// @flow strict

import * as React from 'react';

import type {GroupAlign} from '../../types/common';
import classify from '../../utils/classify';

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

/**
 * Note:
 * Do not wrap Radio in a label. For simplicity's sake, Radio 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, radio?: string}>;

export type RadioButtonProps = {
  children?: React.Node,
  value?: string,
  disabled?: boolean,
  focused?: boolean,
  name?: string,
  selectedValue?: string,
  align?: GroupAlign,
  classNames?: ClassNames,
  error?: boolean,
  onChange?: (newValue: string) => mixed,
  tabIndex?: number,
  ariaLabel?: string,
};

export const RadioButton: React$AbstractComponent<
  RadioButtonProps,
  HTMLInputElement,
> = React.forwardRef<RadioButtonProps, HTMLInputElement>(
  (
    {
      children,
      disabled = false,
      value = '',
      focused = false,
      name = 'radio',
      selectedValue,
      onChange,
      align = 'vertical',
      classNames,
      error = false,
      tabIndex = 0,
      ariaLabel = '',
      ...props
    }: RadioButtonProps,
    forwardRef,
  ): React.Node => {
    const radioInput = React.createRef<HTMLInputElement>();
    React.useImperativeHandle(forwardRef, () => radioInput.current);

    const checked = selectedValue === value;

    React.useEffect(() => {
      if (radioInput.current && focused) {
        radioInput.current.focus();
      }
    }, [focused]);

    const onWrapClickHandler = () => {
      radioInput.current?.click();
    };

    const onChangeHandler = (e) => {
      if (!disabled) {
        onChange && onChange(e?.target?.value);
      }
    };

    const onKeyDownHandler = (e) => {
      if (e.key === 'Enter') {
        onChangeHandler(e);
      }
    };

    return (
      <div
        className={classify(
          css.container,
          {
            [css.horizontalRadioButton]: align === 'horizontal-fixed',
            [css.fluidRadioButton]: align === 'horizontal-fluid',
            [css.containerDisabled]: disabled,
          },
          classNames?.wrapper,
        )}
        onClick={onWrapClickHandler}
      >
        <input
          type="radio"
          checked={checked}
          disabled={disabled}
          className={classify(
            css.radio,
            {
              [css.unselected]: !checked && !disabled && !error,
              [css.selected]: checked && !disabled && !error,
              [css.disabled]: disabled,
              [css.error]: error && !disabled,
            },
            classNames?.radio,
          )}
          ref={radioInput}
          onChange={onChangeHandler}
          onKeyDown={onKeyDownHandler}
          tabIndex={disabled ? -1 : tabIndex}
          name={name}
          value={value || ''}
          aria-label={ariaLabel || children}
          {...props}
        />
        {React.Children.count(children) > 0 && (
          <div
            color="secondary"
            className={classify(
              css.radioLabel,
              {[css.labelDisabled]: disabled},
              classNames?.label,
            )}
          >
            {children}
          </div>
        )}
      </div>
    );
  },
);