rgoue/game/weapons.go

//nolint:mnd // C-faithful literals; names hurt C-greppability (approved 2026-07-07)
package game

import "fmt"

// weapons.c — functions for dealing with problems brought about by weapons.

const noWeapon WeaponKind = -1

// missile fires a missile in a given direction (weapons.c missile).
func (g *RogueGame) missile(ydelta, xdelta int) {
	// Get which thing we are hurling
	obj, ok := g.promptPackItem("throw", KindWeapon)
	if !ok {
		return
	}

	if !g.dropCheck(obj) || g.isCurrent(obj) {
		return
	}

	obj = g.leavePack(obj, true, false)
	g.doMotion(obj, ydelta, xdelta)
	// AHA! Here it has hit something.  If it is a wall or a door, or if
	// it misses (combat) the monster, put it on the floor
	if g.Level.MonsterAt(obj.Pos.Y, obj.Pos.X) == nil ||
		!g.hitMonster(obj.Pos, obj) {
		g.fall(obj, true)
	}
}

// doMotion does the actual motion on the screen done by an object
// traveling across the room (weapons.c do_motion).
func (g *RogueGame) doMotion(obj *Object, ydelta, xdelta int) {
	p := &g.Player
	// Come fly with us ...
	obj.Pos = p.Pos
	for {
		g.eraseFlight(obj, p.Pos)
		// Get the new position
		obj.Pos.Y += ydelta
		obj.Pos.X += xdelta

		ch := g.Level.VisibleChar(obj.Pos.Y, obj.Pos.X)
		if !stepOk(ch) || ch == Door {
			break
		}
		// It hasn't hit anything yet, so display it if it's alright.
		if g.canSee(obj.Pos.Y, obj.Pos.X) && !g.Options.Terse {
			g.mvaddch(obj.Pos.Y, obj.Pos.X, obj.Kind.Glyph())
			g.refresh()
		}
	}
}

// eraseFlight erases a flying object from its current square, unless it
// still sits on the hero (the erase step of weapons.c do_motion).
func (g *RogueGame) eraseFlight(obj *Object, heroPos Coord) {
	if obj.Pos == heroPos || !g.canSee(obj.Pos.Y, obj.Pos.X) || g.Options.Terse {
		return
	}

	ch := g.Level.Char(obj.Pos.Y, obj.Pos.X)
	if ch == Floor && !g.showFloor() {
		ch = ' '
	}

	g.mvaddch(obj.Pos.Y, obj.Pos.X, ch)
}

// fall drops an item someplace around here (weapons.c fall).
func (g *RogueGame) fall(obj *Object, pr bool) {
	if fpos, ok := g.fallpos(obj.Pos); ok {
		pp := g.Level.At(fpos.Y, fpos.X)
		pp.Ch = obj.Kind.Glyph()

		obj.Pos = fpos
		if g.canSee(fpos.Y, fpos.X) {
			if pp.Monst != nil {
				pp.Monst.OldCh = obj.Kind.Glyph()
			} else {
				g.mvaddch(fpos.Y, fpos.X, obj.Kind.Glyph())
			}
		}

		g.Level.AddObject(obj)

		return
	}

	if pr {
		if g.HasHit {
			g.endmsg()
			g.HasHit = false
		}

		g.msg("the %s vanishes as it hits the ground",
			g.Items.Weapons[obj.Which].Name)
	}
}

// hitMonster checks if the missile hits the monster (weapons.c
// hit_monster).
func (g *RogueGame) hitMonster(mp Coord, obj *Object) bool {
	return g.fight(mp, obj, true)
}

// wield pulls out a certain weapon (weapons.c wield).
func (g *RogueGame) wield() {
	p := &g.Player

	oweapon := p.CurWeapon
	if !g.dropCheck(p.CurWeapon) {
		p.CurWeapon = oweapon

		return
	}

	p.CurWeapon = oweapon

	obj, ok := g.promptPackItem("wield", KindWeapon)
	if !ok {
		g.After = false

		return
	}

	if obj.Kind == KindArmor {
		g.msg("you can't wield armor")
		g.After = false

		return
	}

	if g.isCurrent(obj) {
		g.After = false

		return
	}

	sp := g.inventoryName(obj, true)
	p.CurWeapon = obj

	if !g.Options.Terse {
		g.addmsgf("you are now ")
	}

	g.msg("wielding %s (%c)", sp, obj.PackCh)
}

// weaponSetup is one row of the weapons.c init_dam[] table (see
// gameData.initWeaps).
type weaponSetup struct {
	dam    DiceSpec   // damage when wielded
	hrl    DiceSpec   // damage when thrown
	launch WeaponKind // launching weapon
	flags  ObjFlags
}

// initWeapon sets up a new weapon (weapons.c init_weapon).
func (g *RogueGame) initWeapon(weap *Object, which WeaponKind) {
	// init_dam[] has a row only for the real weapons: WeaponFlame (dragon
	// breath) and anything past it have none. createObj rejects such a
	// choice before calling here, so this arm is unreachable in practice;
	// it exists so a malformed kind leaves the weapon untouched instead of
	// panicking on the table read.
	if which < 0 || int(which) >= int(NumWeaponTypes) {
		return
	}

	iwp := &g.data.initWeaps[which]
	weap.Kind = KindWeapon
	weap.Which = int(which)
	weap.Damage = iwp.dam
	weap.HurlDmg = iwp.hrl
	weap.Launch = iwp.launch
	weap.Flags = iwp.flags
	weap.HPlus = 0

	weap.DPlus = 0

	switch {
	case which == WeaponDagger:
		weap.Count = g.rnd(4) + 2
		weap.Group = g.Items.Group
		g.Items.Group++
	case weap.Flags.Has(Stackable):
		weap.Count = g.rnd(8) + 8
		weap.Group = g.Items.Group
		g.Items.Group++
	default:
		weap.Count = 1
		weap.Group = 0
	}
}

// num formats a hit/damage or armor bonus string (weapons.c num).
func num(n1, n2 int, typ byte) string {
	out := fmt.Sprintf("%+d", n1)
	if typ == Weapon {
		out += fmt.Sprintf(",%+d", n2)
	}

	return out
}

// fallpos picks a random empty position around (pos) for a dropped item
// (weapons.c fallpos).
func (g *RogueGame) fallpos(pos Coord) (Coord, bool) {
	var newpos Coord

	cnt := 0

	for y := pos.Y - 1; y <= pos.Y+1; y++ {
		for x := pos.X - 1; x <= pos.X+1; x++ {
			// check to make certain the spot is empty, if it is, put the
			// object there, set it in the level list and re-draw the room
			// if he can see it
			if (y == g.Player.Pos.Y && x == g.Player.Pos.X) ||
				y < 0 || x < 0 {
				continue
			}

			ch := g.Level.Char(y, x)
			if ch == Floor || ch == Passage {
				if cnt++; g.rnd(cnt) == 0 {
					newpos.Y = y
					newpos.X = x
				}
			}
		}
	}

	return newpos, cnt != 0
}