import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Scanner;
import com.caoccao.javet.interop.V8Host;
import com.caoccao.javet.interop.V8Runtime;

public class SheetJSJavet {
  public static void main(String[] args) throws Exception {
    /* initialize */
    V8Runtime v8Runtime = V8Host.getV8Instance().createV8Runtime();

    /* read script file */
    v8Runtime.getExecutor("var global = (function(){ return this; }).call(null);").executeVoid();
    v8Runtime.getExecutor(new Scanner(SheetJSJavet.class.getResourceAsStream("/xlsx.full.min.js")).useDelimiter("\\Z").next()).executeVoid();

    System.out.println(v8Runtime.getExecutor("'SheetJS Version ' + XLSX.version").executeString());

    /* read spreadsheet bytes */
    v8Runtime.getGlobalObject().set("i8", Files.readAllBytes(Paths.get(args[0])));
    v8Runtime.getExecutor("var u8 = new Uint8Array(i8.buffer, i8.byteOffset, i8.length);").executeVoid();

    /* parse workbook */
    v8Runtime.getExecutor("var wb = XLSX.read(u8, {type: 'array'})").executeVoid();

    /* get first worksheet as CSV */
    v8Runtime.getExecutor("var ws = wb.Sheets[wb.SheetNames[0]];").executeVoid();
    String res = v8Runtime.getExecutor("XLSX.utils.sheet_to_csv(ws)").executeString();
    System.out.println(res);
  }
}