feat: add Quests.generate, Quests.describe and Ranged.ammoIndex

src/ranged.lua

@@ -0,0 +1,73 @@
+-- Player ranged combat via an equipped bow and a stack of arrows carried in
+-- the inventory. Unlike throwing, firing never costs the launcher itself -
+-- only ammunition - so a bow stays equipped shot after shot as long as the
+-- quiver holds out. A loosed arrow lands where the target stood either way,
+-- recoverable exactly like a thrown weapon.
+
+local Los = require("los")
+local Items = require("items")
+local Skills = require("skills")
+local Artifacts = require("artifacts")
+local Resistances = require("resistances")
+local Proficiency = require("proficiency")
+local Durability = require("durability")
+
+local Ranged = {}
+
+-- Inventory index of the first non-empty arrow stack, or nil if the quiver
+-- is dry. Ammo of the same name merges into one stack on pickup, so in
+-- practice there is at most one.
+function Ranged.ammoIndex(entity)
+  for i, item in ipairs(entity.inventory) do
+    if item.kind == Items.AMMO and item.count > 0 then return i end
+  end
+  return nil
+end
+
+function Ranged.canReach(game, x1, y1, x2, y2, range)
+  local dist = math.max(math.abs(x1 - x2), math.abs(y1 - y2))
+  return dist <= range and Los.clear(game.level.map, x1, y1, x2, y2)
+end
+
+-- Looses one arrow from `shooter`'s equipped bow at `target`. Returns (true,
+-- lines) if a shot went out - whatever it did on arrival - or (false, lines)
+-- if it never left the string: no bow readied, no arrows, or no clear shot.
+-- Damage comes from baseAttack rather than effectiveAttack so a melee
+-- weapon's power does not also inflate every arrow; the bow's own power and
+-- the target's armour are what separate a longbow from a sling. Mastery of
+-- that specific bow (see proficiency.lua) still applies on top, since it is
+-- read and recorded explicitly by the bow's own name rather than riding
+-- effectiveAttack's blended total.
+function Ranged.fire(game, shooter, target)
+  local bow = shooter.bow
+  if not bow then return false, { "you have no bow readied" } end
+  if not target or not target:isAlive() then return false, { "no target" } end
+  local ammoIdx = Ranged.ammoIndex(shooter)
+  if not ammoIdx then return false, { "you have no arrows left" } end
+  if not Ranged.canReach(game, shooter.x, shooter.y, target.x, target.y, bow.range) then
+    return false, { "you have no clear shot" }
+  end
+  local ammo = shooter.inventory[ammoIdx]
+  ammo.count = ammo.count - 1
+  if ammo.count <= 0 then table.remove(shooter.inventory, ammoIdx) end
+  local defense = math.max(0, target:effectiveDefense() - Artifacts.bowPierce(shooter))
+  local dealt = shooter.baseAttack + Durability.effectivePower(bow) + Skills.rangedDamageBonus(shooter)
+    + Proficiency.bonusFor(shooter, bow.name) - defense
+  if dealt < 1 then dealt = 1 end
+  dealt = Resistances.apply(target, dealt, Resistances.PHYSICAL)
+  target.hp = target.hp - dealt
+  local lines = { string.format("your %s hits %s for %d", ammo.name, target.name, dealt) }
+  game.level.floorItems[#game.level.floorItems + 1] = {
+    x = target.x, y = target.y, item = { kind = Items.AMMO, name = ammo.name, glyph = ammo.glyph, count = 1 },
+  }
+  local masteredKey, masteredBonus = Proficiency.onHitWith(shooter, bow.name)
+  if masteredKey then
+    lines[#lines + 1] = string.format("you grow more skilled with your %s (+%d attack)", masteredKey, masteredBonus)
+  end
+  local broke = Durability.wearBow(shooter)
+  if broke then lines[#lines + 1] = broke end
+  if not target:isAlive() then game:awardKill(target) end
+  return true, lines
+end
+
+return Ranged