feat(db): add wiki-link extraction, resolution, and backlinks

[[wiki-links]] in entry bodies are extracted at save time, resolved to entity IDs (title match first, body substring fallback), and stored in entity_links junction table. Backlinks surface in TUI detail view showing entries that link to the current entry. Schema migration v5 adds entity_links with CASCADE/SET NULL semantics. Links sync on Create, Update, and Absorb.
2026-05-21 13:34:56 -04:00
parent d24df8432f
commit 1e58433936
10 changed files with 454 additions and 8 deletions
@@ -56,7 +56,7 @@ func (s *Store) Backup(dst string) error {
 	return err
 }

-const currentSchema = 4
+const currentSchema = 5

 var migrations = []func(db *sql.DB) error{
 	// v1: initial schema
@@ -188,6 +188,20 @@ var migrations = []func(db *sql.DB) error{
 		}
 		return nil
 	},
+
+	// v5: add entity_links table for wiki-links
+	func(db *sql.DB) error {
+		_, err := db.Exec(`
+			CREATE TABLE entity_links (
+				from_id   TEXT NOT NULL REFERENCES entities(id) ON DELETE CASCADE,
+				to_id     TEXT REFERENCES entities(id) ON DELETE SET NULL,
+				link_text TEXT NOT NULL,
+				PRIMARY KEY (from_id, link_text)
+			);
+			CREATE INDEX idx_entity_links_to ON entity_links(to_id) WHERE to_id IS NOT NULL;
+		`)
+		return err
+	},
 }

 func (s *Store) migrate() error {
@@ -152,6 +152,10 @@ func (s *Store) Create(ctx context.Context, e *Entity) error {
 		return err
 	}

+	if err := syncLinks(ctx, tx, s, e.ID, e.Body); err != nil {
+		return err
+	}
+
 	return tx.Commit()
 }

@@ -383,6 +387,12 @@ func (s *Store) Update(ctx context.Context, id string, u *EntityUpdate) error {
 		}
 	}

+	if u.Body != nil {
+		if err := syncLinks(ctx, tx, s, existing.ID, *u.Body); err != nil {
+			return err
+		}
+	}
+
 	return tx.Commit()
 }

@@ -495,6 +505,10 @@ func (s *Store) Absorb(ctx context.Context, targetID, sourceID string) error {
 		}
 	}

