site/components/nav.js

import React, { Component } from 'react'
import styled from '@emotion/styled'
import { css, keyframes } from '@emotion/core'
import { Box, Container, Flex, Link, Text } from 'theme-ui'
import theme from '../lib/theme'
import Icon from './icon'
import Flag from './flag'
import ScrollLock from 'react-scrolllock'

const rgbaBgColor = (props, opacity) =>
  `rgba(
    ${props.bgColor[0]},
    ${props.bgColor[1]},
    ${props.bgColor[2]},
    ${opacity}
  )`

const unfixed = props =>
  !props.unfixed &&
  css`
    position: absolute;
    top: 0;
  `
// const bg = (props) =>
//   props.dark
//     ? css`
//         -webkit-backdrop-filter: saturate(90%) blur(20px);
//         backdrop-filter: saturate(90%) blur(20px);
//       `
//     : css`
//         -webkit-backdrop-filter: saturate(180%) blur(20px);
//         backdrop-filter: saturate(180%) blur(20px);
//       `
const fixed = props =>
  (props.scrolled || props.toggled || props.fixed) &&
  css`
    position: fixed;
    background-color: ${rgbaBgColor(props, 0.96875)};
    border-bottom: 1px solid rgba(48, 48, 48, 0.125);
    @supports (-webkit-backdrop-filter: none) or (backdrop-filter: none) {
      background-color: ${props.transparent
        ? 'transparent'
        : rgbaBgColor(props, 0.75)};
      -webkit-backdrop-filter: saturate(180%) blur(20px);
      backdrop-filter: saturate(180%) blur(20px);
      /* {bg}; to support dark mode later */
    }
  `

const Root = styled(Box)`
  ${unfixed};
  width: 100%;
  z-index: 1000;
  ${fixed};
  @media print {
    display: none;
  }
`

export const Content = styled(Container)`
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: relative;
  z-index: 2;
  padding-left: ${theme.space[3]}px;
  @media (min-width: ${theme.breakpoints[2]}em) {
    padding: 0 ${theme.space[4]}px;
  }
`

const hoverColor = name =>
  ({
    white: 'smoke',
    smoke: 'muted',
    muted: 'slate',
    slate: 'black',
    black: 'slate',
    primary: 'error'
  }[name] || 'black')

const slide = keyframes({
  from: { transform: 'translateY(-25%)', opacity: 0 },
  to: { transform: 'translateY(0)', opacity: 1 }
})

const layout = props =>
  props.isMobile
    ? css`
        display: ${props.toggled ? 'flex' : 'none'};
        flex-direction: column;
        overflow-y: auto;
        text-align: left;
        height: 100vh;
        @media (prefers-reduced-motion: no-preference) {
          animation: ${slide} 0.25s ease-in;
        }
        a {
          color: ${theme.colors[props.dark ? 'white' : 'black']} !important;
          margin: 0 auto;
          height: 64px;
          font-weight: bold;
          font-size: ${theme.fontSizes[2]}px;
          width: 100%;
          max-width: 18rem;
          &:not(:last-child) {
            border-bottom: 1px solid rgba(48, 48, 48, 0.125);
          }
          @media screen and (max-width: 22em) {
            max-width: 16rem;
          }
        }
      `
    : css`
        @media (min-width: 56em) {
          display: flex;
          position: absolute;
          left: 50%;
          transform: translateX(-50%);
        }
        a {
          font-size: ${theme.fontSizes[1]}px;
          text-transform: uppercase;
          &:hover {
            color: ${theme.colors[hoverColor(props.color)]};
          }
        }
      `
const NavBar = styled(Box)`
  display: none;
  ${layout};
  a {
    margin-left: ${theme.space[3]}px;
    padding: ${theme.space[3]}px;
    text-decoration: none;
    @media (min-width: 56em) {
      color: ${props => theme.colors[props.color] || color};
    }
  }
`

