Add local-first refactor foundation

internal/store/migrations.go

@@ -0,0 +1,92 @@
+package store
+
+import (
+	"embed"
+	"fmt"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+//go:embed migrations/*.sql
+var migrationFS embed.FS
+
+func (s *Store) applyMigrations() error {
+	if _, err := s.db.Exec(`
+		CREATE TABLE IF NOT EXISTS schema_migrations (
+			version    INTEGER PRIMARY KEY,
+			applied_at INTEGER NOT NULL
+		)
+	`); err != nil {
+		return fmt.Errorf("bootstrap schema_migrations: %w", err)
+	}
+
+	entries, err := migrationFS.ReadDir("migrations")
+	if err != nil {
+		return fmt.Errorf("read migrations: %w", err)
+	}
+
+	var files []string
+	for _, entry := range entries {
+		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".sql") {
+			continue
+		}
+		files = append(files, entry.Name())
+	}
+	sort.Strings(files)
+
+	for _, name := range files {
+		version, err := migrationVersion(name)
+		if err != nil {
+			return err
+		}
+
+		applied, err := s.isMigrationApplied(version)
+		if err != nil {
+			return err
+		}
+		if applied {
+			continue
+		}
+
+		sqlBytes, err := migrationFS.ReadFile("migrations/" + name)
+		if err != nil {
+			return fmt.Errorf("read migration %s: %w", name, err)
+		}
+
+		if _, err := s.db.Exec(string(sqlBytes)); err != nil {
+			return fmt.Errorf("apply migration %s: %w", name, err)
+		}
+
+		if _, err := s.db.Exec(
+			`INSERT INTO schema_migrations (version, applied_at) VALUES (?, ?)`,
+			version, time.Now().Unix(),
+		); err != nil {
+			return fmt.Errorf("record migration %s: %w", name, err)
+		}
+	}
+
+	return nil
+}
+
+func migrationVersion(name string) (int, error) {
+	prefix := strings.SplitN(name, "_", 2)[0]
+	version, err := strconv.Atoi(prefix)
+	if err != nil {
+		return 0, fmt.Errorf("invalid migration filename %q: %w", name, err)
+	}
+	return version, nil
+}
+
+func (s *Store) isMigrationApplied(version int) (bool, error) {
+	var count int
+	err := s.db.QueryRow(
+		`SELECT COUNT(*) FROM schema_migrations WHERE version = ?`,
+		version,
+	).Scan(&count)
+	if err != nil {
+		return false, err
+	}
+	return count > 0, nil
+}