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

import * as events from "events";
import * as Q from "q";
import * as stream from "stream";

/** A module for sequencing and executing tasks and dependencies in maximum concurrency
 */
declare class Orchestrator extends events.EventEmitter {
    doneCallback?: ((error?: any) => any) | undefined;
    isRunning: boolean;
    seq: any[];
    tasks: { [name: string]: Orchestrator.Task };

    reset(): Orchestrator;

    /** Define a task
     * @param name The name of the task.
     * @param fn The function that performs the task's operations. For asynchronous tasks, you need to provide a hint when the task is complete:
     *  - Take in a callback
     *  - Return a stream or a promise
     */
    add(name: string, fn?: Orchestrator.TaskFunc): Orchestrator;
    /** Define a task
     * @param name The name of the task.
     * @param deps An array of task names to be executed and completed before your task will run.
     * @param fn The function that performs the task's operations. For asynchronous tasks, you need to provide a hint when the task is complete:
     *  - Take in a callback
     *  - Return a stream or a promise
     */
    add(name: string, deps?: string[], fn?: Orchestrator.TaskFunc): Orchestrator;

    task(name: string): Orchestrator.Task;
    task(name: string, fn: Orchestrator.TaskFunc): void;
    task(name: string, dep: string[], fn: Orchestrator.TaskFunc): void;

    /** Have you defined a task with this name?
     * @param name The task name to query
     */
    hasTask(name: string): boolean;

    start: Orchestrator.StartMethod;

    stop(err?: any, successfulFinish?: boolean): void;

    sequence: Orchestrator.Sequencify;

    allDone(): boolean;

    /** Listen to orchestrator internals
     * @param event Event name to listen to:
     *  - start: from start() method, shows you the task sequence
     *  - stop: from stop() method, the queue finished successfully
     *  - err: from stop() method, the queue was aborted due to a task error
     *  - task_start: from _runTask() method, task was started
     *  - task_stop: from _runTask() method, task completed successfully
     *  - task_err: from _runTask() method, task errored
     *  - task_not_found: from start() method, you're trying to start a task that doesn't exist
     *  - task_recursion: from start() method, there are recursive dependencies in your task list
     * @param cb Passes single argument: e: event details
     */
    on(event: Orchestrator.EventNames, cb: (e: Orchestrator.OnCallbackEvent) => any): this;

    /** Listen to all orchestrator events from one callback
     * @param cb Passes single argument: e: event details
     */
    onAll(cb: (e: Orchestrator.OnAllCallbackEvent) => any): void;

    // probably supposed to be private methods, but still available on Orchestrator prototype
    _resetTask(task: Orchestrator.Task): void;

    _resetAllTasks(): void;

    _resetSpecificTasks(names: string[]): void;

    _runStep(): void;

    _readyToRunTask(task: Orchestrator.Task): boolean;

    _stopTask(task: Orchestrator.Task, meta: Orchestrator.Meta): void;

    _emitTaskDone(task: Orchestrator.Task, message: string, err?: any): void;

    _runTask(task: Orchestrator.Task): void;
}

declare namespace Orchestrator {
    type Strings = string | string[];

    /** The method export generated by orchestrator/lib/runTask.js */
    type RunTask = (task: Orchestrator.TaskFunc, done: (err: any, meta: Orchestrator.Meta) => void) => void;

    /** The module export of the sequencify package: https://www.npmjs.com/package/sequencify */
    type Sequencify = (tasks: Array<{ dep: string[] }>, names: string[]) => {
        sequence: string[];
        missingTasks: string[];
        recursiveDependencies: string[];
    };

    /** A task, can either call a callback to indicate task completion or return a promise or a stream: (task is marked complete when promise.then() resolves/fails or stream ends)
     */
    type TaskFunc = (callback: (err?: any) => void) => Q.Promise<any> | stream.Stream | any;

    interface AddMethod {
        /** Define a task
         * @param name The name of the task.
         * @param fn The function that performs the task's operations. For asynchronous tasks, you need to provide a hint when the task is complete:
         *  - Take in a callback
         *  - Return a stream or a promise
         */
        (name: string, fn?: TaskFunc): Orchestrator;
        /** Define a task
         * @param name The name of the task.
         * @param deps An array of task names to be executed and completed before your task will run.
         * @param fn The function that performs the task's operations. For asynchronous tasks, you need to provide a hint when the task is complete:
         *  - Take in a callback
         *  - Return a stream or a promise
         */
        (name: string, deps?: string[], fn?: TaskFunc): Orchestrator;
    }

    /** Start running the tasks
     */
    interface StartMethod {
        /** Start running the tasks
         * @param tasks Tasks to be executed. You may pass any number of tasks as individual arguments.
         * @param cb Callback to call after run completed.
         */
        (tasks: Strings, cb?: (error?: any) => any): Orchestrator;
        /** Start running the tasks
         * @param tasks Tasks to be executed. You may pass any number of tasks as individual arguments.
         * @param cb Callback to call after run completed.
         */
        (...tasks: Strings[] /*, cb?: (error: any) => any */): Orchestrator;
        // TODO: TypeScript 2.1.5 cannot express varargs followed by callback as a last argument...
        (task1: Strings, task2: Strings, cb?: (error?: any) => any): Orchestrator;
        (task1: Strings, task2: Strings, task3: Strings, cb?: (error?: any) => any): Orchestrator;
        (task1: Strings, task2: Strings, task3: Strings, task4: Strings, cb?: (error?: any) => any): Orchestrator;
        (
            task1: Strings,
            task2: Strings,
            task3: Strings,
            task4: Strings,
            task5: Strings,
            cb?: (error?: any) => any,
        ): Orchestrator;
        (
            task1: Strings,
            task2: Strings,
            task3: Strings,
            task4: Strings,
            task5: Strings,
            task6: Strings,
            cb?: (error?: any) => any,
        ): Orchestrator;
    }

    interface OnCallbackEvent {
        message: string;
        task: string;
        err: any;
        duration?: number | undefined;
    }

    interface OnAllCallbackEvent extends OnCallbackEvent {
        src: string;
    }

    interface Task {
        fn: TaskFunc;
        dep: string[];
        name: string;
        done?: boolean | undefined;
        duration?: number | undefined;
        hrDuration?: [number, number] | undefined;
        running?: boolean | undefined;
    }

    interface Meta {
        duration: number;
        hrDuration: [number, number];
        runMethod: "callback" | "catch" | "promise" | "stream" | "sync";
    }

    type EventNames =
        | "start"
        | "stop"
        | "err"
        | "task_start"
        | "task_stop"
        | "task_err"
        | "task_not_found"
        | "task_recursion";
}

export = Orchestrator;