class_name StaffCommuteService
extends RefCounted

## Commutes derive from the saved work plan, Shift and current actor position.
## Runtime owns movement credit, Path projection, elevator rides and events.
## This adapter deliberately owns no additional snapshot payload.
const ROUTE_BLOCKED := &"COMMUTE_ROUTE_BLOCKED"
const WORKPLACE_MISSING := &"COMMUTE_WORKPLACE_MISSING"
const WAITING_SHIFT := &"WAITING_FOR_SHIFT"
const MOVING_TO_WORK := &"MOVING_TO_WORK"

var _runtime: Variant


func configure(runtime: Variant) -> StaffCommuteService:
	_runtime = runtime
	_runtime.staff_service.configure_attendance_driver(Callable(self, "can_attend_shift"))
	return self


## A porter checks in once at the warehouse, then remains dispatchable at the
## end of a delivery. Fixed-post workers return before resuming desk service.
func can_attend_shift(staff: StaffRuntime, shift: ShiftInstance, _minute: int) -> bool:
	if _runtime == null or staff == null or shift == null:
		return false
	if _in_transit(staff.staff_id) and (staff.current_task_id.is_empty() or shift.actual_started_at < 0):
		return false
	if shift.actual_started_at >= 0 and (staff.role_id == &"porter" or not staff.current_task_id.is_empty()):
		return true
	var facility: FacilityInstance = _runtime.facility_service.get_instance(shift.assigned_facility_id)
	return is_at_facility(staff, facility)


## Physical attendance is separate from dispatch availability. A porter away
## with goods does not provide staff capacity to an empty warehouse.
func is_present(staff: StaffRuntime, facility: FacilityInstance) -> bool:
	if _runtime == null or staff == null or facility == null \
			or staff.assigned_facility_id != facility.instance_id \
			or staff.state != StaffRuntime.State.AVAILABLE or not staff.can_take_shift():
		return false
	if _in_transit(staff.staff_id):
		return false
	if not _runtime.staff_service.requires_attendance(staff.staff_id):
		return true
	return is_at_facility(staff, facility)


func tick(absolute_minute: int) -> Dictionary:
	if _runtime == null:
		return {&"ok": false, &"reason": &"NOT_CONFIGURED"}
	var moved: Array[StringName] = []
	var waiting: Array[StringName] = []
	for staff: StaffRuntime in _runtime.staff_service.get_staff_members():
		if not _runtime.staff_service.requires_attendance(staff.staff_id) \
				or staff.state != StaffRuntime.State.COMMUTING \
				or not staff.can_take_shift() or not staff.current_task_id.is_empty():
			continue
		var shift: ShiftInstance = _runtime.staff_service.get_shift(staff.shift_id)
		if shift == null or (not shift.contains_minute(absolute_minute) and not shift.is_commute_window(absolute_minute)):
			continue
		if _in_transit(staff.staff_id):
			_wait(staff, absolute_minute, &"ELEVATOR_WAIT")
			waiting.append(staff.staff_id)
			continue
		var facility: FacilityInstance = _runtime.facility_service.get_instance(shift.assigned_facility_id)
		if facility == null:
			_wait(staff, absolute_minute, WORKPLACE_MISSING)
			waiting.append(staff.staff_id)
			continue
		if is_at_facility(staff, facility):
			staff.absence_reason = &""
			_wait(staff, absolute_minute, WAITING_SHIFT if shift.is_commute_window(absolute_minute) else &"COMMUTE_ARRIVED")
			waiting.append(staff.staff_id)
			continue
		var access := find_facility_access_path(staff.current_cell, facility)
		if not bool(access.get(&"reachable", false)):
			_wait(staff, absolute_minute, ROUTE_BLOCKED)
			waiting.append(staff.staff_id)
			continue
		staff.absence_reason = &""
		var result: Dictionary = _runtime.advance_staff_commute(staff.staff_id, access[&"cell"], absolute_minute)
		if bool(result.get(&"moved", false)):
			moved.append(staff.staff_id)
		else:
			waiting.append(staff.staff_id)
	return {&"ok": true, &"moved_staff_ids": moved, &"waiting_staff_ids": waiting}


