Traders come through the portal and sell rune plans, rare creatures, wood and mana

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

src/game.rs

@@ -130,6 +130,7 @@ pub enum EK {
     // wild beasts of the caverns (beasts.rs): neutral until tamed
     CaveBear, // strong and shaggy, likes the mushroom garden
     Beetle,   // a giant armoured beetle, likes the lair
+    Trader,   // a merchant visiting through the portal (traders.rs)
 }
 
 pub struct St {
@@ -176,6 +177,7 @@ pub fn st(k: EK) -> St {
         EK::Catapult => s("unit.catapult", 320.0, 40.0, 7.5, 0.9, 3.5, 0, 200),
         EK::CaveBear => s("unit.cavebear", 420.0, 24.0, 1.0, 1.9, 1.4, 110, 0),
         EK::Beetle => s("unit.beetle", 300.0, 13.0, 1.0, 1.7, 1.1, 70, 0),
+        EK::Trader => s("unit.trader", 200.0, 1.0, 1.0, 1.5, 2.0, 0, 0),
     }
 }
 
@@ -391,7 +393,7 @@ impl Ent {
     }
     // the player's creatures (not imps, heroes or the rivals' units)
     pub fn creature(&self) -> bool {
-        !self.hero && self.side == me_side() && self.kind != EK::Worker && !self.chained
+        !self.hero && self.side == me_side() && self.kind != EK::Worker && self.kind != EK::Trader && !self.chained
     }
     // 0 player, 1 humans, 2 and 3 rival masters
     pub fn side(&self) -> u8 {
@@ -609,6 +611,8 @@ pub struct Game {
     #[serde(default)]
     pub bridgework: crate::bridges::BridgeWork, // burning and worn bridges
     #[serde(default)]
+    pub trading: crate::traders::Trading, // the visiting trader (traders.rs)
+    #[serde(default)]
     pub happenings: Option<crate::events::Events>, // random events (free games and versus), see events.rs
     #[serde(default)]
     pub stats: crate::stats::GameStats, // statistics of the master at this computer (see stats.rs)
@@ -950,6 +954,7 @@ impl Game {
             vrng: crate::particles::vrng(),
             dwarf_caves: Vec::new(),
             bridgework: Default::default(),
+            trading: Default::default(),
             happenings: None,
             stats: Default::default(),
             wall_plans: Vec::new(),
@@ -1724,6 +1729,7 @@ impl Game {
         self.update_bridges(dt);
         self.update_wood(dt);
         self.update_events(dt);
+        self.update_traders(dt);
         // fallen hearts of a match are shared state: every client marks them in the same step
         self.update_fallen_masters();
         // the end of the game and the fog are about the master at this computer
@@ -2400,6 +2406,8 @@ impl Game {
             self.captive_update(e, dt);
         } else if self.is_rival_side(e.side) || (e.rival() && !self.is_master(e.side)) {
             self.rival_ai(e, dt);
+        } else if e.kind == EK::Trader {
+            self.trader_ai(e, dt);
         } else if e.dwarf() {
             self.dwarf_ai(e, dt);
         } else if e.hero {
@@ -5412,6 +5420,9 @@ impl Game {
             return false;
         }
         let Some(j) = target.filter(|&j| j < self.ents.len() && self.ents[j].alive && !self.ents[j].held) else { return false };
+        if self.buy_from_trader(j) {
+            return false;
+        }
         let e = &self.ents[j];
         if e.rival() || e.dwarf() {
             return false; // the rivals' creatures and the dwarves cannot be picked up