/**
 * mutate-cli.ts — CLI wrapper for Push3 mutation operators.
 *
 * Commands:
 *   mutate    <push3file> <rate>           Apply `rate` random mutations.
 *   crossover <push3file1> <push3file2>    Single-point crossover of two programs.
 *
 * Outputs the resulting Push3 program text to stdout.
 * Exits 1 on invalid input or mutation failure.
 */

import { readFileSync } from 'fs';
import { parse } from '../push3-transpiler/src/parser';
import { mutate, crossover, serialize } from './mutate';

function loadProgram(filePath: string) {
  const src = readFileSync(filePath, 'utf8');
  return parse(src);
}

const [, , cmd, ...args] = process.argv;

switch (cmd) {
  case 'mutate': {
    const [file, rateStr] = args;
    if (!file || !rateStr) {
      process.stderr.write('Usage: mutate-cli mutate <push3file> <rate>\n');
      process.exit(1);
    }
    const rate = parseInt(rateStr, 10);
    if (isNaN(rate) || rate < 0) {
      process.stderr.write(`Invalid rate: ${rateStr}\n`);
      process.exit(1);
    }
    const program = loadProgram(file);
    const mutated = mutate(program, rate);
    process.stdout.write(serialize(mutated) + '\n');
    break;
  }

  case 'crossover': {
    const [file1, file2] = args;
    if (!file1 || !file2) {
      process.stderr.write('Usage: mutate-cli crossover <push3file1> <push3file2>\n');
      process.exit(1);
    }
    const a = loadProgram(file1);
    const b = loadProgram(file2);
    const crossed = crossover(a, b);
    process.stdout.write(serialize(crossed) + '\n');
    break;
  }

  default:
    process.stderr.write(`Unknown command: ${cmd}\nCommands: mutate, crossover\n`);
    process.exit(1);
}