const Navigation = props => (
  <NavBar role="navigation" {...props}>
    <Link href="https://hackclub.com/clubs/" children="Clubs" />
    <Link href="https://workshops.hackclub.com/" children="Workshops" />
    <Link href="https://hackathons.hackclub.com/" children="Hackathons" />
    <Link href="https://hackclub.com/bank/" children="Bank" />
    <Link href="https://hackclub.com/donate/" children="Donate" />
  </NavBar>
)

const ToggleContainer = styled(Flex)`
  align-items: center;
  justify-content: center;
  min-width: 64px;
  min-height: 44px;
  cursor: pointer;
  user-select: none;
  margin-left: auto;
  @media (min-width: 56em) {
    display: none;
  }
`

class Header extends Component {
  state = {
    scrolled: false,
    toggled: false
  }

  static defaultProps = {
    dark: false,
    color: 'white'
  }

  componentDidMount() {
    this.bindScroll(true)
    if (typeof window !== 'undefined') {
      const mobileQuery = window.matchMedia('(max-width: 48em)')
      mobileQuery.addListener(() => {
        this.setState({ mobile: true, toggled: false })
      })
    }
    if (window.location.pathname === '/') {
      this.setState({ dark: true })
    }
  }

  componentWillUnmount = () => {
    this.bindScroll(false)
  }

  bindScroll = add => {
    if (typeof window !== 'undefined' && !this.props.unfixed) {
      window[add ? 'addEventListener' : 'removeEventListener'](
        'scroll',
        this.onScroll
      )
    }
  }

  onScroll = () => {
    const newState = window.scrollY >= 16
    const { scrolled: oldState } = this.state

    if (newState !== oldState) {
      this.setState({ scrolled: newState })
    }
    if (window.location.pathname === '/') {
      this.setState({ dark: window.scrollY < document.body.clientHeight / 2 })
    }
  }

  handleToggleMenu = () => {
    this.setState(state => ({ toggled: !state.toggled }))
  }

  render() {
    const { color, fixed, bgColor, ...props } = this.props
    const { mobile, scrolled, toggled } = this.state
    const dark = this.props.dark || this.state.dark
    const baseColor = dark
      ? color || 'white'
      : color === 'white' && scrolled
      ? 'black'
      : color
    const toggleColor = dark
      ? color || 'snow'
      : toggled || (color === 'white' && scrolled)
      ? 'slate'
      : color

    return [
      <Box
        sx={{
          pt: 5,
          pb: 3,
          bg: 'dark',
          color: 'white',
          textAlign: 'center',
          a: { color: 'inherit', fontWeight: 'bold' }
        }}
        key="blm"
      >
        <Container variant="copy">
          <Text as="p">
            <Link href="https://twitter.com/hackclub/status/1266565380820160514?s=21">
              Black Lives Matter
            </Link>
            {'. We’re sending '}
            <Link href="https://twitter.com/lachlanjc/status/1269702361037058048?s=21">
              laptops to 80&nbsp;Black & underserved teenagers
            </Link>
            .
          </Text>
        </Container>
      </Box>,
      <Root
        {...props}
        key="nav"
        fixed={fixed}
        scrolled={scrolled}
        toggled={toggled}
        dark={dark}
        bgColor={bgColor || (dark ? [32, 34, 36] : [255, 255, 255])}
        as="header"
      >
        <Content>
          <Flag scrolled={scrolled || fixed} />
          <Navigation
            as="nav"
            aria-hidden={!!mobile}
            color={baseColor}
            dark={dark}
          />
          <ToggleContainer color={toggleColor} onClick={this.handleToggleMenu}>
            <Icon glyph={toggled ? 'view-close' : 'menu'} />
          </ToggleContainer>
        </Content>
        <Navigation
          as="nav"
          aria-hidden={!mobile}
          isMobile
          toggled={toggled}
          color={baseColor}
          dark={dark}
        />
        {toggled && <ScrollLock />}
      </Root>
    ]
  }
}

export default Header