feat: reconcile retained client commands

internal/server/session/agent_server.go

@@ -185,15 +185,14 @@ func (server *AgentServer) serveConnection(parent context.Context, connection *w
 			return
 		}
 		if snapshot := envelope.GetReconcileSnapshot(); snapshot != nil {
-			// A retained command requires the command-store reconciliation phase,
-			// which is deliberately not substituted with a no-op result.
-			if len(snapshot.GetRetainedCommands()) != 0 {
-				server.close(connection, websocket.StatusPolicyViolation, "reconciliation for retained commands is unavailable")
+			result, reconcileErr := server.Store.ReconcileClientSnapshot(sessionContext, hello.GetClientId(), snapshot)
+			if reconcileErr != nil {
+				server.close(connection, websocket.StatusPolicyViolation, "reconciliation failed")
 				return
 			}
 			encoded, err := proto.Marshal(&rvboxv1.AgentEnvelope{
 				SessionId: encodedSessionID, SessionGeneration: registration.Generation,
-				Payload: &rvboxv1.AgentEnvelope_ReconcileResult{ReconcileResult: &rvboxv1.ReconcileResult{}},
+				Payload: &rvboxv1.AgentEnvelope_ReconcileResult{ReconcileResult: result},
 			})
 			if err != nil || queue.EnqueueControl(Frame{Kind: FrameControl, Payload: encoded}) != nil {
 				server.close(connection, websocket.StatusInternalError, "could not queue reconciliation result")

internal/server/store/reconcile.go

@@ -0,0 +1,63 @@
+package store
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+
+	rvboxv1 "github.com/rvbox/rvbox/gen/go/rvbox/v1"
+	"github.com/rvbox/rvbox/internal/domain"
+)
+
+// ReconcileClientSnapshot compares client evidence with this client's durable
+// server rows. It intentionally performs no lifecycle mutation yet: callers
+// receive only the safe local terminate/discard instructions.
+func (store *Store) ReconcileClientSnapshot(ctx context.Context, clientID string, snapshot *rvboxv1.ReconcileSnapshot) (*rvboxv1.ReconcileResult, error) {
+	if snapshot == nil {
+		return nil, errors.New("missing client reconciliation snapshot")
+	}
+	result := &rvboxv1.ReconcileResult{}
+	for _, client := range snapshot.GetRetainedCommands() {
+		issue, err := domain.ParseUUIDv7(client.GetIssueUuid())
+		if err != nil {
+			return nil, err
+		}
+		input := domain.ReconcileInput{ClientEvidence: domain.ClientEvidenceRetained, ClientLifecycle: client.GetLifecycle(), ClientRevision: domain.CommandRevision(client.GetCommandRevision()), ClientLastEventSeq: client.GetLastClientEventSeq(), ImmutableHashMatches: true}
+		if client.GetTombstoned() {
+			input.ClientEvidence = domain.ClientEvidenceTombstone
+		}
+		var lifecycle uint32
+		var revision, lastSequence uint64
+		var hash []byte
+		err = store.db.QueryRowContext(ctx, `SELECT lifecycle, revision, last_event_seq, immutable_request_sha256 FROM commands WHERE issue_uuid = ? AND client_id = ?`, issue[:], clientID).Scan(&lifecycle, &revision, &lastSequence, &hash)
+		if err == nil {
+			input.ServerPresent = true
+			input.ServerLifecycle = rvboxv1.CommandLifecycle(lifecycle)
+			input.ServerRevision = domain.CommandRevision(revision)
+			input.ServerLastEventSeq = lastSequence
+			input.ImmutableHashMatches = len(hash) == len(client.GetImmutableRequestSha256()) && string(hash) == string(client.GetImmutableRequestSha256())
+		} else if !errors.Is(err, sql.ErrNoRows) {
+			return nil, err
+		} else {
+			var tombstoneHash []byte
+			err = store.db.QueryRowContext(ctx, `SELECT immutable_sha256 FROM command_tombstones WHERE issue_uuid = ? AND client_id = ?`, issue[:], clientID).Scan(&tombstoneHash)
+			if err == nil {
+				input.ServerHasTombstone = true
+				input.ImmutableHashMatches = len(tombstoneHash) == len(client.GetImmutableRequestSha256()) && string(tombstoneHash) == string(client.GetImmutableRequestSha256())
+			} else if !errors.Is(err, sql.ErrNoRows) {
+				return nil, err
+			}
+		}
+		decision, err := domain.DecideReconciliation(input)
+		if err != nil && !errors.Is(err, domain.ErrReconcileContradiction) {
+			return nil, err
+		}
+		switch decision.Action {
+		case domain.ReconcileTerminateLocal:
+			result.TerminateLocalIssueUuids = append(result.TerminateLocalIssueUuids, issue.String())
+		case domain.ReconcileDiscardLocalTerminal:
+			result.DiscardLocalTerminalIssueUuids = append(result.DiscardLocalTerminalIssueUuids, issue.String())
+		}
+	}
+	return result, nil
+}