/* eslint-disable @typescript-eslint/no-use-before-define */
/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
// based on https://github.com/microsoft/vscode/blob/04c36be045a94fee58e5f8992d3e3fd980294a84/src/vs/platform/files/common/files.ts

import type { Disposable as IDisposable, Event } from '@difizen/mana-common';
import { URI } from '@difizen/mana-common';

export enum FileOperation {
  CREATE,
  DELETE,
  MOVE,
  COPY,
}

export class FileOperationEvent {
  public readonly resource: URI;
  public readonly operation: FileOperation;
  public readonly target?: FileStatWithMetadata | undefined;

  constructor(resource: URI, operation: FileOperation.DELETE);
  constructor(
    resource: URI,
    operation: FileOperation.CREATE | FileOperation.MOVE | FileOperation.COPY,
    target: FileStatWithMetadata,
  );
  constructor(resource: URI, operation: FileOperation, target?: FileStatWithMetadata) {
    this.resource = resource;
    this.operation = operation;
    this.target = target;
  }

  isOperation(operation: FileOperation.DELETE): boolean;
  isOperation(
    operation: FileOperation.MOVE | FileOperation.COPY | FileOperation.CREATE,
  ): this is { readonly target: FileStatWithMetadata };
  isOperation(operation: FileOperation): boolean {
    return this.operation === operation;
  }
}

/**
 * Possible changes that can occur to a file.
 */
export enum FileChangeType {
  UPDATED = 0,
  ADDED = 1,
  DELETED = 2,
}

/**
 * Identifies a single change in a file.
 */
export interface FileChange {
  /**
   * The type of change that occurred to the file.
   */
  readonly type: FileChangeType;

  /**
   * The unified resource identifier of the file that changed.
   */
  readonly resource: URI;
}

export class FileChangesEvent {
  public readonly changes: readonly FileChange[];
  constructor(changes: readonly FileChange[]) {
    this.changes = changes;
  }

  /**
   * Returns true if this change event contains the provided file with the given change type (if provided). In case of
   * type DELETED, this method will also return true if a folder got deleted that is the parent of the
   * provided file path.
   */
  contains(resource: URI, type?: FileChangeType): boolean {
    if (!resource) {
      return false;
    }

    const checkForChangeType = typeof type === 'number';

    return this.changes.some((change) => {
      if (checkForChangeType && change.type !== type) {
        return false;
      }

      // For deleted also return true when deleted folder is parent of target path
      if (change.type === FileChangeType.DELETED) {
        return resource.includes(change.resource);
      }

      return resource.toString() === change.resource.toString();
    });
  }

  /**
   * Returns the changes that describe added files.
   */
  getAdded(): FileChange[] {
    return this.getOfType(FileChangeType.ADDED);
  }

  /**
   * Returns if this event contains added files.
   */
  gotAdded(): boolean {
    return this.hasType(FileChangeType.ADDED);
  }

  /**
   * Returns the changes that describe deleted files.
   */
  getDeleted(): FileChange[] {
    return this.getOfType(FileChangeType.DELETED);
  }

  /**
   * Returns if this event contains deleted files.
   */
  gotDeleted(): boolean {
    return this.hasType(FileChangeType.DELETED);
  }

  /**
   * Returns the changes that describe updated files.
   */
  getUpdated(): FileChange[] {
    return this.getOfType(FileChangeType.UPDATED);
  }

  /**
   * Returns if this event contains updated files.
   */
  gotUpdated(): boolean {
    return this.hasType(FileChangeType.UPDATED);
  }

  private getOfType(type: FileChangeType): FileChange[] {
    return this.changes.filter((change) => change.type === type);
  }

  private hasType(type: FileChangeType): boolean {
    return this.changes.some((change) => change.type === type);
  }
}

export interface BaseStat {
  /**
   * The unified resource identifier of this file or folder.
   */
  resource: URI;

  /**
   * The name which is the last segment
   * of the {{path}}.
   */
  name: string;

  /**
   * The size of the file.
   *
   * The value may or may not be resolved as
   * it is optional.
   */
  size?: number | undefined;

