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Created Jul 18, 2016
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RPG Kata
(ns rpg-kata-clj.core
(:require [clojure.set :refer [intersection]]))
(defrecord Entity [health level attack factions type])
(defn new-character []
(->Entity 1000 1 :melee #{} :character))
(defn new-prop [health]
(->Entity health 1 :melee #{} :property))
(defn damage-multiplier [source-level target-level]
(let [delta (- source-level target-level)]
(cond (>= delta 5) 2.0
(<= delta -5) 0.5
:else 1.0)))
(defn in-range? [attack distance]
(<= distance ({:melee 2 :ranged 20} attack)))
(defn allies? [source-factions target-factions]
(boolean (not-empty (intersection source-factions target-factions))))
(defn attack [source target amount distance]
(assert (not (identical? source target)) "a character cannot deal damage to himself")
(assert (in-range? (:attack source) distance) "target is not in range")
(assert (not (allies? (:factions source) (:factions target))) "cannot attack allies")
(assert (not= :property (:type source)) "properties cannot attack")
(let [damage (* amount (damage-multiplier (:level source) (:level target)))
health (int (max 0 (- (:health target) damage)))]
(assoc target :health health)))
(defn heal [source target amount]
(assert (not= :property (:type source)) "properties cannot heal")
(assert (not= :property (:type target)) "properties cannot be healed")
(assert (or (identical? source target)
(allies? (:factions source) (:factions target)))
"a character can only heal himself or allies")
(if (zero? (:health target))
(assoc target :health (min 1000 (+ amount (:health target))))))
(ns rpg-kata-clj.core-test
(:require [clojure.test :refer :all]
[rpg-kata-clj.core :refer :all]))
(defn a-char
([] (a-char {}))
(into {:level 1 :health 1000 :attack :melee :factions #{} :type :character}
(defn a-prop
([] (a-prop {:health 1000}))
(into {:level 1 :health 1000 :attack :melee :factions #{} :type :property}
(deftest when-a-new-character-is-created
(let [c (new-character)]
(testing "it starts with health 1000"
(is (= 1000 (:health c))))
(testing "it-starts with level 1"
(is (= 1 (:level c))))))
(deftest when-calculating-damage-multiplier
(testing "it is 2 when source level is at least 5 above target level"
(is (= 2.0 (damage-multiplier 10 5)))
(is (= 2.0 (damage-multiplier 11 0))))
(testing "it is 0.5 when target level is at least 5 above source level"
(is (= 0.5 (damage-multiplier 5 10)))
(is (= 0.5 (damage-multiplier 0 11))))
(testing "it is 1 when source and target level are closer than 5"
(is (= 1.0 (damage-multiplier 1 4)))
(is (= 1.0 (damage-multiplier 4 1)))))
(deftest when-calculating-if-an-attack-is-in-range
(testing "a melee attack is in range when distance is at most 2"
(is (true? (in-range? :melee 1)))
(is (true? (in-range? :melee 2)))
(is (false? (in-range? :melee 3))))
(testing "a ranged attack is in range when distance is at most 20"
(is (true? (in-range? :ranged 10)))
(is (true? (in-range? :ranged 20)))
(is (false? (in-range? :ranged 21)))))
(deftest when-detecting-allies
(testing "two characters are allies when have a common faction"
(is (true? (allies? #{:green} #{:red :green}))))
(testing "two characters are not allies when have no common factions"
(is (false? (allies? #{:red} #{:blue}))))
(testing "two characters are not allies when any of them have no factions"
(is (false? (allies? #{} #{:green})))
(is (false? (allies? #{:green} #{})))
(is (false? (allies? #{} #{})))))
(deftest when-attacking-a-character
(let [source (a-char {:level 1})
target (a-char {:level 3})
level-10 (a-char {:level 10})
level-1 (a-char {:level 1})
door (a-prop {:health 1000})]
(testing "it cannot attack himself"
(is (thrown? AssertionError (attack source source 100 1))))
(testing "it cannot attack targets out of range"
(is (thrown? AssertionError
(attack (a-char {:attack :melee}) (a-char) 100 3)))
(is (thrown? AssertionError
(attack (a-char {:attack :ranged}) (a-char) 100 21))))
(testing "it cannot attack allies"
(is (thrown? AssertionError
(attack (a-char {:factions #{:red}})
(a-char {:factions #{:red}})
100 1))))
(testing "its health is decreased"
(is (= 5 (:health (attack source target 995 1)))))
(testing "the damage is adjusted depending on character levels"
(is (= 0 (:health (attack level-10 level-1 500 1))))
(is (= 750 (:health (attack level-1 level-10 500 1)))))
(testing "its health cannot be less than zero"
(is (= 0 (:health (attack source target 1500 1)))))
(testing "properties cannot attack"
(is (thrown? AssertionError (attack door source 100 1))))
(testing "properties can be attacked"
(is (= 500 (:health (attack source door 500 1)))))))
(deftest when-healing-a-caracter
(let [wounded (a-char {:health 800 :level 3 :factions #{:red}})
wounded-ally (a-char {:health 800 :level 5 :factions #{:red}})
dead (a-char {:health 0})
door (a-prop)]
(testing "it cannot heal enemies"
(is (thrown? AssertionError (heal wounded (new-character) 100))))
(testing "it can health allies"
(is (= 900 (:health (heal wounded wounded-ally 100)))))
(testing "its health is increased"
(is (= 900 (:health (heal wounded wounded 100)))))
(testing "its health cannot be greater than 1000"
(is (= 1000 (:health (heal wounded wounded 1500)))))
(testing "its health does not change if it is dead"
(is (= 0 (:health (heal dead dead 100)))))
(testing "properties cannot heal"
(is (thrown? AssertionError (heal door wounded 100))))
(testing "properties cannot be healed"
(is (thrown? AssertionError (heal wounded door 100))))))
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