'use strict';

var LE = require('../');
var ipc = {}; // in-process cache

module.exports.create = function (defaults, handlers, backend) {
  defaults.server = defaults.server || LE.liveServer;
  handlers.merge = require('./common').merge;
  handlers.tplCopy = require('./common').tplCopy;

  var PromiseA = require('bluebird');
  var RSA = PromiseA.promisifyAll(require('rsa-compat').RSA);
  var LeCore = PromiseA.promisifyAll(require('letiny-core'));
  var crypto = require('crypto');

  function createAccount(args, handlers) {
    // arg.rsaBitLength args.rsaExponent
    return RSA.generateKeypairAsync(args.rsaKeySize || 2048, 65537, { public: true, pem: true }).then(function (keypair) {

      return LeCore.registerNewAccountAsync({
        email: args.email
      , newRegUrl: args._acmeUrls.newReg
      , agreeToTerms: function (tosUrl, agree) {
          // args.email = email; // already there
          args.tosUrl = tosUrl;
          handlers.agreeToTerms(args, agree);
        }
      , accountKeypair: keypair

      , debug: defaults.debug || args.debug || handlers.debug
      }).then(function (body) {
        // TODO XXX use sha256 (the python client uses md5)
        // TODO ssh fingerprint (noted on rsa-compat issues page, I believe)
        keypair.publicKeyMd5 = crypto.createHash('md5').update(RSA.exportPublicPem(keypair)).digest('hex');
        keypair.publicKeySha256 = crypto.createHash('sha256').update(RSA.exportPublicPem(keypair)).digest('hex');

        var accountId = keypair.publicKeyMd5;
        var regr = { body: body };
        var account = {};

        args.accountId = accountId;

        account.keypair = keypair;
        account.regr = regr;
        account.accountId = accountId;
        account.id = accountId;

        args.account = account;

        return backend.setAccountAsync(args, account).then(function () {
          return account;
        });
      });
    });
  }

  function getAcmeUrls(args) {
    var now = Date.now();

    // TODO check response header on request for cache time
    if ((now - ipc.acmeUrlsUpdatedAt) < 10 * 60 * 1000) {
      return PromiseA.resolve(ipc.acmeUrls);
    }

    return LeCore.getAcmeUrlsAsync(args.server).then(function (data) {
      ipc.acmeUrlsUpdatedAt = Date.now();
      ipc.acmeUrls = data;

      return ipc.acmeUrls;
    });
  }

  function getCertificateAsync(args, defaults, handlers) {
    function log() {
      if (args.debug || defaults.debug) {
        console.log.apply(console, arguments);
      }
    }

    var account = args.account;
    var promise;
    var keypairOpts = { public: true, pem: true };

    promise = backend.getPrivatePem(args).then(function (pem) {
      return RSA.import({ privateKeyPem: pem });
    }, function (/*err*/) {
      return RSA.generateKeypairAsync(args.rsaKeySize, 65537, keypairOpts).then(function (keypair) {
        keypair.privateKeyPem = RSA.exportPrivatePem(keypair);
        keypair.privateKeyJwk = RSA.exportPrivateJwk(keypair);
        return backend.setPrivatePem(args, keypair);
      });
    });

    return promise.then(function (domainKeypair) {
      log("[le/core.js] get certificate");

      args.domainKeypair = domainKeypair;
      //args.registration = domainKey;

      return LeCore.getCertificateAsync({
        debug: args.debug

      , newAuthzUrl: args._acmeUrls.newAuthz
      , newCertUrl: args._acmeUrls.newCert

      , accountKeypair: RSA.import(account.keypair)
      , domainKeypair: domainKeypair
      , domains: args.domains

