Marks and dig selection in each master's colour; imps dig only their master's marks; AI marks near its ground, acts calmer, re-summons imps; allies never claim each other's ground

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/game.rs

@@ -3269,12 +3269,13 @@ impl Game {
 
     // ---------------------------------------------------------------- pit imps (workers)
 
-    fn dig_neighbor(&self, i: usize, me: u32) -> Option<usize> {
+    // a neighbour of tile i that this imp may dig: marked by its own master (side)
+    fn dig_neighbor(&self, i: usize, me: u32, side: u8) -> Option<usize> {
         let (x, y) = xy(i);
         let mut found = None;
         for &(dx, dy) in &DIR4 {
             if let Some(t) = self.map.get(x + dx, y + dy) {
-                if t.marked && t.diggable() {
+                if t.marked && t.mark_by == side && t.diggable() {
                     if t.reserved == me {
                         return Some(idx(x + dx, y + dy));
                     }
@@ -3312,14 +3313,16 @@ impl Game {
         None
     }
 
-    fn claimable(&self, i: usize, me: u32) -> bool {
+    pub(crate) fn claimable(&self, i: usize, me: u32) -> bool {
         let t = &self.map.t[i];
         let ok = if t.owner == self.me {
             false
         } else if t.owner == Owner::None {
             matches!(t.kind, Kind::Floor | Kind::Portal | Kind::Bridge | Kind::LavaBridge | Kind::Shard | Kind::Treasury | Kind::ManaSpring | Kind::RuneChest)
+        } else if t.owner != Owner::Hero && self.allied(self.me_side, t.owner.side()) {
+            false // an ally's ground is never taken
         } else {
-            // knight and other masters' ground (also vaults and shard chambers), but not while enemies fight there
+            // knight and enemy masters' ground (also vaults and shard chambers), but not while enemies fight there
             matches!(t.kind, Kind::Floor | Kind::Treasury | Kind::Bridge | Kind::LavaBridge | Kind::Shard | Kind::Lair | Kind::Training) && !self.contested.get(i).copied().unwrap_or(false)
         };
         if !ok {
@@ -3412,7 +3415,7 @@ impl Game {
         match e.job {
             Job::Dig(t) => {
                 let tile = self.map.t[t];
-                if !tile.marked || !tile.diggable() || !adj4(cur, t) {
+                if !tile.marked || tile.mark_by != e.side || !tile.diggable() || !adj4(cur, t) {
                     self.unreserve(me);
                     e.job = Job::None;
                     return;
@@ -3647,9 +3650,9 @@ impl Game {
                         return;
                     }
                 }
-                if let Some(p) = self.map.search(cur, self.map.walk_cost(), |i| self.dig_neighbor(i, me).is_some(), true) {
+                if let Some(p) = self.map.search(cur, self.map.walk_cost(), |i| self.dig_neighbor(i, me, e.side).is_some(), true) {
                     let end = p.last().copied().unwrap_or(cur);
-                    if let Some(t) = self.dig_neighbor(end, me) {
+                    if let Some(t) = self.dig_neighbor(end, me, e.side) {
                         self.map.t[t].reserved = me;
                         e.path = p;
                         e.job = Job::Dig(t);
@@ -4851,9 +4854,11 @@ impl Game {
             for x in x0.min(x1)..=x0.max(x1) {
                 if inb(x, y) {
                     let t = &mut self.map.t[idx(x, y)];
-                    if t.diggable() {
+                    // a master sets and clears only his own marks
+                    let side = self.me.side().min(7);
+                    if t.diggable() && (!t.marked || t.mark_by == side) {
                         t.marked = on;
-                        t.mark_by = self.me.side().min(7);
+                        t.mark_by = side;
                     }
                 }
             }