feat(session): export PrependHistory for shared use across skills

internal/session/history.go

@@ -36,3 +36,21 @@ func FormatHistory(entries []Entry, excludePhase string) string {
 	}
 	return b.String()
 }
+
+// PrependHistory reads the session log for sessionID and prepends a formatted
+// history block to task. Returns task unchanged if sessionID or sessionsDir is
+// empty, or if no prior entries exist.
+func PrependHistory(sessionsDir, sessionID, currentPhase, task string) string {
+	if sessionID == "" || sessionsDir == "" {
+		return task
+	}
+	entries, err := Read(sessionsDir, sessionID)
+	if err != nil || len(entries) == 0 {
+		return task
+	}
+	history := FormatHistory(entries, currentPhase)
+	if history == "" {
+		return task
+	}
+	return history + "\n---\n\n" + task
+}

internal/session/history_test.go

@@ -2,11 +2,13 @@
 package session_test
 
 import (
+	"strings"
 	"testing"
 	"time"
 
 	"github.com/mathiasbq/supervisor/internal/session"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestFormatHistoryEmpty(t *testing.T) {
@@ -39,3 +41,45 @@ func TestFormatHistoryExcludesCurrentPhase(t *testing.T) {
 	assert.Contains(t, result, "red done")
 	assert.NotContains(t, result, "green done")
 }
+
+func TestPrependHistoryNoSessionID(t *testing.T) {
+	result := session.PrependHistory("", "", "review", "do the task")
+	assert.Equal(t, "do the task", result)
+}
+
+func TestPrependHistoryNoLog(t *testing.T) {
+	dir := t.TempDir()
+	result := session.PrependHistory(dir, "sess-abc", "review", "do the task")
+	assert.Equal(t, "do the task", result)
+}
+
+func TestPrependHistoryPrependsHistory(t *testing.T) {
+	dir := t.TempDir()
+	entry := session.Entry{
+		SessionID: "sess-abc", Skill: "tdd", Phase: "red",
+		FinalStatus: "pass", Message: "wrote test",
+		Timestamp: time.Now(),
+	}
+	require.NoError(t, session.Append(dir, "sess-abc", entry))
+
+	result := session.PrependHistory(dir, "sess-abc", "review", "do the task")
+	assert.Contains(t, result, "## Session history")
+	assert.Contains(t, result, "wrote test")
+	assert.True(t, strings.HasSuffix(result, "do the task"))
+}
+
+func TestPrependHistoryExcludesCurrentPhase(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, session.Append(dir, "sess-abc", session.Entry{
+		SessionID: "sess-abc", Skill: "tdd", Phase: "red",
+		FinalStatus: "pass", Message: "red done", Timestamp: time.Now(),
+	}))
+	require.NoError(t, session.Append(dir, "sess-abc", session.Entry{
+		SessionID: "sess-abc", Skill: "tdd", Phase: "green",
+		FinalStatus: "pass", Message: "green done", Timestamp: time.Now(),
+	}))
+
+	result := session.PrependHistory(dir, "sess-abc", "green", "do the task")
+	assert.Contains(t, result, "red done")
+	assert.NotContains(t, result, "green done")
+}