package ai

import (
	"fmt"
	"time"
)

// BaseBrain implements the basic AI brain functionality
type BaseBrain struct {
	npc        NPC
	logger     Logger
	brainType  int8
	state      *BrainState
	hateList   *HateList
	encounter  *EncounterList
	statistics *BrainStatistics
}

// NewBaseBrain creates a new base brain
func NewBaseBrain(npc NPC, logger Logger) *BaseBrain {
	return &BaseBrain{
		npc:        npc,
		logger:     logger,
		brainType:  BrainTypeDefault,
		state:      NewBrainState(),
		hateList:   NewHateList(),
		encounter:  NewEncounterList(),
		statistics: NewBrainStatistics(),
	}
}

// Think implements the main AI logic
func (bb *BaseBrain) Think() error {
	if bb.npc == nil {
		return fmt.Errorf("brain has no body")
	}

	// Update last think time
	currentTime := time.Now().UnixMilli()
	bb.state.SetLastThink(currentTime)
	bb.statistics.ThinkCycles++

	// Skip thinking if mezzzed, stunned, feared, or dazed
	if bb.npc.IsMezzedOrStunned() || bb.npc.IsFeared() || bb.npc.IsDazed() {
		return nil
	}

	// Check if we need to runback
	if bb.npc.IsRunningBack() || bb.npc.ShouldCallRunback() {
		return bb.handleRunback()
	}

	// Get most hated target
	mostHatedID := bb.hateList.GetMostHated()
	var target Entity

	if mostHatedID > 0 {
		target = bb.getEntityByID(mostHatedID)
		if target == nil {
			// Target no longer exists, remove from hate list
			bb.hateList.RemoveHate(mostHatedID)
			mostHatedID = bb.hateList.GetMostHated()
			if mostHatedID > 0 {
				target = bb.getEntityByID(mostHatedID)
			}
		}
	}

	// Handle combat state
	if target != nil && bb.npc.GetInCombat() {
		return bb.handleCombat(target)
	} else if bb.npc.GetInCombat() {
		// No target but still in combat - exit combat
		bb.npc.InCombat(false)
		bb.npc.SetTarget(nil)
		bb.state.SetState(AIStateIdle)
		
		if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelBasic {
			bb.logger.LogDebug("NPC %s exiting combat - no targets", bb.npc.GetName())
		}
		return nil
	}

	// Handle idle state
	return bb.handleIdle()
}

// handleCombat handles combat AI logic
func (bb *BaseBrain) handleCombat(target Entity) error {
	if target == nil {
		return nil
	}

	// Set target if not already set
	if bb.npc.GetTarget() != target {
		bb.npc.SetTarget(target)
		bb.npc.FaceTarget(target, false)
	}

	distance := bb.npc.GetDistance(target)

	// Check if target is too far away
	maxRange := bb.getMaxCombatRange()
	if distance > maxRange {
		// Try to move closer or runback if too far
		if distance > MaxChaseDistance {
			if bb.npc.ShouldCallRunback() {
				bb.npc.Runback(bb.npc.GetRunbackDistance())
				return nil
			}
		} else {
			bb.MoveCloser(target)
		}
		return nil
	}

	bb.state.SetState(AIStateCombat)

	// Try to cast spells first if we have line of sight
	if bb.npc.CheckLoS(target) && !bb.npc.IsCasting() {
		if bb.HasRecovered() && bb.ProcessSpell(target, distance) {
			return nil
		}
	}

	// Try melee combat
	bb.ProcessMelee(target, distance)
	
	return nil
}

// handleIdle handles idle AI logic
func (bb *BaseBrain) handleIdle() error {
	bb.state.SetState(AIStateIdle)
	
	// Set slower think tick when idle
	bb.state.SetThinkTick(SlowThinkTick)
	
	return nil
}

// handleRunback handles runback logic
func (bb *BaseBrain) handleRunback() error {
	// Clear hate and encounter when running back
	bb.hateList.Clear()
	bb.encounter.Clear()
	
