/**
 * Abstract base class for configuration migrations
 *
 * Each migration represents an upgrade from one config version to another.
 * Migrations run in order based on the `order` field, allowing users to jump
 * multiple versions (e.g., v1 → v4 runs migrations 2, 3, and 4).
 */
/**
 * Abstract base class for configuration migrations
 *
 * Each migration represents an upgrade from one config version to another.
 * Migrations run in order based on the `toVersion` field, allowing users to jump
 * multiple versions (e.g., v1 → v4 runs migrations 2, 3, and 4).
 */
export abstract class BaseMigration {
  /**
   * Source version this migration upgrades from
   * e.g., "1.x", "3.x"
   */
  abstract readonly fromVersion: string;

  /**
   * Target version this migration upgrades to
   * e.g., "2.0", "4.0", "4.1"
   */
  abstract readonly toVersion: string;

  /**
   * Check if this migration should run on the given config
   *
   * @param config - Raw configuration object to check (unknown schema for migrations)
   * @returns True if migration should run, false otherwise
   */
  abstract shouldRun(config: Record<string, unknown>): Promise<boolean>;

  /**
   * Perform the migration on the given config
   *
   * @param config - Raw configuration object to migrate (unknown schema for migrations)
   * @returns Migrated configuration object
   */
  abstract migrate(config: Record<string, unknown>): Promise<Record<string, unknown>>;

  /**
   * Get human-readable name for this migration
   *
   * @returns Migration name
   */
  getName(): string {
    return `Migration ${this.fromVersion} → ${this.toVersion}`;
  }

  /**
   * Parse version string into a comparable number
   * Supports formats like "2.0", "4.1", etc.
   * Returns a number like 2.0, 4.1 for sorting
   *
   * @returns Parsed version number for ordering
   */
  getVersionOrder(): number {
    const parsed = parseFloat(this.toVersion);
    if (isNaN(parsed)) {
      throw new Error(`Invalid version format: ${this.toVersion}`);
    }
    return parsed;
  }
}