Init

src/db/index.ts

@@ -0,0 +1,154 @@
+/**
+ * Database Layer
+ *
+ * Handles SQLite database initialization and connection management.
+ */
+
+import Database from 'better-sqlite3';
+import * as fs from 'fs';
+import * as path from 'path';
+import { SchemaVersion } from '../types';
+import { runMigrations, getCurrentVersion, CURRENT_SCHEMA_VERSION } from './migrations';
+
+/**
+ * Database connection wrapper with lifecycle management
+ */
+export class DatabaseConnection {
+  private db: Database.Database;
+  private dbPath: string;
+
+  private constructor(db: Database.Database, dbPath: string) {
+    this.db = db;
+    this.dbPath = dbPath;
+  }
+
+  /**
+   * Initialize a new database at the given path
+   */
+  static initialize(dbPath: string): DatabaseConnection {
+    // Ensure parent directory exists
+    const dir = path.dirname(dbPath);
+    if (!fs.existsSync(dir)) {
+      fs.mkdirSync(dir, { recursive: true });
+    }
+
+    // Create and configure database
+    const db = new Database(dbPath);
+
+    // Enable foreign keys and WAL mode for better performance
+    db.pragma('foreign_keys = ON');
+    db.pragma('journal_mode = WAL');
+
+    // Run schema initialization
+    const schemaPath = path.join(__dirname, 'schema.sql');
+    const schema = fs.readFileSync(schemaPath, 'utf-8');
+    db.exec(schema);
+
+    return new DatabaseConnection(db, dbPath);
+  }
+
+  /**
+   * Open an existing database
+   */
+  static open(dbPath: string): DatabaseConnection {
+    if (!fs.existsSync(dbPath)) {
+      throw new Error(`Database not found: ${dbPath}`);
+    }
+
+    const db = new Database(dbPath);
+
+    // Enable foreign keys and WAL mode
+    db.pragma('foreign_keys = ON');
+    db.pragma('journal_mode = WAL');
+
+    // Check and run migrations if needed
+    const conn = new DatabaseConnection(db, dbPath);
+    const currentVersion = getCurrentVersion(db);
+
+    if (currentVersion < CURRENT_SCHEMA_VERSION) {
+      runMigrations(db, currentVersion);
+    }
+
+    return conn;
+  }
+
+  /**
+   * Get the underlying database instance
+   */
+  getDb(): Database.Database {
+    return this.db;
+  }
+
+  /**
+   * Get database file path
+   */
+  getPath(): string {
+    return this.dbPath;
+  }
+
+  /**
+   * Get current schema version
+   */
+  getSchemaVersion(): SchemaVersion | null {
+    const row = this.db
+      .prepare('SELECT version, applied_at, description FROM schema_versions ORDER BY version DESC LIMIT 1')
+      .get() as { version: number; applied_at: number; description: string | null } | undefined;
+
+    if (!row) return null;
+
+    return {
+      version: row.version,
+      appliedAt: row.applied_at,
+      description: row.description ?? undefined,
+    };
+  }
+
+  /**
+   * Execute a function within a transaction
+   */
+  transaction<T>(fn: () => T): T {
+    return this.db.transaction(fn)();
+  }
+
+  /**
+   * Get database file size in bytes
+   */
+  getSize(): number {
+    const stats = fs.statSync(this.dbPath);
+    return stats.size;
+  }
+
+  /**
+   * Optimize database (vacuum and analyze)
+   */
+  optimize(): void {
+    this.db.exec('VACUUM');
+    this.db.exec('ANALYZE');
+  }
+
+  /**
+   * Close the database connection
+   */
+  close(): void {
+    this.db.close();
+  }
+
+  /**
+   * Check if the database connection is open
+   */
+  isOpen(): boolean {
+    return this.db.open;
+  }
+}
+
+/**
+ * Default database filename
+ */
+export const DATABASE_FILENAME = 'codegraph.db';
+
+/**
+ * Get the default database path for a project
+ */
+export function getDatabasePath(projectRoot: string): string {
+  return path.join(projectRoot, '.codegraph', DATABASE_FILENAME);
+}