/*!
 * letiny
 * Copyright(c) 2015 Anatol Sommer <anatol@anatol.at>
 * Some code used from https://github.com/letsencrypt/boulder/tree/master/test/js
 * MPL 2.0
*/
'use strict';

module.exports.create = function (deps) {
  var NOOP=function () {}, log=NOOP;
  var request=require('request');
  var toStandardB64 = deps.leUtils.toStandardB64;
  var importPemPrivateKey = deps.leCrypto.importPemPrivateKey;
  var thumbprinter = deps.leCrypto.thumbprint;
  var generateCsr = deps.leCrypto.generateCsr || deps.leCrypto.generateCSR;
  var Acme = deps.Acme;

  function getCert(options, cb) {
    var state={
      validatedDomains:[]
    , validAuthorizationUrls:[]
    , newAuthzUrl: options.newAuthzUrl
    , newCertUrl: options.newCertUrl
    };

    console.log('state');
    console.log(state);
    if (!options.newAuthzUrl) {
      return handleErr(new Error("options.newAuthzUrl must be the authorization url"));
    }
    if (!options.newCertUrl) {
      return handleErr(new Error("options.newCertUrl must be the new certificate url"));
    }
    if (!options.accountPrivateKeyPem) {
      return handleErr(new Error("options.accountPrivateKeyPem must be an ascii private key pem"));
    }
    if (!options.domainPrivateKeyPem) {
      return handleErr(new Error("options.domainPrivateKeyPem must be an ascii private key pem"));
    }
    if (!options.setChallenge) {
      return handleErr(new Error("options.setChallenge must be function(hostname, challengeKey, tokenValue, done) {}"));
    }
    if (!options.removeChallenge) {
      return handleErr(new Error("options.removeChallenge must be function(hostname, challengeKey, done) {}"));
    }
    if (!(options.domains && options.domains.length)) {
      return handleErr(new Error("options.domains must be an array of domains such as ['example.com', 'www.example.com']"));
    }

    state.domains = options.domains.slice(0); // copy array
    try {
      state.accountKeyPem=options.accountPrivateKeyPem;
      state.accountKeyPair=importPemPrivateKey(state.accountKeyPem);
      state.acme=new Acme(state.accountKeyPair);
      state.certPrivateKeyPem=options.domainPrivateKeyPem;
      state.certPrivateKey=importPemPrivateKey(state.certPrivateKeyPem);
    } catch(err) {
      return handleErr(err, 'Failed to parse privateKey');
    }

    nextDomain();

    function nextDomain() {
      if (state.domains.length > 0) {
        getChallenges(state.domains.shift());
        return;
      } else {
        getCertificate();
      }
    }

    function getChallenges(domain) {
      state.domain=domain;

      state.acme.post(state.newAuthzUrl, {
        resource:'new-authz',
        identifier:{
          type:'dns',
          value:state.domain,
        }
      }, getReadyToValidate);
    }

    function getReadyToValidate(err, res, body) {
      var links, authz, httpChallenges, challenge, thumbprint, keyAuthorization, challengePath;

      if (err) {
        return handleErr(err);
      }

      if (Math.floor(res.statusCode/100)!==2) {
        return handleErr(null, 'Authorization request failed ('+res.statusCode+')');
      }

      links=Acme.parseLink(res.headers.link);
      if (!links || !('next' in links)) {
        return handleErr(err, 'Server didn\'t provide information to proceed (2)');
      }

      state.authorizationUrl=res.headers.location;
      state.newCertUrl=links.next;

      authz=JSON.parse(body);

      httpChallenges=authz.challenges.filter(function(x) {
        return x.type==='http-01';
      });
      if (httpChallenges.length===0) {
        return handleErr(null, 'Server didn\'t offer any challenge we can handle.');
      }
      challenge=httpChallenges[0];

      thumbprint=thumbprinter(state.accountKeyPair.publicKey);
      keyAuthorization=challenge.token+'.'+thumbprint;
      state.responseUrl=challenge.uri;

