From 456e899b50051e306322e7640ad7f61e57044271 Mon Sep 17 00:00:00 2001
From: Carl Niklas Rydberg <carlniklasrydberg@gmail.com>
Date: Sun, 21 Dec 2025 21:11:36 +0100
Subject: [PATCH] Added the snapshot/epoch type and getter in the public API,
 plus the store wrapper implementation:

---
 include/amduat/tgk/tgk_store_mem.h         |  2 ++
 src/adapters/tgk_store_fs/tgk_store_fs.c   | 12 ++++++++++++
 src/adapters/tgk_store_mem/tgk_store_mem.c | 15 +++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/include/amduat/tgk/tgk_store_mem.h b/include/amduat/tgk/tgk_store_mem.h
index 10c73a7..b1d3590 100644
--- a/include/amduat/tgk/tgk_store_mem.h
+++ b/include/amduat/tgk/tgk_store_mem.h
@@ -18,6 +18,8 @@ typedef struct {
 } amduat_tgk_store_mem_artifact_t;
 
 typedef struct {
+  /* Monotonic snapshot/epoch; increments when ingest/remove mutates state. */
+  amduat_tgk_snapshot_id_t snapshot_id;
   amduat_tgk_store_config_t config;
   const amduat_tgk_store_mem_artifact_t *artifacts;
   size_t artifacts_len;
diff --git a/src/adapters/tgk_store_fs/tgk_store_fs.c b/src/adapters/tgk_store_fs/tgk_store_fs.c
index fbfc254..16ad7ec 100644
--- a/src/adapters/tgk_store_fs/tgk_store_fs.c
+++ b/src/adapters/tgk_store_fs/tgk_store_fs.c
@@ -122,6 +122,17 @@ static bool amduat_tgk_store_fs_get_config(void *ctx,
   return mem_ops.get_config(&fs->mem, out_config);
 }
 
+static bool amduat_tgk_store_fs_snapshot_id(void *ctx,
+                                            amduat_tgk_snapshot_id_t *out_id) {
+  amduat_tgk_store_fs_t *fs = (amduat_tgk_store_fs_t *)ctx;
+  amduat_tgk_store_ops_t mem_ops = amduat_tgk_store_mem_ops();
+
+  if (fs == NULL || mem_ops.snapshot_id == NULL) {
+    return false;
+  }
+  return mem_ops.snapshot_id(&fs->mem, out_id);
+}
+
 static amduat_tgk_graph_error_t amduat_tgk_store_fs_resolve_edge(
     void *ctx,
     amduat_reference_t ref,
@@ -349,6 +360,7 @@ amduat_tgk_store_ops_t amduat_tgk_store_fs_ops(void) {
 
   memset(&ops, 0, sizeof(ops));
   ops.get_config = amduat_tgk_store_fs_get_config;
+  ops.snapshot_id = amduat_tgk_store_fs_snapshot_id;
   ops.resolve_edge = amduat_tgk_store_fs_resolve_edge;
   ops.edges_from = amduat_tgk_store_fs_edges_from;
   ops.edges_to = amduat_tgk_store_fs_edges_to;
diff --git a/src/adapters/tgk_store_mem/tgk_store_mem.c b/src/adapters/tgk_store_mem/tgk_store_mem.c
index 3753396..a95dbc0 100644
--- a/src/adapters/tgk_store_mem/tgk_store_mem.c
+++ b/src/adapters/tgk_store_mem/tgk_store_mem.c
@@ -555,6 +555,18 @@ static bool amduat_tgk_store_mem_get_config(void *ctx,
   return true;
 }
 
+static bool amduat_tgk_store_mem_snapshot_id(
+    void *ctx,
+    amduat_tgk_snapshot_id_t *out_id) {
+  amduat_tgk_store_mem_t *mem = (amduat_tgk_store_mem_t *)ctx;
+
+  if (mem == NULL || out_id == NULL) {
+    return false;
+  }
+  *out_id = mem->snapshot_id;
+  return true;
+}
+
 static amduat_tgk_graph_error_t amduat_tgk_store_mem_resolve_edge(
     void *ctx,
     amduat_reference_t ref,
@@ -829,6 +841,7 @@ bool amduat_tgk_store_mem_init(amduat_tgk_store_mem_t *mem,
   if (mem == NULL) {
     return false;
   }
+  mem->snapshot_id = 0;
   mem->config = config;
   mem->artifacts = artifacts;
   mem->artifacts_len = artifacts_len;
@@ -926,6 +939,7 @@ void amduat_tgk_store_mem_free(amduat_tgk_store_mem_t *mem) {
   mem->edges_len = 0;
   mem->artifacts = NULL;
   mem->artifacts_len = 0;
+  mem->snapshot_id = 0;
 }
 
 amduat_tgk_store_ops_t amduat_tgk_store_mem_ops(void) {
@@ -933,6 +947,7 @@ amduat_tgk_store_ops_t amduat_tgk_store_mem_ops(void) {
 
   memset(&ops, 0, sizeof(ops));
   ops.get_config = amduat_tgk_store_mem_get_config;
+  ops.snapshot_id = amduat_tgk_store_mem_snapshot_id;
   ops.resolve_edge = amduat_tgk_store_mem_resolve_edge;
   ops.edges_from = amduat_tgk_store_mem_edges_from;
   ops.edges_to = amduat_tgk_store_mem_edges_to;