From 52f01da40069c05fab92cebf8ad58a1ca762c319 Mon Sep 17 00:00:00 2001
From: Lucien Greathouse <me@lpghatguy.com>
Date: Wed, 12 Dec 2018 23:11:59 -0800
Subject: [PATCH] Flesh out reconciler routine

---
 server/src/rbx_session.rs  | 10 +++---
 server/src/rbx_snapshot.rs | 69 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/server/src/rbx_session.rs b/server/src/rbx_session.rs
index a6028cb6..c697ee7f 100644
--- a/server/src/rbx_session.rs
+++ b/server/src/rbx_session.rs
@@ -18,7 +18,7 @@ use crate::{
 
 pub struct RbxSession {
     tree: RbxTree,
-    path_id_tree: PathMap<RbxId>,
+    paths_to_node_ids: PathMap<RbxId>,
     ids_to_project_paths: HashMap<RbxId, String>,
     message_queue: Arc<MessageQueue>,
     imfs: Arc<Mutex<Imfs>>,
@@ -33,12 +33,12 @@ impl RbxSession {
         };
 
         // TODO: Restore these?
-        let path_id_tree = PathMap::new();
+        let paths_to_node_ids = PathMap::new();
         let ids_to_project_paths = HashMap::new();
 
         RbxSession {
             tree,
-            path_id_tree,
+            paths_to_node_ids,
             ids_to_project_paths,
             message_queue,
             imfs,
@@ -47,7 +47,7 @@ impl RbxSession {
     }
 
     fn path_created_or_updated(&mut self, path: &Path) {
-        if let Some(instance_id) = self.path_id_tree.get(path) {
+        if let Some(instance_id) = self.paths_to_node_ids.get(path) {
             // TODO: Replace instance with ID `instance_id` with new instance
         }
 
@@ -81,7 +81,7 @@ impl RbxSession {
     pub fn path_removed(&mut self, path: &Path) {
         info!("Path removed: {}", path.display());
 
-        let instance_id = match self.path_id_tree.remove(path) {
+        let instance_id = match self.paths_to_node_ids.remove(path) {
             Some(id) => id,
             None => return,
         };
diff --git a/server/src/rbx_snapshot.rs b/server/src/rbx_snapshot.rs
index 05654cad..28fb0137 100644
--- a/server/src/rbx_snapshot.rs
+++ b/server/src/rbx_snapshot.rs
@@ -64,4 +64,73 @@ fn reify_child(snapshot: &RbxSnapshotInstance, tree: &mut RbxTree, parent_id: Rb
     for child in &snapshot.children {
         reify_child(child, tree, id);
     }
+}
+
+fn reconcile_instance_properties(instance: &mut RbxInstance, snapshot: &RbxSnapshotInstance) -> bool {
+    let mut has_diffs = false;
+
+    if instance.name != snapshot.name {
+        instance.name = snapshot.name.to_string();
+        has_diffs = true;
+    }
+
+    if instance.class_name != snapshot.class_name {
+        instance.class_name = snapshot.class_name.to_string();
+        has_diffs = true;
+    }
+
+    let mut property_updates = HashMap::new();
+
+    for (key, instance_value) in &instance.properties {
+        match snapshot.properties.get(key) {
+            Some(snapshot_value) => {
+                if &snapshot_value.to_rbx_value() != instance_value {
+                    property_updates.insert(key.clone(), Some(snapshot_value.clone()));
+                }
+            },
+            None => {
+                property_updates.insert(key.clone(), None);
+            },
+        }
+    }
+
+    for (key, snapshot_value) in &snapshot.properties {
+        if property_updates.contains_key(key) {
+            continue;
+        }
+
+        match instance.properties.get(key) {
+            Some(instance_value) => {
+                if &snapshot_value.to_rbx_value() != instance_value {
+                    property_updates.insert(key.clone(), Some(snapshot_value.clone()));
+                }
+            },
+            None => {
+                property_updates.insert(key.clone(), Some(snapshot_value.clone()));
+            },
+        }
+    }
+
+    has_diffs = has_diffs || !property_updates.is_empty();
+
+    for (key, change) in property_updates.drain() {
+        match change {
+            Some(value) => instance.properties.insert(key, value.to_rbx_value()),
+            None => instance.properties.remove(&key),
+        };
+    }
+
+    has_diffs
+}
+
+fn reconcile_instance_children(tree: &mut RbxTree, id: RbxId, snapshot: &RbxSnapshotInstance, changed_ids: &mut Vec<RbxId>) {
+    // TODO: enumerate and match up children, update props, construct and delete IDs
+}
+
+pub fn reconcile_subtree(tree: &mut RbxTree, id: RbxId, snapshot: &RbxSnapshotInstance, changed_ids: &mut Vec<RbxId>) {
+    if reconcile_instance_properties(tree.get_instance_mut().unwrap(), snapshot) {
+        changed_ids.push(id);
+    }
+
+    reconcile_instance_children(tree, id, snapshot, changed_ids);
 }
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