// @flow strict

import * as React from 'react';

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

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


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

/*
  Note: An indeterminate state has a higher priority.
  If true checkbox would be in an indeterminate state. If indeterminate is false, it will owner checked value.
*/

export type CheckboxProps = {
  name?: string,
  value?: string,
  children?: React.Node,
  checked?: boolean,
  indeterminate?: boolean,
  focused?: boolean,
  disabled?: boolean,
  error?: boolean,
  onChange?: (
    {value: string, checked: boolean},
    ?SyntheticEvent<HTMLElement>,
  ) => mixed,
  align?: GroupAlign,
  classNames?: ClassNames,
  tabIndex?: number,
  ariaLabel?: string,
};

export const Checkbox: React$AbstractComponent<
  CheckboxProps,
  HTMLInputElement,
> = React.forwardRef<CheckboxProps, HTMLInputElement>(
  (
    {
      name = 'checkbox',
      value = '',
      children,
      checked = false,
      indeterminate = false,
      focused = false,
      disabled = false,
      error = false,
      onChange,
      align,
      classNames,
      tabIndex = 0,
      ariaLabel = '',
    }: CheckboxProps,
    forwardRef,
  ): React.Node => {
    const checkboxInput = React.createRef<HTMLInputElement>();
    React.useImperativeHandle(forwardRef, () => checkboxInput.current);

    const handleOnClick = (event) => {
      if (!disabled) {
        onChange &&
          onChange(
            {
              value,
              checked: !checked,
            },
            event,
          );
      }
    };

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

    React.useEffect(() => {
      if (checkboxInput.current && indeterminate) {
        checkboxInput.current.indeterminate = true;
      }
      if (checkboxInput.current && !indeterminate) {
        checkboxInput.current.indeterminate = false;
      }
    }, [indeterminate]);

    return (
      <div
        data-testid="checkbox"
        className={classify(
          css.checkboxContainer,
          {
            [css.disabled]: disabled,
            [css.horizontalCheckbox]: align === 'horizontal-fixed',
            [css.fluidCheckbox]: align === 'horizontal-fluid',
          },
          classNames?.wrapper,
        )}
        onClick={handleOnClick}
      >
        <span
          className={classify(
            css.checkboxSquare,
            {
              [css.disabled]: disabled,
            },
            classNames?.checkboxSquare,
          )}
        >
          <input
            tabIndex={disabled ? -1 : tabIndex}
            type="checkbox"
            checked={checked}
            readOnly
            ref={checkboxInput}
            className={classify(css.inputCheckbox)}
            disabled={disabled}
            name={name}
            aria-label={ariaLabel || children}
          />
          <span
            className={classify(css.checkboxSquareInner, {
              [css.enabled]: !disabled && !error,
              [css.disabled]: disabled,
              [css.error]: error && !disabled,
            })}
          >
            {indeterminate && (
              <Icon
                color={disabled ? 'disabled' : 'inversePrimary'}
                name="hyphen"
                size="small"
                type="regular"
              />
            )}
            {checked && !indeterminate && (
              <Icon
                color={disabled ? 'disabled' : 'inversePrimary'}
                name="check"
                size="small"
                type="regular"
              />
            )}
          </span>
        </span>
        {React.Children.count(children) > 0 && (
          <div
            className={classify(
              css.checkboxLabel,
              {[css.labelDisabled]: disabled},
              classNames?.label,
            )}
          >
            {children}
          </div>
        )}
      </div>
    );
  },
);