chance to log dungeon features per clock turn

src/map/interval_spawning_system.rs

@@ -3,6 +3,33 @@ use specs::prelude::*;
 use crate::data::events::*;
 
 const TRY_SPAWN_CHANCE: i32 = 70;
+const FEATURE_MESSAGE_CHANCE: i32 = 110;
+
+pub fn maybe_map_message(ecs: &mut World) {
+    let mut maybe_message = false;
+    let map = ecs.fetch::<Map>();
+    if map.messages.is_empty() {
+        return;
+    }
+    // Scope for borrow checker (ECS)
+    {
+        let clock = ecs.read_storage::<Clock>();
+        let turns = ecs.read_storage::<TakingTurn>();
+        let mut rng = ecs.write_resource::<rltk::RandomNumberGenerator>();
+        for (_c, _t) in (&clock, &turns).join() {
+            if rng.roll_dice(1, FEATURE_MESSAGE_CHANCE) == 1 {
+                maybe_message = true;
+            }
+        }
+    }
+    if maybe_message {
+        let mut logger = gamelog::Logger::new();
+        for message in map.messages.clone() {
+            logger = logger.append(message);
+        }
+        logger.log();
+    }
+}
 
 pub fn try_spawn_interval(ecs: &mut World) {
     let mut try_spawn = false;

src/map/mod.rs

@@ -4,7 +4,7 @@ use std::collections::{ HashSet, HashMap };
 mod tiletype;
 pub use tiletype::{ tile_cost, tile_opaque, tile_walkable, TileType, get_dest, Destination };
 mod interval_spawning_system;
-pub use interval_spawning_system::try_spawn_interval;
+pub use interval_spawning_system::{ maybe_map_message, try_spawn_interval };
 pub mod dungeon;
 pub use dungeon::{ level_transition, MasterDungeonMap };
 pub mod themes;
@@ -30,6 +30,7 @@ pub struct Map {
     pub name: String,
     pub short_name: String,
     pub depth: i32,
+    pub messages: HashSet<String>,
     pub difficulty: i32,
     pub bloodstains: HashMap<usize, RGB>,
     pub view_blocked: HashSet<usize>,
@@ -70,6 +71,7 @@ impl Map {
             id: new_id,
             name: name.to_string(),
             short_name: short_name.to_string(),
+            messages: HashSet::new(),
             depth: depth,
             difficulty: difficulty,
             bloodstains: HashMap::new(),