretty string for the crossword', () {
+        final board = Crossword1();
+
+        final prettyString = board.toPrettyString();
+        expect(
+          prettyString,
+          equals(
+            'ALBUS\n'
+            '--E--\n'
+            '--H--\n'
+            '--A--\n'
+            '--N--\n',
+          ),
+        );
+      });
+    });
   });
 }