const readline = require('readline');

const CFG = require('./machine.config.js');
const { num2hex } = require('./logging.js');

function readKeyMem(mem) {
  return mem[CFG.keypadAddr];
}

function getKeypadInput(cpu) {
  readline.emitKeypressEvents(process.stdin);
  if (process.stdin.setRawMode != null) {
    process.stdin.setRawMode(true);
  }
  process.stdin.on('keypress', (str, key) => {
    if (key.sequence === '\x03') process.exit();
    let name = key.name.toUpperCase();
    if (name in CFG.keyMap) {
      cpu.memory[CFG.keypadAddr] = CFG.keyMap[name];
    }
  });
}

/**
 * Print the contents of display memory
 * by default, each pixel is shown as a hex number
 * @param {Uint8Array} mem - CPU memory
 * @param {Boolean} pretty - Display pixels using black and white emoji circles
 **/
function showDisplay(mem, pretty=false) {
  const disp = mem[CFG.pointerToDisplay];
  const num2pic = (n) => n > 0 ? '⚫' : '⚪';
  let fmt = (n) => num2hex(n);
  if (pretty) fmt = (n) => num2pic(n);
  for (let i = disp; i < disp + 25; i += 5) {
    console.log(`${fmt(mem[i])} ${fmt(mem[i+1])} ${fmt(mem[i+2])} ${fmt(mem[i+3])} ${fmt(mem[i+4])}`);
  }
}

module.exports = {
  "showDisplay": showDisplay,
  "getKeypadInput": getKeypadInput,
  "readKeyMem": readKeyMem,
}