1 files changed, 61 insertions, 0 deletions
diff --git a/rust/crates/animation/src/id.rs b/rust/crates/animation/src/id.rs
new file mode 100644
index 00000000..95288660
--- /dev/null
+++ b/rust/crates/animation/src/id.rs
@@ -0,0 +1,61 @@
+use std::cell::Cell;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+thread_local! {
+    static RNG_STATE: Cell<u64> = const { Cell::new(0) };
+}
+
+fn next_u64() -> u64 {
+    RNG_STATE.with(|state| {
+        let mut value = state.get();
+        if value == 0 {
+            let nanos = SystemTime::now()
+                .duration_since(UNIX_EPOCH)
+                .map(|duration| duration.as_nanos() as u64)
+                .unwrap_or(0x9e37_79b9_7f4a_7c15);
+            value = nanos
+                ^ (std::process::id() as u64).rotate_left(32)
+                ^ 0x9e37_79b9_7f4a_7c15;
+        }
+        value ^= value << 13;
+        value ^= value >> 7;
+        value ^= value << 17;
+        state.set(value);
+        value
+    })
+}
+
+pub fn generate_uuid() -> String {
+    let mut bytes = [0u8; 16];
+    for chunk in bytes.chunks_mut(8) {
+        let random = next_u64().to_le_bytes();
+        chunk.copy_from_slice(&random[..chunk.len()]);
+    }
+    bytes[6] = (bytes[6] & 0x0f) | 0x40;
+    bytes[8] = (bytes[8] & 0x3f) | 0x80;
+    let hex: Vec<String> = bytes.iter().map(|byte| format!("{byte:02x}")).collect();
+    format!(
+        "{}-{}-{}-{}-{}",
+        hex[0..4].join(""),
+        hex[4..6].join(""),
+        hex[6..8].join(""),
+        hex[8..10].join(""),
+        hex[10..16].join("")
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn generates_uuid_shaped_unique_ids() {
+        let id = generate_uuid();
+        let parts: Vec<&str> = id.split('-').collect();
+        assert_eq!(parts.len(), 5);
+        assert_eq!(parts[0].len(), 8);
+        assert_eq!(parts[1].len(), 4);
+        assert_eq!(parts[4].len(), 12);
+        assert_ne!(generate_uuid(), generate_uuid());
+    }
+}