Changeset discussions

Add support for commenting on changesets with RSS feeds and email
notification of comments to other commenters and people that have
chosen to subscribe to a changeset.

app/assets/javascripts/index/changeset.js

@@ -0,0 +1,80 @@
+OSM.Changeset = function (map) {
+  var page = {},
+    content = $('#sidebar_content'),
+    currentChangesetId;
+
+  page.pushstate = page.popstate = function(path, id) {
+    OSM.loadSidebarContent(path, function() {
+      page.load(path, id);
+    });
+  };
+
+  page.load = function(path, id) {
+    if(id)
+      currentChangesetId = id;
+    initialize();
+    addChangeset(currentChangesetId, true);
+  };
+
+  function addChangeset(id, center) {
+    var bounds = map.addObject({type: 'changeset', id: parseInt(id)}, function(bounds) {
+      if (!window.location.hash && bounds.isValid() &&
+          (center || !map.getBounds().contains(bounds))) {
+        OSM.router.withoutMoveListener(function () {
+          map.fitBounds(bounds);
+        });
+      }
+    });
+  }
+
+  function updateChangeset(form, method, url, include_data) {
+    $(form).find("input[type=submit]").prop("disabled", true);
+    if(include_data) {
+      data = {text: $(form.text).val()};
+    } else {
+      data = {};
+    }
+
+    $.ajax({
+      url: url,
+      type: method,
+      oauth: true,
+      data: data,
+      success: function () {
+        OSM.loadSidebarContent(window.location.pathname, page.load);
+      }
+    });
+  }
+
+  function initialize() {
+    content.find("input[name=comment]").on("click", function (e) {
+      e.preventDefault();
+      var data = $(e.target).data();
+      updateChangeset(e.target.form, data.method, data.url, true);
+    });
+
+    content.find(".action-button").on("click", function (e) {
+      e.preventDefault();
+      var data = $(e.target).data();
+      updateChangeset(e.target.form, data.method, data.url);
+    });
+
+    content.find("textarea").on("input", function (e) {
+      var form = e.target.form;
+
+      if ($(e.target).val() == "") {
+        $(form.comment).prop("disabled", true);
+      } else {
+        $(form.comment).prop("disabled", false);
+      }
+    });
+
+    content.find("textarea").val('').trigger("input");
+  };
+
+  page.unload = function() {
+    map.removeObject();
+  };
+
+  return page;
+};