import 'rxjs/add/observable/of';

import { EventEmitter } from 'events';

import { Observable } from 'rxjs/Observable';

import { ChildProcess } from 'child_process';

import {

ExecutionResult,

IProcessService,

ObservableExecutionResult,

Output,

ShellOptions,

SpawnOptions,

} from '../../client/common/process/types';

import { noop } from '../core';

type ExecObservableCallback = (result: Observable<Output<string>> | Output<string>) => void;

type ExecCallback = (result: ExecutionResult<string>) => void;

export const IOriginalProcessService = Symbol('IProcessService');

export class MockProcessService extends EventEmitter implements IProcessService {

constructor(private procService: IProcessService) {

super();

}

public onExecObservable(

handler: (file: string, args: string[], options: SpawnOptions, callback: ExecObservableCallback) => void,

): void {

this.on('execObservable', handler);

}

public execObservable(file: string, args: string[], options: SpawnOptions = {}): ObservableExecutionResult<string> {

let value: Observable<Output<string>> | Output<string> | undefined;

let valueReturned = false;

this.emit('execObservable', file, args, options, (result: Observable<Output<string>> | Output<string>) => {

value = result;

valueReturned = true;

});

if (valueReturned) {

const output = value as Output<string>;

if (['stderr', 'stdout'].some((source) => source === output.source)) {

return {

proc: {} as ChildProcess,

out: Observable.of(output),

dispose: () => {

noop();

},

};

}

return {

proc: {} as ChildProcess,

out: value as Observable<Output<string>>,

dispose: () => {

noop();

},

};

}

return this.procService.execObservable(file, args, options);

}

public onExec(

handler: (file: string, args: string[], options: SpawnOptions, callback: ExecCallback) => void,

): void {

this.on('exec', handler);

}

public async exec(file: string, args: string[], options: SpawnOptions = {}): Promise<ExecutionResult<string>> {

let value: ExecutionResult<string> | undefined;

let valueReturned = false;

this.emit('exec', file, args, options, (result: ExecutionResult<string>) => {

value = result;

valueReturned = true;

});

return valueReturned ? value! : this.procService.exec(file, args, options);

}

public async shellExec(command: string, options?: ShellOptions): Promise<ExecutionResult<string>> {

let value: ExecutionResult<string> | undefined;

let valueReturned = false;

this.emit('shellExec', command, options, (result: ExecutionResult<string>) => {

value = result;

valueReturned = true;

});

return valueReturned ? value! : this.procService.shellExec(command, options);

}

// eslint-disable-next-line @typescript-eslint/no-empty-function

public dispose(): void {}

}