import { IExecuteFunctions } from 'n8n-core';
import {
	INodeExecutionData,
	INodeType,
	INodeTypeDescription,
	NodeOperationError
} from 'n8n-workflow';

import { exec } from 'child_process';


export interface IExecReturnData {
	exitCode: number;
	error?: Error;
	stderr: string;
	stdout: string;
}


/**
 * Promisifiy exec manually to also get the exit code
 *
 * @param {string} command
 * @returns {Promise<IExecReturnData>}
 */
function execPromise(command: string): Promise<IExecReturnData> {
	const returnData: IExecReturnData = {
		error: undefined,
		exitCode: 0,
		stderr: '',
		stdout: '',
	};

	return new Promise((resolve, reject) => {
		exec(command, { cwd: process.cwd() }, (error, stdout, stderr) => {
			returnData.stdout = stdout.trim();
			returnData.stderr = stderr.trim();

			if (error) {
				returnData.error = error;
			}

			resolve(returnData);
		}).on('exit', code => { returnData.exitCode = code || 0; });
	});
}


export class ExecuteCommand implements INodeType {
	description: INodeTypeDescription = {
		displayName: 'Execute Command',
		name: 'executeCommand',
		icon: 'fa:terminal',
		group: ['transform'],
		version: 1,
		description: 'Executes a command on the host',
		defaults: {
			name: 'Execute Command',
			color: '#886644',
		},
		inputs: ['main'],
		outputs: ['main'],
		properties: [
			{
				displayName: 'Execute Once',
				name: 'executeOnce',
				type: 'boolean',
				default: true,
				description: 'If activated it executes only once instead of once for each entry.',
			},
			{
				displayName: 'Command',
				name: 'command',
				typeOptions: {
					rows: 5,
				},
				type: 'string',
				default: '',
				placeholder: 'echo "test"',
				description: 'The command to execute',
			},
		],
	};


	async execute(this: IExecuteFunctions): Promise<INodeExecutionData[][]> {

		let items = this.getInputData();

		let command: string;
		const executeOnce = this.getNodeParameter('executeOnce', 0) as boolean;

		if (executeOnce === true) {
			items = [items[0]];
		}

		const returnItems: INodeExecutionData[] = [];
		for (let itemIndex = 0; itemIndex < items.length; itemIndex++) {

			try{

				command = this.getNodeParameter('command', itemIndex) as string;

				const {
					error,
					exitCode,
					stdout,
					stderr,
				} = await execPromise(command);

				if (error !== undefined) {
					throw new NodeOperationError(this.getNode(), error.message);
				}

				returnItems.push(
					{
						json: {
							exitCode,
							stderr,
							stdout,
						},
					},
				);

			} catch (error) {
				if (this.continueOnFail()) {
					returnItems.push({json:{ error: error.message }});
					continue;
				}
				throw error;
			}
		}

		return this.prepareOutputData(returnItems);
	}
}