fix sorted file iterator

src/tangara/lua/file_iterator.cpp

@@ -95,7 +95,7 @@ auto FileIterator::iterate(bool show_hidden) -> bool {
 
 
 FileIteratorSorted::FileIteratorSorted(std::string filepath, bool showHidden)
-    : files_(), offset_(-1) {
+    : offset_(-1) {
 
   FileIterator iter(filepath, showHidden);
 
@@ -103,7 +103,6 @@ FileIteratorSorted::FileIteratorSorted(std::string filepath, bool showHidden)
     iter.next();
     std::optional<FileEntry> res = iter.value();
     if (res) {
-      auto file = *res;
       files_.push_back(*res);
     } else {
       break;
@@ -112,8 +111,19 @@ FileIteratorSorted::FileIteratorSorted(std::string filepath, bool showHidden)
 
   std::sort(files_.begin(), files_.end(),
     [](const auto& lhs, const auto& rhs) {
+        if (lhs.isDirectory > rhs.isDirectory) {
+          return true;
+        } else if (lhs.isDirectory < rhs.isDirectory) {
+          return false;
+        }
+
         return lhs.name < rhs.name;
     });
+
+  // reindex the files
+  for(size_t i = 0; i != files_.size(); i++) {
+    files_[i].index = i + 1;
+  }
 }
 
 FileIteratorSorted::~FileIteratorSorted() {
@@ -127,15 +137,18 @@ auto FileIteratorSorted::value() const -> const std::optional<FileEntry> {
 }
 
 auto FileIteratorSorted::next() -> void {
-  if (offset_ < files_.size()) {
+  if (offset_ < (int) files_.size()) {
     offset_++;
   }
 }
 
 auto FileIteratorSorted::prev() -> void {
-  if (offset_ >= 0) {
-    offset_--;
+  if (offset_ <= 0) {
+    offset_ = -1;
+    return;
   }
+
+  offset_--;
 }