// Package game is a Go port of Rogue 5.4.4 ("Exploring the Dungeons of
// Doom", Michael Toy, Ken Arnold and Glenn Wichman, 1980-1999).
//
// The port is function-by-function faithful to the C sources kept in the
// repository root; ARCHITECTURE.md documents both the original program and
// the design of this port. All formerly-global state lives on the RogueGame
// type.
package game

// Maximum number of different things (rogue.h)
const (
	MaxRooms    = 9
	MaxThings   = 9
	MaxObj      = 9
	MaxPack     = 23
	MaxTraps    = 10
	AmuletLevel = 26
	NumThings   = 7  // number of types of things
	MaxPass     = 13 // upper limit on number of passages
	NumLines    = 24
	NumCols     = 80
	StatLine    = NumLines - 1
	BoreLevel   = 50

	MaxStr   = 1024 // maximum length of strings
	MaxLines = 32   // maximum number of screen lines used
	MaxCols  = 80   // maximum number of screen columns used
)

// Return values for get functions (rogue.h)
const (
	Norm  = 0 // normal exit
	Quit  = 1 // quit option setting
	Minus = 2 // back up one option
)

// Inventory types (rogue.h)
const (
	InvOver  = 0
	InvSlow  = 1
	InvClear = 2
)

// Things that appear on the screens (rogue.h). These byte values serve both
// as map characters and as Object.Type discriminators, exactly as in C.
const (
	Passage  byte = '#'
	Door     byte = '+'
	Floor    byte = '.'
	PlayerCh byte = '@'
	Trap     byte = '^'
	Stairs   byte = '%'
	Gold     byte = '*'
	Potion   byte = '!'
	Scroll   byte = '?'
	Magic    byte = '$'
	Food     byte = ':'
	Weapon   byte = ')'
	Armor    byte = ']'
	Amulet   byte = ','
	Ring     byte = '='
	Stick    byte = '/'
)

// Various constants (rogue.h)
const (
	HealTime    = 30
	HuhDuration = 20
	SeeDuration = 850
	HungerTime  = 1300
	MoreTime    = 150
	StomachSize = 2000
	StarveTime  = 850
	Escape      = 27
	Left        = 0
	Right       = 1
	BoltLength  = 6
	LampDist    = 3
	MaxDaemons  = 20
	MaxInp      = 50 // options.c: max string entered by the user
	MaxNameLen  = 40 // init.c MAXNAME: max chars in a generated scroll name
)

// Save against things (rogue.h)
const (
	VsPoison       = 0
	VsParalyzation = 0
	VsDeath        = 0
	VsBreath       = 2
	VsMagic        = 3
)

// RoomFlags are the room state bits (rogue.h room flags).
type RoomFlags int16

// Room state bits (rogue.h ISDARK/ISGONE/ISMAZE).
const (
	Dark RoomFlags = 1 << iota // room is dark
	Gone                       // room is gone (a corridor)
	Maze                       // room is a maze
)

// Has reports whether any of the given bits are set.
func (f *RoomFlags) Has(b RoomFlags) bool { return *f&b != 0 }

// Set turns the given bits on.
func (f *RoomFlags) Set(b RoomFlags) { *f |= b }

// Clear turns the given bits off.
func (f *RoomFlags) Clear(b RoomFlags) { *f &^= b }

// ObjFlags are the object state bits (rogue.h object flags).
type ObjFlags int32

// Object state bits (rogue.h).
const (
	Cursed    ObjFlags = 1 << iota // ISCURSED: object is cursed
	Known                          // ISKNOW: player knows details about the object
	Missile                        // ISMISL: object is a missile type
	Stackable                      // ISMANY: object comes in groups
	WasFound                       // ISFOUND (objects): object has been seen (ISFOUND shares the bit with creatures)
	Protected                      // ISPROT: armor is permanently protected
)

// Has reports whether any of the given bits are set.
func (f *ObjFlags) Has(b ObjFlags) bool { return *f&b != 0 }

// Set turns the given bits on.
func (f *ObjFlags) Set(b ObjFlags) { *f |= b }

// Clear turns the given bits off.
func (f *ObjFlags) Clear(b ObjFlags) { *f &^= b }

// CreatureFlags are the creature state bits (rogue.h creature flags). The
// C bit collisions are deliberate and preserved: one name of each pair
// applies to monsters, the other to the hero, and they never coexist on
// one creature.
type CreatureFlags int32