	// Set target to nil
	bb.npc.SetTarget(nil)
	bb.npc.InCombat(false)
	
	bb.state.SetState(AIStateRunback)
	
	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
		bb.logger.LogDebug("NPC %s running back", bb.npc.GetName())
	}
	
	return nil
}

// ProcessSpell processes spell casting for the brain
func (bb *BaseBrain) ProcessSpell(target Entity, distance float32) bool {
	if bb.npc == nil || target == nil {
		return false
	}

	// Check if we can cast
	if bb.npc.IsCasting() || !bb.HasRecovered() {
		return false
	}

	// Get next spell to cast
	spell := bb.npc.GetNextSpell(target, distance)
	if spell == nil {
		return false
	}

	// Check range
	if distance < spell.GetMinRange() || distance > spell.GetRange() {
		return false
	}

	// Cast the spell
	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
		bb.logger.LogDebug("NPC %s casting spell %s on %s", 
			bb.npc.GetName(), spell.GetName(), target.GetName())
	}

	// Set spell recovery time
	recoveryTime := time.Now().UnixMilli() + int64(spell.GetRecoveryTime()*RecoveryTimeMultiple) + int64(SpellRecoveryBuffer)
	bb.state.SetSpellRecovery(recoveryTime)
	bb.state.SetState(AIStateCasting)
	bb.statistics.SpellsCast++

	return true
}

// ProcessMelee processes melee combat for the brain
func (bb *BaseBrain) ProcessMelee(target Entity, distance float32) {
	if bb.npc == nil || target == nil {
		return
	}

	// Check if we can attack
	if !bb.npc.AttackAllowed(target) {
		return
	}

	// Try primary weapon
	if bb.npc.PrimaryWeaponReady() {
		if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
			bb.logger.LogDebug("NPC %s melee attacking %s with primary weapon", 
				bb.npc.GetName(), target.GetName())
		}
		
		bb.npc.MeleeAttack(target, distance, true)
		bb.npc.SetPrimaryLastAttackTime(time.Now().UnixMilli())
		bb.statistics.MeleeAttacks++
		return
	}

	// Try secondary weapon
	if bb.npc.SecondaryWeaponReady() {
		if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
			bb.logger.LogDebug("NPC %s melee attacking %s with secondary weapon", 
				bb.npc.GetName(), target.GetName())
		}
		
		bb.npc.MeleeAttack(target, distance, false)
		bb.npc.SetSecondaryLastAttackTime(time.Now().UnixMilli())
		bb.statistics.MeleeAttacks++
	}
}

// MoveCloser moves the NPC closer to the target
func (bb *BaseBrain) MoveCloser(target Entity) {
	if bb.npc == nil || target == nil {
		return
	}

	// Face the target
	bb.npc.FaceTarget(target, false)

	// Calculate running location towards target
	bb.npc.CalculateRunningLocation(true)
	bb.state.SetState(AIStateMoving)

	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
		bb.logger.LogDebug("NPC %s moving closer to %s", bb.npc.GetName(), target.GetName())
	}
}

// Brain interface implementation

// GetBrainType returns the brain type
func (bb *BaseBrain) GetBrainType() int8 {
	return bb.brainType
}

// IsActive returns whether the brain is active
func (bb *BaseBrain) IsActive() bool {
	return bb.state.IsActive()
}

// SetActive sets the brain's active state
func (bb *BaseBrain) SetActive(active bool) {
	bb.state.SetActive(active)
}

// GetLastThink returns the timestamp of the last think cycle
func (bb *BaseBrain) GetLastThink() int64 {
	return bb.state.GetLastThink()
}

// SetLastThink sets the timestamp of the last think cycle
func (bb *BaseBrain) SetLastThink(timestamp int64) {
	bb.state.SetLastThink(timestamp)
}

// GetThinkTick returns the think tick interval
func (bb *BaseBrain) GetThinkTick() int32 {
	return bb.state.GetThinkTick()
}

// SetThinkTick sets the think tick interval
func (bb *BaseBrain) SetThinkTick(tick int32) {
	bb.state.SetThinkTick(tick)
}