  /**
   * The last modification date represented as millis from unix epoch.
   *
   * The value may or may not be resolved as
   * it is optional.
   */
  mtime?: number | undefined;

  /**
   * The creation date represented as millis from unix epoch.
   *
   * The value may or may not be resolved as
   * it is optional.
   */
  ctime?: number | undefined;

  /**
   * A unique identifier that represents the
   * current state of the file or directory.
   *
   * The value may or may not be resolved as
   * it is optional.
   */
  etag?: string | undefined;
}
export namespace BaseStat {
  export function is(arg: Record<any, any> | undefined): arg is BaseStat {
    return (
      !!arg &&
      typeof arg === 'object' &&
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      'resource' in arg &&
      (arg as any).resource instanceof URI &&
      'name' in arg &&
      typeof (arg as any).name === 'string'
    );
  }
}

export interface BaseStatWithMetadata extends BaseStat {
  mtime: number;
  ctime: number;
  etag: string;
  size: number;
}

/**
 * A file resource with meta information.
 */
export interface FileStat extends BaseStat {
  /**
   * The resource is a file.
   */
  isFile: boolean;

  /**
   * The resource is a directory.
   */
  isDirectory: boolean;

  /**
   * The resource is a symbolic link.
   */
  isSymbolicLink: boolean;

  /**
   * The children of the file stat or undefined if none.
   */
  children?: FileStat[];
}
export namespace FileStat {
  export function is(arg: Record<any, any> | undefined): arg is FileStat {
    if (BaseStat.is(arg) && 'isFile' in arg) {
      return (
        'isFile' in arg &&
        typeof (arg as any).isFile === 'boolean' &&
        'isDirectory' in arg &&
        typeof (arg as any).isDirectory === 'boolean' &&
        'isSymbolicLink' in arg &&
        typeof (arg as any).isSymbolicLink === 'boolean'
      );
    }
    return false;
  }
  export function asFileType(stat: FileStat): FileType {
    let res = 0;
    if (stat.isFile) {
      res += FileType.File;
    } else if (stat.isDirectory) {
      res += FileType.Directory;
    }
    if (stat.isSymbolicLink) {
      res += FileType.SymbolicLink;
    }
    return res;
  }
  export function toStat(stat: FileStat): Stat | ({ type: FileType } & Partial<Stat>) {
    return {
      type: asFileType(stat),
      ctime: stat.ctime!,
      mtime: stat.mtime!,
      size: stat.size!,
    };
  }
  export function fromStat(resource: URI, stat: Stat): FileStatWithMetadata;
  export function fromStat(
    resource: URI,
    stat: { type: FileType } & Partial<Stat>,
  ): FileStat;
  export function fromStat(
    resource: URI,
    stat: Stat | ({ type: FileType } & Partial<Stat>),
  ): FileStat {
    return {
      resource,
      name: resource.path.base || resource.path.toString(),
      isFile: (stat.type & FileType.File) !== 0,
      isDirectory: (stat.type & FileType.Directory) !== 0,
      isSymbolicLink: (stat.type & FileType.SymbolicLink) !== 0,
      mtime: stat.mtime,
      ctime: stat.ctime,
      size: stat.size,
      etag: etag({ mtime: stat.mtime, size: stat.size }),
    };
  }
  export function dir(
    resource: string | URI,
    stat?: Partial<Omit<Stat, 'type'>>,
  ): FileStat {
    return fromStat(resource instanceof URI ? resource : new URI(resource), {
      type: FileType.Directory,
      ...stat,
    });
  }
  export function file(
    resource: string | URI,
    stat?: Partial<Omit<Stat, 'type'>>,
  ): FileStat {
    return fromStat(resource instanceof URI ? resource : new URI(resource), {
      type: FileType.File,
      ...stat,
    });
  }
}

export interface FileStatWithMetadata extends FileStat, BaseStatWithMetadata {
  mtime: number;
  ctime: number;
  etag: string;
  size: number;
  children?: FileStatWithMetadata[];
}

export interface ResolveFileResult {
  stat?: FileStat;
  success: boolean;
}

export interface ResolveFileResultWithMetadata extends ResolveFileResult {
  stat?: FileStatWithMetadata;
}

export interface WriteFileOptions {
  /**
   * The last known modification time of the file. This can be used to prevent dirty writes.
   */
  readonly mtime?: number;

