// Type definitions for pathwatcher 8.x
// Project: https://github.com/atom/node-pathwatcher, http://atom.github.io/node-pathwatcher
// Definitions by: GlenCFL <https://github.com/GlenCFL>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
// TypeScript Version: 2.3

/// <reference types="node" />

import { Disposable } from "event-kit";
import { ReadStream, WriteStream } from "fs";

export function watch(): PathWatcher;
export function closeAllWatchers(): void;
export function getWatchedPaths(): string[];

/** Represents an individual file that can be watched, read from, and written to. */
export class File {
    // Properties
    realPath: string|null;
    path: string;
    symlink: boolean;

    // Construction
    /** Configures a new File instance, no files are accessed. */
    constructor(filePath: string, symlink?: boolean);

    /**
     *  Creates the file on disk that corresponds to ::getPath() if no such file
     *  already exists.
     */
    create(): Promise<boolean>;

    // Event Subscription
    /** Invoke the given callback when the file's contents change. */
    onDidChange(callback: () => void): Disposable;

    /** Invoke the given callback when the file's path changes. */
    onDidRename(callback: () => void): Disposable;

    /** Invoke the given callback when the file is deleted. */
    onDidDelete(callback: () => void): Disposable;

    /**
     *  Invoke the given callback when there is an error with the watch. When
     *  your callback has been invoked, the file will have unsubscribed from the
     *  file watches.
     */
    onWillThrowWatchError(callback: (errorObject: PathWatchErrorThrownEvent) =>
        void): Disposable;

    // File Metadata
    /** Returns a boolean, always true. */
    isFile(): boolean;

    /** Returns a boolean, always false. */
    isDirectory(): boolean;

    /** Returns a boolean indicating whether or not this is a symbolic link. */
    isSymbolicLink(): boolean;

    /**
     *  Returns a promise that resolves to a boolean, true if the file exists,
     *  false otherwise.
     */
    exists(): Promise<boolean>;

    /** Returns a boolean, true if the file exists, false otherwise. */
    existsSync(): boolean;

    /** Get the SHA-1 digest of this file. */
    getDigest(): Promise<string>;

    /** Get the SHA-1 digest of this file. */
    getDigestSync(): string;

    /** Sets the file's character set encoding name. */
    setEncoding(encoding: string): void;

    /** Returns the string encoding name for this file (default: "utf8"). */
    getEncoding(): string;

    // Managing Paths
    /** Returns the string path for the file. */
    getPath(): string;

    /** Returns this file's completely resolved string path. */
    getRealPathSync(): string;

    /**
     *  Returns a promise that resolves to the file's completely resolved
     *  string path.
     */
    getRealPath(): Promise<string>;

    /** Return the string filename without any directory information. */
    getBaseName(): string;

    // Traversing
    /** Return the Directory that contains this file. */
    getParent(): Directory;

    // Reading and Writing
    /** Reads the contents of the file. */
    read(flushCache?: boolean): Promise<string>;

    /** Returns a stream to read the content of the file. */
    createReadStream(): ReadStream;

    /** Overwrites the file with the given text. */
    write(text: string): Promise<undefined>;

    /** Returns a stream to write content to the file. */
    createWriteStream(): WriteStream;

    /** Overwrites the file with the given text. */
    writeSync(text: string): undefined;
}

/** Represents a directory on disk that can be watched for changes. */
export class Directory {
    // Properties
    realPath: string|null;
    path: string;
    symlink: boolean;

    // Construction
    /** Configures a new Directory instance, no files are accessed. */
    constructor(directoryPath: string, symlink?: boolean);

    /**
     *  Creates the directory on disk that corresponds to ::getPath() if no such
     *  directory already exists.
     */
    create(mode?: number): Promise<boolean>;

    // Event Subscription
    /** Invoke the given callback when the directory's contents change. */
    onDidChange(callback: () => void): Disposable;

    // Directory Metadata
    /** Returns a boolean, always false. */
    isFile(): boolean;

    /** Returns a roolean, always true. */
    isDirectory(): boolean;

    /** Returns a boolean indicating whether or not this is a symbolic link. */
    isSymbolicLink(): boolean;

    /**
     *  Returns a promise that resolves to a boolean, true if the directory
     *  exists, false otherwise.
     */
    exists(): Promise<boolean>;

    /** Returns a boolean, true if the directory exists, false otherwise. */
    existsSync(): boolean;

    /**
     *  Return a boolean, true if this Directory is the root directory of the
     *  filesystem, or false if it isn't.
     */
    isRoot(): boolean;

    // Managing Paths
    /**
     *  This may include unfollowed symlinks or relative directory entries.
     *  Or it may be fully resolved, it depends on what you give it.
     */
    getPath(): string;

    /**
     *  All relative directory entries are removed and symlinks are resolved to
     *  their final destination.
     */
    getRealPathSync(): string;

    /** Returns the string basename of the directory. */
    getBaseName(): string;

    /** Returns the relative string path to the given path from this directory. */
    relativize(fullPath: string): string;

    // Traversing
    /** Traverse to the parent directory. */
    getParent(): Directory;

    /**
     *  Traverse within this Directory to a child File. This method doesn't actually
     *  check to see if the File exists, it just creates the File object.
     */
    getFile(filename: string): File;

    /**
     *  Traverse within this a Directory to a child Directory. This method doesn't actually
     *  check to see if the Directory exists, it just creates the Directory object.
     */
    getSubdirectory(dirname: string): Directory;

    /** Reads file entries in this directory from disk synchronously. */
    getEntriesSync(): Array<File|Directory>;

    /** Reads file entries in this directory from disk asynchronously. */
    getEntries(callback: (error: Error, entries: Array<File|Directory>) => void): void;

    /**
     *  Determines if the given path (real or symbolic) is inside this directory. This
     *  method does not actually check if the path exists, it just checks if the path
     *  is under this directory.
     */
    contains(pathToCheck: string): boolean;
}

// Events =====================================================================
// The event objects that are passed into the callbacks which the user provides
// to specific API calls.

export interface PathWatchErrorThrownEvent {
    /** The error object. */
    error: Error;

    /**
     *  Call this function to indicate you have handled the error.
     *  The error will not be thrown if this function is called.
     */
    handle(): void;
}

export interface WatchedFilePathChangedEvent {
    event: string;
    newFilePath: string;
}

// Structures =================================================================
// The structures that are passed to the user by Atom following specific API calls.

export interface PathWatcher {
    onDidChange(callback: (change: WatchedFilePathChangedEvent) => void): Disposable;

    close(): void;
}