from sys import stderr, argv;
from base64 import b64encode, b64decode;
from STPyV8 import JSContext, JSClass;

# Create context with methods for file i/o
class Base64Context(JSClass):
  def read_file(self, path):
    with open(path, "rb") as f:
      data = f.read();
    return b64encode(data).decode("ascii");
  def write_file(self, data, path):
    with open(path, "wb") as f:
      f.write(b64decode(data));
globals = Base64Context();

# Read xlsx.full.min.js
with open("xlsx.full.min.js", "r") as f:
  sheetjs = f.read();

# The JSContext starts and cleans up the V8 engine
with JSContext(globals) as ctxt:
  # Load SheetJS library and display version number
  ctxt.eval(sheetjs);
  version = ctxt.eval("XLSX.version");
  print(f"SheetJS Version: {version}", file=stderr);

  # Parse workbook
  ctxt.eval(f"globalThis.wb = XLSX.read(read_file('{argv[1]}'), {{type:'base64'}}); void 0;");

  # Print CSV from first worksheet
  csv = ctxt.eval("XLSX.utils.sheet_to_csv(wb.Sheets[wb.SheetNames[0]]);");
  print(csv);

  # Generate XLSB
  xlsb = ctxt.eval("XLSX.write(wb, {type: 'base64', bookType: 'xlsb'})");
  globals.write_file(xlsb,"SheetJSSTPyV8.xlsb");