  /**
   * The etag of the file. This can be used to prevent dirty writes.
   */
  readonly etag?: string;
}

export interface ReadFileOptions extends FileReadStreamOptions {
  /**
   * The optional etag parameter allows to return early from resolving the resource if
   * the contents on disk match the etag. This prevents accumulated reading of resources
   * that have been read already with the same etag.
   * It is the task of the caller to makes sure to handle this error case from the promise.
   */
  readonly etag?: string;
}

export interface WriteFileOptions {
  /**
   * The last known modification time of the file. This can be used to prevent dirty writes.
   */
  readonly mtime?: number;

  /**
   * The etag of the file. This can be used to prevent dirty writes.
   */
  readonly etag?: string;
}

export interface ResolveFileOptions {
  /**
   * Automatically continue resolving children of a directory until the provided resources
   * are found.
   */
  readonly resolveTo?: readonly URI[];

  /**
   * Automatically continue resolving children of a directory if the number of children is 1.
   */
  readonly resolveSingleChildDescendants?: boolean;

  /**
   * Will resolve mtime, ctime, size and etag of files if enabled. This can have a negative impact
   * on performance and thus should only be used when these values are required.
   */
  readonly resolveMetadata?: boolean;
}

export interface ResolveMetadataFileOptions extends ResolveFileOptions {
  readonly resolveMetadata: true;
}

export interface FileOperationOptions {
  /**
   * Indicates that a user action triggered the opening, e.g.
   * via mouse or keyboard use. Default is true.
   */
  fromUserGesture?: boolean;
}

export interface MoveFileOptions
  extends FileOperationOptions,
    Partial<FileOverwriteOptions> {}

export interface CopyFileOptions
  extends FileOperationOptions,
    Partial<FileOverwriteOptions> {}

export interface CreateFileOptions
  extends FileOperationOptions,
    Partial<FileOverwriteOptions> {}

export class FileOperationError extends Error {
  public fileOperationResult: FileOperationResult;
  public options?: (ReadFileOptions & WriteFileOptions & CreateFileOptions) | undefined;

  constructor(
    message: string,
    fileOperationResult: FileOperationResult,
    options?: ReadFileOptions & WriteFileOptions & CreateFileOptions,
  ) {
    super(message);
    this.fileOperationResult = fileOperationResult;
    this.options = options;
    Object.setPrototypeOf(this, FileOperationError.prototype);
  }
}

export enum FileOperationResult {
  FILE_IS_DIRECTORY,
  FILE_NOT_FOUND,
  FILE_NOT_MODIFIED_SINCE,
  FILE_MODIFIED_SINCE,
  FILE_MOVE_CONFLICT,
  FILE_READ_ONLY,
  FILE_PERMISSION_DENIED,
  FILE_TOO_LARGE,
  FILE_INVALID_PATH,
  FILE_EXCEEDS_MEMORY_LIMIT,
  FILE_NOT_DIRECTORY,
  FILE_OTHER_ERROR,
}

export interface FileOverwriteOptions {
  /**
   * Overwrite the file to create if it already exists on disk. Otherwise
   * an error will be thrown (FILE_MODIFIED_SINCE).
   */
  overwrite: boolean;
}

export interface FileReadStreamOptions {
  /**
   * Is an integer specifying where to begin reading from in the file. If position is undefined,
   * data will be read from the current file position.
   */
  readonly position?: number;

  /**
   * Is an integer specifying how many bytes to read from the file. By default, all bytes
   * will be read.
   */
  readonly length?: number;

  /**
   * If provided, the size of the file will be checked against the limits.
   */
  limits?: {
    readonly size?: number;
    readonly memory?: number;
  };
}

export interface FileUpdateOptions {
  readEncoding: string;
  writeEncoding: string;
  overwriteEncoding: boolean;
}
export interface FileUpdateResult extends Stat {
  encoding: string;
}

export interface FileWriteOptions {
  overwrite: boolean;
  create: boolean;
}

export interface FileOpenOptions {
  create: boolean;
}

export interface FileDeleteOptions {
  recursive: boolean;
  useTrash: boolean;
}

export enum FileType {
  Unknown = 0,
  File = 1,
  Directory = 2,
  SymbolicLink = 64,
}

export interface Stat {
  type: FileType;

