import { DatabaseContext, LogLevel } from '../entity/db-context';
/**
 * Migration interface that all migration files must implement.
 *
 * Each migration has an up() method to apply changes and a down() method to revert them.
 * The db parameter provides full access to the DataContext for raw SQL execution.
 *
 * @example
 * ```typescript
 * export default class implements Migration {
 *   async up(db: AppDatabase): Promise<void> {
 *     await db.client.querySimple(`
 *       ALTER TABLE users ADD COLUMN new_field TEXT;
 *     `);
 *   }
 *
 *   async down(db: AppDatabase): Promise<void> {
 *     await db.client.querySimple(`
 *       ALTER TABLE users DROP COLUMN new_field;
 *     `);
 *   }
 * }
 * ```
 */
export interface Migration {
    /**
     * Apply the migration (upgrade)
     * @param db - The DataContext instance for executing queries
     */
    up(db: DatabaseContext): Promise<void>;
    /**
     * Revert the migration (downgrade)
     * @param db - The DataContext instance for executing queries
     */
    down(db: DatabaseContext): Promise<void>;
}
/**
 * Configuration for the migration system
 */
export interface MigrationConfig {
    /**
     * Directory containing migration files.
     * Can be relative to process.cwd() or absolute.
     */
    migrationsDirectory: string;
    /**
     * Name of the journal table that tracks applied migrations.
     * @default '__migrations'
     */
    journalTable?: string;
    /**
     * PostgreSQL schema for the journal table.
     * @default 'public'
     */
    journalSchema?: string;
    /**
     * Enable verbose logging of migration progress.
     * @default false
     */
    verbose?: boolean;
    /**
     * Custom logger function. If not provided, uses console.log.
     * Level indicates the type of log message ('info', 'error', 'debug').
     */
    logger?: (message: string, level?: LogLevel) => void;
}
/**
 * Journal entry representing an applied migration stored in the database
 */
export interface MigrationJournalEntry {
    /** Auto-generated ID */
    id: number;
    /** Migration filename (e.g., '20260204-143052.ts') */
    filename: string;
    /** Timestamp when the migration was applied */
    applied_at: Date;
}
/**
 * Loaded migration with metadata from the filesystem
 */
export interface LoadedMigration {
    /** Migration filename */
    filename: string;
    /** Parsed timestamp from filename (YYYYMMDD-HHMMSS) */
    timestamp: string;
    /** The migration instance */
    migration: Migration;
    /** Absolute path to the migration file */
    filePath: string;
}
/**
 * Result of running migrations
 */
export interface MigrationRunResult {
    /** List of successfully applied migration filenames */
    applied: string[];
    /** List of skipped migration filenames (already applied) */
    skipped: string[];
    /** If a migration failed, contains the filename and error */
    failed?: {
        filename: string;
        error: Error;
    };
}
/**
 * Direction for migration execution
 */
export type MigrationDirection = 'up' | 'down';
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