Early battle system

src/minibaldur/core.clj

@@ -3,20 +3,36 @@
   (:require [minibaldur.ecs :refer :all]
             [minibaldur.engine :refer :all]))
 
-(defcomponent goblin-ai :void)
+(defcomponent name)
+(defcomponent position)
+(defcomponent health)
+(defcomponent attack)
 
 (defentity
   (name "Goblin")
   (position {:x 0 :y 0 :z 0})
   (health 10)
-  (attack "1d4 + 2")
-  (goblin-ai))
+  (attack "1d4 + 2"))
 
 (defentity
-  (:name "Adventurer")
-  (:position {:x 0 :y 0 :z 0})
-  (:health 20)
-  (:attack "1d6 + 3"))
+  (name "Adventurer")
+  (position {:x 0 :y 0 :z 0})
+  (health 20)
+  (attack "1d6 + 3"))
+
+(defn battle-system
+  [entity]
+  (let [opponent (if (= (name entity) "Goblin")
+                   (find-by :name "Adventurer")
+                   (find-by :name "Goblin"))]
+    (health opponent (max 0 (- (health opponent) (first (roll (attack entity))))))))
+
+(defn do-battle
+  []
+  (let [goblin (find-by :name "Goblin")
+        adventurer (find-by :name "Adventurer")]
+    (while (every? pos? [(health goblin) (health adventurer)])
+      (run-e battle-system [:name :health]))))
 
 (defn -main
   "I don't do a whole lot ... yet."

src/minibaldur/ecs.clj

@@ -36,7 +36,7 @@
   (doseq [entity (query-e query)]
     (apply f entity args)))
 
-(defn find-entity-by
+(defn find-by
   [component value]
   (some #(and (= value (val %)) (key %))
         (@*components* component)))

src/minibaldur/engine.clj

@@ -1,19 +1,18 @@
 (ns minibaldur.engine)
 
-(defn diceroll
+(defn- diceroll
   [x]
-  (re-find #"(\d+)d(\d+)" x))
+  (if-let [match (re-find #"(\d+)d(\d+)" x)]
+    (map #(Integer/parseInt %) (next match))))
 
-(defn diceval
+(defn- diceval
   [x]
-  (if-let [[_ a b] (diceroll x)]
-    (apply + (repeat (Integer/parseInt a)
-                     (+ (rand-int (Integer/parseInt b)) 1)))
+  (if-let [[a b] (diceroll x)]
+    (apply + (repeat a (inc (rand-int b))))
     (Integer/parseInt x)))
 
 (defn roll
-  "Takes a standard ttrpg roll specifier and returns a vector, starting with the sum, and 
-  then each roll in the order listed in the specifier"
+  "Takes a standard ttrpg roll specifier and returns a vector, starting with the sum, and then each roll in the order listed in the specifier"
   [specifier]
   (let [dies-and-ops (clojure.string/split specifier #"\s+")
         first-die-val (diceval (first dies-and-ops))
@@ -28,3 +27,17 @@
             "+" (recur (+ sum val) (if roll? (conj rolls val) rolls) (nnext tail))
             "-" (recur (- sum val) (if roll? (conj rolls val) rolls) (nnext tail))))
         (into [sum] rolls)))))
+
+(defn roll-advantage
+  "Rolls 2d20 and returns the highest. Takes an optional specifier for bonuses"
+  ([] (max-key first (roll "1d20") (roll "1d20")))
+  ([bonuses]
+   (let [spec (str "1d20 + " bonuses)]
+     (max-key first (roll spec) (roll spec)))))
+
+(defn roll-disadvantage
+  "Rolls 2d20 and returns the lowest. Takes an optional specifier for bonuses"
+  ([] (min-key first (roll "1d20") (roll "1d20")))
+    ([bonuses]
+   (let [spec (str "1d20 + " bonuses)]
+     (min-key first (roll spec) (roll spec)))))

test/minibaldur/ecs_test.clj

@@ -19,7 +19,7 @@
 
 (deftest basic
   (run-e age-up :age)
-  (is (= 28 (age (find-entity-by :name "Dane")))))
+  (is (= 28 (age (find-by :name "Dane")))))
 
 (defcomponent alignment)
 (defcomponent health)
@@ -45,5 +45,5 @@
 
 (deftest full
   (run-e damage-evil-creatures [:alignment :health] 2)
-  (is (= 2 (health (find-entity-by :name "Fey"))))
-  (is (= 8 (health (find-entity-by :name "Goblin")))))
+  (is (= 2 (health (find-by :name "Fey"))))
+  (is (= 8 (health (find-by :name "Goblin")))))