  /**
   * The last modification date represented as millis from unix epoch.
   */
  mtime: number;

  /**
   * The creation date represented as millis from unix epoch.
   */
  ctime: number;

  size: number;
}

export interface WatchOptions {
  recursive: boolean;
  excludes: string[];
}

export enum FileSystemProviderCapabilities {
  FileReadWrite = 1 << 1,
  FileOpenReadWriteClose = 1 << 2,
  FileReadStream = 1 << 4,

  FileFolderCopy = 1 << 3,

  PathCaseSensitive = 1 << 10,
  Readonly = 1 << 11,

  Trash = 1 << 12,

  Access = 1 << 24,
  Update = 1 << 25,
}

export enum FileSystemProviderErrorCode {
  FileExists = 'EntryExists',
  FileNotFound = 'EntryNotFound',
  FileNotADirectory = 'EntryNotADirectory',
  FileIsADirectory = 'EntryIsADirectory',
  FileExceedsMemoryLimit = 'EntryExceedsMemoryLimit',
  FileTooLarge = 'EntryTooLarge',
  NoPermissions = 'NoPermissions',
  Unavailable = 'Unavailable',
  Unknown = 'Unknown',
}

export class FileSystemProviderError extends Error {
  public readonly code: FileSystemProviderErrorCode;

  constructor(message: string, code: FileSystemProviderErrorCode) {
    super(message);
    this.code = code;
    Object.setPrototypeOf(this, FileSystemProviderError.prototype);
  }
}

export function createFileSystemProviderError(
  error: Error | string,
  code: FileSystemProviderErrorCode,
): FileSystemProviderError {
  const providerError = new FileSystemProviderError(error.toString(), code);
  markAsFileSystemProviderError(providerError, code);

  return providerError;
}

export function ensureFileSystemProviderError(error?: Error): Error {
  if (!error) {
    return createFileSystemProviderError(
      'Unknown Error',
      FileSystemProviderErrorCode.Unknown,
    ); // https://github.com/Microsoft/vscode/issues/72798
  }

  return error;
}

export const FileSystemProvider = Symbol('FileSystemProvider');
/**
 * A {@link FileSystemProvider} provides the capabilities to read, write, discover, and to manage files and folders
 * of the underlying (potentially virtual) file system. {@link FileSystemProvider}s can be used to serve files from both the
 * local disk as well as remote locations like ftp-servers, REST-services etc. A {@link FileSystemProvider} is registered for a certain
 * scheme and can handle all resources whose uri does conform to that scheme.
 */
export interface FileSystemProvider {
  /** The {@link FileSystemProviderCapabilities} for this provider. */
  readonly capabilities: FileSystemProviderCapabilities;

  /** * Event that is fired if the capabilities of this provider have changed. */
  readonly onDidChangeCapabilities: Event<void>;

  /** Event that is fired if a (watched) file in the filesystem of this provider has changed. */
  readonly onDidChangeFile: Event<readonly FileChange[]>;

  /** Event that is fired if an error occurred when watching files in the filesystem of this provider. */
  readonly onFileWatchError: Event<void>;

  /**
   * Watch the given resource and react to changes by firing the {@link FileSystemProvider#onDidChangeFile} event.
   * @param resource `URI` of the resource to be watched.
   * @param opts Options to define if the resource should be watched recursively and to
   *  provide a set of resources that should be excluded from watching.
   *
   * @returns A `Disposable` that can be invoked to stop watching the resource.
   */
  watch: (resource: URI, opts: WatchOptions) => IDisposable;

  /**
   * Retrieve metadata about a given file.
   *
   * @param uri The `URI` of the file to retrieve meta data about.
   * @returns A promise of the metadata about the resource.
   */
  stat: (resource: URI) => Promise<Stat>;

  /**
   * Create a new directory using the given resource uri.
   * @param resource The `URI` of the new folder.
   */
  mkdir: (resource: URI) => Promise<void>;

