import React from 'react';
import { Theme, ThemeProvider, useTheme, createMuiTheme } from '@material-ui/core/styles';
import useMediaQuery from '@material-ui/core/useMediaQuery';
import { Breakpoint } from '@material-ui/core/styles/createBreakpoints';

type BreakpointOrNull = Breakpoint | null;

/**
 * Be careful using this hook. It only works because the number of
 * breakpoints in theme is static. It will break once you change the number of
 * breakpoints. See https://reactjs.org/docs/hooks-rules.html#only-call-hooks-at-the-top-level
 */
function useWidth() {
  const theme: Theme = useTheme();
  const keys: Breakpoint[] = [...theme.breakpoints.keys].reverse();
  return (
    keys.reduce((output: BreakpointOrNull, key: Breakpoint) => {
      // eslint-disable-next-line react-hooks/rules-of-hooks
      const matches = useMediaQuery(theme.breakpoints.up(key));
      return !output && matches ? key : output;
    }, null) || 'xs'
  );
}

function MyComponent() {
  const width = useWidth();
  return <span>{`width: ${width}`}</span>;
}

const theme = createMuiTheme();

export default function UseWidth() {
  return (
    <ThemeProvider theme={theme}>
      <MyComponent />
    </ThemeProvider>
  );
}