#!/usr/bin/env node

const fs = require('fs');

const DBG = require('./dbg.js');
const Opter = require('./opter/opter.js');
const { num2hex, bool2bit } = require('./conversions.js');

const CFG = require('./machine.config.js');
const CPU = require('./cpu.js');
const io = require('./io.js');


/** SETUP **/
const dbg = new DBG('nitpick');
let cpu = new CPU(CFG.initialIP, CFG.defaultCycleLimit);

main();

async function main() {
  const opter = new Opter();
  opter.addOption('-i', '--in', false, true, 1);
  const opts = opter.parse(process.argv);

  let input = null;
  if ('in' in opts) { // Read from file
    input = fs.readFileSync(opts.in[0], 'utf8');
  } else { // Read from stdin
    input = await readPipedStdin();
  }

  let code = null;
  let sourceAnnotations = null;

  try {
    const parsedInput = JSON.parse(input);
    sourceAnnotations = parsedInput.sourceAnnotations;
    code = new Uint8Array(parsedInput.machineCode);
  } catch (error) {
    if (error.name === 'SyntaxError') {
      code = new Uint8Array(input.split(' '));
    }
  }

  cpu.loadMemory(code);
  if (sourceAnnotations !== null) { cpu.loadSourceAnnotations(sourceAnnotations); }

  cpu.onCycleEnd(tick);
  cpu.onCycleEnd(logCPUState);

  cpu.start();
  io.getKeypadInput(cpu);
  cpu.step();
}


async function tick() {
  const sleep = ms => new Promise(resolve => setTimeout(resolve, ms))
  await sleep(100);
  cpu.step();
  if (!cpu.running) {
    console.log('Halted');
    process.exit();
  }
}

function logCPUState() {
  let lineInfo = null;
  if (cpu.dbg.sourceAnnotations) {
    lineInfo = cpu.dbg.sourceAnnotations[cpu.dbg.previousIP];
  }
  console.group(`Step ${cpu.dbg.cycleCounter}`);
    console.log();
    io.showDisplay(cpu.memory, true); // FIXME - display - allow printing hex as well as pretty-printing
    console.log();
    if (lineInfo) {
      console.log(`Line ${lineInfo.lineNumber}: ${lineInfo.source}`);
      console.log();
    }
    console.log('Mnemonic:', cpu.dbg.currentMnemonic);
    console.log(`Machine:  $${num2hex(cpu.instruction.opcode)} $${num2hex(cpu.instruction.operand)}`);
    console.log();
    console.log(`IP: $${num2hex(cpu.IP)}  Acc: $${num2hex(cpu.acc)}  ONZC ${bool2bit(cpu.flags.O)}${bool2bit(cpu.flags.N)}${bool2bit(cpu.flags.Z)}${bool2bit(cpu.flags.C)}`);
    console.log(`KEY: ${io.readKeyMem(cpu.memory)}   ${cpu.running ? "running" : "halted" }`);
    console.log();
  console.groupEnd();
};

async function readPipedStdin() {
  // https://wellingguzman.com/notes/node-pipe-input
  return new Promise(function (resolve, reject) {
    const stdin = process.stdin;
    stdin.setEncoding('utf8');
    let data = '';
    stdin.on('data', function (chunk) { data += chunk; });
    stdin.on('end', function () { resolve(data); });
    stdin.on('error', reject);
  });
}