  /**
   * Retrieve the content of a given directory.
   * @param resource The `URI` of the directory.
   *
   * @returns A map containing the {@link FileType} for each child resource, identified by name.
   */
  readdir: (resource: URI) => Promise<[string, FileType][]>;

  /**
   * Delete the given resource.
   * @param resource The `URI` of the resource to delete.
   * @param opts Options to define if files should be deleted recursively and if the trash should be used.
   */
  delete: (resource: URI, opts: FileDeleteOptions) => Promise<void>;

  /**
   * Rename a file or folder.
   * @param from `URI` of the existing file or folder.
   * @param to `URI` of the target location.
   * @param opts Options to define if existing files should be overwritten.
   */
  rename: (from: URI, to: URI, opts: FileOverwriteOptions) => Promise<void>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithFileFolderCopyCapability}.
   * See {@link FileSystemProviderWithFileFolderCopyCapability#copy}} for additional documentation.
   */
  copy?: (from: URI, to: URI, opts: FileOverwriteOptions) => Promise<void>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithFileReadWriteCapability}.
   * See {@link FileSystemProviderWithFileReadWriteCapability#readFile} for additional documentation.
   */
  readFile?: (resource: URI) => Promise<Uint8Array>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithFileReadWriteCapability}.
   * See {@link FileSystemProviderWithFileReadWriteCapability#writeFile} for additional documentation.
   */
  writeFile?: (
    resource: URI,
    content: Uint8Array,
    opts: FileWriteOptions,
  ) => Promise<void>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithOpenReadWriteCloseCapability}.
   * See {@link FileSystemProviderWithOpenReadWriteCloseCapability#open} for additional documentation.
   */
  open?: (resource: URI, opts: FileOpenOptions) => Promise<number>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithOpenReadWriteCloseCapability}.
   * See {@link FileSystemProviderWithOpenReadWriteCloseCapability#close} for additional documentation.
   */
  close?: (fd: number) => Promise<void>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithOpenReadWriteCloseCapability}.
   * See {@link FileSystemProviderWithOpenReadWriteCloseCapability#read} for additional documentation.
   */
  read?: (
    fd: number,
    pos: number,
    data: Uint8Array,
    offset: number,
    length: number,
  ) => Promise<number>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithOpenReadWriteCloseCapability}.
   * See {@link FileSystemProviderWithOpenReadWriteCloseCapability#write} for additional documentation.
   */
  write?: (
    fd: number,
    pos: number,
    data: Uint8Array,
    offset: number,
    length: number,
  ) => Promise<number>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithAccessCapability}.
   * See {@link FileSystemProviderWithAccessCapability#access} for additional documentation.
   */
  access?: (resource: URI, mode?: number) => Promise<void>;

  /**
   * Optional function that has to be implemented by {@link FileSystemProviderWithAccessCapability}.
   * See {@link FileSystemProviderWithAccessCapability#fsPath} for additional documentation.
   */
  fsPath?: (resource: URI) => Promise<string>;
}

/**
 * Subtype of {@link FileSystemProvider} that ensures that the optional functions needed for providers, that should be
 * able access files, are implemented.
 */
export interface FileSystemProviderWithAccessCapability extends FileSystemProvider {
  /**
   * Test if the user has the permission to access the given file in the specified mode.
   * @param resource The `URI` of the file that should be tested.
   * @param mode The access mode that should be tested.
   *
   * @returns A promise that resolves if the user has the required permissions, should be rejected otherwise.
   */
  access: (resource: URI, mode?: number) => Promise<void>;

  /**
   * Derive the platform specific file system path that is represented by the resource.
   * @param resource `URI` of the resource to derive the path from.
   *
   * @returns A promise of the corresponding file system path.
   */
  fsPath: (resource: URI) => Promise<string>;
}

export function hasAccessCapability(
  provider: FileSystemProvider,
): provider is FileSystemProviderWithAccessCapability {
  return !!(provider.capabilities & FileSystemProviderCapabilities.Access);
}

