trufflesuite/truffle

const colors = require("colors");
const commandExistsSync = require("command-exists").sync;

module.exports = async function (options) {
  const OS = require("os");
  const deprecationMessage = colors.yellow(
    `> The watch command is planned ` +
      `for deprecation in version 6 of Truffle.${OS.EOL}` +
      `> See https://github.com/trufflesuite/truffle/issues/3227 for more ` +
      `information.`
  );
  console.log(deprecationMessage);
  const Config = require("@truffle/config");
  const sane = require("sane");
  const path = require("path");

  const config = Config.detect(options);

  const watchOptions = {
    ignored: [
      "build/**/**",
      /[/\\]\./ // Ignore files prefixed with .
    ]
  };
  // Certain large codebases have trouble with the watch command.
  // Installing watchman resolves some of these issues.
  if (commandExistsSync("watchman")) {
    watchOptions.watchman = true;
  } else {
    config.logger.log(
      "If you have trouble using watch, try installing watchman."
    );
  }

  const watchCallback = filePath => {
    const displayPath = path.join(
      "./",
      filePath.replace(config.working_directory, "")
    );
    config.logger.log(colors.cyan(">> File " + displayPath + " changed."));

    build(config);
  };

  const watcher = sane(config.working_directory, watchOptions);
  watcher.on("change", watchCallback);
  watcher.on("add", watchCallback);
  watcher.on("delete", watchCallback);

  config.logger.log(colors.green("Watching for a change in project files..."));
  return new Promise(() => {});
};

const build = config => {
  const Build = require("../build");

  config.logger.log("Rebuilding...");

  Build.build(config, function (error) {
    printSummary(config, error);
  });
};

const printSummary = (config, error) => {
  if (error) {
    const TruffleError = require("@truffle/error");
    if (error instanceof TruffleError) {
      console.log(error.message);
    } else {
      // Bubble up all other unexpected errors.
      console.log(error.stack || error.toString());
    }
  } else {
    config.logger.log(
      colors.green("Completed without errors on " + new Date().toString())
    );
  }
};