// Hate management

// AddHate adds hate for an entity
func (bb *BaseBrain) AddHate(entityID, hate int32) {
	bb.hateList.AddHate(entityID, hate)
	bb.statistics.HateEvents++
	
	// Enter combat if not already
	if !bb.npc.GetInCombat() {
		bb.npc.InCombat(true)
		bb.state.SetThinkTick(FastThinkTick)
	}
	
	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
		bb.logger.LogDebug("NPC %s gained %d hate for entity %d", bb.npc.GetName(), hate, entityID)
	}
}

// GetHate returns hate for an entity
func (bb *BaseBrain) GetHate(entityID int32) int32 {
	return bb.hateList.GetHate(entityID)
}

// GetMostHated returns the most hated entity ID
func (bb *BaseBrain) GetMostHated() int32 {
	return bb.hateList.GetMostHated()
}

// ClearHate clears all hate
func (bb *BaseBrain) ClearHate() {
	bb.hateList.Clear()
	
	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelBasic {
		bb.logger.LogDebug("NPC %s cleared all hate", bb.npc.GetName())
	}
}

// ClearHateForEntity clears hate for a specific entity
func (bb *BaseBrain) ClearHateForEntity(entityID int32) {
	bb.hateList.RemoveHate(entityID)
	
	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
		bb.logger.LogDebug("NPC %s cleared hate for entity %d", bb.npc.GetName(), entityID)
	}
}

// Encounter management

// AddToEncounter adds an entity to the encounter
func (bb *BaseBrain) AddToEncounter(entityID, characterID int32, isPlayer, isBot bool) bool {
	success := bb.encounter.AddEntity(entityID, characterID, isPlayer, isBot)
	if success {
		bb.statistics.EncounterEvents++
		
		if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
			bb.logger.LogDebug("NPC %s added entity %d to encounter", bb.npc.GetName(), entityID)
		}
	}
	return success
}

// RemoveFromEncounter removes an entity from the encounter
func (bb *BaseBrain) RemoveFromEncounter(entityID int32) {
	bb.encounter.RemoveEntity(entityID)
	
	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelDetailed {
		bb.logger.LogDebug("NPC %s removed entity %d from encounter", bb.npc.GetName(), entityID)
	}
}

// IsInEncounter checks if an entity is in the encounter
func (bb *BaseBrain) IsInEncounter(entityID int32) bool {
	return bb.encounter.IsEntityInEncounter(entityID)
}

// ClearEncounter clears the encounter
func (bb *BaseBrain) ClearEncounter() {
	bb.encounter.Clear()
	
	if bb.logger != nil && bb.state.GetDebugLevel() >= DebugLevelBasic {
		bb.logger.LogDebug("NPC %s cleared encounter", bb.npc.GetName())
	}
}

// GetEncounterSize returns the encounter size
func (bb *BaseBrain) GetEncounterSize() int {
	return bb.encounter.Size()
}

// State management

// GetState returns the current AI state
func (bb *BaseBrain) GetState() int32 {
	return bb.state.GetState()
}

// SetState sets the current AI state
func (bb *BaseBrain) SetState(state int32) {
	bb.state.SetState(state)
}

// HasRecovered checks if the brain has recovered from spell casting
func (bb *BaseBrain) HasRecovered() bool {
	return bb.state.HasRecovered()
}

// SetSpellRecovery sets the spell recovery time
func (bb *BaseBrain) SetSpellRecovery(timestamp int64) {
	bb.state.SetSpellRecovery(timestamp)
}

// GetStatistics returns brain statistics
func (bb *BaseBrain) GetStatistics() *BrainStatistics {
	return bb.statistics
}

// GetDebugLevel returns the debug level
func (bb *BaseBrain) GetDebugLevel() int8 {
	return bb.state.GetDebugLevel()
}

// SetDebugLevel sets the debug level
func (bb *BaseBrain) SetDebugLevel(level int8) {
	bb.state.SetDebugLevel(level)
}

