class_name HeatState
extends RefCounted

## Authoritative short-term attention state for the Authority domain.  Heat is
## deliberately separate from suspicion and discovered evidence.

const MAX_HEAT := 100
const MAX_SUSPICION := 100

var heat := 0
var suspicion := 0
var evidence_points := 0
var inspection_level := 0
var next_inspection_window := 360
var active_case_ids: Array[StringName] = []
var fines_due := 0
var known_illegal_facility_ids: Array[StringName] = []
var last_decay_day := 0
var revision := 0
var heat_history: Array[Dictionary] = []
var _next_history_sequence := 1


func configure(options: Dictionary = {}) -> HeatState:
	heat = clampi(int(_value(options, &"heat", 0)), 0, MAX_HEAT)
	suspicion = clampi(int(_value(options, &"suspicion", 0)), 0, MAX_SUSPICION)
	evidence_points = maxi(int(_value(options, &"evidence_points", 0)), 0)
	inspection_level = clampi(int(_value(options, &"inspection_level", 0)), 0, 5)
	next_inspection_window = maxi(int(_value(options, &"next_inspection_window", 360)), 0)
	active_case_ids = _sorted_unique_names(_value(options, &"active_case_ids", []))
	fines_due = maxi(int(_value(options, &"fines_due", 0)), 0)
	known_illegal_facility_ids = _sorted_unique_names(
		_value(options, &"known_illegal_facility_ids", [])
	)
	last_decay_day = maxi(int(_value(options, &"last_decay_day", 0)), 0)
	revision = maxi(int(_value(options, &"revision", 0)), 0)
	heat_history.clear()
	var saved_history: Variant = _value(options, &"heat_history", [])
	if saved_history is Array:
		for raw_entry: Variant in saved_history:
			if raw_entry is Dictionary:
				heat_history.append((raw_entry as Dictionary).duplicate(true))
	_next_history_sequence = maxi(
		int(_value(options, &"next_history_sequence", heat_history.size() + 1)),
		1
	)
	return self


func apply_heat_delta(
	delta: int,
	source_id: StringName,
	absolute_minute: int,
	reason: StringName = &""
) -> Dictionary:
	if absolute_minute < 0:
		return {&"ok": false, &"reason": &"INVALID_MINUTE"}
	var old_value := heat
	heat = clampi(heat + delta, 0, MAX_HEAT)
	var applied := heat - old_value
	if applied != 0:
		revision += 1
		heat_history.append({
			&"sequence": _next_history_sequence,
			&"absolute_minute": absolute_minute,
			&"source_id": String(source_id),
			&"reason": String(reason),
			&"requested_delta": delta,
			&"applied_delta": applied,
			&"old_value": old_value,
			&"new_value": heat,
		})
		_next_history_sequence += 1
	return {
		&"ok": true,
		&"old_value": old_value,
		&"new_value": heat,
		&"requested_delta": delta,
		&"applied_delta": applied,
	}


## Applies a given day at most once.  An active-case floor can stop decay, but
## decay never raises an already-lower Heat value up to that floor.
func apply_daily_decay(day_index: int, amount: int, active_case_floor: int) -> Dictionary:
	if day_index <= last_decay_day:
		return {&"ok": true, &"is_replay": true, &"old_value": heat, &"new_value": heat}
	if amount < 0:
		return {&"ok": false, &"reason": &"INVALID_DECAY"}
	var old_value := heat
	var floor_value := 0
	if not active_case_ids.is_empty():
		floor_value = clampi(active_case_floor, 0, MAX_HEAT)
	if floor_value > 0 and heat > floor_value:
		heat = maxi(heat - amount, floor_value)
	else:
		heat = maxi(heat - amount, 0) if floor_value == 0 else heat
	last_decay_day = day_index
	revision += 1
	if heat != old_value:
		heat_history.append({
			&"sequence": _next_history_sequence,
			&"absolute_minute": day_index * 1_440,
			&"source_id": "daily_decay",
			&"reason": "DAILY_DECAY",
			&"requested_delta": -amount,
			&"applied_delta": heat - old_value,
			&"old_value": old_value,
			&"new_value": heat,
		})
		_next_history_sequence += 1
	return {
		&"ok": true,
		&"is_replay": false,
		&"old_value": old_value,
		&"new_value": heat,
		&"floor": floor_value,
	}


func set_suspicion(value: int) -> void:
	var normalized := clampi(value, 0, MAX_SUSPICION)
	if suspicion == normalized:
		return
	suspicion = normalized
	revision += 1


func set_evidence_points(value: int) -> void:
	var normalized := maxi(value, 0)
	if evidence_points == normalized:
		return
	evidence_points = normalized
	revision += 1


func add_active_case(case_id: StringName) -> bool:
	if case_id.is_empty() or active_case_ids.has(case_id):
		return false
	active_case_ids.append(case_id)
	active_case_ids.sort_custom(_name_less)
	revision += 1
	return true


func remove_active_case(case_id: StringName) -> bool:
	var index := active_case_ids.find(case_id)
	if index < 0:
		return false
	active_case_ids.remove_at(index)
	revision += 1
	return true


func add_known_illegal_facility(facility_id: StringName) -> bool:
	if facility_id.is_empty() or known_illegal_facility_ids.has(facility_id):
		return false
	known_illegal_facility_ids.append(facility_id)
	known_illegal_facility_ids.sort_custom(_name_less)
	revision += 1
	return true


func add_fine_due(amount: int) -> bool:
	if amount <= 0:
		return false
	fines_due += amount
	revision += 1
	return true


