import * as React from 'react';
import { QuickNav } from '../quick-nav';
import {
  TabContent,
  TabContentTitle,
  TabTitleRow,
  TabViewStyled,
} from './TabView.styled';

export type TabViewProps = {
  children: React.ReactNode[];
  initialTab?: number;
  masthead?: React.ReactNode;
};

type TabProps = {
  title: string;
  children: () => React.ReactNode;
};

export const TabView = (props: TabViewProps) => {
  const tabNames = React.Children.map(props.children, (child) => {
    if (!React.isValidElement(child)) {
      return '(Oops)';
    }

    return child.props.title;
  }) as string[];

  if (tabNames.length === 0) {
    return null;
  }

  const [currentTab, setCurrentTab] = React.useState<number>(props.initialTab ?? 0);
  const tabRefs = tabNames.reduce<{ [name: string]: React.RefObject<HTMLDivElement> }>(
    (acc, name) => ({ ...acc, [name]: React.createRef() }),
    {}
  );

  return (
    <TabViewStyled>
      <TabTitleRow>
        {props.masthead && props.masthead}
        <QuickNav
          currentNavItem={tabNames[currentTab]}
          navItems={tabNames}
          onNavChange={(newTabName) => {
            setCurrentTab(tabNames.findIndex((name) => newTabName === name));
            tabRefs[newTabName].current?.scrollIntoView({
              behavior: 'smooth',
            });
          }}
        />
      </TabTitleRow>
      <TabContent>
        {React.Children.map(props.children, (child) => {
          if (!React.isValidElement(child)) {
            return null;
          }

          return (
            <div key={child.props.title}>
              <TabContentTitle ref={tabRefs[child.props.title]}>
                {child.props.title}
              </TabContentTitle>
              {child}
            </div>
          );
        })}
      </TabContent>
    </TabViewStyled>
  );
};

export const Tab = (props: TabProps) => <div>{props.children()}</div>;