/* Copyright (c) 2015-present, salesforce.com, inc. All rights reserved */
/* Licensed under BSD 3-Clause - see LICENSE.txt or git.io/sfdc-license */

// Implements the [Button Group design pattern](https://lightningdesignsystem.com/components/button-groups/) in React.
// Based on SLDS v2.1.1

import React from 'react';
import PropTypes from 'prop-types';
import classNames from 'classnames';

import assign from 'lodash.assign';

// ### shortid
// [npmjs.com/package/shortid](https://www.npmjs.com/package/shortid)
// shortid is a short, non-sequential, url-friendly, unique id generator
import shortid from 'shortid';

import { BUTTON_GROUP } from '../../utilities/constants';

const propTypes = {
	/**
	 * Children are expected to be components. If last button triggers a dropdown menu, use Dropdown instead of Button. _Tested with snapshot testing._
	 */
	children: PropTypes.node.isRequired,
	/**
	 * CSS classes added to `slds-button-group` or `slds-checkbox_button-group` tag
	 */
	className: PropTypes.oneOfType([
		PropTypes.array,
		PropTypes.object,
		PropTypes.string,
	]),
	/**
	 * If the `labels.label` prop is set, a `.slds-form-element` classed fieldset element is added as a container. This prop applies classes to that element
	 */
	classNameContainer: PropTypes.oneOfType([
		PropTypes.array,
		PropTypes.object,
		PropTypes.string,
	]),
	/**
	 * HTML id for component.
	 */
	id: PropTypes.string,
	/**
	 * **Text labels for internationalization**
	 * This object is merged with the default props object on every render.
	 * * `error`: Message to display when any of Checkboxes are in an error state. _Tested with snapshot testing._
	 * * `label`: This label appears above the button group. _Tested with snapshot testing._
	 */
	labels: PropTypes.shape({
		error: PropTypes.string,
		label: PropTypes.string,
	}),
	/**
	 * Use checkbox variant for "Checkbox Button Group" styling and add Checkbox components as children _Tested with snapshot testing._
	 */
	variant: PropTypes.oneOf(['checkbox', 'list']),
};

const defaultProps = { labels: {} };

/**
 * The ButtonGroup component wraps other components (ie. Button, MenuDropdown, PopoverTooltip, Checkboxes, etc).
 */
class ButtonGroup extends React.Component {
	constructor(props) {
		super(props);
		this.generatedId = shortid.generate();
	}

	getId() {
		return this.props.id || this.generatedId;
	}

	render() {
		// Merge objects of strings with their default object
		const labels = assign({}, defaultProps.labels, this.props.labels);

		const zeroIndexLength = React.Children.count(this.props.children) - 1;
		let { children } = this.props;
		if (zeroIndexLength > 0) {
			children = React.Children.map(this.props.children, (child, index) => {
				let newChild;
				if (index === zeroIndexLength) {
					newChild = React.cloneElement(child, {
						triggerClassName: 'slds-button_last',
					});
				}

				return newChild || child;
			});
		}

		let component;

		if (this.props.variant === 'checkbox') {
			children = React.Children.map(this.props.children, (child) => {
				const cloneProps = {
					variant: 'button-group',
				};
				if (labels.error) {
					cloneProps['aria-describedby'] = `button-group-error-${this.getId()}`;
				}
				return React.cloneElement(child, cloneProps);
			});

			component = (
				<div
					className={classNames(
						'slds-checkbox_button-group',
						this.props.className
					)}
					id={this.getId()}
				>
					{children}
				</div>
			);
		} else if (this.props.variant === 'list') {
			component = (
				<ul
					className={classNames('slds-button-group-list', this.props.className)}
					id={this.getId()}
				>
					{React.Children.map(this.props.children, (child) => <li>{child}</li>)}
				</ul>
			);
		} else {
			component = (
				<div
					className={classNames('slds-button-group', this.props.className)}
					id={this.getId()}
					role="group"
				>
					{children}
				</div>
			);
		}

		if (this.props.variant === 'checkbox' || this.props.labels.label) {
			component = (
				<fieldset
					className={classNames(
						'slds-form-element',
						{
							'slds-has-error': labels.error,
						},
						this.props.classNameContainer
					)}
				>
					<legend className="slds-form-element__legend slds-form-element__label">
						{this.props.labels.label}
					</legend>
					<div className="slds-form-element__control">
						{component}
						{labels.error ? (
							<div
								className="slds-form-element__help"
								id={`button-group-error-${this.getId()}`}
							>
								{labels.error}
							</div>
						) : null}
					</div>
				</fieldset>
			);
		}

		return component;
	}
}

ButtonGroup.displayName = BUTTON_GROUP;
ButtonGroup.propTypes = propTypes;
ButtonGroup.defaultProps = defaultProps;

export default ButtonGroup;