1 files changed, 92 insertions, 0 deletions
diff --git a/rust/crates/animation/src/channel_data.rs b/rust/crates/animation/src/channel_data.rs
new file mode 100644
index 00000000..a05396e5
--- /dev/null
+++ b/rust/crates/animation/src/channel_data.rs
@@ -0,0 +1,92 @@
+use scene::{AnimationChannel, ChannelData, CompositeChannelData};
+
+const LEGACY_ANIMATION_STORAGE_KEYS: [&str; 2] = ["bindings", "channels"];
+
+pub fn is_animation_storage_key(key: &str) -> bool {
+    !LEGACY_ANIMATION_STORAGE_KEYS.contains(&key)
+}
+
+fn component_order(key: &str) -> usize {
+    match key {
+        "value" => 0,
+        "r" => 1,
+        "g" => 2,
+        "b" => 3,
+        "a" => 4,
+        _ => 5,
+    }
+}
+
+pub fn ordered_composite_entries(data: &CompositeChannelData) -> Vec<(&String, &AnimationChannel)> {
+    let mut entries: Vec<(&String, &AnimationChannel)> = data.iter().collect();
+    entries.sort_by_key(|(key, _)| component_order(key));
+    entries
+}
+
+pub fn get_channels_from_data(data: Option<&ChannelData>) -> Vec<&AnimationChannel> {
+    match data {
+        Some(ChannelData::Single(channel)) => vec![channel],
+        Some(ChannelData::Composite(components)) => ordered_composite_entries(components)
+            .into_iter()
+            .map(|(_, channel)| channel)
+            .collect(),
+        None => Vec::new(),
+    }
+}
+
+pub fn get_channel_entries_from_data(data: Option<&ChannelData>) -> Vec<(String, &AnimationChannel)> {
+    match data {
+        Some(ChannelData::Single(channel)) => vec![("value".to_string(), channel)],
+        Some(ChannelData::Composite(components)) => ordered_composite_entries(components)
+            .into_iter()
+            .map(|(key, channel)| (key.clone(), channel))
+            .collect(),
+        None => Vec::new(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use scene::{AnimationChannel, DiscreteChannel, ScalarChannel};
+    use std::collections::BTreeMap;
+
+    fn scalar_channel() -> AnimationChannel {
+        AnimationChannel::Scalar(ScalarChannel {
+            keys: Vec::new(),
+            extrapolation: None,
+        })
+    }
+
+    #[test]
+    fn leaf_data_yields_value_entry() {
+        let data = ChannelData::Single(scalar_channel());
+        let entries = get_channel_entries_from_data(Some(&data));
+        assert_eq!(entries.len(), 1);
+        assert_eq!(entries[0].0, "value");
+    }
+
+    #[test]
+    fn composite_entries_follow_canonical_component_order() {
+        let mut components = BTreeMap::new();
+        components.insert("a".to_string(), scalar_channel());
+        components.insert("b".to_string(), scalar_channel());
+        components.insert("g".to_string(), scalar_channel());
+        components.insert("r".to_string(), scalar_channel());
+        components.insert(
+            "mode".to_string(),
+            AnimationChannel::Discrete(DiscreteChannel { keys: Vec::new() }),
+        );
+        let data = ChannelData::Composite(components);
+        let entries = get_channel_entries_from_data(Some(&data));
+        let keys: Vec<&str> = entries.iter().map(|(key, _)| key.as_str()).collect();
+        assert_eq!(keys, ["r", "g", "b", "a", "mode"]);
+    }
+
+    #[test]
+    fn legacy_storage_keys_are_rejected() {
+        assert!(!is_animation_storage_key("bindings"));
+        assert!(!is_animation_storage_key("channels"));
+        assert!(is_animation_storage_key("opacity"));
+    }
+}