func is_valid() -> bool:
	if heat < 0 or heat > MAX_HEAT or suspicion < 0 or suspicion > MAX_SUSPICION:
		return false
	if evidence_points < 0 or inspection_level < 0 or inspection_level > 5:
		return false
	if next_inspection_window < 0 or fines_due < 0 or last_decay_day < 0 or revision < 0:
		return false
	if active_case_ids != _sorted_unique_names(active_case_ids):
		return false
	if known_illegal_facility_ids != _sorted_unique_names(known_illegal_facility_ids):
		return false
	var last_sequence := 0
	for entry: Dictionary in heat_history:
		var sequence := int(entry.get(&"sequence", 0))
		if sequence <= last_sequence:
			return false
		last_sequence = sequence
	return _next_history_sequence > last_sequence


func create_snapshot() -> Dictionary:
	return {
		&"heat": heat,
		&"suspicion": suspicion,
		&"evidence_points": evidence_points,
		&"inspection_level": inspection_level,
		&"next_inspection_window": next_inspection_window,
		&"active_case_ids": _names_to_strings(active_case_ids),
		&"fines_due": fines_due,
		&"known_illegal_facility_ids": _names_to_strings(known_illegal_facility_ids),
		&"last_decay_day": last_decay_day,
		&"revision": revision,
		&"heat_history": heat_history.duplicate(true),
		&"next_history_sequence": _next_history_sequence,
	}


static func from_snapshot(snapshot: Dictionary) -> HeatState:
	if not _snapshot_is_valid(snapshot):
		return null
	var state := HeatState.new().configure(snapshot)
	return state if state.is_valid() else null


static func _snapshot_is_valid(snapshot: Dictionary) -> bool:
	for key: StringName in [
		&"heat", &"suspicion", &"evidence_points", &"inspection_level",
		&"next_inspection_window", &"active_case_ids", &"fines_due",
		&"known_illegal_facility_ids", &"last_decay_day", &"revision",
		&"heat_history", &"next_history_sequence",
	]:
		if not _has_key(snapshot, key):
			return false
	if not _value(snapshot, &"active_case_ids", null) is Array \
		or not _value(snapshot, &"known_illegal_facility_ids", null) is Array \
		or not _value(snapshot, &"heat_history", null) is Array:
		return false
	if not _name_array_is_canonical(_value(snapshot, &"active_case_ids", [])) \
		or not _name_array_is_canonical(_value(snapshot, &"known_illegal_facility_ids", [])):
		return false
	var raw_heat := int(_value(snapshot, &"heat", -1))
	var raw_suspicion := int(_value(snapshot, &"suspicion", -1))
	var raw_level := int(_value(snapshot, &"inspection_level", -1))
	if raw_heat < 0 or raw_heat > MAX_HEAT or raw_suspicion < 0 or raw_suspicion > MAX_SUSPICION:
		return false
	if int(_value(snapshot, &"evidence_points", -1)) < 0 or raw_level < 0 or raw_level > 5:
		return false
	if int(_value(snapshot, &"next_inspection_window", -1)) < 0 \
		or int(_value(snapshot, &"fines_due", -1)) < 0 \
		or int(_value(snapshot, &"last_decay_day", -1)) < 0 \
		or int(_value(snapshot, &"revision", -1)) < 0:
		return false
	var last_sequence := 0
	for raw_entry: Variant in _value(snapshot, &"heat_history", []):
		if not raw_entry is Dictionary:
			return false
		for entry_key: StringName in [
			&"sequence", &"absolute_minute", &"source_id", &"reason",
			&"requested_delta", &"applied_delta", &"old_value", &"new_value",
		]:
			if not _has_key(raw_entry, entry_key):
				return false
		var sequence := int(_value(raw_entry, &"sequence", 0))
		var old_value := int(_value(raw_entry, &"old_value", -1))
		var new_value := int(_value(raw_entry, &"new_value", -1))
		var applied_delta := int(_value(raw_entry, &"applied_delta", 999))
		if sequence <= last_sequence or int(_value(raw_entry, &"absolute_minute", -1)) < 0:
			return false
		if old_value < 0 or old_value > MAX_HEAT or new_value < 0 or new_value > MAX_HEAT:
			return false
		if new_value - old_value != applied_delta:
			return false
		last_sequence = sequence
	return int(_value(snapshot, &"next_history_sequence", 0)) > last_sequence


static func _sorted_unique_names(values: Variant) -> Array[StringName]:
	var result: Array[StringName] = []
	if values is Array:
		for raw_value: Variant in values:
			var value := StringName(raw_value)
			if not value.is_empty() and not result.has(value):
				result.append(value)
	result.sort_custom(_name_less)
	return result


static func _names_to_strings(values: Array[StringName]) -> Array[String]:
	var result: Array[String] = []
	for value: StringName in values:
		result.append(String(value))
	return result


static func _name_less(a: StringName, b: StringName) -> bool:
	return String(a) < String(b)


static func _value(source: Dictionary, key: StringName, fallback: Variant) -> Variant:
	if source.has(key):
		return source[key]
	return source.get(String(key), fallback)


static func _has_key(source: Dictionary, key: StringName) -> bool:
	return source.has(key) or source.has(String(key))


static func _name_array_is_canonical(value: Variant) -> bool:
	if not value is Array:
		return false
	var previous := ""
	for index: int in range(value.size()):
		var current := String(value[index])
		if current.is_empty() or (index > 0 and current <= previous):
			return false
		previous = current
	return true