Improving the way attacks are represented.

1 files changed, 303 insertions, 0 deletions

diff --git a/src/struct/attack.erl b/src/struct/attack.erl
new file mode 100644
index 0000000..b27ff48
--- /dev/null
+++ b/src/struct/attack.erl
@@ -0,0 +1,303 @@
+-module(attack).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% TYPES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-type order() :: ('first' | 'second' | 'counter').
+-type precision() :: ('misses' | 'grazes' | 'hits').
+
+-record
+(
+   attack,
+   {
+      order :: order(),
+      precision :: precision(),
+      is_critical :: boolean(),
+      is_parry :: boolean(),
+      damage :: non_neg_integer()
+   }
+).
+
+-opaque struct() :: #attack{}.
+-type maybe_struct() :: ('nothing' | struct()).
+-opaque step() :: {order(), boolean()}.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% EXPORTS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-export_type([struct/0, maybe_struct/0, step/0]).
+
+-export
+(
+   [
+      get_sequence/3,
+      get_description_of/3,
+      apply_to_healths/3
+   ]
+).
+
+-export
+(
+   [
+      encode/1
+   ]
+).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% LOCAL FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-spec roll_precision
+   (
+      statistics:struct(),
+      statistics:struct()
+   )
+   -> precision().
+roll_precision (AttackerStatistics, DefenderStatistics) ->
+   DefenderDodges = statistics:get_dodges(DefenderStatistics),
+   AttackerAccuracy = statistics:get_accuracy(AttackerStatistics),
+   MissChance = max(0, (DefenderDodges - AttackerAccuracy)),
+   case roll:percentage() of
+      X when (X =< MissChance) -> misses;
+      X when (X =< (MissChance * 2)) -> grazes;
+      _ -> hits
+   end.
+
+-spec roll_damage
+   (
+      statistics:struct(),
+      statistics:struct()
+   )
+   -> {non_neg_integer(), boolean()}.
+roll_damage (AttackerStatistics, _DefenderStatistics) ->
+   {MinimumDamage, MaximumDamage} = statistics:get_damages(AttackerStatistics),
+   MaximumRoll = max(1, MaximumDamage - MinimumDamage),
+   BaseDamage = MinimumDamage + (rand:uniform(MaximumRoll) - 1),
+   CriticalHitChance = statistics:get_critical_hits(AttackerStatistics),
+   case roll:percentage() of
+      X when (X =< CriticalHitChance) -> {(BaseDamage * 2), true};
+      _ -> {BaseDamage, false}
+   end.
+
+-spec roll_parry (statistics:struct()) -> boolean().
+roll_parry (DefenderStatistics) ->
+   DefenderParryChance = statistics:get_parries(DefenderStatistics),
+   (roll:percentage() =< DefenderParryChance).
+
+-spec effect_of_attack
+   (
+      order(),
+      statistics:struct(),
+      statistics:struct(),
+      boolean()
+   )
+   -> struct().
+effect_of_attack (Order, AttackerStatistics, DefenderStatistics, CanParry) ->
+   ParryIsSuccessful = (CanParry and roll_parry(DefenderStatistics)),
+   {ActualAtkStatistics, ActualDefStatistics} =
+      case ParryIsSuccessful of
+         true -> {DefenderStatistics, AttackerStatistics};
+         false -> {AttackerStatistics, DefenderStatistics}
+      end,
+
+   Precision = roll_precision(ActualAtkStatistics, ActualDefStatistics),
+   {Damage, IsCritical} = roll_damage(ActualAtkStatistics, ActualDefStatistics),
+   ActualDamage =
+      case Precision of
+         misses -> 0;
+         grazes -> trunc(Damage / 2);
+         hits -> Damage
+      end,
+
+   #attack
+   {
+      order = Order,
+      precision = Precision,
+      is_critical = IsCritical,
+      is_parry = ParryIsSuccessful,
+      damage = ActualDamage
+   }.
+
+-spec encode_order (order()) -> binary().
+encode_order (first) -> <<"f">>;
+encode_order (counter) -> <<"c">>;
+encode_order (second) -> <<"s">>.
+
+-spec encode_precision (precision()) -> binary().
+encode_precision (hits) -> <<"h">>;
+encode_precision (grazes) -> <<"g">>;
+encode_precision (misses) -> <<"m">>.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% EXPORTED FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+-spec get_description_of
+   (
+      step(),
+      statistics:struct(),
+      statistics:struct()
+   )
+   -> maybe_struct().
