feat(v0.4): add SessionSummary type with round-trip and launch-context formatter

2026-04-21 17:07:47 -04:00
parent 67138584d4
commit 68a4f7e4cc
2 changed files with 257 additions and 0 deletions
@@ -0,0 +1,148 @@
+package session
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// SessionSummary is the on-disk format of .ctask/last-session-summary.json.
+// It records what the last session changed and what the workspace looked like
+// at end-of-session, so the next session can (a) detect external modifications
+// (Layer 3) and (b) display a launch-context banner (Layer 4).
+type SessionSummary struct {
+	SessionID       string    `json:"session_id"`
+	Hostname        string    `json:"hostname"`
+	Agent           string    `json:"agent"`
+	Mode            string    `json:"mode"`
+	StartedAt       time.Time `json:"started_at"`
+	EndedAt         time.Time `json:"ended_at"`
+	DurationSeconds int64     `json:"duration_seconds"`
+	FilesAdded      []string  `json:"files_added"`
+	FilesModified   []string  `json:"files_modified"`
+	FilesDeleted    []string  `json:"files_deleted"`
+	NotesUpdated    bool      `json:"notes_updated"`
+	// EndManifest captures the workspace file list at end-of-session so the
+	// next session can diff current state against it (Layer 3). This field
+	// is ctask-internal; it is not part of the public summary format shown
+	// in the spec examples, but it enables stale-workspace detection from a
+	// single source file.
+	EndManifest []FileEntry `json:"end_manifest"`
+}
+
+// SummaryPath returns the absolute path of the summary file for wsDir.
+func SummaryPath(wsDir string) string {
+	return filepath.Join(wsDir, ".ctask", "last-session-summary.json")
+}
+
+// WriteSummary serializes s to path with indented JSON. Creates .ctask/ if needed.
+func WriteSummary(path string, s *SessionSummary) error {
+	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+		return err
+	}
+	if s.FilesAdded == nil {
+		s.FilesAdded = []string{}
+	}
+	if s.FilesModified == nil {
+		s.FilesModified = []string{}
+	}
+	if s.FilesDeleted == nil {
+		s.FilesDeleted = []string{}
+	}
+	if s.EndManifest == nil {
+		s.EndManifest = []FileEntry{}
+	}
+	data, err := json.MarshalIndent(s, "", "  ")
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(path, data, 0644)
+}
+
+// ReadSummary reads a summary from path.
+//   - missing file: returns (nil, nil) — normal pre-v0.4 case
+//   - corrupt JSON: returns (nil, wrapped err)
+//   - other I/O errors: returned to caller as-is
+func ReadSummary(path string) (*SessionSummary, error) {
+	data, err := os.ReadFile(path)
+	if errors.Is(err, os.ErrNotExist) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	var s SessionSummary
+	if err := json.Unmarshal(data, &s); err != nil {
+		return nil, fmt.Errorf("parsing summary: %w", err)
+	}
+	return &s, nil
+}
+
+// SummarizeFromDiff builds a SessionSummary from a session's identity,
+// start/end times, the diff, and the end manifest.
+func SummarizeFromDiff(
+	sessionID, hostname, agent, mode string,
+	startedAt, endedAt time.Time,
+	diff *ManifestDiff,
+	endManifest *Manifest,
+) *SessionSummary {
+	s := &SessionSummary{
+		SessionID:       sessionID,
+		Hostname:        hostname,
+		Agent:           agent,
+		Mode:            mode,
+		StartedAt:       startedAt,
+		EndedAt:         endedAt,
+		DurationSeconds: int64(endedAt.Sub(startedAt).Seconds()),
+		FilesAdded:      append([]string{}, diff.Added...),
+		FilesModified:   append([]string{}, diff.Modified...),
+		FilesDeleted:    append([]string{}, diff.Deleted...),
+		NotesUpdated:    NotesUpdated(diff),
+	}
+	if endManifest != nil {
+		s.EndManifest = append([]FileEntry{}, endManifest.Files...)
+	} else {
+		s.EndManifest = []FileEntry{}
+	}
+	return s
+}
+
+// FormatLaunchContext renders the short "Last session: ... Changed: ..." banner
+// printed on session start (Layer 4). Returns empty string when s is nil.
+func FormatLaunchContext(s *SessionSummary) string {
+	if s == nil {
+		return ""
+	}
+	var b strings.Builder
+
+	fmt.Fprintf(&b, "[ctask] Last session: %s-%s (%s, %s)\n",
+		s.StartedAt.Local().Format("2006-01-02 15:04"),
+		s.EndedAt.Local().Format("15:04"),
+		s.Hostname, s.Agent)
+
+	changed := append([]string{}, s.FilesModified...)
+	changed = append(changed, s.FilesAdded...)
+	const maxShown = 2
+	more := 0
+	preview := changed
+	if len(changed) > maxShown {
+		preview = changed[:maxShown]
+		more = len(changed) - maxShown
+	}
+	if len(preview) == 0 && len(s.FilesDeleted) == 0 {
+		fmt.Fprintln(&b, "[ctask]   (no tracked file changes)")
+		return b.String()
+	}
+	if len(preview) > 0 {
+		fmt.Fprintf(&b, "[ctask]   Changed: %s", strings.Join(preview, ", "))
+		if more > 0 {
+			fmt.Fprintf(&b, " (+%d more)", more)
+		}
+		fmt.Fprintln(&b)
+	}
+	return b.String()
+}