feat(citygen): naming stage

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

crates/citygen/src/generate/mod.rs

@@ -6,6 +6,7 @@ pub mod districts;
 pub mod dressing;
 pub mod interiors;
 pub mod lots;
+pub mod naming;
 pub mod streets;
 pub mod terrain;
 pub mod verticals;
@@ -237,6 +238,7 @@ pub(crate) fn runner_for(stage: Stage) -> Box<dyn StageRunner> {
         Stage::Interiors => Box::new(interiors::InteriorsStage::default()),
         Stage::Connectivity => Box::new(connectivity::ConnectivityStage::default()),
         Stage::Dressing => Box::new(dressing::DressingStage::default()),
+        Stage::Naming => Box::new(naming::NamingStage::default()),
         _ => Box::new(NoopStage),
     }
 }

crates/citygen/src/generate/naming.rs

@@ -0,0 +1,98 @@
+//! Stage 10: names for the city, districts and notable buildings.
+
+use super::{GenCtx, Stage, StageRunner, StepOut};
+use crate::params::GenError;
+use rand_chacha::ChaCha8Rng;
+
+#[derive(Default)]
+pub(crate) struct NamingStage {
+    next: usize,
+    rng: Option<ChaCha8Rng>,
+}
+
+impl StageRunner for NamingStage {
+    fn begin(&mut self, ctx: &mut GenCtx) -> Result<(), GenError> {
+        let mut rng = ctx.rng(Stage::Naming);
+        ctx.city.name = ctx.flavor.city_name(&mut rng);
+        self.rng = Some(rng);
+        self.next = 0;
+        Ok(())
+    }
+
+    fn step(&mut self, ctx: &mut GenCtx) -> Result<StepOut, GenError> {
+        let n = ctx.city.districts.len();
+        if self.next >= n {
+            return Ok(StepOut::Finished);
+        }
+        let rng = self.rng.as_mut().expect("begin sets rng");
+        let d = self.next;
+        let theme = ctx.city.districts[d].theme;
+        let district_name = ctx.flavor.district_name(theme, rng);
+        ctx.city.districts[d].name = district_name.clone();
+
+        let id = ctx.city.districts[d].id;
+        let mut corp_names: Vec<String> = Vec::new();
+        for i in 0..ctx.city.buildings.len() {
+            if ctx.city.buildings[i].district != id {
+                continue;
+            }
+            let kind = ctx.city.buildings[i].kind;
+            let name = if kind.is_corp() {
+                let corp = ctx.flavor.corp_name(rng);
+                corp_names.push(corp.clone());
+                Some(corp)
+            } else {
+                ctx.flavor.shop_name(kind, rng)
+            };
+            ctx.city.buildings[i].name = name;
+        }
+
+        // Two landmarks per district: the largest footprints get grand names.
+        let mut candidates: Vec<usize> = (0..ctx.city.buildings.len())
+            .filter(|i| ctx.city.buildings[*i].district == id)
+            .collect();
+        candidates.sort_by_key(|i| std::cmp::Reverse(ctx.city.buildings[*i].footprint.area()));
+        for i in candidates.into_iter().take(2) {
+            let corp = corp_names
+                .first()
+                .cloned()
+                .unwrap_or_else(|| ctx.flavor.corp_name(rng));
+            let name = ctx.flavor.landmark_name(&corp, &district_name, rng);
+            ctx.city.buildings[i].name = Some(name);
+        }
+
+        self.next += 1;
+        Ok(StepOut::Continue(self.next as f32 / n as f32))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::generate::testutil::small;
+    use crate::params::WaterMode;
+
+    #[test]
+    fn names_are_filled_and_deterministic() {
+        let a = small(91, WaterMode::Bay, 7);
+        let b = small(91, WaterMode::Bay, 7);
+        assert!(!a.name.is_empty());
+        assert_eq!(a.name, b.name);
+        assert!(a.districts.iter().all(|d| !d.name.is_empty()));
+        let named = a.buildings.iter().filter(|b| b.name.is_some()).count();
+        assert!(named >= a.buildings.iter().filter(|b| b.kind.is_corp()).count());
+        let landmarks = a
+            .buildings
+            .iter()
+            .filter(|b| {
+                b.name.as_deref().is_some_and(|n| {
+                    n.contains("Tower")
+                        || n.contains("Terminal")
+                        || n.contains("Arcology")
+                        || n.contains("Plaza")
+                        || n.contains("Station")
+                })
+            })
+            .count();
+        assert!(landmarks >= a.districts.len(), "landmarks {landmarks}");
+    }
+}