+get_description_of
+(
+   {first, CanParry},
+   AttackerStatistics,
+   DefenderStatistics
+) ->
+   effect_of_attack(first, AttackerStatistics, DefenderStatistics, CanParry);
+get_description_of
+(
+   {second, CanParry},
+   AttackerStatistics,
+   DefenderStatistics
+) ->
+   AttackerDoubleAttackChange = statistics:get_double_hits(AttackerStatistics),
+
+   case roll:percentage() of
+      X when (X =< AttackerDoubleAttackChange) ->
+         effect_of_attack
+         (
+            second,
+            AttackerStatistics,
+            DefenderStatistics,
+            CanParry
+         );
+
+      _ ->
+         nothing
+   end;
+get_description_of
+(
+   {counter, CanParry},
+   AttackerStatistics,
+   DefenderStatistics
+) ->
+   effect_of_attack(counter, DefenderStatistics, AttackerStatistics, CanParry).
+
+-spec apply_to_healths
+   (
+      maybe_struct(),
+      non_neg_integer(),
+      non_neg_integer()
+   )
+   -> {maybe_struct(), non_neg_integer(), non_neg_integer()}.
+apply_to_healths
+(
+   nothing,
+   AttackerHealth,
+   DefenderHealth
+) ->
+   {nothing, AttackerHealth, DefenderHealth};
+apply_to_healths
+(
+   Attack,
+   AttackerHealth,
+   DefenderHealth
+)
+when
+(
+   (Attack#attack.order == first)
+   or (Attack#attack.order == second)
+   or ((Attack#attack.order == counter) and Attack#attack.is_parry)
+) ->
+   Damage = Attack#attack.damage,
+
+   case AttackerHealth of
+      0 ->
+         {nothing, AttackerHealth, DefenderHealth};
+
+      _ ->
+         {
+            Attack,
+            AttackerHealth,
+            max(0, (DefenderHealth - Damage))
+         }
+   end;
+apply_to_healths
+(
+   {Attack, Effect},
+   AttackerHealth,
+   DefenderHealth
+)
+when
+(
+   (Attack#attack.order == counter)
+   or
+   (
+      (Attack#attack.is_parry)
+      and ((Attack#attack.order == first) or (Attack#attack.order == second))
+   )
+) ->
+   {_Hits, _Critical, Damage} = Effect,
+   case DefenderHealth of
+      0 ->
+         {nothing, AttackerHealth, DefenderHealth};
+
+      _ ->
+         {
+            {Attack, Effect},
+            max(0, (AttackerHealth - Damage)),
+            DefenderHealth
+         }
+   end.
+
+-spec get_sequence
+   (
+      non_neg_integer(),
+      weapon:struct(),
+      weapon:struct()
+   )
+   -> list(step()).
+get_sequence (AttackRange, AttackerWeapon, DefenderWeapon) ->
+   {AttackerDefenseRange, AttackerAttackRange} =
+      weapon:get_ranges(AttackerWeapon),
+   {DefenderDefenseRange, DefenderAttackRange} =
+      weapon:get_ranges(DefenderWeapon),
+
+   AttackerCanAttack = (AttackRange =< AttackerAttackRange),
+   AttackerCanDefend =
+      (AttackerCanAttack and (AttackRange > AttackerDefenseRange)),
+   AttackerCanParry =
+      (AttackerCanDefend and weapon:can_parry(AttackerWeapon)),
+
+   DefenderCanAttack = (AttackRange =< DefenderAttackRange),
+   DefenderCanDefend =
+      (DefenderCanAttack and (AttackRange > DefenderDefenseRange)),
+   DefenderCanParry =
+      (DefenderCanDefend and weapon:can_parry(DefenderWeapon)),
+
+   First = {first, DefenderCanParry},
+   Second = {second, DefenderCanParry},
+   Counter = {counter, AttackerCanParry},
+
+   if
+      (not AttackerCanAttack) ->
+         [];
+
+      (not DefenderCanDefend) ->
+         [First, Second];
+
+      true ->
+         [First, Counter, Second]
+   end.
+
+-spec encode (struct()) -> binary().
+% This shouldn't be a possibility. Types in this module are a mess...
+encode (Attack) ->
+   Order = Attack#attack.order,
+   Precision = Attack#attack.precision,
+   IsCritical = Attack#attack.is_critical,
+   IsParry = Attack#attack.is_parry,
+   Damage = Attack#attack.damage,
+
+   jiffy:encode
+   (
+      {
+         [
+            {<<"ord">>, encode_order(Order)},
+            {<<"pre">>, encode_precision(Precision)},
+            {<<"cri">>, IsCritical},
+            {<<"par">>, IsParry},
+            {<<"dmg">>, Damage}
+         ]
+      }
+   ).