From 449c4d235da1f974f2b9c660baeb63a3c431c7b9 Mon Sep 17 00:00:00 2001
From: Ansis Brammanis <ansis.brammanis@gmail.com>
Date: Wed, 6 Feb 2013 14:03:31 -0500
Subject: [PATCH] Add option to restore or reset unsaved changes

---
 index.html             |  1 +
 js/id/graph/history.js | 34 +++++++++++++++++++++++++++-------
 js/id/id.js            |  1 +
 js/id/ui.js            |  5 +++++
 js/id/ui/restore.js    | 34 ++++++++++++++++++++++++++++++++++
 5 files changed, 68 insertions(+), 7 deletions(-)
 create mode 100644 js/id/ui/restore.js

diff --git a/index.html b/index.html
index 807e6a413..18f1b275b 100644
--- a/index.html
+++ b/index.html
@@ -67,6 +67,7 @@
         <script src='js/id/ui/flash.js'></script>
         <script src='js/id/ui/save.js'></script>
         <script src='js/id/ui/splash.js'></script>
+        <script src='js/id/ui/restore.js'></script>
         <script src='js/id/ui/tag_reference.js'></script>
         <script src='js/id/ui/key_reference.js'></script>
 
diff --git a/js/id/graph/history.js b/js/id/graph/history.js
index dba04ec7e..ac36d564f 100644
--- a/js/id/graph/history.js
+++ b/js/id/graph/history.js
@@ -1,7 +1,8 @@
 iD.History = function(context) {
     var stack, index,
         imagery_used = 'Bing',
-        dispatch = d3.dispatch('change', 'undone', 'redone');
+        dispatch = d3.dispatch('change', 'undone', 'redone'),
+        lock = false;
 
     function perform(actions) {
         actions = Array.prototype.slice.call(actions);
@@ -152,11 +153,20 @@ iD.History = function(context) {
         reset: function() {
             stack = [{graph: iD.Graph()}];
             index = 0;
-            this.load();
             dispatch.change();
         },
 
         save: function() {
+            if (!lock) return;
+            context.storage(getKey('lock'), null);
+
+            if (!stack.length) {
+                context.storage(getKey('history'), null);
+                context.storage(getKey('nextIDs'), null);
+                context.storage(getKey('index'), null);
+                return;
+            }
+
             var json = JSON.stringify(stack.map(function(i) {
                 return _.extend(i, {
                     graph: i.graph.entities
@@ -166,17 +176,22 @@ iD.History = function(context) {
             context.storage(getKey('history'), json);
             context.storage(getKey('nextIDs'), JSON.stringify(iD.Entity.id.next));
             context.storage(getKey('index'), index);
-            context.storage(getKey('lock'), '');
         },
 
         lock: function() {
             if (context.storage(getKey('lock'))) return false;
             context.storage(getKey('lock'), true);
-            return true;
+            lock = true;
+            return lock;
+        },
+
+        restorableChanges: function() {
+            if (!this.lock()) return false;
+            return !!context.storage(getKey('history'));
         },
 
         load: function() {
-            if (!this.lock()) return;
+            if (!lock) return;
 
             var json = context.storage(getKey('history')),
                 nextIDs = context.storage(getKey('nextIDs')),
@@ -186,10 +201,15 @@ iD.History = function(context) {
             if (nextIDs) iD.Entity.id.next = JSON.parse(nextIDs);
             if (index_ !== null) index = parseInt(index_, 10);
 
-            stack = JSON.parse(json).map(function(d) {
-                d.graph = iD.Graph().load(d.graph);
+            context.storage(getKey('history', null));
+            context.storage(getKey('nextIDs', null));
+            context.storage(getKey('index', null));
+
+            stack = JSON.parse(json).map(function(d, i) {
+                d.graph = iD.Graph(stack[0].graph).load(d.graph);
                 return d;
             });
+            dispatch.change();
 
         }
 
diff --git a/js/id/id.js b/js/id/id.js
index e20b3b111..d58464ecb 100644
--- a/js/id/id.js
+++ b/js/id/id.js
@@ -4,6 +4,7 @@ window.iD = function () {
 
     context.storage = function(k, v) {
         if (arguments.length === 1) return storage[k];
+        else if (v === null) delete storage[k];
         else storage[k] = v;
     };
 
diff --git a/js/id/ui.js b/js/id/ui.js
index dbbff15c8..c22ca6b83 100644
--- a/js/id/ui.js
+++ b/js/id/ui.js
@@ -256,5 +256,10 @@ iD.ui = function(context) {
             iD.ui.splash(context.container());
             context.storage('sawSplash', true);
         }
+
+        if (history.restorableChanges()) {
+            iD.ui.restore(context.container(), history);
+        }
+
     };
 };
diff --git a/js/id/ui/restore.js b/js/id/ui/restore.js
new file mode 100644
index 000000000..3df275d89
--- /dev/null
+++ b/js/id/ui/restore.js
@@ -0,0 +1,34 @@
+iD.ui.restore = function(selection, history) {
+    var modal = iD.ui.modal(selection);
+
+    modal.select('.modal')
+        .attr('class', 'modal-splash modal');
+
+    var introModal = modal.select('.content')
+        .append('div')
+        .attr('class', 'modal-section fillL')
+        .text('You have unsaved changes from a previous editing session. Do you wish to restore these changes?');
+
+    buttons = introModal
+        .append('div')
+        .attr('class', 'buttons cf')
+            .append('div')
+            .attr('class', 'button-wrap joined col4');
+
+    buttons.append('button')
+        .attr('class', 'save action button col6')
+        .text('Restore')
+        .on('click', function() {
+            history.load();
+            modal.remove();
+        });
+
+    buttons.append('button')
+        .attr('class', 'cancel button col6')
+        .text('Reset')
+        .on('click', function() {
+            modal.remove();
+        });
+
+    return modal;
+};