// Copyright 2019-2021 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

/**
 * Access the file system.
 *
 * This package is also accessible with `window.__TAURI__.fs` when `tauri.conf.json > build > withGlobalTauri` is set to true.
 *
 * The APIs must be allowlisted on `tauri.conf.json`:
 * ```json
 * {
 *   "tauri": {
 *     "allowlist": {
 *       "fs": {
 *         "all": true, // enable all FS APIs
 *         "readFile": true,
 *         "writeFile": true,
 *         "readDir": true,
 *         "copyFile": true,
 *         "createDir": true,
 *         "removeDir": true,
 *         "removeFile": true,
 *         "renameFile": true
 *       }
 *     }
 *   }
 * }
 * ```
 * It is recommended to allowlist only the APIs you use for optimal bundle size and security.
 *
 * ## Security
 *
 * This module prevents path traversal, not allowing absolute paths or parent dir components
 * (i.e. "/usr/path/to/file" or "../path/to/file" paths are not allowed).
 * Paths accessed with this API must be relative to one of the [[BaseDirectory | base directories]]
 * so if you need access to arbitrary filesystem paths, you must write such logic on the core layer instead.
 *
 * The API has a scope configuration that forces you to restrict the paths that can be accessed using glob patterns.
 *
 * The scope configuration is an array of glob patterns describing folder paths that are allowed.
 * For instance, this scope configuration only allows accessing files on the
 * *databases* folder of the [[path.appDir | $APP directory]]:
 * ```json
 * {
 *   "tauri": {
 *     "allowlist": {
 *       "fs": {
 *         "scope": ["$APP/databases/*"]
 *       }
 *     }
 *   }
 * }
 * ```
 *
 * Notice the use of the `$APP` variable. The value is injected at runtime, resolving to the [[path.appDir | app directory]].
 * The available variables are:
 * [[path.audioDir | `$AUDIO`]], [[path.cacheDir | `$CACHE`]], [[path.configDir | `$CONFIG`]], [[path.dataDir | `$DATA`]],
 * [[path.localDataDir | `$LOCALDATA`]], [[path.desktopDir | `$DESKTOP`]], [[path.documentDir | `$DOCUMENT`]],
 * [[path.downloadDir | `$DOWNLOAD`]], [[path.executableDir | `$EXE`]], [[path.fontDir | `$FONT`]], [[path.homeDir | `$HOME`]],
 * [[path.pictureDir | `$PICTURE`]], [[path.publicDir | `$PUBLIC`]], [[path.runtimeDir | `$RUNTIME`]],
 * [[path.templateDir | `$TEMPLATE`]], [[path.videoDir | `$VIDEO`]], [[path.resourceDir | `$RESOURCE`]], [[path.appDir | `$APP`]].
 *
 * Trying to execute any API with a URL not configured on the scope results in a promise rejection due to denied access.
 *
 * Note that this scope applies to **all** APIs on this module.
 *
 * @module
 */

import { invokeTauriCommand } from './helpers/tauri'

export enum BaseDirectory {
  Audio = 1,
  Cache,
  Config,
  Data,
  LocalData,
  Desktop,
  Document,
  Download,
  Executable,
  Font,
  Home,
  Picture,
  Public,
  Runtime,
  Template,
  Video,
  Resource,
  App,
  Log
}

interface FsOptions {
  dir?: BaseDirectory
}

interface FsDirOptions {
  dir?: BaseDirectory
  recursive?: boolean
}

/** Options object used to write a UTF-8 string to a file. */
interface FsTextFileOption {
  /** Path to the file to write. */
  path: string
  /** The UTF-8 string to write to the file. */
  contents: string
}

/** Options object used to write a binary data to a file. */
interface FsBinaryFileOption {
  /** Path to the file to write. */
  path: string
  /** The byte array contents. */
  contents: Iterable<number> | ArrayLike<number>
}

interface FileEntry {
  path: string
  /**
   * Name of the directory/file
   * can be null if the path terminates with `..`
   */
  name?: string
  /** Children of this entry if it's a directory; null otherwise */
  children?: FileEntry[]
}

/**
 * Reads a file as an UTF-8 encoded string.
 *
 * @param filePath Path to the file.
 * @param options Configuration object.
 * @returns A promise resolving to the file content as a UTF-8 encoded string.
 */
async function readTextFile(
  filePath: string,
  options: FsOptions = {}
): Promise<string> {
  return invokeTauriCommand<number[]>({
    __tauriModule: 'Fs',
    message: {
      cmd: 'readFile',
      path: filePath,
      options
    }
  }).then((data) => new TextDecoder().decode(new Uint8Array(data)))
}

