// @flow
import * as ICONS from 'constants/icons';
import React, { useRef } from 'react';
import { parseURI } from 'lbry-redux';
import Button from 'component/button';
import useHover from 'effects/use-hover';
import { useIsMobile } from 'effects/use-screensize';

type SubscriptionArgs = {
  channelName: string,
  uri: string,
  notificationsDisabled?: boolean,
};

type Props = {
  permanentUrl: ?string,
  isSubscribed: boolean,
  doChannelSubscribe: SubscriptionArgs => void,
  doChannelUnsubscribe: SubscriptionArgs => void,
  showSnackBarOnSubscribe: boolean,
  doToast: ({ message: string }) => void,
  shrinkOnMobile: boolean,
  notificationsDisabled: boolean,
  user: ?User,
};

export default function SubscribeButton(props: Props) {
  const {
    permanentUrl,
    doChannelSubscribe,
    doChannelUnsubscribe,
    isSubscribed,
    showSnackBarOnSubscribe,
    doToast,
    shrinkOnMobile = false,
    notificationsDisabled,
    user,
  } = props;

  const buttonRef = useRef();
  const isMobile = useIsMobile();
  let isHovering = useHover(buttonRef);
  isHovering = isMobile ? true : isHovering;
  const uiNotificationsEnabled = user && user.experimental_ui;

  const { channelName } = parseURI(permanentUrl);
  const claimName = '@' + channelName;

  const subscriptionHandler = isSubscribed ? doChannelUnsubscribe : doChannelSubscribe;
  const subscriptionLabel = isSubscribed
    ? __('Following --[button label indicating a channel has been followed]--')
    : __('Follow');
  const unfollowOverride = isSubscribed && isHovering && __('Unfollow');

  const label = isMobile && shrinkOnMobile ? '' : unfollowOverride || subscriptionLabel;
  const titlePrefix = isSubscribed ? __('Unfollow this channel') : __('Follow this channel');

  return permanentUrl ? (
    <div className="button-group">
      <Button
        ref={buttonRef}
        iconColor="red"
        largestLabel={isMobile && shrinkOnMobile ? '' : subscriptionLabel}
        icon={unfollowOverride ? ICONS.UNSUBSCRIBE : ICONS.SUBSCRIBE}
        button={'alt'}
        requiresAuth={IS_WEB}
        label={label}
        title={titlePrefix}
        onClick={e => {
          e.stopPropagation();

          subscriptionHandler({
            channelName: claimName,
            uri: permanentUrl,
            notificationsDisabled: true,
          });

          if (showSnackBarOnSubscribe) {
            doToast({ message: __('Now following %channel%!', { channel: claimName }) });
          }
        }}
      />
      {isSubscribed && uiNotificationsEnabled && (
        <Button
          button="alt"
          icon={notificationsDisabled ? ICONS.BELL : ICONS.BELL_ON}
          onClick={() => {
            const newNotificationsDisabled = !notificationsDisabled;

            doChannelSubscribe({
              channelName: claimName,
              uri: permanentUrl,
              notificationsDisabled: newNotificationsDisabled,
            });

            if (newNotificationsDisabled === false) {
              doToast({ message: __('Notifications turned on for %channel%!', { channel: claimName }) });
            }
          }}
        />
      )}
    </div>
  ) : null;
}