import type { File } from '../utils/virtual-module'

export type FindPages = (
  pagesDir: string,
  helpers: PageHelpers
) => void | Promise<void>

export interface PageHelpers extends PageAPIs {
  /**
   * Read the static data from a file.
   */
  readonly extractStaticData: (file: File) => Promise<{
    readonly [key: string]: any
    readonly sourceType: string
  }>
  /**
   * Scan the fileSystem and
   * set page data in the file handler.
   * File deletion will be handled automatically
   */
  readonly watchFiles: WatchFilesHelper
}

export interface WatchFilesHelper {
  /** Watch all files within a directory (except node_modules and .git) */
  (baseDir: string, fileHandler?: FileHandler): void
  /** Watch files matching the given glob */
  (baseDir: string, glob: string, fileHandler?: FileHandler): void
  /** Watch files matching one of the given globs */
  (baseDir: string, globs: string[], fileHandler?: FileHandler): void
}

export type FileHandler = (
  file: File,
  api: PageAPIs
) => void | Promise<void> | DataPiece | Promise<DataPiece>

export interface PageAPIs {
  /**
   * Get a mutable data object of runtimeData
   */
  getRuntimeData: (pageId: string) => {
    [key: string]: string
  }
  /**
   * Get a mutable data object of staticData
   */
  getStaticData: (pageId: string) => {
    [key: string]: any
  }
  /**
   * Add page data.
   * If the data already exists, overwrite it.
   */
  addPageData: (pageData: DataPiece) => void
}

export interface DataPiece {
  /**
   * The page route path.
   * User can register multiple page data with same pageId,
   * as long as they have different keys.
   * Page data with same pageId will be merged.
   *
   * @example '/posts/hello-world'
   */
  readonly pageId: string
  /**
   * The data key.
   * For a same page, users can register multiple data pieces,
   * each with its own key. (Composed Page Data)
   *
   * @default 'main'
   */
  readonly key?: string
  /**
   * The path to the runtime data module.
   * It will be registered with the `key`.
   */
  readonly dataPath?: string
  /**
   * The value of static data.
   * It will be registered with the `key`.
   */
  readonly staticData?: any
  /**
   * when multiple data pieces have same key (conflict),
   * the data piece with highest priority will win
   * @default 1
   */
  readonly priority?: number
}