fix retain, replace by filter

crates/cli/src/commands/purge.rs

@@ -1,7 +1,10 @@
 use clap::Args;
 use std::{collections::HashSet, path::PathBuf};
 use tracing::{error, info, warn};
-use uts_core::codec::{Decode, Encode, VersionedProof, v1::DetachedTimestamp};
+use uts_core::codec::{
+    Decode, Encode, VersionedProof,
+    v1::{Attestation, DetachedTimestamp, PendingAttestation},
+};
 use uts_sdk::Sdk;
 
 #[derive(Debug, Args)]
@@ -26,9 +29,13 @@ impl Purge {
 
     async fn purge_one(&self, path: &PathBuf) -> eyre::Result<()> {
         let file = tokio::fs::read(path).await?;
-        let mut proof = VersionedProof::<DetachedTimestamp>::decode(&mut &*file)?;
+        let proof = VersionedProof::<DetachedTimestamp>::decode(&mut &*file)?;
 
-        let pending = Sdk::list_pending(&proof);
+        let pending = proof
+            .attestations()
+            .filter(|att| att.tag == PendingAttestation::TAG)
+            .map(|att| PendingAttestation::from_raw(att).map(|p| p.uri))
+            .collect::<Result<Vec<_>, _>>()?;
         if pending.is_empty() {
             info!(
                 "[{}] no pending attestations found, skipping",
@@ -48,7 +55,7 @@ impl Purge {
 
         let uris_to_purge = if self.yes {
             // Purge all when --yes flag is used
-            None
+            pending.into_iter().collect()
         } else {
             // Interactive selection
             print!("Enter numbers to purge (comma-separated), 'all', or 'none' to skip: ");
@@ -64,7 +71,7 @@ impl Purge {
             }
 
             if input.eq_ignore_ascii_case("all") {
-                None
+                pending.into_iter().collect()
             } else {
                 let mut selected = HashSet::new();
                 for part in input.split(',') {
@@ -82,32 +89,28 @@ impl Purge {
                     info!("[{}] no valid selections, skipping", path.display());
                     return Ok(());
                 }
-                Some(selected)
+                selected
             }
         };
 
-        let result = Sdk::purge_pending_by_uris(&mut proof, uris_to_purge.as_ref());
+        let Some(result) = Sdk::filter_pending_by_uris(&proof, |uri| uris_to_purge.contains(uri))
+        else {
+            error!("won't purge [{}], results in empty proof", path.display());
+            return Ok(());
+        };
 
         if result.purged.is_empty() {
             info!("[{}] nothing to purge", path.display());
             return Ok(());
         }
 
-        if !result.has_remaining {
-            warn!(
-                "[{}] purging would leave no attestations in the file, skipping",
-                path.display()
-            );
-            return Ok(());
-        }
-
         let mut buf = Vec::new();
-        proof.encode(&mut buf)?;
+        VersionedProof::new(result.new_stamp).encode(&mut buf)?;
         tokio::fs::write(path, buf).await?;
         info!(
-            "[{}] purged {} pending attestation(s)",
+            "purged {} pending attestation(s) from [{}] ",
+            result.purged.len(),
             path.display(),
-            result.purged.len()
         );
         Ok(())
     }

crates/core/src/codec/v1/digest.rs

@@ -11,7 +11,7 @@ use core::fmt;
 use digest::{Output, typenum::Unsigned};
 
 /// Header describing the digest that anchors a timestamp.
-#[derive(Clone, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Copy, Clone, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[cfg_attr(
     feature = "serde",
     serde_with::serde_as,