'use strict';
/*global Promise*/

var Challenge = module.exports;

// If your implementation needs config options, set them. Otherwise, don't bother (duh).
Challenge.create = function (config) {

  var challenger = {};

  // Note: normally you'd these right in the method body, but for the sake of
  // "Table of Contents"-style documentation, I've pulled them out.

  // Note: All of these methods can be synchronous, async, Promise, and callback-style
  // (the calling functions check function.length and then Promisify accordingly)

  // Called when it's tiem to set the challenge
  challenger.set = function (opts, cb) {
    return Challenge._setHttp(opts, cb);
  };

  // Called when it's time to remove the challenge
  challenger.remove = function (opts) {
    return Challenge._removeHttp(opts);
  };

  // Optional (only really useful for http)
  // Called when the challenge needs to be retrieved
  challenger.get = function (opts) {
    return Challenge._getHttp(opts);
  };

  // Whatever you assign to 'options' will be merged into the incoming 'opts' beforehand
  // (for convenience, so you don't have to do the if (!x) { x = y; } dance)
  // (also, some defaults are layered, so it's good to set it any that you have)
  challenger.options = { debug: config.debug };

  return challenger;
};

// Prints the challenge URL and keyAuthorization to the screen
// (so that you can go set it and then continue)
// if you need per-run / per-domain options set them in approveDomains() and they'll be on 'args' here.
Challenge._setHttp = function (args, cb) {
  // Note: You can receive cb and use that, or omit cb and return a Promise

  var ch = args.challenge;
  console.info("[ACME http-01 '" + ch.altname + "' CHALLENGE]");
  console.info("You're about to receive the following HTTP request:");
  console.info("");
  // TODO let acme-v2 handle generating this url
  console.info('\tGET http://' + ch.altname + '/.well-known/acme-challenge/' + ch.token);
  console.info("");
  console.info("The ACME server expects the following plaintext \"key authorization\" response:");
  console.info("");
  console.info("\t" + ch.keyAuthorization);
  console.info("");
  console.info("Depending on what you're implementing you'll either enter that again in the next step,"
    + " simulating a webserver response, or you'll actually copy it over to your true webserver");
  if (args.debug) {
    console.info("Debug Info:");
    console.info("");
    console.info(JSON.stringify(httpChallengeToJson(ch), null, 2).replace(/^/gm, '\t'));
    console.info("");
  }
  console.info("[Press the ANY key to continue...]");

  process.stdin.resume();
  process.stdin.once('data', function () {
    process.stdin.pause();

    // The return value will checked. It must not be 'undefined'.
    cb(null, null);
  });
};

// might as well tell the user that whatever they were setting up has been checked
Challenge._removeHttp = function (args) {
  // I'm not defining 'cb' here, which means I'll either have to return a value or a Promise

  var ch = args.challenge;
  console.info("");
  console.info("[ACME http-01 '" + ch.altname + "' COMPLETE]: " + ch.status);
  console.info("Challenge complete. You may now remove the challenge file:");
  console.info("");
  console.info('\thttp://' + ch.altname + '/.well-known/acme-challenge/' + ch.token);
  console.info("");

  // The return value will checked. It must not be 'undefined'.
  return null;
};

Challenge._getHttp = function (args) {
  var ch = args.challenge;
  var altname = ch.altname || ch.identifier.value;
  var hostname = ch.hostname || ch.identifier.value;

  console.log(args);
  if (ch._test || !Challenge._getCache[ch.token]) {
    Challenge._getCache[ch.token] = true;
    console.info("");
    console.info("[ACME " + ch.type + " '" + altname + "' REQUEST]: " + ch.status);
    console.info('GET http://' + hostname + '/.well-known/acme-challenge/' + ch.token);
    console.info("(paste in the \"Key Authorization\" you received a moment ago to respond)");
    process.stdout.write("> ");
  }

  // Using a promise here just to show that Promises are support
  // (in fact, they're the default)
  return new Promise(function (resolve, reject) {
    process.stdin.resume();
    process.stdin.once('error', reject);
    process.stdin.once('data', function (chunk) {
      process.stdin.pause();

      var result = chunk.toString('utf8').trim();
      try {
        result = JSON.parse(result);
      } catch(e) {
        args.challenge.keyAuthorization = result;
        result = args.challenge;
      }
      if (result.keyAuthorization) {
        resolve(result);
        return;
      }

      // The return value will checked. It must not be 'undefined'.
      resolve(null);
    });
  });
};
// Because the ACME server will hammer us with requests, and that's confusing during a manual test:
Challenge._getCache = {};

function httpChallengeToJson(ch) {
  return {
    type: ch.type
  , altname: ch.altname
  , identifier: ch.identifier
  , wildcard: false
  , expires: ch.expires
  , token: ch.token
  , thumbprint: ch.thumbprint
  , keyAuthorization: ch.keyAuthorization
  };
}