package world

import (
	"fmt"
	"math/rand"
	"os"
	"path/filepath"
	"strings"
	"sync"

	"gopkg.in/yaml.v3"
	"thehouseoficarus/internal/behavior"
)

type MobDropTable struct {
	Remains string               `yaml:"remains"`
	Loot    []behavior.DropEntry `yaml:"loot"`
}

type MobSteal struct {
	Drops []behavior.DropEntry `yaml:"drops"`
	Level int                  `yaml:"level"`
	XP    int                  `yaml:"xp"`
	Speed float64              `yaml:"speed"`
}

type MobTask struct {
	Verb            string `yaml:"verb"`
	ProgressNoun    string `yaml:"progress_noun"`
	CompleteMessage string `yaml:"complete_message"`
}

type MobCombatBonuses struct {
	AttackBonus         int `yaml:"attack_bonus"`
	StrengthBonus       int `yaml:"strength_bonus"`
	ScienceBonus        int `yaml:"science_bonus"`
	SciencePercentBonus int `yaml:"science_percent_bonus"`
	RangedBonus         int `yaml:"ranged_bonus"`
	RangedStrengthBonus int `yaml:"ranged_strength_bonus"`
}

type MobCombatDefenses struct {
	StabDefense     int    `yaml:"stab_defense"`
	SlashDefense    int    `yaml:"slash_defense"`
	CrushDefense    int    `yaml:"crush_defense"`
	ScienceDefense  int    `yaml:"science_defense"`
	RangedDefense   int    `yaml:"ranged_defense"`
	Weakness        string `yaml:"weakness"`
	WeaknessPercent int    `yaml:"weakness_percent"`
}

type MobCombatStats struct {
	HP            int               `yaml:"hp"`
	Attack        int               `yaml:"attack"`
	Strength      int               `yaml:"strength"`
	Defense       int               `yaml:"defense"`
	Ranged        int               `yaml:"ranged"`
	Science       int               `yaml:"science"`
	Speed         float64           `yaml:"speed"`
	MaxMeleeHit   int               `yaml:"max_melee_hit"`
	MaxRangedHit  int               `yaml:"max_ranged_hit"`
	MaxScienceHit int               `yaml:"max_science_hit"`
	Bonuses       MobCombatBonuses  `yaml:"bonuses"`
	Defenses      MobCombatDefenses `yaml:"defenses"`
}

type MobCombat struct {
	Kind               string         `yaml:"kind"`
	AttackTypes        []string       `yaml:"attack_types"`
	Aggressive         bool           `yaml:"aggressive"`
	RespawnTicks       float64        `yaml:"respawn_ticks"`
	Stats              MobCombatStats `yaml:"stats"`
	AssassinLevel      int            `yaml:"assassin_level"`
	FinishingBlow      string         `yaml:"finishing_blow"`
	DamageWithout      string         `yaml:"damage_without"`
	Size               string         `yaml:"size"`
	CombatDescriptions []string       `yaml:"combat_descriptions"`
}

type MobDef struct {
	ID               string       `yaml:"id"`
	Name             string       `yaml:"name"`
	Description      string       `yaml:"description"`
	IdleDescriptions []string     `yaml:"idle_descriptions"`
	Protected        bool         `yaml:"protected"`
	Unique           bool         `yaml:"unique"`
	Drops            MobDropTable `yaml:"drops"`

	Steal *MobSteal `yaml:"steal,omitempty"`
	Task  *MobTask  `yaml:"task,omitempty"`

	Combat *MobCombat `yaml:"combat,omitempty"`

	Talk *behavior.TalkConfig `yaml:"talk,omitempty"`
	Shop *behavior.ShopConfig `yaml:"shop,omitempty"`

	OnKill []behavior.Trigger `yaml:"on_kill,omitempty"`
}

func (d *MobDef) IsTalkable() bool { return d.Talk != nil }

func (d *MobDef) HasShop() bool { return d.Shop != nil }

func (d *MobDef) IsTask() bool { return d.Combat != nil && d.Combat.Kind == "task" }

type MobInstance struct {
	InstanceID         string
	DefID              string
	Name               string
	Description        string
	HP                 int
	MaxHP              int
	Attack             int
	Strength           int
	Defense            int
	Ranged             int
	Science            int
	Speed              float64
	Aggressive         bool
	Protected          bool
	Unique             bool
	RespawnTicks       float64
	RoomID             int
	HomeRoomID         int
	Drops              MobDropTable
	IdleDescription    string
	CombatDescriptions []string
	WanderRooms        []int
	WanderInterval     float64
	WanderTickCounter  int
	regenerateTick     int