// Creature state bits (rogue.h).
const (
	CanConfuse      CreatureFlags = 0o000001 // CANHUH: creature can confuse
	CanSeeInvisible CreatureFlags = 0o000002 // CANSEE: creature can see invisible creatures
	Blind           CreatureFlags = 0o000004 // ISBLIND: creature is blind
	Cancelled       CreatureFlags = 0o000010 // ISCANC: creature has special qualities cancelled
	Levitating      CreatureFlags = 0o000010 // ISLEVIT: hero is levitating
	Found           CreatureFlags = 0o000020 // ISFOUND: creature has been seen
	Greedy          CreatureFlags = 0o000040 // ISGREED: creature runs to protect gold
	Hasted          CreatureFlags = 0o000100 // ISHASTE: creature has been hastened
	Targeted        CreatureFlags = 0o000200 // ISTARGET: creature is the target of an 'f' command
	Held            CreatureFlags = 0o000400 // ISHELD: creature has been held
	Confused        CreatureFlags = 0o001000 // ISHUH: creature is confused
	Invisible       CreatureFlags = 0o002000 // ISINVIS: creature is invisible
	Mean            CreatureFlags = 0o004000 // ISMEAN: creature can wake when player enters room
	Hallucinating   CreatureFlags = 0o004000 // ISHALU: hero is on acid trip
	Regenerates     CreatureFlags = 0o010000 // ISREGEN: creature can regenerate
	Awake           CreatureFlags = 0o020000 // ISRUN: creature is running at the player
	SenseMonsters   CreatureFlags = 0o040000 // SEEMONST: hero can detect unseen monsters
	Flying          CreatureFlags = 0o040000 // ISFLY: creature can fly
	Slowed          CreatureFlags = 0o100000 // ISSLOW: creature has been slowed
)

// Has reports whether any of the given bits are set.
func (f *CreatureFlags) Has(b CreatureFlags) bool { return *f&b != 0 }

// Set turns the given bits on.
func (f *CreatureFlags) Set(b CreatureFlags) { *f |= b }

// Clear turns the given bits off.
func (f *CreatureFlags) Clear(b CreatureFlags) { *f &^= b }

// PlaceFlags are the per-map-cell bits (rogue.h level map flags). The low
// bits double as the passage number (FPassNum) or trap kind (FTrapMask).
type PlaceFlags uint8

// Map cell bits (rogue.h).
const (
	FPassage  PlaceFlags = 0x80 // F_PASS: is a passageway
	FSeen     PlaceFlags = 0x40 // have seen this spot before
	FDropped  PlaceFlags = 0x20 // object was dropped here
	FLocked   PlaceFlags = 0x20 // door is locked
	FReal     PlaceFlags = 0x10 // what you see is what you get
	FPassNum  PlaceFlags = 0x0f // F_PNUM: passage number mask
	FTrapMask PlaceFlags = 0x07 // F_TMASK: trap number mask
)

// Has reports whether any of the given bits are set.
func (f *PlaceFlags) Has(b PlaceFlags) bool { return *f&b != 0 }

// Set turns the given bits on.
func (f *PlaceFlags) Set(b PlaceFlags) { *f |= b }

// Clear turns the given bits off.
func (f *PlaceFlags) Clear(b PlaceFlags) { *f &^= b }

// TrapKind identifies a trap (rogue.h trap types). The kind is stored in
// the low bits of a map cell's PlaceFlags (FTrapMask).
type TrapKind int

// Trap kinds (rogue.h T_* constants).
const (
	TrapDoor     TrapKind = 0
	TrapArrow    TrapKind = 1
	TrapSleep    TrapKind = 2
	TrapBear     TrapKind = 3
	TrapTeleport TrapKind = 4
	TrapDart     TrapKind = 5
	TrapRust     TrapKind = 6
	TrapMystery  TrapKind = 7
	NumTrapTypes          = 8
)

// PotionKind identifies a potion (rogue.h potion types).
type PotionKind int

// Potion kinds (rogue.h)
const (
	PotionConfusion PotionKind = iota
	PotionLSD
	PotionPoison
	PotionGainStrength
	PotionSeeInvisible
	PotionHealing
	PotionDetectMonsters
	PotionDetectMagic
	PotionRaiseLevel
	PotionExtraHealing
	PotionHaste
	PotionRestoreStrength
	PotionBlindness
	PotionLevitation
	NumPotionTypes
)

