implement agent change conflict/merge detection

1 files changed, 40 insertions, 4 deletions

diff --git a/src/world/agent.js b/src/world/agent.js
index 7ab501c..f7e5a63 100644
--- a/src/world/agent.js
+++ b/src/world/agent.js
@@ -1,4 +1,4 @@
-import { pairs } from '../util.js';
+import { pairs, deepEqual } from '../util.js';
 
 /* agent structure:
  * {
@@ -33,6 +33,7 @@ import { pairs } from '../util.js';
  *   x, y: number
  *   from: string
  *   to:   string
+ *   flags: object?
  * }
  */
 
@@ -45,6 +46,10 @@ import { pairs } from '../util.js';
  */
 
 
+// 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]; }
@@ -54,15 +59,46 @@ function world_change_conflict(a, b) {
 }
 
 
+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 {
+    // no conflict c:
+    return [false, false];
+  }
+}
+
+
 function proposal_conflict_merge(a, b) {
-  const [world_conflict, world_merge] = pairs(a.world_changes, b.world_changes).reduce(
+  const [world_conflict, world_merge] = pairs(a.world_changes || [], b.world_changes || []).reduce(
     (acc, [a, b]) => {
       const [conflict, merge] = world_change_conflict(a, b);
       return [acc[0] || conflict, acc[1] || merge];
     }, 
     [false, false]
-  )
-  return [world_conflict, world_merge];
+  );
+  const [agent_conflict, agent_merge] = pairs(a.agent_changes || [], b.agent_changes || []).reduce(
+    (acc, [a, b]) => {
+      const [conflict, merge] = agent_change_conflict(a, b);
+      return [acc[0] || conflict, acc[1] || merge];
+    },
+    [false, false]
+  );
+  return [world_conflict || agent_conflict, world_merge || agent_merge];
 }