From b526d963fb4d216dff5134422ef1210ca5147ef1 Mon Sep 17 00:00:00 2001
From: Gilles De Mey <gilles.de.mey@gmail.com>
Date: Sun, 21 Dec 2014 19:11:09 +0100
Subject: [PATCH] Added simple levenshtein distance algorithm to stations route

---
 db/stations.js     | 27 +++++++++++++++++++++++-
 package.json       |  1 +
 routes/stations.js | 52 +++++++++++++++++++++++++++++++++-------------
 utils/error.js     |  4 ++++
 4 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/db/stations.js b/db/stations.js
index a6c7d65..d3ad9af 100644
--- a/db/stations.js
+++ b/db/stations.js
@@ -2,7 +2,8 @@
 
 var redis   = require('redis'),
     client  = redis.createClient(),
-    _       = require('lodash-node');
+    _       = require('lodash-node'),
+    leven   = require('leven');
 
 exports.byId = function(id, callback) {
   client.hgetall('station:' + id, function(err, station) {
@@ -27,3 +28,27 @@ exports.deserialize = function(object) {
 
   return object;
 };
+
+/**
+ * Lookup the ID of a train station based on the Levenshtein distance algo
+ */
+exports.levenLookup = function(needle, callback) {
+
+  client.HGETALL(['station:names'], function(err, stations) {
+
+    if (err)
+      return callback(err);
+
+    var results = [];
+
+    // itterate over stations to find lowest levenshtein distance string
+    _.forOwn(stations, function(id, station) {
+      var score = leven(needle, station);
+      if (score < 5 ) // if the score is larger than 5, it's probably nonsense
+        results.push({ score: score, id: id, station: station });
+    });
+
+    return callback(null, _.min(results, 'score'));
+  });
+
+};
diff --git a/package.json b/package.json
index a0b7025..85777f4 100644
--- a/package.json
+++ b/package.json
@@ -20,6 +20,7 @@
     "debug": "~0.7.4",
     "express": "~4.2.0",
     "hiredis": "^0.1.17",
+    "leven": "^1.0.1",
     "locale": "0.0.17",
     "lodash-node": "^2.4.1",
     "moment": "^2.8.1",
diff --git a/routes/stations.js b/routes/stations.js
index 9f83c16..fd525c8 100644
--- a/routes/stations.js
+++ b/routes/stations.js
@@ -1,29 +1,17 @@
 'use strict';
 
 var express   = require('express'),
+    ex        = require('../utils/error'),
     request   = require('request'),
     router    = express.Router(),
     _         = require('lodash-node'),
     maps      = require('../maps'),
     utils     = require('../utils'),
     datetime  = require('../utils/datetime'),
+    db        = require('../db/stations'),
     OAuth     = require('../utils/oauth');
 
-/* GET status */
-router.get('/:id([0-9]+)/:subset(arrivals|departures)?', function(req, res, next) {
-
-  var dateTimeFrom = datetime.toCET().format('YYYY-MM-DD HH:mm:ss');
-
-  var dateTimeTo   = datetime.toCET()
-    .add(1, 'hours')
-    .format('YYYY-MM-DD HH:mm:ss');
-
-  var params = {
-    'dateTimeFrom'  : dateTimeFrom,
-    'dateTimeTo'    : dateTimeTo,
-    'searchType'    : 0,
-    'stationID'     : req.params.id
-  };
+function makeRequest(req, res, next, params) {
 
   request.get(new OAuth('RetrieveStationSchedule', params), function(err, resp, body) {
 
@@ -65,6 +53,40 @@ router.get('/:id([0-9]+)/:subset(arrivals|departures)?', function(req, res, next
     });
   });
 
+}
+
+/* GET status */
+router.get('/:station/:subset(arrivals|departures)?', function(req, res, next) {
+
+  var dateTimeFrom = datetime.toCET().format('YYYY-MM-DD HH:mm:ss');
+
+  var dateTimeTo   = datetime.toCET()
+    .add(1, 'hours')
+    .format('YYYY-MM-DD HH:mm:ss');
+
+  var params = {
+    'dateTimeFrom'  : dateTimeFrom,
+    'dateTimeTo'    : dateTimeTo,
+    'searchType'    : 0,
+  };
+
+  if (isFinite(req.params.station)) {
+    params.stationID = req.params.station;
+    makeRequest(req, res, next, params);
+  }
+
+  else if (isNaN(req.params.station))
+    db.levenLookup(req.params.station, function(err, result) {
+
+      params.stationID = result.id;
+
+      // no results from lookup returns Infinity
+      if (isFinite(result.score))
+        makeRequest(req, res, next, params);
+      else
+        return res.json(404, new ex.StationNotFoundException());
+    });
+
 });
 
 /* GET index */
diff --git a/utils/error.js b/utils/error.js
index 10b60ff..c6503e7 100644
--- a/utils/error.js
+++ b/utils/error.js
@@ -8,6 +8,10 @@ exports.UnknownException = function(msg, code) {
   return new exports.Exception(msg, undefined, code);
 };
 
+exports.StationNotFoundException = function() {
+  return new exports.Exception('Could not find station', 'StationNotFoundException', 404);
+};
+
 exports.Exception = function(msg, type, code) {
   return {
     'error' : {