'use strict';

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

  var path = require('path');
  var tokensPath = path.join(__dirname, '..', 'var', 'tokens.json');
  var storage = {
    _read: function () {
      var tokens;
      try {
        tokens = require(tokensPath);
      } catch (err) {
        tokens = {};
      }
      return tokens;
    }
  , _write: function (tokens) {
      return fs.mkdirAsync(path.dirname(tokensPath)).catch(function (err) {
        if (err.code !== 'EEXIST') {
          console.error('failed to mkdir', path.dirname(tokensPath), err.toString());
        }
      }).then(function () {
        return fs.writeFileAsync(tokensPath, JSON.stringify(tokens), 'utf8');
      });
    }

  , all: function () {
      var tokens = storage._read();
      return PromiseA.resolve(Object.keys(tokens).map(function (key) {
        return tokens[key];
      }));
    }
  , save: function (result) {
      var tokens = storage._read();
      tokens[result.jwt] = result;
      storage._write(tokens);
    }
  , del: function (id) {
      var tokens = storage._read();
      delete tokens[id];
      storage._write(tokens);
    }
  };

  function addToken(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 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 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 removeToken(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 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 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 PromiseA.resolve();
    }

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

  if (typeof config.tunnel === 'string') {
    config.tunnel.split(',').forEach(function (jwt) {
      addToken({ jwt: jwt, owner: 'config' });
    });
  }
  storage.all().then(function (stored) {
    stored.forEach(function (result) {
      addToken(result);
    });
  });

  return {
    add: function (data) {
      return addToken(data).then(function () {
        return storage.save(data);
      });
    }
  , remove: function (data) {
      return storage.del(data.jwt).then(function () {
        return removeToken(data);
      });
    }
  , get: function (owner) {
      return storage.all().then(function (tokens) {
        var result = {};
        tokens.forEach(function (data) {
          if (!result[data.owner]) {
            result[data.owner] = {};
          }
          if (!result[data.owner][data.tunnelUrl]) {
            result[data.owner][data.tunnelUrl] = [];
          }
          data.decoded = JSON.parse(new Buffer(data.jwt.split('.')[0], 'base64'));
          result[data.owner][data.tunnelUrl].push(data);
        });

        if (owner) {
          return result[owner] || {};
        }
        return result;
      });
    }
  };
};