class_name NPCController
extends RefCounted

const Rules := preload("res://src/core/rules.gd")
const NpcProfile := preload("res://src/core/npc_profile.gd")
const FSM := preload("res://src/core/fsm.gd")
## Simulation-side NPC (PLAN.md: NPC Behavior Types). Owns intent, an FSM, and
## reaction logic. The presentation layer adds a visual avatar and navigation.
## RefCounted on purpose: headless tests and CI do not need a scene tree.

signal interacted(level: int)

var npc_id: String = ""
var profile: NpcProfile = null
var intent: String = "roam" # enter | photo | sit | roam | deliver | film | trespass
var fsm: FSM = null
var rng := RandomNumberGenerator.new()

var highest_escalation_received: int = Rules.Level.OBSERVATION
var leave_requested := false
var reaction: int = Rules.Reaction.COMPLY
var reaction_set := false

## Returning-trespasser state: an NPC directed away may circle back later.
var will_return := false
var return_delay_s := 0.0
var return_elapsed_s := 0.0

## Perception pass: NPCs notice the guard's proximity and react (PLAN.md:
## Level 0 Observation). Proximity bands in meters.
const AWARE_RADIUS := 6.0
const NEAR_RADIUS := 2.0
var guard_noticed := false

## Whether this NPC has passed the handheld wand screening (The Joke Shop).
var screened := false
## Whether the guard has declared they recognize this person (a player decision
## recorded as evidence, PLAN.md: Authorized Access).
var player_recognized := false
## Last reply the NPC gave when asked for their reason for entry.
var last_reason_reply := ""
## Event-level access payload (`has_id`, `has_ticket`, statuses). Empty means
## venue/type defaults from AccessLoadout.
var access_override: Dictionary = {}

func _init() -> void:
	fsm = FSM.new(self)

## initial_state: APPROACH, AT_ENTRANCE, LOITERING, QUEUE, ARGUING
func setup(p_id: String, p_profile: NpcProfile, p_intent: String = "roam", seed_value: int = 0, initial_state: String = "APPROACH") -> void:
	npc_id = p_id
	profile = p_profile
	intent = p_intent
	rng.seed = seed_value if seed_value != 0 else hash(npc_id)
	_build_fsm(initial_state)

func _build_fsm(initial_state: String) -> void:
	fsm.add_transition("APPROACH", "AT_ENTRANCE")
	fsm.add_transition("AT_ENTRANCE", "ARGUING")
	fsm.add_transition("AT_ENTRANCE", "LEAVING")
	fsm.add_transition("AT_ENTRANCE", "THREATENING")
	fsm.add_transition("AT_ENTRANCE", "FORCING_ENTRY")
	fsm.add_transition("APPROACH", "LEAVING")
	fsm.add_transition("ARGUING", "LEAVING")
	fsm.add_transition("ARGUING", "THREATENING")
	fsm.add_transition("ARGUING", "FORCING_ENTRY")
	fsm.add_transition("LEAVING", "LOITERING_DISTANT") # potential return later
	fsm.add_transition("LOITERING_DISTANT", "APPROACH")
	fsm.add_transition("THREATENING", "FORCING_ENTRY")
	fsm.start(initial_state)

func roll_reaction(level: int) -> int:
	## Weighted pick from profile's reaction table for `level`.
	highest_escalation_received = maxi(highest_escalation_received, level)
	var weights: Dictionary = profile.pickup_reactions_per_level(level).duplicate()
	var roll_value := rng.randf()
	var total := 0.0
	for key in weights.keys():
		total += weights[key]
	if total <= 0.0:
		return Rules.Reaction.ARGUE
	var cursor := 0.0
	for key in weights.keys():
		cursor += float(weights[key])
		if roll_value < cursor / total:
			return key
	return Rules.Reaction.LEAVE

func apply_player_action(level: int) -> Dictionary:
	## Returns reaction to the player's action and updates FSM when needed.
	var performed_reaction := roll_reaction(level)
	reaction = performed_reaction
	reaction_set = true
	_update_state_for_reaction(performed_reaction)
	return {
		"npc_id": npc_id,
		"level_used": level,
		"reaction": performed_reaction,
		"reaction_name": Rules.Reaction.find_key(performed_reaction),
		"new_state": fsm.current_state,
	}

