1 files changed, 71 insertions, 20 deletions
diff --git a/src/world/agent.js b/src/world/agent.js
index f7e5a63..95d869c 100644
--- a/src/world/agent.js
+++ b/src/world/agent.js
@@ -46,39 +46,90 @@ import { pairs, deepEqual } from '../util.js';
  */
 
 
+function flags_compatible(a, b) {
+  const keys = [...new Set(Object.keys(a).concat(Object.keys(b)))];
+  return keys.reduce(
+    (acc, key) => {
+      const eq = (a[key] === undefined || b[key] === undefined) ? true : deepEqual(a[key], b[key]);
+      return acc && eq;
+    },
+    true
+  );
+}
+
+
 // return a tuple [conflict, merge]
 // conflict is true if the two world_changes are incompatible
 // merge is true if the two world changes are identical
 // otherwise they are false
 function world_change_conflict(a, b) {
-  if (a.x != b.x) { return [false, false]; }
-  if (a.y != b.y) { return [false, false]; }
-  if (a.to != b.to) { return [true, false]; }
-  // x, y, and to all match -- merge
-  return [false, true];
+  if (deepEqual(a, b)) {
+    // merge
+    return [false, true];
+  } 
+  if (
+    a.x === b.x && 
+    a.y === b.y &&
+    (a.to != b.to || !flags_compatible(a.flags || {}, b.flags || {}))
+  ) {
+    // conflict!
+    return [true, false];
+  } else {
+    // no conflict c:
+    return [false, false];
+  }
 }
 
 
+// returns true as long as x & y are both defined
+function pos_exists(a) {
+  if (a.x !== undefined && a.y !== undefined) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+
+function pos_equal(a, b) {
+  if (a.x !== b.x) { return false; }
+  if (a.y !== b.y) { return false; }
+  return true;
+}
+
+
+// agent changes merge if they are identical
+// they conflict if two agents are trying to move to the same tile, or
+// if the same agent is trying to move to two different tiles, or if an agent
+// is being updated to incompatible flags
+//
+//
 function agent_change_conflict(a, b) {
   if (deepEqual(a, b)) {
     // identical: merge
     return [false, true];
-  } else if (
-    (a.agent_id === b.agent_id) &&
-    ((a.x != b.x) || (a.y != b.y))
-  ) {
-    // same agent, different tiles: conflict
-    return [true, false];
-  } else if (
-    (a.agent_id != b.agent_id) &&
-    (a.x === b.x) &&
-    (a.y === b.y)
-  ) {
-    // different agents, same tile: conflict
-    return [true, false];
+  } else if (a.agent_id === b.agent_id) {
+    if (
+      pos_exists(a) && pos_exists(b) && !pos_equal(a, b)
+    ) {
+      // same agent, different positions: conflict
+      return [true, false];
+    } else if (!flags_compatible(a.flags, b.flags)) {
+      // same agent, incompatible flags: conflict
+      return [true, false];
+    } else {
+      // no conflict c:
+      return [false, false];
+    }
   } else {
-    // no conflict c:
-    return [false, false];
+    // different agents
+    if (pos_exists(a) && pos_exists(b) && pos_equal(a, b)) {
+      // different agents, same position: conflict
+      return [true, false];
+    } else {
+      // no conflict c:
+      return [false, false];
+    }
   }
 }