feat(memory/projectindex): 项目索引分层（索引+描述+章节，Search 定位行+上下文，级联删除）

internal/runtime/memory/projectindex/chapter.go

@@ -0,0 +1,110 @@
+package projectindex
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// Chapter is a project chapter (layer 3 of the hierarchy): the deep content a
+// project is split into. ProjectID links it to the owning project. The zero
+// value is not a valid chapter: AddChapter requires a non-blank title and
+// content, and generates the id.
+type Chapter struct {
+	ID        string
+	ProjectID string
+	Title     string
+	Content   string
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}
+
+// AddChapter persists ch under projectID, assigning an id and missing
+// timestamps. It requires a non-blank projectID, title and content; a blank id
+// is generated. The project row itself does not have to exist, so chapters may
+// be added before or after their parent project, but DeleteProject cascades
+// them away together.
+func (s *Store) AddChapter(ctx context.Context, projectID string, ch Chapter) error {
+	if strings.TrimSpace(projectID) == "" {
+		return ErrMissingProject
+	}
+	if strings.TrimSpace(ch.Title) == "" {
+		return ErrMissingTitle
+	}
+	if strings.TrimSpace(ch.Content) == "" {
+		return ErrMissingContent
+	}
+	now := time.Now().UTC()
+	if ch.ID == "" {
+		id, err := newID()
+		if err != nil {
+			return err
+		}
+		ch.ID = id
+	}
+	if ch.CreatedAt.IsZero() {
+		ch.CreatedAt = now
+	}
+	if ch.UpdatedAt.IsZero() {
+		ch.UpdatedAt = now
+	}
+	_, err := s.db.ExecContext(ctx, `INSERT INTO project_chapter
+		(id, project_id, title, content, created_at, updated_at)
+		VALUES (?, ?, ?, ?, ?, ?)`,
+		ch.ID, projectID, ch.Title, ch.Content,
+		formatTime(ch.CreatedAt), formatTime(ch.UpdatedAt))
+	if err != nil {
+		return fmt.Errorf("projectindex: insert chapter: %w", err)
+	}
+	s.log.Debug("chapter added", "project_id", projectID, "chapter_id", ch.ID)
+	return nil
+}
+
+// ListChapters returns every chapter for projectID in insertion order. It returns
+// an empty (non-nil) slice when there are none; a blank projectID returns
+// ErrMissingProject.
+func (s *Store) ListChapters(ctx context.Context, projectID string) ([]Chapter, error) {
+	if strings.TrimSpace(projectID) == "" {
+		return nil, ErrMissingProject
+	}
+	rows, err := s.db.QueryContext(ctx, `SELECT id, project_id, title, content,
+		created_at, updated_at FROM project_chapter
+		WHERE project_id = ? ORDER BY created_at ASC, id ASC`, projectID)
+	if err != nil {
+		return nil, fmt.Errorf("projectindex: list chapters: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	chapters := make([]Chapter, 0)
+	for rows.Next() {
+		ch, err := scanChapter(rows)
+		if err != nil {
+			return nil, fmt.Errorf("projectindex: scan chapter: %w", err)
+		}
+		chapters = append(chapters, ch)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("projectindex: iterate chapters: %w", err)
+	}
+	return chapters, nil
+}
+
+// scanChapter reads one project_chapter row.
+func scanChapter(sc rowScanner) (Chapter, error) {
+	var (
+		ch                  Chapter
+		createdAt, updatedAt string
+	)
+	if err := sc.Scan(&ch.ID, &ch.ProjectID, &ch.Title, &ch.Content, &createdAt, &updatedAt); err != nil {
+		return Chapter{}, err
+	}
+	var err error
+	if ch.CreatedAt, err = parseTime(createdAt); err != nil {
+		return Chapter{}, err
+	}
+	if ch.UpdatedAt, err = parseTime(updatedAt); err != nil {
+		return Chapter{}, err
+	}
+	return ch, nil
+}