import React from 'react';
import PropTypes from 'prop-types';
import classNames from 'classnames';
import omit from 'omit.js';
import Icon from '../icon';
import Group from './button-group';

const rxTwoCNChar = /^[\u4e00-\u9fa5]{2}$/;
const isTwoCNChar = rxTwoCNChar.test.bind(rxTwoCNChar);
function isString(str: any) {
  return typeof str === 'string';
}

// Insert one space between two chinese characters automatically.
function insertSpace(child: React.ReactChild, needInserted: boolean) {
  // Check the child if is undefined or null.
  if (child == null) {
    return;
  }
  const SPACE = needInserted ? ' ' : '';
  // strictNullChecks oops.
  if (typeof child !== 'string' && typeof child !== 'number' &&
    isString(child.type) && isTwoCNChar(child.props.children)) {
    return React.cloneElement(child, {},
      child.props.children.split('').join(SPACE));
  }
  if (typeof child === 'string') {
    if (isTwoCNChar(child)) {
      child = child.split('').join(SPACE);
    }
    return <span>{child}</span>;
  }
  return child;
}

export type ButtonType = 'primary' | 'ghost' | 'dashed' | 'danger';
export type ButtonShape = 'circle' | 'circle-outline';
export type ButtonSize = 'small' | 'default' | 'large';

export interface ButtonProps {
  type?: ButtonType;
  htmlType?: string;
  icon?: string;
  shape?: ButtonShape;
  size?: ButtonSize;
  onClick?: React.FormEventHandler<any>;
  onMouseUp?: React.FormEventHandler<any>;
  onMouseDown?: React.FormEventHandler<any>;
  loading?: boolean | { delay?: number };
  disabled?: boolean;
  style?: React.CSSProperties;
  prefixCls?: string;
  className?: string;
  ghost?: boolean;
}

export default class Button extends React.Component<ButtonProps, any> {
  static Group: typeof Group;
  static __ANT_BUTTON = true;

  static defaultProps = {
    prefixCls: 'ant-btn',
    loading: false,
    ghost: false,
  };

  static propTypes = {
    type: PropTypes.string,
    shape: PropTypes.oneOf(['circle', 'circle-outline']),
    size: PropTypes.oneOf(['large', 'default', 'small']),
    htmlType: PropTypes.oneOf(['submit', 'button', 'reset']),
    onClick: PropTypes.func,
    loading: PropTypes.oneOfType([PropTypes.bool, PropTypes.object]),
    className: PropTypes.string,
    icon: PropTypes.string,
  };

  timeout: number;
  delayTimeout: number;

  constructor(props: ButtonProps) {
    super(props);
    this.state = {
      loading: props.loading,
      clicked: false,
    };
  }

  componentWillReceiveProps(nextProps: ButtonProps) {
    const currentLoading = this.props.loading;
    const loading = nextProps.loading;

    if (currentLoading) {
      clearTimeout(this.delayTimeout);
    }

    if (typeof loading !== 'boolean' && loading && loading.delay) {
      this.delayTimeout = window.setTimeout(() => this.setState({ loading }), loading.delay);
    } else {
      this.setState({ loading });
    }
  }

  componentWillUnmount() {
    if (this.timeout) {
      clearTimeout(this.timeout);
    }
    if (this.delayTimeout) {
      clearTimeout(this.delayTimeout);
    }
  }

  handleClick = (e: React.MouseEvent<HTMLButtonElement>) => {
    // Add click effect
    this.setState({ clicked: true });
    clearTimeout(this.timeout);
    this.timeout = window.setTimeout(() => this.setState({ clicked: false }), 500);

    const onClick = this.props.onClick;
    if (onClick) {
      onClick(e);
    }
  }

  render() {
    const {
      type, shape, size, className, htmlType, children, icon, prefixCls, ghost, ...others,
    } = this.props;

    const { loading, clicked } = this.state;

    // large => lg
    // small => sm
    let sizeCls = '';
    switch (size) {
      case 'large':
        sizeCls = 'lg';
        break;
      case 'small':
        sizeCls = 'sm';
      default:
        break;
    }

    const classes = classNames(prefixCls, className, {
      [`${prefixCls}-${type}`]: type,
      [`${prefixCls}-${shape}`]: shape,
      [`${prefixCls}-${sizeCls}`]: sizeCls,
      [`${prefixCls}-icon-only`]: !children && icon,
      [`${prefixCls}-loading`]: loading,
      [`${prefixCls}-clicked`]: clicked,
      [`${prefixCls}-background-ghost`]: ghost,
    });

    const iconType = loading ? 'loading' : icon;
    const iconNode = iconType ? <Icon type={iconType} /> : null;
    const needInserted = React.Children.count(children) === 1 && (!iconType || iconType === 'loading');
    const kids = React.Children.map(children, child => insertSpace(child, needInserted));

    return (
      <button
        {...omit(others, ['loading'])}
        type={htmlType || 'button'}
        className={classes}
        onClick={this.handleClick}
      >
        {iconNode}{kids}
      </button>
    );
  }
}