func get_report() -> Dictionary:
	var rows: Array[Dictionary] = []
	if _runtime == null:
		return {&"staff": rows}
	for staff: StaffRuntime in _runtime.staff_service.get_staff_members():
		if not _runtime.staff_service.requires_attendance(staff.staff_id):
			continue
		var shift: ShiftInstance = _runtime.staff_service.get_shift(staff.shift_id)
		var facility: FacilityInstance = _runtime.facility_service.get_instance(staff.assigned_facility_id)
		var reason := staff.absence_reason
		var target := staff.current_cell
		if _in_transit(staff.staff_id):
			reason = &"ELEVATOR_WAIT"
		if facility != null:
			var access := find_facility_access_path(staff.current_cell, facility)
			target = access.get(&"cell", facility.origin)
			if staff.state == StaffRuntime.State.COMMUTING and reason.is_empty():
				reason = WAITING_SHIFT if is_at_facility(staff, facility) else MOVING_TO_WORK
		rows.append({
			&"staff_id": staff.staff_id, &"state": StaffRuntime.State.keys()[staff.state],
			&"reason": reason, &"facility_id": staff.assigned_facility_id,
			&"current_cell": staff.current_cell, &"target_cell": target,
			&"present": is_present(staff, facility),
			&"late_minutes": shift.late_minutes if shift != null else 0,
		})
	return {&"staff": rows}


func find_facility_access_path(start: Vector3i, facility: FacilityInstance) -> Dictionary:
	if _runtime == null or facility == null:
		return {&"reachable": false}
	var candidates: Dictionary = {}
	var occupied := facility.occupied_cells.duplicate()
	if occupied.is_empty():
		occupied.append(facility.origin)
	for cell: Vector3i in occupied:
		for delta: Vector3i in [Vector3i.ZERO, Vector3i.LEFT, Vector3i.RIGHT]:
			if _runtime.path_service.has_cell(cell + delta):
				candidates[cell + delta] = true
	var ordered: Array = candidates.keys()
	ordered.sort_custom(func(a: Vector3i, b: Vector3i) -> bool:
		if a.z != b.z: return a.z < b.z
		if a.y != b.y: return a.y < b.y
		return a.x < b.x)
	var best: Array[Vector3i] = []
	var best_cost := 9223372036854775807
	for cell: Vector3i in ordered:
		var path: Array[Vector3i] = _runtime.path_service.find_path(start, cell,
			[WorldService.LAYER_FRONT, WorldService.LAYER_BACK], [&"staff"])
		var cost: int = _runtime.path_service.calculate_path_cost(path, [&"staff"]) if not path.is_empty() else -1
		if cost >= 0 and (best.is_empty() or cost < best_cost):
			best = path
			best_cost = cost
	return {&"reachable": not best.is_empty(), &"path": best,
		&"cell": best[-1] if not best.is_empty() else facility.origin,
		&"steps": maxi(0, best.size() - 1)}


static func is_at_facility(staff: StaffRuntime, facility: FacilityInstance) -> bool:
	if staff == null or facility == null:
		return false
	var occupied := facility.occupied_cells.duplicate()
	if occupied.is_empty():
		occupied.append(facility.origin)
	for cell: Vector3i in occupied:
		if cell.z == staff.current_cell.z and cell.y == staff.current_cell.y \
				and absi(cell.x - staff.current_cell.x) <= 1:
			return true
	return false


func _wait(staff: StaffRuntime, minute: int, reason: StringName) -> void:
	if reason in [ROUTE_BLOCKED, WORKPLACE_MISSING]:
		staff.absence_reason = reason
	_runtime.advance_staff_commute(staff.staff_id, staff.current_cell, minute, reason)


func _in_transit(staff_id: StringName) -> bool:
	return _runtime != null and _runtime.has_method("is_staff_in_transit") \
		and bool(_runtime.is_staff_in_transit(staff_id))