	AttackBonus   int
	StrengthBonus int
	AttackTypes   []string

	RangedBonus         int
	ScienceBonus        int
	SciencePercentBonus int

	StabDefense    int
	SlashDefense   int
	CrushDefense   int
	ScienceDefense int
	RangedDefense  int

	Weakness        string
	WeaknessPercent int

	MaxMeleeHit   int
	MaxRangedHit  int
	MaxScienceHit int
	StealDrops    []behavior.DropEntry
	StealLevel    int
	StealXP       int
	StealSpeed    float64

	AssassinLevel int
	FinishingBlow string
	DamageWithout string
	Size          string

	Kind            string
	Verb            string
	ProgressNoun    string
	CompleteMessage string

	TalkConfig *behavior.TalkConfig

	// OnKill is copied from the def at spawn time and fires from endCombat
	// when this mob is defeated — either by a combat kill or by a task mob's
	// HP draining to zero (the "completion" of the work). The first entry
	// whose item filter, Condition, and the first-match-wins rule all pass
	// fires.
	OnKill []behavior.Trigger

	// Shop is the (shared, read-only) shop config from the def. Per-instance
	// live stock is tracked in ShopStock; ShopRestock holds per-item countdown
	// timers. All three are only mutated under MobStore.mu.
	Shop        *behavior.ShopConfig
	ShopStock   map[string]int
	ShopRestock map[string]int

	Owner            string
	OwnerOnly        bool
	SpawnedByTrigger bool
	DespawnOnLeave   bool
	DespawnRooms     []int
	DespawnTicks     float64
	DespawnCounter   int
}

func (m *MobInstance) IsTalkable() bool { return m.TalkConfig != nil }

func (m *MobInstance) HasShop() bool { return m.Shop != nil }

func (m *MobInstance) IsTask() bool { return m.Kind == "task" }

func NewMobInstance(def *MobDef, instanceID string, roomID int, wanderRooms []int, wanderInterval float64) *MobInstance {
	hp := 0
	attack := 0
	strength := 0
	defense := 0
	ranged := 0
	science := 0
	speed := 0.0
	aggressive := false
	respawnTicks := 0.0
	attackBonus := 0
	strengthBonus := 0
	rangedBonus := 0
	scienceBonus := 0
	sciencePercentBonus := 0
	var attackType []string
	stabDef := 0
	slashDef := 0
	crushDef := 0
	scienceDef := 0
	rangedDef := 0
	weakness := ""
	weaknessPercent := 0
	maxMeleeHit := 0
	maxRangedHit := 0
	maxScienceHit := 0
	assassinLevel := 0
	finishingBlow := ""
	damageWithout := ""
	size := ""
	kind := ""
	verb := ""
	progressNoun := ""
	completeMessage := ""
	var combatDescriptions []string
	var stealDrops []behavior.DropEntry
	stealLevel := 0
	stealXP := 0
	stealSpeed := 0.0

	if def.Combat != nil {
		aggressive = def.Combat.Aggressive
		respawnTicks = def.Combat.RespawnTicks
		attackType = append([]string(nil), def.Combat.AttackTypes...)

		cs := def.Combat.Stats
		hp = cs.HP
		attack = cs.Attack
		strength = cs.Strength
		defense = cs.Defense
		ranged = cs.Ranged
		science = cs.Science
		speed = cs.Speed
		attackBonus = cs.Bonuses.AttackBonus
		strengthBonus = cs.Bonuses.StrengthBonus
		rangedBonus = cs.Bonuses.RangedBonus
		scienceBonus = cs.Bonuses.ScienceBonus
		sciencePercentBonus = cs.Bonuses.SciencePercentBonus
		stabDef = cs.Defenses.StabDefense
		slashDef = cs.Defenses.SlashDefense
		crushDef = cs.Defenses.CrushDefense
		scienceDef = cs.Defenses.ScienceDefense
		rangedDef = cs.Defenses.RangedDefense
		weakness = cs.Defenses.Weakness
		weaknessPercent = cs.Defenses.WeaknessPercent
		maxMeleeHit = cs.MaxMeleeHit
		maxRangedHit = cs.MaxRangedHit
		maxScienceHit = cs.MaxScienceHit