func _update_state_for_reaction(r: int) -> void:
	match r:
		Rules.Reaction.COMPLY, Rules.Reaction.LEAVE:
			leave_requested = true
			fsm.transition_to("LEAVING")
			_maybe_schedule_return()
		Rules.Reaction.ARGUE, Rules.Reaction.RECORD:
			fsm.transition_to("ARGUING")
		Rules.Reaction.THREATEN:
			fsm.transition_to("THREATENING")
		Rules.Reaction.FORCE_ENTRY:
			fsm.transition_to("FORCING_ENTRY")
		Rules.Reaction.RETURN_LATER:
			fsm.transition_to("LOITERING_DISTANT")
			will_return = true
			return_delay_s = _roll_return_delay()
		Rules.Reaction.CALL_SOMEONE:
			# The NPC stops to call someone for help (PLAN.md: Level 2 reactions).
			fsm.transition_to("ARGUING")
		_:
			pass

## Decide whether a directed-away NPC will circle back, and after how long.
## Deterministic via the NPC's seeded RNG. Only trespassers and people in
## crisis have a nonzero default return probability (set on their profiles).
func _maybe_schedule_return() -> void:
	if profile == null or profile.return_probability <= 0.0:
		return
	if rng.randf() < profile.return_probability:
		will_return = true
		return_delay_s = _roll_return_delay()
		# Move to the loitering state so the return transition is reachable.
		fsm.transition_to("LOITERING_DISTANT")

func _roll_return_delay() -> float:
	# 20-60 seconds before circling back.
	return 20.0 + rng.randf() * 40.0

## Advance the return timer. When it elapses, the NPC transitions from
## LOITERING_DISTANT back to APPROACH. Returns true when a return just fired.
func tick_return(delta: float) -> bool:
	if not will_return:
		return false
	return_elapsed_s += delta
	if return_elapsed_s >= return_delay_s:
		will_return = false
		return_elapsed_s = 0.0
		leave_requested = false
		fsm.transition_to("APPROACH")
		return true
	return false

func decide_leave() -> bool:
	return leave_requested

## Level 3 ask: request the person's reason for entry (PLAN.md). Pure and
## headless-testable; returns the line this NPC answers with ("" if silent).
func request_reason() -> String:
	var lines: Array[String] = profile.dialogue_lines if profile else []
	if lines.is_empty():
		last_reason_reply = ""
		return ""
	last_reason_reply = lines[rng.randi_range(0, lines.size() - 1)]
	return last_reason_reply

## Perception pass: given the guard's distance (meters), return a perception
## result describing how the NPC reacts to the guard's presence. Pure and
## headless-testable; the presentation layer feeds it the real distance.
## bonus_range widens awareness when the guard uses a flashlight at night.
## Returns { noticed: bool, band: String, reaction: int }.
func perceive_guard(distance: float, bonus_range: float = 0.0) -> Dictionary:
	var band := "unaware"
	if distance <= NEAR_RADIUS:
		band = "near"
	elif distance <= AWARE_RADIUS + bonus_range:
		band = "aware"
	var noticed := band != "unaware"
	if noticed and not guard_noticed:
		guard_noticed = true
	var reaction := Rules.Reaction.IGNORE
	if band == "near":
		# Close proximity makes calm NPCs uneasy and hot-headed ones hostile.
		if profile != null and profile.temperament >= 0.6:
			reaction = Rules.Reaction.ARGUE
		else:
			reaction = Rules.Reaction.COMPLY
	elif band == "aware":
		reaction = Rules.Reaction.IGNORE
	return {"noticed": noticed, "band": band, "reaction": reaction}

func to_dict() -> Dictionary:
	return {
		"id": npc_id,
		"name": profile.display_name if profile else "",
		"type": profile.npc_type if profile else -1,
		"intent": intent,
		"state": fsm.current_state,
		"highest_escalation": highest_escalation_received,
		"reaction": reaction,
	}