import { Logger } from "./logger.js";
import { MigrationBuilderActions } from "./sqlMigration.js";
import { Jiti } from "jiti";

//#region src/migrationLoader.d.ts
/***
 * Migration loader module.
 *
 * This module is responsible for loading migrations from the file system, allowing for custom loading behaviours.
 * If no configuration is provided, loading will be performed in a manner that is identical to the classic loading behaviour.
 *
 * A new SQL migration loading behaviour is available that supports pairing up/down migrations in separate files using up/down
 * suffixes before the .sql extension.
 *
 * This has been kept intentionally simple for maintainability and readability reasons.
 *
 */
/**
 * The jiti instance to use to load migration files.
 */
declare const jiti: Jiti;
/*************************
 * Types and interfaces
 *************************/
/**
 * A migration unit is a collection of file paths and related migration actions that are related to a single migration.
 */
interface MigrationUnit {
  /**
   * The unique identifier for the migration unit. Represents the significant part of the file name.
   * Used for tracking which migrations have been performed.
   */
  id: string;
  /**
   * The file paths that are part of the migration unit.
   */
  filePaths: string[];
  /**
   * The migration builder actions that are contained within the migration files.
   */
  actions: MigrationBuilderActions;
}
/**
 * Loader function type.
 *
 * @param filePaths - The file paths to load migrations from.
 * @returns A list of migration units.
 */
type MigrationLoader = (filePaths: string[]) => Promise<MigrationUnit[]>;
/**
 * Predefined loader references.
 */
type PredefinedLoader = 'default' | 'legacySql' | 'sql';
/**
 * Configuration extension to support multiple loader strategies.
 */
interface MigrationLoaderConfig {
  /**
   * Configuration for the migration loader strategies.
   * Strategies are used to load migrations from different sources based on file patterns.
   *
   * If no strategy matches, the default strategy is used.
   */
  migrationLoaderStrategies?: MigrationLoaderStrategy[];
  /**
   * Enable [`jiti`](https://github.com/unjs/jiti) tsconfig paths resolution when
   * loading TypeScript/JavaScript migration files. This makes `compilerOptions.paths`
   * aliases defined in your `tsconfig.json` resolvable from within migration files.
   *
   * - `true`: auto-discover the nearest `tsconfig.json` (walking up from `cwd()`)
   * - `string`: explicit path to a `tsconfig.json` file
   * - `false` / `undefined` (default): disabled
   *
   * Has no effect on the built-in SQL loaders.
   *
   * @default false
   */
  tsconfigPaths?: boolean | string;
  /**
   * Redirect messages to this logger object, rather than `console`.
   */
  logger?: Logger;
}
/**
 * A migration loader strategy is a configuration object that defines a specific loader for given file extensions.
 */
interface MigrationLoaderStrategy {
  /**
   * File extensions handled by this strategy.
   */
  extensions: string[];
  /**
   * Loader that handles conversion of file paths to migration units.
   * Can be a loader function, when used as an API, or a predefined loader when using a json configuration file.
   *
   * @param filePaths - The file paths to load migrations from.
   * @returns The migration units.
   */
  loader: MigrationLoader | PredefinedLoader;
}
/*************************
 * Loader implementations
 *************************/
/**
 * Creates a default migration loader that uses jiti to load migrations from the file paths.
 * @param jitiInstance - The jiti instance to use to load migration files. Defaults to the shared {@link jiti} instance.
 * @returns The default migration loader.
 */
declare function createDefaultMigrationLoader(jitiInstance?: Jiti): MigrationLoader;
/**
 * Creates a legacy SQL migration loader that loads migrations from the file paths using the legacy SQL migration loading behaviour.
 * @returns The legacy SQL migration loader.
 */
declare function createLegacySqlMigrationLoader(): MigrationLoader;
/**
 * Creates a SQL migration loader that loads migrations from the file paths using the new SQL migration loading behaviour.
 * While it handles the legacy format, it does add new behaviour that may be unwanted in existing usage so it has been
 * separated from the legacy loader and can be used enabled as needed.
 *
 * @returns The SQL migration loader.
 */
declare function createSqlMigrationLoader(): MigrationLoader;
/*************************
 * Loader instances
 *************************/
/**
 * Built-in predefined loaders.
 */
declare const builtInLoaders: Record<PredefinedLoader, MigrationLoader>;
/***********************************
 * Migration loader main function
 ***********************************/
/**
 * Loads the migration units from the file paths.
 * @param config - The migration loader configuration.
 * @param filePaths - List of files containing migrations.
 * @returns List of migration units, sorted according to the given file paths.
 */
declare function loadMigrationUnits(config: MigrationLoaderConfig, filePaths: string[]): Promise<MigrationUnit[]>;
//#endregion
export { MigrationLoader, MigrationLoaderConfig, MigrationLoaderStrategy, MigrationUnit, builtInLoaders, createDefaultMigrationLoader, createLegacySqlMigrationLoader, createSqlMigrationLoader, jiti, loadMigrationUnits };