// @flow strict

import * as React from 'react';

import classify from '../../utils/classify';

import css from './Toggle.module.css';

/**
 * Note:
 * Do not wrap Toggle in a label. For simplicity's sake, Toggle uses an
 * internal label tag to handle click delegation to the hidden input, and
 * nesting labels is a bad idea.
 */

type ClassNames = $ReadOnly<{wrapper?: string, label?: string}>;

export type ToggleProps = {
  name?: string,
  classNames?: ClassNames,
  children?: React.Node,
  checked?: boolean,
  onChange?: ({value: string, checked: boolean}) => mixed,
  disabled?: boolean,
  focused?: boolean,
  value?: string,
  ariaLabel?: string,
  labelPosition?: 'left' | 'right',
};

export const Toggle: React$AbstractComponent<ToggleProps, HTMLInputElement> =
  React.forwardRef<ToggleProps, HTMLInputElement>(
    (
      {
        name = 'toggle',
        value = '',
        classNames,
        children,
        disabled,
        checked,
        focused,
        onChange,
        ariaLabel,
        labelPosition = 'right',
        ...props
      }: ToggleProps,
      forwardRef,
    ): React.Node => {
      const toggleInput = React.createRef<HTMLInputElement>();
      React.useImperativeHandle(forwardRef, () => toggleInput.current);
      const handleOnChange = () => {
        if (!disabled) {
          onChange &&
            onChange({
              value,
              checked: !checked,
            });
        }
      };

      const onWrapClickHandler = (e) => {
        e.nativeEvent.stopImmediatePropagation();
        toggleInput.current?.click();
      };

      React.useEffect(() => {
        if (toggleInput.current && focused) {
          toggleInput.current.focus();
        }
      }, [focused]);
      return (
        <div
          className={classify(
            css.container,
            {
              [css.disabled]: disabled,
            },
            classNames?.wrapper,
          )}
          onClick={onWrapClickHandler}
        >
          {labelPosition === 'left' && React.Children.count(children) > 0 && (
            <div className={classify(css.toggleLabel, classNames?.label)}>
              {children}
            </div>
          )}
          <span className={css.toggleWrap}>
            <input
              type="checkbox"
              name={name}
              value={value}
              checked={checked}
              onChange={handleOnChange}
              ref={toggleInput}
              disabled={disabled}
              aria-label={ariaLabel || children}
              {...props}
            />
            <span
              className={classify(css.toggle, {
                [css.disabledButton]: disabled,
              })}
            />
          </span>
          {labelPosition === 'right' && React.Children.count(children) > 0 && (
            <div className={classify(css.toggleLabel, classNames?.label)}>
              {children}
            </div>
          )}
        </div>
      );
    },
  );