// @flow strict

import * as React from 'react';

import {colorBackgroundTertiary} from '../../styles/variables/_color';
import {
  spaceSmall,
  spaceXSmall,
  spaceXXSmall,
} from '../../styles/variables/_space';
import classify from '../../utils/classify';
import type {AvatarSize} from '../Avatar';
import {BaseAvatar} from '../Avatar';
import type {ElevationType, PlacementType} from '../Tooltip';
import {Tooltip} from '../Tooltip';

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


const COLOR_SEQUENCE = ['blue', 'green', 'orange', 'red', 'gray'];

export type AvatarGroupProps = {
  children?: React.Node,
  size?: AvatarSize,
  borderColor?: string,
  maxTooltipLines?: number,
  placement?: PlacementType,
  maxAvatars?: number,
  tooltipElevation?: ElevationType,
};

export const AvatarGroup: React$AbstractComponent<
  AvatarGroupProps,
  HTMLDivElement,
> = React.forwardRef<AvatarGroupProps, HTMLDivElement>(
  (
    {
      children,
      size = 'medium',
      borderColor = colorBackgroundTertiary,
      maxTooltipLines = 7,
      placement = 'top',
      maxAvatars = 5,
      tooltipElevation,
    }: AvatarGroupProps,
    ref,
  ): React.Node => {
    const childAvatarCount = React.Children.count(children);

    const leftOverlap = {
      small: spaceXXSmall,
      medium: `${parseInt(spaceSmall) / 2}px`,
      large: spaceXSmall,
      extraLarge: spaceSmall,
    };

    let colorIndex = -1;

    const avatarInGroup = (child, index, color) => {
      const {classNames, text} = child.props;
      const {wrapper, ...restClassNames} = classNames || {};
      const avatar = React.cloneElement(child, {
        size,
        classNames: {
          wrapper: classify(css.avatarInGroup, wrapper),
          ...restClassNames,
        },
        style: {
          borderColor,
          marginLeft: `-${index !== 0 ? leftOverlap[size] : 0}`,
        },
        color,
      });
      return text ? (
        <Tooltip body={text} placement={placement} elevation={tooltipElevation}>
          {avatar}
        </Tooltip>
      ) : (
        avatar
      );
    };

    const childrenArray = React.Children.toArray(children);
    const totalAvatarCount = childrenArray.length;
    const plusAvatar = () => {
      const nameList = [];

      for (let i = maxAvatars - 1; i < totalAvatarCount; i++) {
        const child = childrenArray[i];
        const {text} = child.props;
        if (text) {
          nameList.push(text);
        }
      }

      const NameListNode = () => (
        <span>
          {nameList.map((name) => (
            <React.Fragment key={name}>
              {name}
              <br />
            </React.Fragment>
          ))}
        </span>
      );
      return (
        <Tooltip
          body={<NameListNode />}
          bodyMaxLines={maxTooltipLines}
          placement={placement}
          elevation={tooltipElevation}
        >
          <div className={css.plusAvatar}>
            <BaseAvatar
              size={size}
              color="gray"
              text={`+${childAvatarCount - maxAvatars + 1}`}
              classNames={{wrapper: css.avatarInGroup}}
              style={{
                borderColor,
                marginLeft: `-${leftOverlap[size]}`,
              }}
            />
          </div>
        </Tooltip>
      );
    };

    const childrenWithProps = React.Children.map(children, (child, index) => {
      const {imageSrc} = child.props;
      if (!imageSrc) {
        colorIndex++;
        if (colorIndex === COLOR_SEQUENCE.length) {
          colorIndex = 0;
        }
      }

      const color = COLOR_SEQUENCE[colorIndex];
      if (childAvatarCount <= maxAvatars) {
        return avatarInGroup(child, index, color);
      } else {
        if (index < maxAvatars - 1) {
          return avatarInGroup(child, index, color);
        } else if (index === maxAvatars) {
          return plusAvatar();
        }
      }
    });

    return (
      <div
        className={classify(css.avatarGroupContainer, {
          [css.extraLargeSize]: size === 'extraLarge',
          [css.largeSize]: size === 'large',
          [css.mediumSize]: size === 'medium',
          [css.smallSize]: size === 'small',
        })}
        ref={ref}
      >
        {childrenWithProps}
      </div>
    );
  },
);