+	if err := syncLinks(ctx, tx, s, targetID, merged); err != nil {
+		return err
+	}
+
 	if source.CardType != nil {
 		if _, err := tx.ExecContext(ctx, `UPDATE entities SET card_type = NULL, card_data = NULL,
 			use_count = 0, last_used_at = NULL, modified_at = ? WHERE id = ?`,
@@ -0,0 +1,83 @@
+package db
+
+import (
+	"context"
+	"database/sql"
+	"strings"
+
+	"github.com/lerko/nib/internal/link"
+)
+
+type Backlink struct {
+	EntityID string
+	Title    *string
+	Body     string
+	LinkText string
+}
+
+func (s *Store) resolveLink(ctx context.Context, tx *sql.Tx, linkText string, excludeID string) *string {
+	lower := strings.ToLower(linkText)
+
+	var id string
+	err := tx.QueryRowContext(ctx, `
+		SELECT id FROM entities
+		WHERE LOWER(title) = ? AND id != ? AND deleted_at IS NULL
+		ORDER BY created_at DESC LIMIT 1`, lower, excludeID).Scan(&id)
+	if err == nil {
+		return &id
+	}
+
+	err = tx.QueryRowContext(ctx, `
+		SELECT id FROM entities
+		WHERE LOWER(body) LIKE ? AND id != ? AND deleted_at IS NULL
+		ORDER BY created_at DESC LIMIT 1`, "%"+lower+"%", excludeID).Scan(&id)
+	if err == nil {
+		return &id
+	}
+
+	return nil
+}
+
+func syncLinks(ctx context.Context, tx *sql.Tx, s *Store, entityID string, body string) error {
+	if _, err := tx.ExecContext(ctx, "DELETE FROM entity_links WHERE from_id = ?", entityID); err != nil {
+		return err
+	}
+
+	linkTexts := link.ExtractLinks(body)
+	for _, lt := range linkTexts {
+		toID := s.resolveLink(ctx, tx, lt, entityID)
+		if _, err := tx.ExecContext(ctx,
+			"INSERT OR IGNORE INTO entity_links (from_id, to_id, link_text) VALUES (?, ?, ?)",
+			entityID, toID, lt); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (s *Store) LoadBacklinks(ctx context.Context, entityID string) ([]Backlink, error) {
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT e.id, e.title, e.body, el.link_text
+		FROM entity_links el
+		JOIN entities e ON e.id = el.from_id
+		WHERE el.to_id = ? AND e.deleted_at IS NULL
+		ORDER BY e.created_at DESC`, entityID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var backlinks []Backlink
+	for rows.Next() {
+		var bl Backlink
+		var title sql.NullString
+		if err := rows.Scan(&bl.EntityID, &title, &bl.Body, &bl.LinkText); err != nil {
+			return nil, err
+		}
+		if title.Valid {
+			bl.Title = &title.String
+		}
+		backlinks = append(backlinks, bl)
+	}
+	return backlinks, rows.Err()
+}
@@ -0,0 +1,225 @@
+package db
+
+import (
+	"context"
+	"testing"
+)
+
+func TestSyncLinks_OnCreate(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	target := &Entity{Body: "nginx proxy config", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, target); err != nil {
+		t.Fatal(err)
+	}
+
+	source := &Entity{Body: "see [[nginx proxy config]] for setup", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, source); err != nil {
+		t.Fatal(err)
+	}
+
+	backlinks, err := s.LoadBacklinks(ctx, target.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(backlinks) != 1 {
+		t.Fatalf("expected 1 backlink, got %d", len(backlinks))
+	}
+	if backlinks[0].EntityID != source.ID {
+		t.Errorf("backlink entity = %s, want %s", backlinks[0].EntityID, source.ID)
+	}
+	if backlinks[0].LinkText != "nginx proxy config" {
+		t.Errorf("link text = %q, want %q", backlinks[0].LinkText, "nginx proxy config")
+	}
+}
+
+func TestSyncLinks_TitleMatch(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	title := "deploy checklist"
+	target := &Entity{Body: "steps to deploy", Title: &title, Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, target); err != nil {
+		t.Fatal(err)
+	}
+
+	source := &Entity{Body: "follow [[deploy checklist]]", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, source); err != nil {
+		t.Fatal(err)
+	}
+
+	backlinks, err := s.LoadBacklinks(ctx, target.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(backlinks) != 1 {
+		t.Fatalf("expected 1 backlink, got %d", len(backlinks))
+	}
+}
+
+func TestSyncLinks_TitlePriority(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	title := "nginx config"
+	titled := &Entity{Body: "some body", Title: &title, Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, titled); err != nil {
+		t.Fatal(err)
+	}
+
+	bodyMatch := &Entity{Body: "nginx config details", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, bodyMatch); err != nil {
+		t.Fatal(err)
+	}
+
+	source := &Entity{Body: "see [[nginx config]]", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, source); err != nil {
+		t.Fatal(err)
+	}
+
+	backlinks, err := s.LoadBacklinks(ctx, titled.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(backlinks) != 1 {
+		t.Fatalf("title match should win, got %d backlinks on titled entity", len(backlinks))
+	}
+
+	bodyBacklinks, err := s.LoadBacklinks(ctx, bodyMatch.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(bodyBacklinks) != 0 {
+		t.Fatalf("body match entity should have 0 backlinks, got %d", len(bodyBacklinks))
+	}
+}
+
+func TestSyncLinks_Unresolved(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	source := &Entity{Body: "see [[nonexistent entry]]", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, source); err != nil {
+		t.Fatal(err)
+	}
+
+	var count int
+	err := s.db.QueryRow("SELECT COUNT(*) FROM entity_links WHERE from_id = ?", source.ID).Scan(&count)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if count != 1 {
+		t.Fatalf("expected 1 link row (unresolved), got %d", count)
+	}
+
+	var toID *string
+	err = s.db.QueryRow("SELECT to_id FROM entity_links WHERE from_id = ?", source.ID).Scan(&toID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if toID != nil {
+		t.Errorf("expected NULL to_id for unresolved link, got %v", *toID)
+	}
+}
+
+func TestSyncLinks_OnUpdate(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	target := &Entity{Body: "original target", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, target); err != nil {
+		t.Fatal(err)
+	}
+
+	source := &Entity{Body: "no links yet", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, source); err != nil {
+		t.Fatal(err)
+	}
+
+	newBody := "now has [[original target]]"
+	if err := s.Update(ctx, source.ID, &EntityUpdate{Body: &newBody}); err != nil {
+		t.Fatal(err)
+	}
+
+	backlinks, err := s.LoadBacklinks(ctx, target.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(backlinks) != 1 {
+		t.Fatalf("expected 1 backlink after update, got %d", len(backlinks))
+	}
+}
+
+func TestSyncLinks_SelfLinkUnresolved(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	e := &Entity{Body: "I reference [[I reference]]", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, e); err != nil {
+		t.Fatal(err)
+	}
+
+	var toID *string
+	err := s.db.QueryRow("SELECT to_id FROM entity_links WHERE from_id = ?", e.ID).Scan(&toID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if toID != nil {
+		t.Fatalf("self-matching link should be unresolved (NULL to_id), got %v", *toID)
+	}
+}
+
+func TestSyncLinks_NoLinks(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	e := &Entity{Body: "plain text no links", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, e); err != nil {
+		t.Fatal(err)
+	}
+
+	var count int
+	err := s.db.QueryRow("SELECT COUNT(*) FROM entity_links WHERE from_id = ?", e.ID).Scan(&count)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if count != 0 {
+		t.Fatalf("expected 0 links, got %d", count)
+	}
+}
+
+func TestSyncLinks_DeletedSourceHidden(t *testing.T) {
+	s := testStore(t)
+	ctx := context.Background()
+
+	target := &Entity{Body: "target entry", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, target); err != nil {
+		t.Fatal(err)
+	}
+
+	source := &Entity{Body: "see [[target entry]]", Glyph: "note", Tags: []string{}}
+	if err := s.Create(ctx, source); err != nil {
+		t.Fatal(err)
+	}
+
+	backlinks, err := s.LoadBacklinks(ctx, target.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(backlinks) != 1 {
+		t.Fatalf("expected 1 backlink before delete, got %d", len(backlinks))
+	}
+
+	if _, err := s.SoftDelete(ctx, source.ID); err != nil {
+		t.Fatal(err)
+	}
+
+	backlinks, err = s.LoadBacklinks(ctx, target.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(backlinks) != 0 {
+		t.Fatalf("soft-deleted source should not appear in backlinks, got %d", len(backlinks))
+	}
+}