'use strict';

module.exports.create = function (deps, conf) {
  var loopback = require('./loopback').create(deps, conf);

  function dnsType(addr) {
    if (/^\d+\.\d+\.\d+\.\d+$/.test(addr)) {
      return 'A';
    }
    if (-1 !== addr.indexOf(':') && /^[a-f:\.\d]+$/i.test(addr)) {
      return 'AAAA';
    }
  }

  async function getSession() {
    var sessions = await deps.storage.owners.all();
    var session = sessions.filter(function (sess) {
      return sess.token.scp.indexOf('dns') >= 0;
    })[0];

    if (!session) {
      throw new Error('no sessions with DNS grants');
    }

    // The OAUTH3 library stores some things on the root session object that we usually
    // just leave inside the token, but we need to pull those out before we use it here
    session.provider_uri = session.provider_uri || session.token.provider_uri || session.token.iss;
    session.client_uri = session.client_uri || session.token.azp;
    session.scope = session.scope || session.token.scp;
    return session;
  }

  async function setDeviceAddress(addr) {
    var session = await getSession();
    var directives = await deps.OAUTH3.discover(session.token.aud);

    // Set the address of the device to our public address.
    await deps.request({
      url: directives.api+'/api/com.daplie.domains/acl/devices/' + conf.device.hostname
    , method: 'POST'
    , headers: {
        'Authorization': 'Bearer ' + session.refresh_token
      , 'Accept': 'application/json; charset=utf-8'
      }
    , json: {
        addresses: [
          { value: addr, type:  dnsType(addr) }
        ]
      }
    });

    // Then update all of the records attached to our hostname, first removing the old records
    // to remove the reference to the old address, then creating new records for the same domains
    // using our new address.
    var allDns = deps.OAUTH3.api(directives.api, {session: session, api: 'dns.list'});
    var ourDomains = allDns.filter(function (record) {
      return record.device === conf.device.hostname;
    }).map(function (record) {
      var zoneSplit = record.zone.split('.');
      return {
        tld: zoneSplit.slice(1).join('.')
      , sld: zoneSplit[0]
      , sub: record.host.slice(0, -(record.zone.length + 1))
      };
    });

    var common = {
      api: 'devices.detach'
    , session: session
    , device: conf.device.hostname
    };
    await deps.PromiseA.all(ourDomains.map(function (record) {
      return deps.OAUTH3.api(directives.api, Object.assign({}, common, record));
    }));

    common = {
      api: 'devices.attach'
    , session: session
    , device: conf.device.hostname
    , ip: addr
    , ttl: 300
    };
    await deps.PromiseA.all(ourDomains.map(function (record) {
      return deps.OAUTH3.api(directives.api, Object.assign({}, common, record));
    }));
  }

  async function getDeviceAddresses() {
    var session = await getSession();
    var directives = await deps.OAUTH3.discover(session.token.aud);

    var result = await deps.request({
      url: directives.api+'/api/org.oauth3.dns/acl/devices'
    , method: 'GET'
    , headers: {
        'Authorization': 'Bearer ' + session.refresh_token
      , 'Accept': 'application/json; charset=utf-8'
      }
    , json: true
    });

    if (!result.body) {
      throw new Error('No response body in request for device addresses');
    }
    if (result.body.error) {
      throw Object.assign(new Error('error getting device list'), result.body.error);
    }

    var dev = result.body.devices.filter(function (dev) {
      return dev.name === conf.device.hostname;
    })[0];
    return (dev || {}).addresses || [];
  }

  var publicAddress;
  async function recheckPubAddr() {
    if (!conf.ddns.enabled) {
      return;
    }

    var session = await getSession();
    var directives = await deps.OAUTH3.discover(session.token.aud);
    var addr = await loopback.checkPublicAddr(directives.api);

    if (publicAddress === addr) {
      return;
    }

    if (conf.debug) {
      console.log('previous public address',publicAddress, 'does not match current public address', addr);
    }

    await setDeviceAddress(addr);
    publicAddress = addr;
  }

  recheckPubAddr();
  setInterval(recheckPubAddr, 5*60*1000);

  return {
    loopbackServer:     loopback.server
  , setDeviceAddress:   setDeviceAddress
  , getDeviceAddresses: getDeviceAddresses
  , recheckPubAddr:     recheckPubAddr
  };
};