// ScrollKind identifies a scroll (rogue.h scroll types).
type ScrollKind int

// Scroll kinds (rogue.h)
const (
	ScrollMonsterConfusion ScrollKind = iota
	ScrollMagicMapping
	ScrollHoldMonster
	ScrollSleep
	ScrollEnchantArmor
	ScrollIdentifyPotion
	ScrollIdentifyScroll
	ScrollIdentifyWeapon
	ScrollIdentifyArmor
	ScrollIdentifyRingOrStick
	ScrollScareMonster
	ScrollFoodDetection
	ScrollTeleportation
	ScrollEnchantWeapon
	ScrollCreateMonster
	ScrollRemoveCurse
	ScrollAggravateMonsters
	ScrollProtectArmor
	NumScrollTypes
)

// WeaponKind identifies a weapon (rogue.h weapon types).
type WeaponKind int

// Weapon kinds (rogue.h)
const (
	WeaponMace WeaponKind = iota
	WeaponLongSword
	WeaponBow
	WeaponArrow
	WeaponDagger
	WeaponTwoHandedSword
	WeaponDart
	WeaponShuriken
	WeaponSpear
	WeaponFlame // fake entry for dragon breath (ick)
)

// NumWeaponTypes counts the real weapons; the flame pseudo-weapon sits
// just past them in the tables (C's MAXWEAPONS == FLAME).
const NumWeaponTypes = WeaponFlame

// ArmorKind identifies a suit of armor (rogue.h armor types).
type ArmorKind int

// Armor kinds (rogue.h)
const (
	ArmorLeather ArmorKind = iota
	ArmorRingMail
	ArmorStuddedLeather
	ArmorScaleMail
	ArmorChainMail
	ArmorSplintMail
	ArmorBandedMail
	ArmorPlateMail
	NumArmorTypes
)

// RingKind identifies a ring (rogue.h ring types).
type RingKind int

// Ring kinds (rogue.h)
const (
	RingProtection RingKind = iota
	RingAddStrength
	RingSustainStrength
	RingSearching
	RingSeeInvisible
	RingAdornment
	RingAggravateMonsters
	RingDexterity
	RingIncreaseDamage
	RingRegeneration
	RingSlowDigestion
	RingTeleportation
	RingStealth
	RingMaintainArmor
	NumRingTypes
)

// WandKind identifies a wand or staff (rogue.h rod/wand/staff types).
type WandKind int

// Wand kinds (rogue.h)
const (
	WandLight WandKind = iota
	WandInvisibility
	WandLightning
	WandFire
	WandCold
	WandPolymorph
	WandMagicMissile
	WandHasteMonster
	WandSlowMonster
	WandDrainLife
	WandNothing
	WandTeleportAway
	WandTeleportTo
	WandCancellation
	NumWandTypes
)

// Coord is a position on the level (rogue.h coord). A value type: the C
// ce(a,b) macro is plain == here.
type Coord struct {
	X, Y int
}

// Stats describes a fighting being (rogue.h struct stats).
type Stats struct {
	Str        int      // strength (s_str; 3..31)
	Exp        int      // experience
	Lvl        int      // level of mastery
	ArmorClass int      // armor class (s_arm)
	HP         int      // hit points (s_hpt)
	Dmg        DiceSpec // damage dice, e.g. "1x4/1x2"
	MaxHP      int
}

// Room describes a room or passage network (rogue.h struct room).
type Room struct {
	Pos     Coord // upper left corner
	Max     Coord // size of room
	Gold    Coord // where the gold is
	GoldVal int   // how much the gold is worth
	Flags   RoomFlags
	Exits   []Coord // where the exits are (r_exit[12]/r_nexits)
}

// MonsterKind is a bestiary entry (rogue.h struct monster).
type MonsterKind struct {
	Name  string // what to call the monster
	Carry int    // probability of carrying something
	Flags CreatureFlags
	Stats Stats // initial stats
}

// ObjInfo describes one object class: its real name, generation
// probability, score worth, and per-game identification state
// (rogue.h struct obj_info).
type ObjInfo struct {
	Name  string
	Prob  int
	Worth int
	Guess string
	Know  bool
}

// Stone is a ring stone with its worth (rogue.h STONE).
type Stone struct {
	Name  string
	Value int
}

// CTRL maps a letter to its control character, as the C CTRL() macro.
func CTRL(c byte) byte { return c & 0o37 }

// distance returns the squared distance between two points (chase.c dist).
func distance(y1, x1, y2, x2 int) int {
	dx := x2 - x1
	dy := y2 - y1

	return dx*dx + dy*dy
}

// distCp is dist_cp from chase.c.
func distCp(c1, c2 Coord) int { return distance(c1.Y, c1.X, c2.Y, c2.X) }

// sign is misc.c sign(): -1, 0 or 1.
func sign(nm int) int {
	switch {
	case nm < 0:
		return -1
	case nm > 0:
		return 1
	}

	return 0
}