/**
 * Subtype of {@link FileSystemProvider} that ensures that the optional functions, needed for providers
 * that should be able to read & write files, are implemented.
 */
export interface FileSystemProviderWithFileReadWriteCapability
  extends FileSystemProvider {
  /**
   * Read the contents of the given file as stream.
   * @param resource The `URI` of the file.
   *
   * @return The readable stream of the given file.
   */
  readFile: (resource: URI) => Promise<Uint8Array>;

  /**
   *  Write data to a file, replacing its entire contents.
   * @param resource The uri of the file.
   * @param content The new content of the file.
   * @param opts Options to define if the file should be created if missing and if an existing file should be overwritten.
   */
  writeFile: (
    resource: URI,
    content: Uint8Array,
    opts: FileWriteOptions,
  ) => Promise<void>;
}

export function hasReadWriteCapability(
  provider: FileSystemProvider,
): provider is FileSystemProviderWithFileReadWriteCapability {
  return !!(provider.capabilities & FileSystemProviderCapabilities.FileReadWrite);
}

/**
 * Subtype of {@link FileSystemProvider} that ensures that the optional functions, needed for providers that should be able to copy
 * file folders, are implemented.
 */
export interface FileSystemProviderWithFileFolderCopyCapability
  extends FileSystemProvider {
  /**
   * Copy files or folders.
   * @param from `URI` of the existing file or folder.
   * @param to `URI` of the destination location.
   * @param opts Options to define if existing files should be overwritten.
   */
  copy: (from: URI, to: URI, opts: FileOverwriteOptions) => Promise<void>;
}

export function hasFileFolderCopyCapability(
  provider: FileSystemProvider,
): provider is FileSystemProviderWithFileFolderCopyCapability {
  return !!(provider.capabilities & FileSystemProviderCapabilities.FileFolderCopy);
}

/**
 * Subtype of {@link FileSystemProvider} that ensures that the optional functions, needed for providers that should be able to open,read, write
 * or close files, are implemented.
 */
export interface FileSystemProviderWithOpenReadWriteCloseCapability
  extends FileSystemProvider {
  /**
   * Open the give file.
   * @param resource The `URI` of the file to open.
   * @param opts Options to define if the file should be created if it does not exist yet.
   *
   * @returns A promise of the file descriptor that resolves after the file is open.
   */
  open: (resource: URI, opts: FileOpenOptions) => Promise<number>;

  /**
   * Close the file with the given file descriptor.
   * @param fd the file descriptor to close.
   */
  close: (fd: number) => Promise<void>;

  /**
   * Read specified content from a given file descriptor into a data buffer.
   * @param fd The file descriptor referencing the file to read from.
   * @param pos The offset from the beginning of the file from which data should be read.
   * @param data The buffer that the data will be written to.
   * @param offset The offset in the buffer at which to start writing.
   * @param length The number of bytes to read.
   *
   * @returns A promise of the number of bytes read.
   */
  read: (
    fd: number,
    pos: number,
    data: Uint8Array,
    offset: number,
    length: number,
  ) => Promise<number>;

  /**
   * Write specified content from the data buffer to the file referenced by the given file descriptor.
   * @param fd The file descriptor referencing the file to write to.
   * @param pos The offset from the beginning of the file where this data should be written.
   * @param offset The part of the buffer to be read from.
   * @param length The number of bytes to write.
   *
   * @returns A promise of the number of bytes written.
   */
  write: (
    fd: number,
    pos: number,
    data: Uint8Array,
    offset: number,
    length: number,
  ) => Promise<number>;
}

export function hasOpenReadWriteCloseCapability(
  provider: FileSystemProvider,
): provider is FileSystemProviderWithOpenReadWriteCloseCapability {
  return !!(
    provider.capabilities & FileSystemProviderCapabilities.FileOpenReadWriteClose
  );
}

export function markAsFileSystemProviderError(
  error: Error,
  code: FileSystemProviderErrorCode,
): Error {
  error.name = code ? `${code} (FileSystemError)` : 'FileSystemError';

  return error;
}

export function toFileSystemProviderErrorCode(
  error: Error | undefined | null,
): FileSystemProviderErrorCode {
  // Guard against abuse
  if (!error) {
    return FileSystemProviderErrorCode.Unknown;
  }

  // FileSystemProviderError comes with the code
  if (error instanceof FileSystemProviderError) {
    return error.code;
  }