		assassinLevel = def.Combat.AssassinLevel
		finishingBlow = def.Combat.FinishingBlow
		damageWithout = def.Combat.DamageWithout
		size = def.Combat.Size
		kind = def.Combat.Kind
		combatDescriptions = def.Combat.CombatDescriptions
	}

	if def.Steal != nil {
		stealDrops = def.Steal.Drops
		stealLevel = def.Steal.Level
		stealXP = def.Steal.XP
		stealSpeed = def.Steal.Speed
	}

	if def.Task != nil {
		verb = def.Task.Verb
		progressNoun = def.Task.ProgressNoun
		completeMessage = def.Task.CompleteMessage
	}

	if def.Protected && hp <= 0 {
		hp = 1
	}
	inst := &MobInstance{
		InstanceID:          instanceID,
		DefID:               def.ID,
		Name:                def.Name,
		Description:         def.Description,
		HP:                  hp,
		MaxHP:               hp,
		Attack:              attack,
		Strength:            strength,
		Defense:             defense,
		Ranged:              ranged,
		Science:             science,
		Speed:               speed,
		Aggressive:          aggressive,
		Protected:           def.Protected,
		Unique:              def.Unique,
		RespawnTicks:        respawnTicks,
		RoomID:              roomID,
		HomeRoomID:          roomID,
		WanderRooms:         wanderRooms,
		WanderInterval:      wanderInterval,
		Drops:               def.Drops,
		AttackBonus:         attackBonus,
		StrengthBonus:       strengthBonus,
		AttackTypes:         attackType,
		RangedBonus:         rangedBonus,
		ScienceBonus:        scienceBonus,
		SciencePercentBonus: sciencePercentBonus,
		StabDefense:         stabDef,
		SlashDefense:        slashDef,
		CrushDefense:        crushDef,
		ScienceDefense:      scienceDef,
		RangedDefense:       rangedDef,
		Weakness:            weakness,
		WeaknessPercent:     weaknessPercent,
		MaxMeleeHit:         maxMeleeHit,
		MaxRangedHit:        maxRangedHit,
		MaxScienceHit:       maxScienceHit,
		StealDrops:          stealDrops,
		StealLevel:          stealLevel,
		StealXP:             stealXP,
		StealSpeed:          stealSpeed,
		AssassinLevel:       assassinLevel,
		FinishingBlow:       finishingBlow,
		DamageWithout:       damageWithout,
		Size:                size,
		Kind:                kind,
		Verb:                verb,
		ProgressNoun:        progressNoun,
		CompleteMessage:     completeMessage,
		CombatDescriptions:  combatDescriptions,
		TalkConfig:          def.Talk,
		OnKill:              def.OnKill,
	}
	if def.Shop != nil {
		inst.Shop = def.Shop
		inst.ShopStock = make(map[string]int)
		inst.ShopRestock = make(map[string]int)
		for i := range def.Shop.Items {
			it := &def.Shop.Items[i]
			if it.ItemID == "" {
				continue
			}
			inst.ShopStock[it.ItemID] = it.Stock
			inst.ShopRestock[it.ItemID] = def.Shop.RestockInterval(it)
		}
	}
	return inst
}

const (
	MatchNone   = 0
	MatchPrefix = 1
	MatchExact  = 2
)

func (m *MobInstance) MatchQuality(input string) int {
	lower := strings.ToLower(input)
	if strings.ToLower(m.Name) == lower {
		return MatchExact
	}
	if behavior.WordPrefixMatch(input, m.Name) {
		return MatchPrefix
	}
	return MatchNone
}

func pickIdleDescription(descriptions []string) string {
	if len(descriptions) == 0 {
		return ""
	}
	return descriptions[rand.Intn(len(descriptions))]
}

func (m *MobInstance) StartRegen() {
	if m.regenerateTick == 0 {
		m.regenerateTick = 100
	}
}

func (m *MobInstance) DespawnTickCount() int {
	return m.DespawnCounter
}

func (m *MobInstance) DecrementDespawnCounter() {
	if m.DespawnCounter > 0 {
		m.DespawnCounter--
	}
}

func (m *MobInstance) ResetDespawnCounter(ticks int) {
	m.DespawnCounter = ticks
}

type MobStore struct {
	dataDir   string
	mu        sync.Mutex
	pathIndex map[string]string
	defs      map[string]*MobDef
	instances map[string]*MobInstance
}

