// too bound to the request object, but ok for now
var RedisPool = require("./redis_pool")
  , _         = require('underscore')
  , OAuthUtil = require('oauth-client')
  , url       = require('url')
  , Step      = require('step');
  _.mixin(require('underscore.string'));

var oAuth = function(){
  var me = {
    oauth_database: 3,
    oauth_user_key: "rails:oauth_access_tokens:<%= oauth_access_key %>",
    is_oauth_request: true
  };

  // oauth token cases:
  // * in GET request
  // * in header
  me.parseTokens = function(req){
    var query_oauth = _.clone(req.method == "POST" ? req.body: req.query);
    var header_oauth = {};
    var oauth_variables = ['oauth_body_hash',
                           'oauth_consumer_key',
                           'oauth_token',
                           'oauth_signature_method',
                           'oauth_signature',
                           'oauth_timestamp',
                           'oauth_nonce',
                           'oauth_version'];

    // pull only oauth tokens out of query
    var non_oauth  = _.difference(_.keys(query_oauth), oauth_variables);
    _.each(non_oauth, function(key){ delete query_oauth[key]; });

    // pull oauth tokens out of header
    var header_string = req.headers.authorization;
    if (!_.isUndefined(header_string)) {
      _.each(oauth_variables, function(oauth_key){
        var matched_string = header_string.match(new RegExp(oauth_key + '=\"([^\"]+)\"'))
        if (!_.isNull(matched_string))
          header_oauth[oauth_key] = decodeURIComponent(matched_string[1]);
      });
    }

    //merge header and query oauth tokens. preference given to header oauth
    return _.defaults(header_oauth, query_oauth);
  };

  // remove oauthy tokens from an object
  me.splitParams = function(obj) {
    var removed = null;
    for (var prop in obj) {
        if (/^oauth_\w+$/.test(prop)) {
            if(!removed) {
                removed = {};
            }
            removed[prop] = obj[prop];
            delete obj[prop];
        }
    }
    return removed;
  };


  // do new fancy get User ID
  me.verifyRequest = function(req, callback){
    var that = this;
    //TODO: review this
    var httpProto = arguments['2'];
    var passed_tokens;
    var ohash;
    var signature;

    Step(
      function getTokensFromURL(){
        return oAuth.parseTokens(req);
      },
      function getOAuthHash(err, data){
        if (err) throw err;

        // this is oauth request only if oauth headers are present
        this.is_oauth_request = !_.isEmpty(data);

        if (this.is_oauth_request) {
          passed_tokens = data;
          that.getOAuthHash(passed_tokens.oauth_token, this);
        } else {
          return null;
        }
      },
      function regenerateSignature(err, data){
        if (err) throw err;
        if (!this.is_oauth_request) return null;

        ohash = data;
        var consumer     = OAuthUtil.createConsumer(ohash.consumer_key, ohash.consumer_secret);
        var access_token = OAuthUtil.createToken(ohash.access_token_token, ohash.access_token_secret);
        var signer       = OAuthUtil.createHmac(consumer, access_token);

        var method = req.method;
        var host   = req.headers.host;

        if(!httpProto || (httpProto != 'http' && httpProto != 'https')) {
          var msg = "Unknown HTTP protocol " + httpProto + ".";
          err = new Error(msg);
          err.http_status = 500;
          callback(err);
          return;
        }
        
        var path   = httpProto + '://' + host + req.path;
        that.splitParams(req.query);

        // remove signature from passed_tokens
        signature = passed_tokens.oauth_signature;
        delete passed_tokens['oauth_signature'];

        var base64;
        var joined = {};

        // remove oauth_signature from body
        if(req.body) {
            delete req.body['oauth_signature'];
        }
        _.extend(joined, req.body ? req.body : null);
        _.extend(joined, passed_tokens);
        _.extend(joined, req.query);

        return signer.sign(method, path, joined);
      },
      function checkSignature(err, data){
        if (err) throw err;

        //console.log(data + " should equal the provided signature: " + signature);
        callback(err, (signature === data && !_.isUndefined(data)) ? ohash.user_id : null);
      }
    );
  };

  me.getOAuthHash = function(access_key, callback){
    var that = this;
    RedisPool.acquire(this.oauth_database, function(err, client){
      if ( err ) { callback(err); return; }
      var redisClient = client;
      redisClient.HGETALL(_.template(that.oauth_user_key, {oauth_access_key: access_key}), function(err, data){
        RedisPool.release(that.oauth_database, redisClient);
        callback(err, data);
      });
    });
  };

  return me;
}();

module.exports = oAuth;