'use strict';

module.exports.create = function (deps, config) {
  var stunnel = require('stunnel');
  var activeTunnels = {};

  function addToken(data) {
    if (typeof data === 'string') {
      data = { jwt: data };
    }
    if (!data.jwt) {
      return deps.PromiseA.reject(new Error("missing 'jwt' from tunnel data"));
    }
    if (!data.tunnelUrl) {
      var decoded;
      try {
        decoded = JSON.parse(new Buffer(data.jwt.split('.')[1], 'base64').toString('ascii'));
      } catch (err) {
        console.warn('invalid web token given to tunnel manager', err);
        return deps.PromiseA.reject(err);
      }
      if (!decoded.aud) {
        console.warn('tunnel manager given token with no tunnelUrl or audience');
        var err = new Error('missing tunnelUrl and audience');
        return deps.PromiseA.reject(err);
      }
      data.tunnelUrl = 'wss://' + decoded.aud + '/';
    }

    if (!activeTunnels[data.tunnelUrl]) {
      console.log('creating new tunnel client for', data.tunnelUrl);
      // We create the tunnel without an initial token so we can append the token and
      // get the promise that should tell us more about if it worked or not.
      activeTunnels[data.tunnelUrl] = stunnel.connect({
        stunneld: data.tunnelUrl
      , net: deps.tunnel.net
        // NOTE: the ports here aren't that important since we are providing a custom
        // `net.createConnection` that doesn't actually use the port. What is important
        // is that any services we are interested in are listed in this object and have
        // a '*' sub-property.
      , services: {
          https: { '*': 443 }
        , http:  { '*': 80 }
        , smtp:  { '*': 25 }
        , smtps: { '*': 587 /*also 465/starttls*/ }
        , ssh:   { '*': 22 }
        }
      });
    }

    console.log('appending token to tunnel at', data.tunnelUrl);
    return activeTunnels[data.tunnelUrl].append(data.jwt);
  }

  function acquireToken(session, domains) {
    var OAUTH3 = deps.OAUTH3;

    // 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;

    console.log('asking for tunnel token from', session.token.aud);
    return OAUTH3.discover(session.token.aud).then(function (directives) {
      var opts = {
        api: 'tunnel.token'
      , session: session
      , data: {
          domains: domains
        , device: {
            hostname: config.device.hostname
          , id: config.device.uid || config.device.id
          }
        }
      };

      return OAUTH3.api(directives.api, opts).then(addToken);
    });
  }

  function removeToken(data) {
    if (typeof data === 'string') {
      data = { jwt: data };
    }
    if (!data.tunnelUrl) {
      var decoded;
      try {
        decoded = JSON.parse(new Buffer(data.jwt.split('.')[1], 'base64').toString('ascii'));
      } catch (err) {
        console.warn('invalid web token given to tunnel manager', err);
        return deps.PromiseA.reject(err);
      }
      if (!decoded.aud) {
        console.warn('tunnel manager given token with no tunnelUrl or audience');
        var err = new Error('missing tunnelUrl and audience');
        return deps.PromiseA.reject(err);
      }
      data.tunnelUrl = 'wss://' + decoded.aud + '/';
    }

    // Not sure if we actually want to return an error that the token didn't even belong to a
    // server that existed, but since it never existed we can consider it as "removed".
    if (!activeTunnels[data.tunnelUrl]) {
      return deps.PromiseA.resolve();
    }

    console.log('removing token from tunnel at', data.tunnelUrl);
    return activeTunnels[data.tunnelUrl].clear(data.jwt);
  }

  function disconnectAll() {
    Object.keys(activeTunnels).forEach(function (key) {
      activeTunnels[key].end();
    });
  }

  return {
    start:       acquireToken
  , startDirect: addToken
  , remove:      removeToken
  , disconnect:  disconnectAll
  };
};