        //
        // IMPORTANT
        //
        // setChallenge and removeChallenge are handed defaults
        // instead of args because getChallenge does not have
        // access to args
        // (args is per-request, defaults is per instance)
        //
      , setChallenge: function (domain, key, value, done) {
          var copy = handlers.merge({ domains: [domain] }, defaults);
          handlers.tplCopy(copy);

          args.domains = [domain];
          //args.domains = args.domains || [domain];
          if (4 === handlers.setChallenge.length) {
            console.warn('[WARNING] deprecated use. Define setChallenge as function (opts, domain, key, val, cb) { }');
            handlers.setChallenge(copy, key, value, done);
          }
          else if (5 === handlers.setChallenge.length) {
            handlers.setChallenge(copy, domain, key, value, done);
          }
          else {
            done(new Error("handlers.setChallenge receives the wrong number of arguments"));
          }
        }
      , removeChallenge: function (domain, key, done) {
          var copy = handlers.merge({ domains: [domain] }, defaults);
          handlers.tplCopy(copy);

          if (3 === handlers.removeChallenge.length) {
            handlers.removeChallenge(copy, key, done);
          }
          else if (4 === handlers.removeChallenge.length) {
            handlers.removeChallenge(copy, domain, key, done);
          }
          else {
            done(new Error("handlers.removeChallenge receives the wrong number of arguments"));
          }
        }
      });
    }).then(function (results) {
      // { cert, chain, fullchain, privkey }
      args.pems = results;
      return backend.setRegistration(args, defaults, handlers);
    });
  }

  function getOrCreateDomainCertificate(args, defaults, handlers) {
    if (args.duplicate) {
      // we're forcing a refresh via 'dupliate: true'
      return getCertificateAsync(args, defaults, handlers);
    }

    return backend.getRegistration(args).then(function (certs) {
      var halfLife = (certs.expiresAt - certs.issuedAt) / 2;

      if (!certs || (Date.now() - certs.issuedAt) > halfLife) {
        // There is no cert available
        // Or the cert is more than half-expired
        return getCertificateAsync(args, defaults, handlers);
      }

      return PromiseA.reject(new Error(
          "[ERROR] Certificate issued at '"
        + new Date(certs.issuedAt).toISOString() + "' and expires at '"
        + new Date(certs.expiresAt).toISOString() + "'. Ignoring renewal attempt until half-life at '"
        + new Date(certs.issuedA + halfLife).toISOString() + "'. Set { duplicate: true } to force."
      ));
    });
  }

  // returns 'account' from lib/accounts { meta, regr, keypair, accountId (id) }
  function getOrCreateAcmeAccount(args, defaults, handlers) {
    function log() {
      if (args.debug) {
        console.log.apply(console, arguments);
      }
    }

    return backend.getAccountId(args).then(function (accountId) {

      // Note: the ACME urls are always fetched fresh on purpose
      return getAcmeUrls(args).then(function (urls) {
        args._acmeUrls = urls;

        if (accountId) {
          log('[le/core.js] use account');

          args.accountId = accountId;
          return Accounts.getAccount(args, handlers);
        } else {
          log('[le/core.js] create account');
          return Accounts.createAccount(args, handlers);
        }
      });
    }).then(function (account) {
      /*
      if (renewal.account !== account) {
        // the account has become corrupt, re-register
        return;
      }
      */
      log('[le/core.js] created account');
      return account;
    });
  }

  var wrapped = {
   registerAsync: function (args) {
      var copy = handlers.merge(args, defaults);
      handlers.tplCopy(copy);

      return getOrCreateAcmeAccount(copy, defaults, handlers).then(function (account) {
        copy.account = account;

        return backend.getOrCreateRenewal(copy).then(function (pyobj) {

          copy.pyobj = pyobj;
          return getOrCreateDomainCertificate(copy, defaults, handlers);
        });
      }).then(function (result) {
        return result;
      }, function (err) {
        return PromiseA.reject(err);
      });
    }
  , getOrCreateAccount: function (args) {
      // TODO
      keypair.privateKeyPem = RSA.exportPrivatePem(keypair);
      keypair.publicKeyPem = RSA.exportPublicPem(keypair);
      return createAccount(args, handlers);
    }
  , configureAsync: function (hargs) {
      var copy = merge(hargs, defaults);
      tplCopy(copy);

      return getOrCreateAcmeAccount(copy, defaults, handlers).then(function (account) {
        copy.account = account;
        return backend.getOrCreateRenewal(copy);
      });
    }
  };

  return wrapped;
};