func NewMobStore(dataDir string) *MobStore {
	return &MobStore{
		dataDir:   dataDir,
		pathIndex: behavior.BuildPathIndex(filepath.Join(dataDir, "mobs")),
		defs:      make(map[string]*MobDef),
		instances: make(map[string]*MobInstance),
	}
}

func (s *MobStore) LoadDef(id string) (*MobDef, error) {
	s.mu.Lock()
	if def, ok := s.defs[id]; ok {
		s.mu.Unlock()
		return def, nil
	}
	s.mu.Unlock()

	path, ok := s.pathIndex[id]
	if !ok {
		return nil, fmt.Errorf("read mob %s: no such mob", id)
	}
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read mob %s: %w", id, err)
	}
	var def MobDef
	if err := yaml.Unmarshal(data, &def); err != nil {
		return nil, fmt.Errorf("parse mob %s: %w", id, err)
	}
	def.ID = id

	s.mu.Lock()
	s.defs[id] = &def
	s.mu.Unlock()
	return &def, nil
}

func (s *MobStore) AllDefIDs() map[string]bool {
	ids := make(map[string]bool)
	for id := range s.pathIndex {
		ids[id] = true
	}
	return ids
}

func (s *MobStore) ReloadDefs(dataDir string) {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.defs = make(map[string]*MobDef)
	s.pathIndex = behavior.BuildPathIndex(filepath.Join(dataDir, "mobs"))
}

func (s *MobStore) GetInstance(id string) *MobInstance {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.instances[id]
}

func (s *MobStore) AllInstances() []*MobInstance {
	s.mu.Lock()
	defer s.mu.Unlock()
	var out []*MobInstance
	for _, inst := range s.instances {
		out = append(out, inst)
	}
	return out
}

// SetInstanceRoom updates a mob instance's room under the store lock, so it is
// safe against concurrent readers (MobsInRoom, RemoveMobsInRoom) in other
// goroutines.
func (s *MobStore) SetInstanceRoom(instanceID string, roomID int) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if inst := s.instances[instanceID]; inst != nil {
		inst.RoomID = roomID
	}
}

func (s *MobStore) MobsInRoom(roomID int) []*MobInstance {
	s.mu.Lock()
	defer s.mu.Unlock()
	var out []*MobInstance
	for _, inst := range s.instances {
		if inst.RoomID == roomID && inst.HP > 0 {
			out = append(out, inst)
		}
	}
	return out
}

func (s *MobStore) Tick() {
	s.mu.Lock()
	defer s.mu.Unlock()

	for _, inst := range s.instances {
		if inst.Shop != nil {
			s.tickShopLocked(inst)
		}
		if inst.HP <= 0 || inst.HP >= inst.MaxHP {
			inst.regenerateTick = 0
			continue
		}
		inst.regenerateTick--
		if inst.regenerateTick <= 0 {
			inst.HP++
			if inst.HP >= inst.MaxHP {
				inst.HP = inst.MaxHP
				inst.regenerateTick = 0
			} else {
				inst.regenerateTick = 100
			}
		}
	}
}

// tickShopLocked advances restock timers for one shop instance. Current stock
// converges toward each item's target (configured stock for listed items, 0 for
// dynamically-acquired items) one unit per restock interval, in either
// direction. Caller must hold s.mu.
func (s *MobStore) tickShopLocked(inst *MobInstance) {
	for id, cur := range inst.ShopStock {
		target := 0
		var cfgItem *behavior.ShopItem
		if cfgItem = inst.Shop.FindItem(id); cfgItem != nil {
			target = cfgItem.Stock
		}
		if cur == target {
			if cur == 0 && cfgItem == nil {
				delete(inst.ShopStock, id)
				delete(inst.ShopRestock, id)
			}
			continue
		}
		c := inst.ShopRestock[id]
		if c <= 0 {
			c = inst.Shop.RestockInterval(cfgItem)
		}
		c--
		if c <= 0 {
			if cur < target {
				cur++
			} else {
				cur--
			}
			inst.ShopStock[id] = cur
			c = inst.Shop.RestockInterval(cfgItem)
		}
		inst.ShopRestock[id] = c
		if cur == 0 && cfgItem == nil {
			delete(inst.ShopStock, id)
			delete(inst.ShopRestock, id)
		}
	}
}

// ShopStockSnapshot returns a copy of the instance's current stock map.
func (s *MobStore) ShopStockSnapshot(instanceID string) map[string]int {
	s.mu.Lock()
	defer s.mu.Unlock()
	inst := s.instances[instanceID]
	if inst == nil || inst.ShopStock == nil {
		return nil
	}
	out := make(map[string]int, len(inst.ShopStock))
	for k, v := range inst.ShopStock {
		out[k] = v
	}
	return out
}