      options.setChallenge(state.domain, challenge.token, keyAuthorization, challengeDone);

      function challengeDone() {
        state.acme.post(state.responseUrl, {
          resource:'challenge',
          keyAuthorization:keyAuthorization
        }, function(err, res, body) {
          ensureValidation(err, res, body, function unlink() {
            options.removeChallenge(state.domain, challenge.token, function () {
              // ignore
            });
          });
        });
      }
    }

    function ensureValidation(err, res, body, unlink) {
      var authz;

      if (err || Math.floor(res.statusCode/100)!==2) {
        unlink();
        return handleErr(err, 'Authorization status request failed ('+res.statusCode+')');
      }

      authz=JSON.parse(body);

      if (authz.status==='pending') {
        setTimeout(function() {
          request.get(state.authorizationUrl, {}, function(err, res, body) {
            ensureValidation(err, res, body, unlink);
          });
        }, 1000);
      } else if (authz.status==='valid') {
        log('Validating domain ... done');
        state.validatedDomains.push(state.domain);
        state.validAuthorizationUrls.push(state.authorizationUrl);
        unlink();
        nextDomain();
      } else if (authz.status==='invalid') {
        unlink();
        return handleErr(null, 'The CA was unable to validate the file you provisioned', body);
      } else {
        unlink();
        return handleErr(null, 'CA returned an authorization in an unexpected state', authz);
      }
    }

    function getCertificate() {
      var csr=generateCsr(state.certPrivateKey, state.validatedDomains);
      log('Requesting certificate...');
      state.acme.post(state.newCertUrl, {
        resource:'new-cert',
        csr:csr,
        authorizations:state.validAuthorizationUrls
      }, downloadCertificate);
    }

    function downloadCertificate(err, res, body) {
      var links, certUrl;

      if (err || Math.floor(res.statusCode/100)!==2) {
        log('Certificate request failed with error ', err);
        if (body) {
          log(body.toString());
        }
        return handleErr(err, 'Certificate request failed');
      }

      links=Acme.parseLink(res.headers.link);
      if (!links || !('up' in links)) {
        return handleErr(err, 'Failed to fetch issuer certificate');
      }

      log('Requesting certificate: done');

      state.certificate=body;
      certUrl=res.headers.location;
      request.get({
        url:certUrl,
        encoding:null
      }, function(err, res, body) {
        if (err) {
          return handleErr(err, 'Failed to fetch cert from '+certUrl);
        }
        if (res.statusCode!==200) {
          return handleErr(err, 'Failed to fetch cert from '+certUrl, res.body.toString());
        }
        if (body.toString()!==state.certificate.toString()) {
          handleErr(null, 'Cert at '+certUrl+' did not match returned cert');
        } else {
          log('Successfully verified cert at '+certUrl);
          log('Requesting issuer certificate...');
          request.get({
            url:links.up,
            encoding:null
          }, function(err, res, body) {
            if (err || res.statusCode!==200) {
              return handleErr(err, 'Failed to fetch issuer certificate');
            }
            state.caCert=certBufferToPem(body);
            log('Requesting issuer certificate: done');
            done();
          });
        }
      });
    }

    function done() {
      var cert;

      try {
        cert=certBufferToPem(state.certificate);
      } catch(e) {
        console.error(e.stack);
        //cb(new Error("Could not write output files. Please check permissions!"));
        handleErr(e, 'Could not write output files. Please check permissions!');
        return;
      }

      cb(null, {
        cert: cert
      , key: state.certPrivateKeyPem
      , ca: state.caCert
      });
    }

    function handleErr(err, text, info) {
      log(text, err, info);
      cb(err || new Error(text));
    }
  }

  function certBufferToPem(cert) {
    cert=toStandardB64(cert.toString('base64'));
    cert=cert.match(/.{1,64}/g).join('\n');
    return '-----BEGIN CERTIFICATE-----\n'+cert+'\n-----END CERTIFICATE-----';
  }

  return getCert;
};