rgoue/game/scrolls.go

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

// scrolls.c — read a scroll and let it happen.

// readScroll reads a scroll from the pack and does the appropriate thing
// (scrolls.c read_scroll).
func (g *RogueGame) readScroll() {
	p := &g.Player

	obj, ok := g.promptPackItem("read", KindScroll)
	if !ok {
		return
	}

	if obj.Kind != KindScroll {
		if !g.Options.Terse {
			g.msg("there is nothing on it to read")
		} else {
			g.msg("nothing to read")
		}

		return
	}
	// Calculate the effect it has on the poor guy.
	if obj == p.CurWeapon {
		p.CurWeapon = nil
	}
	// Get rid of the thing
	g.leavePack(obj, false, false)

	if h := g.data.readHandler(obj); h != nil {
		h(g, obj)
	}

	g.look(true) // put the result of the scroll on the screen
	g.status()

	// A malformed scroll has no lore entry to name (see quaff).
	if obj.hasValidWhich() {
		g.callIt(&g.Items.Scrolls[obj.Which])
	}
}

// The per-scroll effect handlers, dispatched through
// gameData.readHandlers. Each is one case of the C read_scroll switch.

func (g *RogueGame) readMonsterConfusion(*Object) {
	// Scroll of monster confusion.  Give him that power.
	g.Player.Flags.Set(CanConfuse)
	g.msg("your hands begin to glow %s", g.pickColor("red"))
}

func (g *RogueGame) readEnchantArmor(*Object) {
	p := &g.Player
	if p.CurArmor != nil {
		p.CurArmor.ArmorClass--
		p.CurArmor.Flags.Clear(Cursed)
		g.msg("your armor glows %s for a moment", g.pickColor("silver"))
	}
}

func (g *RogueGame) readHoldMonster(*Object) {
	// Hold monster scroll.  Stop all monsters within two spaces from
	// chasing after the hero.
	held := g.holdMonstersNear()

	if held > 0 {
		g.addmsgf("the monster")

		if held > 1 {
			g.addmsgf("s around you")
		}

		g.addmsgf(" freeze")

		if held == 1 {
			g.addmsgf("s")
		}

		g.endmsg()
		g.Items.Scrolls[ScrollHoldMonster].Know = true
	} else {
		g.msg("you feel a strange sense of loss")
	}
}

// holdMonstersNear freezes every awake monster within two spaces of the
// hero and reports how many froze (the scan of the C S_HOLD case).
func (g *RogueGame) holdMonstersNear() int {
	p := &g.Player
	held := 0

	for x := p.Pos.X - 2; x <= p.Pos.X+2; x++ {
		if x < 0 || x >= NumCols {
			continue
		}

		for y := p.Pos.Y - 2; y <= p.Pos.Y+2; y++ {
			if y < 0 || y > NumLines-1 {
				continue
			}

			if mp := g.Level.MonsterAt(y, x); mp != nil && mp.On(Awake) {
				mp.Flags.Clear(Awake)
				mp.Flags.Set(Held)

				held++
			}
		}
	}

	return held
}

func (g *RogueGame) readSleep(*Object) {
	// Scroll which makes you fall asleep
	g.Items.Scrolls[ScrollSleep].Know = true
	g.NoCommand += g.rnd(g.spread(5)) + 4 // SLEEPTIME

	g.Player.Flags.Clear(Awake)
	g.msg("you fall asleep")
}

func (g *RogueGame) readCreateMonster(*Object) {
	// Create a monster: first look in a circle around him, next try
	// his room, otherwise give up
	mp, ok := g.createMonsterSpot()
	if !ok {
		g.msg("you hear a faint cry of anguish in the distance")
	} else {
		tp := &Monster{}
		g.newMonster(tp, g.randMonster(false), mp)
	}
}

// createMonsterSpot reservoir-samples a legal spot around the hero for a
// created monster; ok is false when every neighbor is blocked (the scan
// of the C S_CREATE case).
func (g *RogueGame) createMonsterSpot() (Coord, bool) {
	p := &g.Player
	i := 0

	var mp Coord

	for y := p.Pos.Y - 1; y <= p.Pos.Y+1; y++ {
		for x := p.Pos.X - 1; x <= p.Pos.X+1; x++ {
			// Don't put a monster on top of the player.
			if y == p.Pos.Y && x == p.Pos.X {
				continue
			}
			// Or anything else nasty
			if ch := g.Level.VisibleChar(y, x); stepOk(ch) {
				if ch == Scroll {
					if fo := g.Level.ObjectAt(y, x); fo != nil &&
						fo.ScrollKind() == ScrollScareMonster {
						continue
					}
				}

				if i++; g.rnd(i) == 0 {
					mp = Coord{Y: y, X: x}
				}
			}
		}
	}

	return mp, i != 0
}

func (g *RogueGame) readIdentify(obj *Object) {
	// Identify, let him figure something out. idType is shorter than the
	// scroll table keying it (it stops after the last identify scroll),
	// so the filter lookup carries its own bound. That bound is not
	// reachable today: readHandlers registers readIdentify only for the
	// identify scrolls, all of which sit inside idType. It is kept as
	// defense-in-depth against a future table resize.
	g.Items.Scrolls[obj.Which].Know = true
	g.msg("this scroll is an %s scroll", g.Items.Scrolls[obj.Which].Name)
	g.whatis(true, g.data.identifyType(obj.ScrollKind()))
}

func (g *RogueGame) readMagicMapping(*Object) {
	// Scroll of magic mapping.
	g.Items.Scrolls[ScrollMagicMapping].Know = true
	g.msg("oh, now this scroll has a map on it")
	// take all the things we want to keep hidden out of the window
	for y := 1; y < NumLines-1; y++ {
		for x := range NumCols {
			g.revealSpot(y, x)
		}
	}
}

