/* sheetjs (C) SheetJS -- https://sheetjs.com */
import { useState, useCallback } from 'react';
import { StyleSheet, Text, Button, Alert, ScrollView } from 'react-native';
import { Table, Row, Rows, TableWrapper } from 'react-native-tabeller';
import { read, utils, WorkSheet } from 'xlsx';

const make_width = (ws: WorkSheet): number[] => {
  const aoa = utils.sheet_to_json(ws, { header: 1 }),
    res: number[] = [];
  aoa.forEach((r) => {
    r.forEach((c, C) => {
      res[C] = Math.max(res[C] || 60, String(c).length * 10);
    });
  });
  for (let C = 0; C < res.length; ++C) if (!res[C]) res[C] = 60;
  return res;
};

function SheetJSExample(): JSX.Element {
  const [data, setData] = useState<any[]>([
    'SheetJS'.split(''),
    [5, 4, 3, 3, 7, 9, 5],
    [8, 6, 7, 5, 3, 0, 9],
  ]);
  const [widths, setWidths] = useState<number[]>(
    Array.from({ length: 7 }, () => 20)
  );

  const importFile = useCallback(async () => {
    try {
      const ab = await (
        await fetch('https://docs.sheetjs.com/pres.numbers')
      ).arrayBuffer();
      const wb = read(ab);

      /* convert first worksheet to AOA */
      const wsname = wb.SheetNames[0];
      const ws = wb.Sheets[wsname];
      const data = utils.sheet_to_json(ws, { header: 1 });
      /* update state */
      setData(data);
      setWidths(make_width(ws));
    } catch (err) {
      Alert.alert('importFile Error', 'Error ' + ((err as any).message || err));
    }
  }, []);

  return (
    <ScrollView contentContainerStyle={styles.container}>
      <Text style={styles.welcome}> </Text>
      <Button
        onPress={importFile}
        title="Import data from a spreadsheet"
        color="#841584"
      />
      <Text style={styles.bolded}>Current Data</Text>
      <ScrollView style={styles.table} horizontal={true}>
        <Table style={styles.table}>
          <TableWrapper>
            <Row
              data={data[0]}
              style={styles.thead}
              textStyle={styles.text}
              widthArr={widths}
            />
          </TableWrapper>
          <ScrollView>
            <TableWrapper>
              <Rows
                data={data.slice(1)}
                style={styles.tr}
                textStyle={styles.text}
                widthArr={widths}
              />
            </TableWrapper>
          </ScrollView>
        </Table>
      </ScrollView>
    </ScrollView>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: { fontSize: 20, textAlign: 'center', margin: 10 },
  bolded: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
    fontWeight: 'bold',
  },
  thead: {
    height: 40,
    backgroundColor: '#f1f8ff',
    borderWidth: 0.5,
    justifyContent: 'center',
  },
  tr: {
    height: 30,
    borderWidth: 0.5,
    justifyContent: 'center',
  },
  text: { marginLeft: 5 },
  table: { width: '100%' },
  image: { height: 16, width: 16 },
});

export default SheetJSExample;