From 117ad7d6b65acf4f3211f26b62a1653c269a45fa Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Fri, 22 Dec 2017 16:57:27 -0500
Subject: [PATCH] Transitionable actionMoveNode

---
 modules/actions/move_node.js   | 21 ++++++++++++----
 test/spec/actions/move_node.js | 46 +++++++++++++++++++++++++++++++---
 2 files changed, 58 insertions(+), 9 deletions(-)

diff --git a/modules/actions/move_node.js b/modules/actions/move_node.js
index 6e2593b45..8de29a16a 100644
--- a/modules/actions/move_node.js
+++ b/modules/actions/move_node.js
@@ -1,7 +1,18 @@
-// https://github.com/openstreetmap/josm/blob/mirror/src/org/openstreetmap/josm/command/MoveCommand.java
-// https://github.com/openstreetmap/potlatch2/blob/master/net/systemeD/halcyon/connection/actions/MoveNodeAction.as
-export function actionMoveNode(nodeId, loc) {
-    return function(graph) {
-        return graph.replace(graph.entity(nodeId).move(loc));
+import { geoInterp } from '../geo';
+
+export function actionMoveNode(nodeID, toLoc) {
+
+    var action = function(graph, t) {
+        if (t === null || !isFinite(t)) t = 1;
+        t = Math.min(Math.max(+t, 0), 1);
+
+        var node = graph.entity(nodeID);
+        return graph.replace(
+            node.move(geoInterp(node.loc, toLoc, t))
+        );
     };
+
+    action.transitionable = true;
+
+    return action;
 }
diff --git a/test/spec/actions/move_node.js b/test/spec/actions/move_node.js
index bc28f748d..771f66b4a 100644
--- a/test/spec/actions/move_node.js
+++ b/test/spec/actions/move_node.js
@@ -1,8 +1,46 @@
 describe('iD.actionMoveNode', function () {
     it('changes a node\'s location', function () {
-        var node   = iD.Node(),
-            loc    = [2, 3],
-            graph  = iD.actionMoveNode(node.id, loc)(iD.Graph([node]));
-        expect(graph.entity(node.id).loc).to.eql(loc);
+        var node = iD.osmNode({id: 'a', loc: [0, 0]});
+        var toLoc = [2, 3];
+        var graph = iD.coreGraph([node]);
+
+        graph = iD.actionMoveNode('a', toLoc)(graph);
+        expect(graph.entity('a').loc).to.eql(toLoc);
+    });
+
+    describe('transitions', function () {
+        it('is transitionable', function() {
+            expect(iD.actionMoveNode().transitionable).to.be.true;
+        });
+
+        it('move node at t = 0', function() {
+            var node = iD.osmNode({id: 'a', loc: [0, 0]});
+            var toLoc = [2, 3];
+            var graph = iD.coreGraph([node]);
+
+            graph = iD.actionMoveNode('a', toLoc)(graph, 0);
+            expect(graph.entity('a').loc[0]).to.be.closeTo(0, 1e-6);
+            expect(graph.entity('a').loc[1]).to.be.closeTo(0, 1e-6);
+        });
+
+        it('move node at t = 0.5', function() {
+            var node = iD.osmNode({id: 'a', loc: [0, 0]});
+            var toLoc = [2, 3];
+            var graph = iD.coreGraph([node]);
+
+            graph = iD.actionMoveNode('a', toLoc)(graph, 0.5);
+            expect(graph.entity('a').loc[0]).to.be.closeTo(1, 1e-6);
+            expect(graph.entity('a').loc[1]).to.be.closeTo(1.5, 1e-6);
+        });
+
+        it('move node at t = 1', function() {
+            var node = iD.osmNode({id: 'a', loc: [0, 0]});
+            var toLoc = [2, 3];
+            var graph = iD.coreGraph([node]);
+
+            graph = iD.actionMoveNode('a', toLoc)(graph, 1);
+            expect(graph.entity('a').loc[0]).to.be.closeTo(2, 1e-6);
+            expect(graph.entity('a').loc[1]).to.be.closeTo(3, 1e-6);
+        });
     });
 });