// ShopStockOf returns the current stock the instance holds of an item.
func (s *MobStore) ShopStockOf(instanceID, itemID string) int {
	s.mu.Lock()
	defer s.mu.Unlock()
	inst := s.instances[instanceID]
	if inst == nil || inst.ShopStock == nil {
		return 0
	}
	return inst.ShopStock[itemID]
}

// ShopTake removes up to qty of an item from the shop's stock, returning the
// amount actually taken (capped by availability). Used when a player buys.
func (s *MobStore) ShopTake(instanceID, itemID string, qty int) int {
	s.mu.Lock()
	defer s.mu.Unlock()
	inst := s.instances[instanceID]
	if inst == nil || inst.ShopStock == nil {
		return 0
	}
	have := inst.ShopStock[itemID]
	if qty > have {
		qty = have
	}
	if qty <= 0 {
		return 0
	}
	inst.ShopStock[itemID] = have - qty
	return qty
}

// ShopAdd adds qty of an item to the shop's stock. Used when a player sells.
func (s *MobStore) ShopAdd(instanceID, itemID string, qty int) {
	if qty <= 0 {
		return
	}
	s.mu.Lock()
	defer s.mu.Unlock()
	inst := s.instances[instanceID]
	if inst == nil || inst.Shop == nil {
		return
	}
	if inst.ShopStock == nil {
		inst.ShopStock = make(map[string]int)
	}
	if inst.ShopRestock == nil {
		inst.ShopRestock = make(map[string]int)
	}
	if _, ok := inst.ShopStock[itemID]; !ok {
		inst.ShopRestock[itemID] = inst.Shop.RestockInterval(inst.Shop.FindItem(itemID))
	}
	inst.ShopStock[itemID] += qty
}

func (s *MobStore) RollIdleDescription(inst *MobInstance) {
	def, err := s.LoadDef(inst.DefID)
	if err != nil {
		return
	}
	inst.IdleDescription = pickIdleDescription(def.IdleDescriptions)
	inst.WanderTickCounter = 0
}

func (s *MobStore) SpawnTransient(def *MobDef, cfg *behavior.SpawnMobConfig, roomID int, owner string) *MobInstance {
	s.mu.Lock()
	defer s.mu.Unlock()

	instID := fmt.Sprintf("trigger_%s_%d_%d", cfg.ID, roomID, len(s.instances))
	inst := NewMobInstance(def, instID, roomID, nil, 0)
	inst.Owner = owner
	inst.OwnerOnly = cfg.OwnerOnly
	inst.SpawnedByTrigger = true
	inst.DespawnOnLeave = cfg.DespawnOnLeave
	inst.DespawnRooms = cfg.DespawnRooms
	inst.DespawnTicks = cfg.DespawnTicks
	inst.IdleDescription = pickIdleDescription(def.IdleDescriptions)
	s.instances[instID] = inst
	return inst
}

func (s *MobStore) RemoveInstance(instanceID string) {
	s.mu.Lock()
	defer s.mu.Unlock()
	delete(s.instances, instanceID)
}

func (s *MobStore) RemoveMobsInRoom(roomID int) {
	s.mu.Lock()
	defer s.mu.Unlock()
	for id, inst := range s.instances {
		if inst.RoomID == roomID {
			delete(s.instances, id)
		}
	}
}

func (s *MobStore) SeedMobs(roomID int, entries []RoomMob) {
	type defWrapper struct {
		def *MobDef
		err error
		rm  RoomMob
	}
	defs := make([]defWrapper, len(entries))
	for i, rm := range entries {
		d, err := s.LoadDef(rm.ID)
		defs[i] = defWrapper{d, err, rm}
	}

	s.mu.Lock()
	defer s.mu.Unlock()
	for i, dw := range defs {
		if dw.err != nil {
			continue
		}
		defID := dw.rm.ID
		instID := fmt.Sprintf("%s_%d_%d", defID, roomID, i)
		if _, exists := s.instances[instID]; exists {
			continue
		}
		inst := NewMobInstance(dw.def, instID, roomID, dw.rm.WanderRooms, dw.rm.WanderInterval)
		inst.IdleDescription = pickIdleDescription(dw.def.IdleDescriptions)
		s.instances[instID] = inst
	}
}