Init

src/db/migrations.ts

@@ -0,0 +1,122 @@
+/**
+ * Database Migrations
+ *
+ * Schema versioning and migration support.
+ */
+
+import Database from 'better-sqlite3';
+
+/**
+ * Current schema version
+ */
+export const CURRENT_SCHEMA_VERSION = 1;
+
+/**
+ * Migration definition
+ */
+interface Migration {
+  version: number;
+  description: string;
+  up: (db: Database.Database) => void;
+}
+
+/**
+ * All migrations in order
+ *
+ * Note: Version 1 is the initial schema, handled by schema.sql
+ * Future migrations go here.
+ */
+const migrations: Migration[] = [
+  // Example migration for version 2 (when needed):
+  // {
+  //   version: 2,
+  //   description: 'Add support for module resolution',
+  //   up: (db) => {
+  //     db.exec(`
+  //       ALTER TABLE nodes ADD COLUMN module_path TEXT;
+  //       CREATE INDEX idx_nodes_module_path ON nodes(module_path);
+  //     `);
+  //   },
+  // },
+];
+
+/**
+ * Get the current schema version from the database
+ */
+export function getCurrentVersion(db: Database.Database): number {
+  try {
+    const row = db
+      .prepare('SELECT MAX(version) as version FROM schema_versions')
+      .get() as { version: number | null } | undefined;
+    return row?.version ?? 0;
+  } catch {
+    // Table doesn't exist yet
+    return 0;
+  }
+}
+
+/**
+ * Record a migration as applied
+ */
+function recordMigration(db: Database.Database, version: number, description: string): void {
+  db.prepare(
+    'INSERT INTO schema_versions (version, applied_at, description) VALUES (?, ?, ?)'
+  ).run(version, Date.now(), description);
+}
+
+/**
+ * Run all pending migrations
+ */
+export function runMigrations(db: Database.Database, fromVersion: number): void {
+  const pending = migrations.filter((m) => m.version > fromVersion);
+
+  if (pending.length === 0) {
+    return;
+  }
+
+  // Sort by version
+  pending.sort((a, b) => a.version - b.version);
+
+  // Run each migration in a transaction
+  for (const migration of pending) {
+    db.transaction(() => {
+      migration.up(db);
+      recordMigration(db, migration.version, migration.description);
+    })();
+  }
+}
+
+/**
+ * Check if the database needs migration
+ */
+export function needsMigration(db: Database.Database): boolean {
+  const current = getCurrentVersion(db);
+  return current < CURRENT_SCHEMA_VERSION;
+}
+
+/**
+ * Get list of pending migrations
+ */
+export function getPendingMigrations(db: Database.Database): Migration[] {
+  const current = getCurrentVersion(db);
+  return migrations
+    .filter((m) => m.version > current)
+    .sort((a, b) => a.version - b.version);
+}
+
+/**
+ * Get migration history from database
+ */
+export function getMigrationHistory(
+  db: Database.Database
+): Array<{ version: number; appliedAt: number; description: string | null }> {
+  const rows = db
+    .prepare('SELECT version, applied_at, description FROM schema_versions ORDER BY version')
+    .all() as Array<{ version: number; applied_at: number; description: string | null }>;
+
+  return rows.map((row) => ({
+    version: row.version,
+    appliedAt: row.applied_at,
+    description: row.description,
+  }));
+}