// revealSpot uncovers one map cell for magic mapping and draws it (the
// loop body of the C SCR_MAP case).
func (g *RogueGame) revealSpot(y, x int) {
	pp := g.Level.At(y, x)

	ch := revealChar(pp)
	if ch != ' ' {
		if tp := pp.Monst; tp != nil {
			tp.OldCh = ch
			if !g.Player.On(SenseMonsters) {
				g.mvaddch(y, x, ch)
			}
		} else {
			g.mvaddch(y, x, ch)
		}
	}
}

// revealChar decides what magic mapping shows at a cell, making secret
// doors, hidden passages, and hidden traps real as a side effect; ' '
// means show nothing (the switch of the C SCR_MAP loop).
func revealChar(pp *Place) byte {
	ch := pp.Ch
	pass := false

	switch ch {
	case Door, Stairs:
	case '-', '|':
		ch = revealWall(pp)
	case ' ':
		pass = revealSolid(pp)
	case Passage:
		pass = true
	case Floor:
		ch = revealFloor(pp)
	default:
		if pp.Flags.Has(FPassage) {
			pass = true
		} else {
			ch = ' '
		}
	}

	if pass {
		if !pp.Flags.Has(FReal) {
			pp.Ch = Passage
		}

		pp.Flags.Set(FSeen | FReal)

		ch = Passage
	}

	return ch
}

// revealWall handles a wall cell for magic mapping: a secret door
// becomes a real door (the '-'/'|' arm).
func revealWall(pp *Place) byte {
	if !pp.Flags.Has(FReal) {
		pp.Ch = Door
		pp.Flags.Set(FReal)

		return Door
	}

	return pp.Ch
}

// revealSolid handles a blank cell for magic mapping, reporting whether
// it is passage: hidden passages become real; hidden things in walls
// stay hidden (the ' ' arm).
func revealSolid(pp *Place) bool {
	if pp.Flags.Has(FReal) {
		return pp.Flags.Has(FPassage)
	}

	pp.Flags.Set(FReal)
	pp.Ch = Passage

	return true
}

// revealFloor handles a floor cell for magic mapping: a hidden trap
// becomes a real, seen trap; real floor shows nothing (the FLOOR arm).
func revealFloor(pp *Place) byte {
	if pp.Flags.Has(FReal) {
		return ' '
	}

	pp.Ch = Trap
	pp.Flags.Set(FSeen | FReal)

	return Trap
}

func (g *RogueGame) readFoodDetection(*Object) {
	// Food detection
	found := false

	g.scr.Hw.Clear()

	for _, fo := range g.Level.Objects {
		if fo.Kind == KindFood {
			found = true

			g.scr.Hw.MvAddCh(fo.Pos.Y, fo.Pos.X, Food)
		}
	}

	if found {
		g.Items.Scrolls[ScrollFoodDetection].Know = true
		g.showWin("Your nose tingles and you smell food.--More--")
	} else {
		g.msg("your nose tingles")
	}
}

func (g *RogueGame) readTeleportation(*Object) {
	// Scroll of teleportation: make him disappear and reappear
	p := &g.Player
	curRoom := p.Room

	g.teleport()

	if curRoom != p.Room {
		g.Items.Scrolls[ScrollTeleportation].Know = true
	}
}

func (g *RogueGame) readEnchantWeapon(*Object) {
	p := &g.Player
	if p.CurWeapon == nil || p.CurWeapon.Kind != KindWeapon {
		g.msg("you feel a strange sense of loss")
	} else {
		p.CurWeapon.Flags.Clear(Cursed)

		if g.rnd(2) == 0 {
			p.CurWeapon.HPlus++
		} else {
			p.CurWeapon.DPlus++
		}

		g.msg("your %s glows %s for a moment",
			g.Items.Weapons[p.CurWeapon.Which].Name, g.pickColor("blue"))
	}
}

func (g *RogueGame) readScareMonster(*Object) {
	// Reading it is a mistake and produces laughter at her poor boo
	// boo.
	g.msg("you hear maniacal laughter in the distance")
}

func (g *RogueGame) readRemoveCurse(*Object) {
	p := &g.Player

	uncurse(p.CurArmor)
	uncurse(p.CurWeapon)
	uncurse(p.CurRing[Left])
	uncurse(p.CurRing[Right])
	g.msg("%s", g.chooseStr("you feel in touch with the Universal Onenes",
		"you feel as if somebody is watching over you"))
}

func (g *RogueGame) readAggravateMonsters(*Object) {
	// This scroll aggravates all the monsters on the current level
	// and sets them running towards the hero
	g.aggravate()
	g.msg("you hear a high pitched humming noise")
}

func (g *RogueGame) readProtectArmor(*Object) {
	p := &g.Player
	if p.CurArmor != nil {
		p.CurArmor.Flags.Set(Protected)
		g.msg("your armor is covered by a shimmering %s shield",
			g.pickColor("gold"))
	} else {
		g.msg("you feel a strange sense of loss")
	}
}

// uncurse uncurses an item (scrolls.c uncurse).
func uncurse(obj *Object) {
	if obj != nil {
		obj.Flags.Clear(Cursed)
	}
}