  // Any other error, check for name match by assuming that the error
  // went through the markAsFileSystemProviderError() method
  const match = /^(.+) \(FileSystemError\)$/.exec(error.name);
  if (!match) {
    return FileSystemProviderErrorCode.Unknown;
  }

  // eslint-disable-next-line default-case
  switch (match[1]) {
    case FileSystemProviderErrorCode.FileExists:
      return FileSystemProviderErrorCode.FileExists;
    case FileSystemProviderErrorCode.FileIsADirectory:
      return FileSystemProviderErrorCode.FileIsADirectory;
    case FileSystemProviderErrorCode.FileNotADirectory:
      return FileSystemProviderErrorCode.FileNotADirectory;
    case FileSystemProviderErrorCode.FileNotFound:
      return FileSystemProviderErrorCode.FileNotFound;
    case FileSystemProviderErrorCode.FileExceedsMemoryLimit:
      return FileSystemProviderErrorCode.FileExceedsMemoryLimit;
    case FileSystemProviderErrorCode.FileTooLarge:
      return FileSystemProviderErrorCode.FileTooLarge;
    case FileSystemProviderErrorCode.NoPermissions:
      return FileSystemProviderErrorCode.NoPermissions;
    case FileSystemProviderErrorCode.Unavailable:
      return FileSystemProviderErrorCode.Unavailable;
  }

  return FileSystemProviderErrorCode.Unknown;
}

export function toFileOperationResult(error: Error): FileOperationResult {
  // FileSystemProviderError comes with the result already
  if (error instanceof FileOperationError) {
    return error.fileOperationResult;
  }

  // Otherwise try to find from code
  switch (toFileSystemProviderErrorCode(error)) {
    case FileSystemProviderErrorCode.FileNotFound:
      return FileOperationResult.FILE_NOT_FOUND;
    case FileSystemProviderErrorCode.FileIsADirectory:
      return FileOperationResult.FILE_IS_DIRECTORY;
    case FileSystemProviderErrorCode.FileNotADirectory:
      return FileOperationResult.FILE_NOT_DIRECTORY;
    case FileSystemProviderErrorCode.NoPermissions:
      return FileOperationResult.FILE_PERMISSION_DENIED;
    case FileSystemProviderErrorCode.FileExists:
      return FileOperationResult.FILE_MOVE_CONFLICT;
    case FileSystemProviderErrorCode.FileExceedsMemoryLimit:
      return FileOperationResult.FILE_EXCEEDS_MEMORY_LIMIT;
    case FileSystemProviderErrorCode.FileTooLarge:
      return FileOperationResult.FILE_TOO_LARGE;
    default:
      return FileOperationResult.FILE_OTHER_ERROR;
  }
}

/**
 * A hint to disable etag checking for reading/writing.
 */
export const ETAG_DISABLED = '';

export function etag(stat: { mtime: number; size: number }): string;
export function etag(stat: {
  mtime: number | undefined;
  size: number | undefined;
}): string | undefined;
export function etag(stat: {
  mtime: number | undefined;
  size: number | undefined;
}): string | undefined {
  if (typeof stat.size !== 'number' || typeof stat.mtime !== 'number') {
    return undefined;
  }

  return stat.mtime.toString(29) + stat.size.toString(31);
}
/**
 * Helper to format a raw byte size into a human readable label.
 */
export class BinarySize {
  static readonly KB = 1024;
  static readonly MB = BinarySize.KB * BinarySize.KB;
  static readonly GB = BinarySize.MB * BinarySize.KB;
  static readonly TB = BinarySize.GB * BinarySize.KB;

  static formatSize(size: number): string {
    if (size < BinarySize.KB) {
      return `${size}B`;
    }
    if (size < BinarySize.MB) {
      return `${(size / BinarySize.KB).toFixed(2)}KB`;
    }
    if (size < BinarySize.GB) {
      return `${(size / BinarySize.MB).toFixed(2)}MB`;
    }
    if (size < BinarySize.TB) {
      return `${(size / BinarySize.GB).toFixed(2)}GB`;
    }
    return `${(size / BinarySize.TB).toFixed(2)}TB`;
  }
}