add support for flexible attacks

1 files changed, 62 insertions, 8 deletions

diff --git a/go/game/attack.go b/go/game/attack.go
index 6b33e8d9..e7d2e836 100644
--- a/go/game/attack.go
+++ b/go/game/attack.go
@@ -7,15 +7,30 @@ import (
 	"strings"
 )
 
+type FlexAttack = func(*Unit, *Tile) (int, bool)
+
 // Attack contains all damage values for each attackable range.
 // The damage value for range 1 is stored at index 0, the value for range 2 at index 1 and so on.
 type Attack struct {
-	attacks []int
+	attacks    []int
+	flexAttack FlexAttack
+}
+
+// Valid reports if there are attackable ranges.
+func (a Attack) Valid() bool {
+	return len(a.attacks) > 0 || a.flexAttack != nil
 }
 
-// INVALID_ATTACK reports if there are no attackable ranges.
-func INVALID_ATTACK(a Attack) bool {
-	return len(a.attacks) == 0
+// DamageForTile returns the damage inflicted by this attack to a tile
+func (a Attack) DamageForTile(u *Unit, t *Tile) (int, bool) {
+	if a.flexAttack != nil {
+		return a.flexAttack(u, t)
+	}
+
+	o := u.Tile().Position
+	trgt := t.Position
+	d := DistanceBetweenPositions(o, trgt)
+	return a.DamageInRange(d), IsPositionInRange(o, trgt, a.MaxRange())
 }
 
 // MaxRange returns the biggest attackable range.
@@ -23,9 +38,18 @@ func (a Attack) MaxRange() int {
 	return len(a.attacks)
 }
 
+// Copy returns a copy of the attack
+func (a Attack) Copy() Attack {
+	copy := Attack{}
+	for _, v := range a.attacks {
+		copy.attacks = append(copy.attacks, v)
+	}
+	return copy
+}
+
 // DamageInRange returns the damage in a certain range.
 func (a Attack) DamageInRange(r int) int {
-	if r > a.MaxRange() {
+	if r == 0 || r > a.MaxRange() {
 		return 0
 	}
 
@@ -51,7 +75,7 @@ func (a *Attack) Shorten(amount int) {
 }
 
 func (a Attack) String() string {
-	if INVALID_ATTACK(a) {
+	if !a.Valid() {
 		return "invalid attack"
 	}
 
@@ -65,7 +89,7 @@ func (a Attack) String() string {
 
 func parseAttack(attack any) Attack {
 	if damage, ok := attack.(int); ok {
-		return Attack{[]int{damage}}
+		return Attack{attacks: []int{damage}}
 	}
 
 	attackStr := attack.(string)
@@ -89,5 +113,35 @@ func parseAttack(attack any) Attack {
 		attacks = append(attacks, a)
 	}
 
-	return Attack{attacks}
+	return Attack{attacks: attacks}
+}
+
+func flexibleRangeAttack(constraint func(*Unit, *Tile) bool) FlexAttack {
+	return func(u *Unit, t *Tile) (int, bool) {
+		baseAttack := u.Attack
+		pos := u.Tile().Position
+		d := DistanceBetweenPositions(pos, t.Position)
+		if IsPositionInRange(pos, t.Position, baseAttack.MaxRange()) {
+			return baseAttack.DamageInRange(d), true
+		}
+
+		if constraint(u, t) {
+			return baseAttack.DamageInRange(baseAttack.MaxRange()), true
+		}
+
+		return 0, false
+	}
+}
+
+func pikeConstraint(u *Unit, t *Tile) bool {
+	if o, ok := t.Permanent.(*Unit); ok {
+		d := DistanceBetweenPositions(u.Tile().Position, t.Position)
+
+		return d < 3 && o.Movement.Range > 2
+	}
+	return false
+}
+
+func pikeAttack() FlexAttack {
+	return flexibleRangeAttack(pikeConstraint)
 }