first commit

pigo/internal/cli/persist.go

@@ -0,0 +1,53 @@
+// This file holds PersistTurn, the session-tree persistence step shared by the
+// REPL loop and the /goal autonomous loop. It reads and advances a session's
+// mutable cursor state through the Host contract, so a command need not import
+// the concrete replDeps aggregate to persist the tail of a turn.
+package cli
+
+import (
+	"fmt"
+	"io"
+	"time"
+)
+
+// PersistTurn appends the messages produced since the last persist as a new
+// branch descending from the host's current leaf, advancing the leaf and the
+// persisted-message cursor. Growing the tree with AppendBranch (rather than a
+// full linear Save) is what lets a later /tree leaf-switch fork the on-disk
+// history instead of clobbering it. If nothing new was produced it is a no-op:
+// rewriting the file would regenerate entry ids and flatten the tree.
+func PersistTurn(out io.Writer, h Host) {
+	agentCtx := h.AgentCtx()
+	// Automatic compaction during a turn rewrites Messages into a summary + recent
+	// tail, shrinking the slice below the persisted cursor. The append-a-tail
+	// branch model no longer holds (the prefix changed and Messages[persisted:]
+	// would be out of range), so re-save the flattened context linearly and reset
+	// the branch cursor to the new leaf, mirroring the /compact handler.
+	if h.Persisted() > len(agentCtx.Messages) {
+		header := h.Header()
+		header.UpdatedAt = time.Now().UTC()
+		if err := h.Store().Save(header, agentCtx.Messages); err != nil {
+			fmt.Fprintf(out, "pigo: session save failed: %v\n", err)
+			return
+		}
+		h.SetPersisted(len(agentCtx.Messages))
+		h.SetCurLeaf("")
+		if _, entries, err := h.Store().LoadEntries(header.ID); err == nil && len(entries) > 0 {
+			h.SetCurLeaf(entries[len(entries)-1].ID)
+		}
+		return
+	}
+	tail := agentCtx.Messages[h.Persisted():]
+	if len(tail) == 0 {
+		return
+	}
+	header := h.Header()
+	header.UpdatedAt = time.Now().UTC()
+	leaf, err := h.Store().AppendBranch(header, h.CurLeaf(), tail)
+	if err != nil {
+		fmt.Fprintf(out, "pigo: session save failed: %v\n", err)
+		return
+	}
+	h.SetCurLeaf(leaf)
+	h.SetPersisted(len(agentCtx.Messages))
+}