From 2e81e71859e85fa23598a397501c7ae655224234 Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Tue, 4 Apr 2017 02:00:01 -0400
Subject: [PATCH] Add history.toIntroGraph() for saving the edited introGraph
 to JSON

---
 data/intro_graph.json   |  4 +--
 modules/core/history.js | 66 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/data/intro_graph.json b/data/intro_graph.json
index 1486f6cd6..c6f543c82 100644
--- a/data/intro_graph.json
+++ b/data/intro_graph.json
@@ -12009,7 +12009,7 @@
     "w170989131": {
       "id": "w170989131",
       "tags": {
-        "name": "St Joseph River",
+        "name": "Saint Joseph River",
         "waterway": "river"
       },
       "nodes": [
@@ -14709,7 +14709,7 @@
       "id": "w17964497",
       "tags": {
         "highway": "tertiary",
-        "name": "Constantine Street"
+        "name": "South Constantine Street"
       },
       "nodes": [
         "n185958643",
diff --git a/modules/core/history.js b/modules/core/history.js
index b881ec9c3..a7118da76 100644
--- a/modules/core/history.js
+++ b/modules/core/history.js
@@ -291,7 +291,7 @@ export function coreHistory(context) {
 
         // restore history state to a given checkpoint or reset completely
         reset: function(key) {
-            if (key !== undefined) {
+            if (key !== undefined && checkpoints.hasOwnProperty(key)) {
                 stack = _.cloneDeep(checkpoints[key].stack);
                 index = checkpoints[key].index;
             } else {
@@ -305,6 +305,70 @@ export function coreHistory(context) {
         },
 
 
+        toIntroGraph: function() {
+            var nextId = { n: 0, r: 0, w: 0 },
+                permIds = {},
+                graph = this.graph(),
+                baseEntities = {};
+
+            // clone base entities..
+            _.forEach(graph.base().entities, function(entity) {
+                var copy = _.cloneDeepWith(entity, customizer);
+                baseEntities[copy.id] = copy;
+            });
+
+            // replace base entities with head entities..
+            _.forEach(graph.entities, function(entity, id) {
+                if (entity) {
+                    var copy = _.cloneDeepWith(entity, customizer);
+                    baseEntities[copy.id] = copy;
+                } else {
+                    delete baseEntities[id];
+                }
+            });
+
+            // swap temporary for permanent ids..
+            _.forEach(baseEntities, function(entity) {
+                if (Array.isArray(entity.nodes)) {
+                    entity.nodes = entity.nodes.map(function(node) {
+                        return permIds[node] || node;
+                    });
+                }
+                if (Array.isArray(entity.members)) {
+                    entity.members = entity.members.map(function(member) {
+                        member.id = permIds[member.id] || member.id;
+                        return member;
+                    });
+                }
+            });
+
+            return JSON.stringify({ dataIntroGraph: baseEntities });
+
+
+            function customizer(src) {
+                var copy = _.omit(_.cloneDeep(src), ['type', 'user', 'v', 'version', 'visible']);
+                if (_.isEmpty(copy.tags)) {
+                    delete copy.tags;
+                }
+
+                if (Array.isArray(copy.loc)) {
+                    copy.loc[0] = +copy.loc[0].toFixed(6);
+                    copy.loc[1] = +copy.loc[1].toFixed(6);
+                }
+
+                var match = src.id.match(/([nrw])-\d*/);  // temporary id
+                if (match !== null) {
+                    var nrw = match[1], permId;
+                    do { permId = nrw + (++nextId[nrw]); }
+                    while (baseEntities.hasOwnProperty(permId));
+
+                    copy.id = permIds[src.id] = permId;
+                }
+                return copy;
+            }
+        },
+
+
         toJSON: function() {
             if (!this.hasChanges()) return;