From 8f3a778aece94db5f382ad44afdb7340a090136c Mon Sep 17 00:00:00 2001
From: Peter Johnson <insomnia@rcpt.at>
Date: Wed, 31 Oct 2018 14:05:37 +0100
Subject: [PATCH] feat(dedupe): consider the user agent language in
 deduplication

---
 helper/diffPlaces.js           | 13 +++++++-----
 middleware/dedupe.js           |  2 +-
 test/unit/helper/diffPlaces.js | 36 ++++++++++++++++++++++++++++++++++
 3 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/helper/diffPlaces.js b/helper/diffPlaces.js
index d9b93478..7a646851 100644
--- a/helper/diffPlaces.js
+++ b/helper/diffPlaces.js
@@ -54,7 +54,7 @@ function isParentHierarchyDifferent(item1, item2){
  * Compare the name properties if they exist.
  * Returns false if the objects are the same, else true.
  */
-function isNameDifferent(item1, item2){
+function isNameDifferent(item1, item2, requestLanguage){
   let names1 = _.get(item1, 'name');
   let names2 = _.get(item2, 'name');
 
@@ -72,15 +72,17 @@ function isNameDifferent(item1, item2){
   // else both have name info
 
   // iterate over all the languages in item2, comparing them to the
-  // 'default' name of item1
+  // 'default' name of item1 and also against the language requested by the user.
   for( let lang in names2 ){
     if( !isPropertyDifferent({[lang]: names1.default}, names2, lang) ){ return false; }
+    if( requestLanguage && !isPropertyDifferent({[lang]: names1[requestLanguage]}, names2, lang) ){ return false; }
   }
 
   // iterate over all the languages in item1, comparing them to the
-  // 'default' name of item2
+  // 'default' name of item2 and also against the language requested by the user.
   for( let lang in names1 ){
     if( !isPropertyDifferent({[lang]: names2.default}, names1, lang) ){ return false; }
+    if( requestLanguage && !isPropertyDifferent({[lang]: names2[requestLanguage]}, names1, lang) ){ return false; }
   }
 
   return true;
@@ -119,11 +121,12 @@ function isAddressDifferent(item1, item2){
 
 /**
  * Compare the two records and return true if they differ and false if same.
+ * Optionally provide $requestLanguage (req.clean.lang.iso6393) to improve name deduplication.
  */
-function isDifferent(item1, item2){
+function isDifferent(item1, item2, requestLanguage){
   if( isLayerDifferent( item1, item2 ) ){ return true; }
   if( isParentHierarchyDifferent( item1, item2 ) ){ return true; }
-  if( isNameDifferent( item1, item2 ) ){ return true; }
+  if( isNameDifferent( item1, item2, requestLanguage ) ){ return true; }
   if( isAddressDifferent( item1, item2 ) ){ return true; }
   return false;
 }
diff --git a/middleware/dedupe.js b/middleware/dedupe.js
index 18054335..c15b6026 100644
--- a/middleware/dedupe.js
+++ b/middleware/dedupe.js
@@ -17,7 +17,7 @@ function dedupeResults(req, res, next) {
   let unique = [ res.data[0] ];
 
   // convenience function to search unique array for an existing element which matches a hit
-  let findMatch = (hit) => unique.findIndex(elem => !isDifferent(elem, hit));
+  let findMatch = (hit) => unique.findIndex(elem => !isDifferent(elem, hit, _.get(req, 'clean.lang.iso6393') ));
 
   // iterate over res.data using an old-school for loop starting at index 1
   // we can call break at any time to end the iterator
diff --git a/test/unit/helper/diffPlaces.js b/test/unit/helper/diffPlaces.js
index 495fab02..a476f784 100644
--- a/test/unit/helper/diffPlaces.js
+++ b/test/unit/helper/diffPlaces.js
@@ -150,6 +150,42 @@ module.exports.tests.dedupe = function(test, common) {
     t.end();
   });
 
+  test('improved matching across languages - if default different, but user language matches default, consider this a match', function(t) {
+    var item1 = {
+      'name': {
+        'default': 'English Name',
+        'eng': 'A Name'
+      }
+    };
+    var item2 = {
+      'name': {
+        'default': 'A Name'
+      }
+    };
+
+    t.false(isDifferent(item1, item2, 'eng'), 'should be the same');
+    t.end();
+  });
+
+
+  test('improved matching across languages - if default different, but user language matches (fra), consider this a match', function(t) {
+    var item1 = {
+      'name': {
+        'default': 'Name',
+        'fra': 'French Name'
+      }
+    };
+    var item2 = {
+      'name': {
+        'default': 'Another Name',
+        'fra': 'French Name'
+      }
+    };
+
+    t.false(isDifferent(item1, item2, 'fra'), 'should be the same');
+    t.end();
+  });
+
   test('improved matching across languages - default names differ but match another language', function(t) {
     var item1 = {
       'name': {