// Helper methods

// getEntityByID gets an entity by ID (placeholder - would be implemented by zone)
func (bb *BaseBrain) getEntityByID(entityID int32) Entity {
	// This would typically call into the zone system to get the entity
	// For now, return nil - concrete implementations should override this
	return nil
}

// getMaxCombatRange returns the maximum combat range
func (bb *BaseBrain) getMaxCombatRange() float32 {
	return MaxCombatRange
}

// Pet Brain Implementations

// CombatPetBrain extends the base brain for combat pets
type CombatPetBrain struct {
	*BaseBrain
}

// NewCombatPetBrain creates a new combat pet brain
func NewCombatPetBrain(npc NPC, logger Logger) *CombatPetBrain {
	brain := &CombatPetBrain{
		BaseBrain: NewBaseBrain(npc, logger),
	}
	brain.brainType = BrainTypeCombatPet
	return brain
}

// Think implements pet-specific AI logic
func (cpb *CombatPetBrain) Think() error {
	// Call parent Think() for default combat behavior
	if err := cpb.BaseBrain.Think(); err != nil {
		return err
	}

	// Additional pet-specific logic
	if cpb.npc.GetInCombat() || !cpb.npc.IsPet() || cpb.npc.IsMezzedOrStunned() {
		return nil
	}

	if cpb.logger != nil && cpb.state.GetDebugLevel() >= DebugLevelDetailed {
		cpb.logger.LogDebug("Combat pet AI for %s", cpb.npc.GetName())
	}

	// Check if owner has stay command set
	owner := cpb.npc.GetOwner()
	if owner != nil && owner.IsPlayer() {
		// TODO: Check player's pet movement setting
		// if player.GetInfoStruct().GetPetMovement() == PetMovementStay {
		//     return nil
		// }
	}

	// Follow owner
	if owner != nil {
		cpb.npc.SetTarget(owner)
		distance := cpb.npc.GetDistance(owner)

		maxRange := cpb.getMaxCombatRange()
		if distance > maxRange {
			cpb.MoveCloser(owner)
		}
	}

	return nil
}

// NonCombatPetBrain handles non-combat pets (cosmetic pets)
type NonCombatPetBrain struct {
	*BaseBrain
}

// NewNonCombatPetBrain creates a new non-combat pet brain
func NewNonCombatPetBrain(npc NPC, logger Logger) *NonCombatPetBrain {
	brain := &NonCombatPetBrain{
		BaseBrain: NewBaseBrain(npc, logger),
	}
	brain.brainType = BrainTypeNonCombatPet
	return brain
}

// Think implements non-combat pet AI (just following)
func (ncpb *NonCombatPetBrain) Think() error {
	// Non-combat pets don't do combat AI
	if !ncpb.npc.IsPet() || ncpb.npc.IsMezzedOrStunned() {
		return nil
	}

	if ncpb.logger != nil && ncpb.state.GetDebugLevel() >= DebugLevelDetailed {
		ncpb.logger.LogDebug("Non-combat pet AI for %s", ncpb.npc.GetName())
	}

	// Just follow owner
	owner := ncpb.npc.GetOwner()
	if owner != nil {
		ncpb.npc.SetTarget(owner)
		distance := ncpb.npc.GetDistance(owner)

		maxRange := ncpb.getMaxCombatRange()
		if distance > maxRange {
			ncpb.MoveCloser(owner)
		}
	}

	return nil
}

// BlankBrain provides a minimal AI that does nothing
type BlankBrain struct {
	*BaseBrain
}

// NewBlankBrain creates a new blank brain
func NewBlankBrain(npc NPC, logger Logger) *BlankBrain {
	brain := &BlankBrain{
		BaseBrain: NewBaseBrain(npc, logger),
	}
	brain.brainType = BrainTypeBlank
	brain.SetThinkTick(BlankBrainTick) // Very slow tick
	return brain
}

// Think does nothing for blank brains
func (bb *BlankBrain) Think() error {
	// Blank brain does nothing
	return nil
}

// DumbFirePetBrain handles dumbfire pets (temporary combat pets)
type DumbFirePetBrain struct {
	*BaseBrain
	expireTime int64
}

