1 files changed, 69 insertions, 1 deletions
diff --git a/src/interactive/app/app_state.rs b/src/interactive/app/app_state.rs
index dd0f9a0..8986f09 100644
--- a/src/interactive/app/app_state.rs
+++ b/src/interactive/app/app_state.rs
@@ -1,4 +1,5 @@
-use dua::WalkResult;
+use dua::{WalkResult, traverse::{TreeIndex, Tree}, inodefilter::InodeFilter};
+use petgraph::Direction;
 
 use super::{navigation::Navigation, EntryDataBundle, SortMode};
 
@@ -27,6 +28,73 @@ pub struct AppState {
     pub message: Option<String>,
     pub focussed: FocussedPane,
     pub is_scanning: bool,
+    pub traversal_state: TraversalState,
+}
+
+
+#[derive(Default)]
+pub struct TraversalState {
+    pub previous_node_idx: TreeIndex,
+    pub parent_node_idx: TreeIndex,
+    pub directory_info_per_depth_level: Vec<EntryInfo>,
+    pub current_directory_at_depth: EntryInfo,
+    pub previous_depth: usize,
+    pub inodes: InodeFilter,
+}
+
+impl TraversalState {
+    pub fn new(root_idx: TreeIndex) -> Self {
+        Self {
+            previous_node_idx: root_idx,
+            parent_node_idx: root_idx,
+            directory_info_per_depth_level: Vec::new(),
+            current_directory_at_depth: EntryInfo::default(),
+            previous_depth: 0,
+            inodes: InodeFilter::default(),
+        }
+    }
+}
+
+#[derive(Default, Copy, Clone)]
+pub struct EntryInfo {
+    pub size: u128,
+    pub entries_count: Option<u64>,
+}
+
+impl EntryInfo {
+    pub fn add_count(&mut self, other: &Self) {
+        self.entries_count = match (self.entries_count, other.entries_count) {
+            (Some(a), Some(b)) => Some(a + b),
+            (None, Some(b)) => Some(b),
+            (Some(a), None) => Some(a),
+            (None, None) => None,
+        };
+    }
+}
+
+pub fn set_entry_info_or_panic(
+    tree: &mut Tree,
+    node_idx: TreeIndex,
+    EntryInfo {
+        size,
+        entries_count,
+    }: EntryInfo,
+) {
+    let node = tree
+        .node_weight_mut(node_idx)
+        .expect("node for parent index we just retrieved");
+    node.size = size;
+    node.entry_count = entries_count;
+}
+
+pub fn parent_or_panic(tree: &mut Tree, parent_node_idx: TreeIndex) -> TreeIndex {
+    tree.neighbors_directed(parent_node_idx, Direction::Incoming)
+        .next()
+        .expect("every node in the iteration has a parent")
+}
+
+pub fn pop_or_panic(v: &mut Vec<EntryInfo>) -> EntryInfo {
+    v.pop().expect("sizes per level to be in sync with graph")
 }
 
 pub enum ProcessingResult {