feat: tag system

internal/storage/sqlite.go

@@ -27,8 +27,23 @@ CREATE TABLE IF NOT EXISTS notes (
     published INTEGER NOT NULL
 );
 
+CREATE TABLE IF NOT EXISTS tags (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name TEXT NOT NULL UNIQUE
+);
+
+CREATE TABLE IF NOT EXISTS note_tags (
+    note_id TEXT NOT NULL,
+    tag_id INTEGER NOT NULL,
+    UNIQUE(note_id, tag_id),
+    FOREIGN KEY(note_id) REFERENCES notes(id) ON DELETE CASCADE,
+    FOREIGN KEY(tag_id) REFERENCES tags(id) ON DELETE CASCADE
+);
+
 CREATE INDEX IF NOT EXISTS notes_updated_at_idx ON notes(updated_at);
 CREATE INDEX IF NOT EXISTS notes_path_idx ON notes(path);
+CREATE INDEX IF NOT EXISTS note_tags_note_idx ON note_tags(note_id);
+CREATE INDEX IF NOT EXISTS note_tags_tag_idx ON note_tags(tag_id);
 `
 
 func NewSQLiteStorage(dbPath string) (*SQLiteStorage, error) {
@@ -68,6 +83,7 @@ func (s *SQLiteStorage) GetAll() []*note.Note {
 		if err != nil {
 			continue
 		}
+		n.Tags = s.GetTags(n.ID)
 		notes = append(notes, n)
 	}
 
@@ -89,6 +105,7 @@ func (s *SQLiteStorage) Get(id string) (*note.Note, error) {
 		return nil, err
 	}
 
+	n.Tags = s.GetTags(n.ID)
 	return n, nil
 }
 
@@ -150,6 +167,7 @@ func (s *SQLiteStorage) Search(query string) []*note.Note {
 		if err != nil {
 			continue
 		}
+		n.Tags = s.GetTags(n.ID)
 		notes = append(notes, n)
 	}
 
@@ -165,6 +183,94 @@ func (s *SQLiteStorage) Count() int {
 	return count
 }
 
+func (s *SQLiteStorage) AddTag(noteID, tag string) error {
+	tx, err := s.db.Begin()
+	if err != nil {
+		return fmt.Errorf("begin tx: %w", err)
+	}
+
+	if _, err := tx.Exec(`INSERT OR IGNORE INTO tags (name) VALUES (?)`, tag); err != nil {
+		_ = tx.Rollback()
+		return fmt.Errorf("insert tag: %w", err)
+	}
+
+	var tagID int64
+	if err := tx.QueryRow(`SELECT id FROM tags WHERE name = ?`, tag).Scan(&tagID); err != nil {
+		_ = tx.Rollback()
+		return fmt.Errorf("lookup tag: %w", err)
+	}
+
+	if _, err := tx.Exec(`INSERT OR IGNORE INTO note_tags (note_id, tag_id) VALUES (?, ?)`, noteID, tagID); err != nil {
+		_ = tx.Rollback()
+		return fmt.Errorf("attach tag: %w", err)
+	}
+
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("commit: %w", err)
+	}
+
+	return nil
+}
+
+func (s *SQLiteStorage) RemoveTag(noteID, tag string) error {
+	tx, err := s.db.Begin()
+	if err != nil {
+		return fmt.Errorf("begin tx: %w", err)
+	}
+
+	var tagID int64
+	err = tx.QueryRow(`SELECT id FROM tags WHERE name = ?`, tag).Scan(&tagID)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			_ = tx.Rollback()
+			return nil
+		}
+		_ = tx.Rollback()
+		return fmt.Errorf("lookup tag: %w", err)
+	}
+
+	if _, err := tx.Exec(`DELETE FROM note_tags WHERE note_id = ? AND tag_id = ?`, noteID, tagID); err != nil {
+		_ = tx.Rollback()
+		return fmt.Errorf("detach tag: %w", err)
+	}
+
+	if _, err := tx.Exec(`DELETE FROM tags WHERE id = ? AND NOT EXISTS (SELECT 1 FROM note_tags WHERE tag_id = ?)`, tagID, tagID); err != nil {
+		_ = tx.Rollback()
+		return fmt.Errorf("cleanup tag: %w", err)
+	}
+
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("commit: %w", err)
+	}
+
+	return nil
+}
+
+func (s *SQLiteStorage) GetTags(noteID string) []string {
+	rows, err := s.db.Query(`
+        SELECT t.name
+        FROM tags t
+        JOIN note_tags nt ON nt.tag_id = t.id
+        WHERE nt.note_id = ?
+        ORDER BY t.name
+    `, noteID)
+	if err != nil {
+		return []string{}
+	}
+	defer rows.Close()
+
+	var tags []string
+	for rows.Next() {
+		var name string
+		if err := rows.Scan(&name); err != nil {
+			continue
+		}
+		tags = append(tags, name)
+	}
+
+	return tags
+}
+
 type scanner interface {
 	Scan(dest ...interface{}) error
 }