/**
 * Reads a file as byte array.
 *
 * @param filePath Path to the file.
 * @param options Configuration object.
 * @returns A promise resolving to the file bytes array.
 */
async function readBinaryFile(
  filePath: string,
  options: FsOptions = {}
): Promise<Uint8Array> {
  const arr = await invokeTauriCommand<number[]>({
    __tauriModule: 'Fs',
    message: {
      cmd: 'readFile',
      path: filePath,
      options
    }
  })

  return Uint8Array.from(arr)
}

/**
 * Writes a UTF-8 text file.
 *
 * @param file File configuration object.
 * @param options Configuration object.
 * @returns A promise indicating the success or failure of the operation.
 */
async function writeFile(
  file: FsTextFileOption,
  options: FsOptions = {}
): Promise<void> {
  if (typeof options === 'object') {
    Object.freeze(options)
  }
  if (typeof file === 'object') {
    Object.freeze(file)
  }

  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'writeFile',
      path: file.path,
      contents: Array.from(new TextEncoder().encode(file.contents)),
      options
    }
  })
}

/**
 * Writes a byte array content to a file.
 *
 * @param file Write configuration object.
 * @param options Configuration object.
 * @returns A promise indicating the success or failure of the operation.
 */
async function writeBinaryFile(
  file: FsBinaryFileOption,
  options: FsOptions = {}
): Promise<void> {
  if (typeof options === 'object') {
    Object.freeze(options)
  }
  if (typeof file === 'object') {
    Object.freeze(file)
  }

  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'writeFile',
      path: file.path,
      contents: Array.from(file.contents),
      options
    }
  })
}

/**
 * List directory files.
 *
 * @param dir Path to the directory to read.
 * @param options Configuration object.
 * @returns A promise resolving to the directory entries.
 */
async function readDir(
  dir: string,
  options: FsDirOptions = {}
): Promise<FileEntry[]> {
  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'readDir',
      path: dir,
      options
    }
  })
}

/**
 * Creates a directory.
 * If one of the path's parent components doesn't exist
 * and the `recursive` option isn't set to true, the promise will be rejected.
 *
 * @param dir Path to the directory to create.
 * @param options Configuration object.
 * @returns A promise indicating the success or failure of the operation.
 */
async function createDir(
  dir: string,
  options: FsDirOptions = {}
): Promise<void> {
  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'createDir',
      path: dir,
      options
    }
  })
}

/**
 * Removes a directory.
 * If the directory is not empty and the `recursive` option isn't set to true, the promise will be rejected.
 *
 * @param dir Path to the directory to remove.
 * @param options Configuration object.
 * @returns A promise indicating the success or failure of the operation.
 */
async function removeDir(
  dir: string,
  options: FsDirOptions = {}
): Promise<void> {
  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'removeDir',
      path: dir,
      options
    }
  })
}

/**
 * Copys a file to a destination.
 *
 * @param source A path of the file to copy.
 * @param destination A path for the destination file.
 * @param options Configuration object.
 * @returns A promise indicating the success or failure of the operation.
 */
async function copyFile(
  source: string,
  destination: string,
  options: FsOptions = {}
): Promise<void> {
  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'copyFile',
      source,
      destination,
      options
    }
  })
}

/**
 * Removes a file.
 *
 * @param file Path to the file to remove.
 * @param options Configuration object.
 * @returns A promise indicating the success or failure of the operation.
 */
async function removeFile(
  file: string,
  options: FsOptions = {}
): Promise<void> {
  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'removeFile',
      path: file,
      options: options
    }
  })
}

/**
 * Renames a file.
 *
 * @param oldPath A path of the file to rename.
 * @param newPath A path of the new file name.
 * @param options Configuration object.
 * @returns A promise indicating the success or failure of the operation.
 */
async function renameFile(
  oldPath: string,
  newPath: string,
  options: FsOptions = {}
): Promise<void> {
  return invokeTauriCommand({
    __tauriModule: 'Fs',
    message: {
      cmd: 'renameFile',
      oldPath,
      newPath,
      options
    }
  })
}

export type {
  FsOptions,
  FsDirOptions,
  FsTextFileOption,
  FsBinaryFileOption,
  FileEntry
}

export {
  BaseDirectory as Dir,
  readTextFile,
  readBinaryFile,
  writeFile,
  writeBinaryFile,
  readDir,
  createDir,
  removeDir,
  copyFile,
  removeFile,
  renameFile
}