// NewDumbFirePetBrain creates a new dumbfire pet brain
func NewDumbFirePetBrain(npc NPC, target Entity, expireTimeMS int32, logger Logger) *DumbFirePetBrain {
	brain := &DumbFirePetBrain{
		BaseBrain:  NewBaseBrain(npc, logger),
		expireTime: time.Now().UnixMilli() + int64(expireTimeMS),
	}
	brain.brainType = BrainTypeDumbFire

	// Add maximum hate for the target
	if target != nil {
		brain.AddHate(target.GetID(), MaxHateValue)
	}

	return brain
}

// AddHate only allows hate for the initial target
func (dfpb *DumbFirePetBrain) AddHate(entityID int32, hate int32) {
	// Only add hate if we don't already have a target
	if dfpb.GetMostHated() == 0 {
		dfpb.BaseBrain.AddHate(entityID, hate)
	}
}

// Think implements dumbfire pet AI
func (dfpb *DumbFirePetBrain) Think() error {
	// Check if expired
	if time.Now().UnixMilli() > dfpb.expireTime {
		if dfpb.npc != nil && dfpb.npc.GetHP() > 0 {
			if dfpb.logger != nil {
				dfpb.logger.LogDebug("Dumbfire pet %s expired", dfpb.npc.GetName())
			}
			dfpb.npc.KillSpawn(dfpb.npc)
		}
		return nil
	}

	// Get target
	targetID := dfpb.GetMostHated()
	if targetID == 0 {
		// No target, kill self
		if dfpb.npc != nil && dfpb.npc.GetHP() > 0 {
			if dfpb.logger != nil {
				dfpb.logger.LogDebug("Dumbfire pet %s has no target", dfpb.npc.GetName())
			}
			dfpb.npc.KillSpawn(dfpb.npc)
		}
		return nil
	}

	target := dfpb.getEntityByID(targetID)
	if target == nil {
		// Target no longer exists, kill self
		if dfpb.npc != nil && dfpb.npc.GetHP() > 0 {
			dfpb.npc.KillSpawn(dfpb.npc)
		}
		return nil
	}

	// Skip if mezzed or stunned
	if dfpb.npc.IsMezzedOrStunned() {
		return nil
	}

	// Set target if not already set
	if dfpb.npc.GetTarget() != target {
		dfpb.npc.SetTarget(target)
		dfpb.npc.FaceTarget(target, false)
	}

	// Enter combat if not already
	if !dfpb.npc.GetInCombat() {
		dfpb.npc.CalculateRunningLocation(true)
		dfpb.npc.InCombat(true)
	}

	distance := dfpb.npc.GetDistance(target)

	// Try to cast spells if we have line of sight
	if dfpb.npc.CheckLoS(target) && !dfpb.npc.IsCasting() &&
		(!dfpb.HasRecovered() || !dfpb.ProcessSpell(target, distance)) {

		if dfpb.logger != nil && dfpb.state.GetDebugLevel() >= DebugLevelDetailed {
			dfpb.logger.LogDebug("Dumbfire pet %s attempting melee on %s",
				dfpb.npc.GetName(), target.GetName())
		}

		dfpb.npc.FaceTarget(target, false)
		dfpb.ProcessMelee(target, distance)
	}

	return nil
}

// GetExpireTime returns when this dumbfire pet will expire
func (dfpb *DumbFirePetBrain) GetExpireTime() int64 {
	return dfpb.expireTime
}

// SetExpireTime sets when this dumbfire pet will expire
func (dfpb *DumbFirePetBrain) SetExpireTime(expireTime int64) {
	dfpb.expireTime = expireTime
}

// IsExpired checks if the dumbfire pet has expired
func (dfpb *DumbFirePetBrain) IsExpired() bool {
	return time.Now().UnixMilli() > dfpb.expireTime
}

// ExtendExpireTime extends the expire time by the given duration
func (dfpb *DumbFirePetBrain) ExtendExpireTime(durationMS int32) {
	dfpb.expireTime += int64(durationMS)
}