'use strict';
const path = require('path');
const pkgUp = require('pkg-up');
const multimatch = require('multimatch');
const arrify = require('arrify');
const resolvePkg = require('resolve-pkg');

module.exports = (grunt, options = {}) => {
	const pattern = arrify(options.pattern || ['grunt-*', '@*/grunt-*']);
	const scope = arrify(options.scope || ['dependencies', 'devDependencies', 'peerDependencies', 'optionalDependencies']);

	let cwd = process.cwd();
	let config = options.config || pkgUp.sync();

	if (config === null) {
		grunt.fail.fatal('package.json not found. Make sure to create a package.json and install dependencies before you run Grunt.');
	}

	if (typeof config === 'string') {
		const configPath = path.resolve(config);
		cwd = path.dirname(configPath);
		config = require(configPath);
	}

	pattern.push('!grunt', '!grunt-cli');

	const names = scope.reduce((result, property) => {
		const dependencies = config[property] || [];
		return result.concat(Array.isArray(dependencies) ? dependencies : Object.keys(dependencies));
	}, []);

	for (const packageName of multimatch(names, pattern)) {
		if (options.requireResolution === true) {
			try {
				grunt.loadTasks(resolvePkg(path.join(packageName, 'tasks'), {cwd}));
			} catch (_) {
				grunt.log.error(`npm package \`${packageName}\` not found. Is it installed?`);
			}
		} else {
			grunt.loadNpmTasks(packageName);
		}
	}
};