From 53121c9842e6f5f5fa356f40a2c37bcaaf8fed49 Mon Sep 17 00:00:00 2001
From: Tom MacWright <tom@macwright.org>
Date: Fri, 15 Mar 2013 16:22:54 -0400
Subject: [PATCH] Support JOSM style templates. Fixes #1023

---
 js/id/renderer/background_source.js | 8 +++++++-
 test/spec/renderer/background.js    | 5 ++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/js/id/renderer/background_source.js b/js/id/renderer/background_source.js
index 2df4d676c..c3a493c6b 100644
--- a/js/id/renderer/background_source.js
+++ b/js/id/renderer/background_source.js
@@ -18,7 +18,13 @@ iD.BackgroundSource.template = function(data) {
             .replace('{u}', u)
             .replace('{x}', coord[0])
             .replace('{y}', coord[1])
-            .replace('{z}', coord[2]);
+            .replace('{z}', coord[2])
+            // JOSM style
+            .replace('{zoom}', coord[2])
+            .replace(/\{(switch\:[^\}]*)\}/, function(s, r) {
+                var subdomains = r.split(':')[1].split(',');
+                return subdomains[coord[2] % subdomains.length];
+            });
     };
 
     generator.data = data;
diff --git a/test/spec/renderer/background.js b/test/spec/renderer/background.js
index 52c825d06..d155814e3 100644
--- a/test/spec/renderer/background.js
+++ b/test/spec/renderer/background.js
@@ -39,6 +39,9 @@ describe('iD.Background', function() {
             var source = iD.BackgroundSource.template({ template: '{t}/{z}/{x}/{y}', subdomains: ['apples', 'oranges'] });
             expect(source([0,1,1])).to.equal('oranges/1/0/1');
         });
+        it('supports josm style templates', function() {
+            var source = iD.BackgroundSource.template({ template: '{switch:foo,bar}/{zoom}/{x}/{y}' });
+            expect(source([0,1,1])).to.equal('bar/1/0/1');
+        });
     });
-
 });