extends Node2D

# #105 (#97g): keeps the vessels stationed at outposts in step with what
# GameState says is stationed there.
#
# Garrison vessels are NOT in Fleet.ships. They are spawned here, under a
# node of their own, so the formation, the fleet's speed fader and
# max_fleet_size() all continue to be about the fleet - a garrison that
# counted against the fleet's slots would mean stationing a vessel cost the
# player a place in their own wedge, which is the opposite of what an outpost
# is for.
#
# The record is the truth, as everywhere else: this node is rebuilt from
# GameState.garrison_crew() when the space scene loads, so a garrison
# survives a trip to a planet surface.

var ship_scene: PackedScene = preload("res://vessels/Ship.tscn")
const GARRISON_COMPONENT = preload("res://vessels/VesselGarrisonComponent.gd")

# {outpost_id: [ship, ...]}
var stationed: Dictionary = {}


func _ready() -> void:
	add_to_group("garrison_field")
	sync()


func _process(_delta: float) -> void:
	sync()


func ships_at(outpost_id: int) -> Array:
	var out: Array = []
	for ship in stationed.get(outpost_id, []):
		if is_instance_valid(ship) and not ship.is_queued_for_deletion():
			out.append(ship)
	return out


func all_ships() -> Array:
	var out: Array = []
	for outpost_id in stationed:
		out.append_array(ships_at(outpost_id))
	return out


func sync() -> void:
	# Retire whole outposts that no longer exist, then reconcile the rest.
	for outpost_id in stationed.keys():
		if GameState.find_building(outpost_id).is_empty():
			for ship in ships_at(outpost_id):
				ship.queue_free()
			stationed.erase(outpost_id)

	for outpost_id in GameState.outpost_ids():
		var record: Dictionary = GameState.find_building(outpost_id)
		var crew: Array = GameState.garrison_crew(outpost_id)
		var here: Array = ships_at(outpost_id)
		stationed[outpost_id] = here
		if here.size() == crew.size():
			continue
		if here.size() > crew.size():
			# The record shrank under us - a vessel was released or lost
			# while this node was not looking.
			for i in range(crew.size(), here.size()):
				here[i].queue_free()
			stationed[outpost_id] = here.slice(0, crew.size())
			continue
		for i in range(here.size(), crew.size()):
			here.append(_spawn(outpost_id, String(crew[i]), record.position, i))


func _spawn(outpost_id: int, vessel_type: String, at: Vector2, index: int) -> Node2D:
	var ship: Area2D = ship_scene.instantiate()
	# Before add_child, so Ship._ready() builds the right vessel - the same
	# order Fleet.add_ship() relies on.
	ship.vessel_type = vessel_type
	var spread: float = TAU * float(index) / 4.0
	ship.position = at + Vector2(cos(spread), sin(spread)) * 170.0
	add_child(ship)
	# #165: marked as belonging to an outpost, so the ram rule leaves it
	# alone. A stationed vessel orbits and re-docks with its own structure
	# constantly; without this the collision damage meant for a charging
	# fleet vessel destroyed the garrison the moment it launched.
	ship.add_to_group("garrison_ships")
	var component: Node = GARRISON_COMPONENT.new()
	component.outpost_id = outpost_id
	component.station = at
	ship.add_child(component)
	component.setup()
	# A garrison vessel that dies frees its berth, so #104 sends another.
	ship.destroyed.connect(_on_garrison_lost.bind(outpost_id, vessel_type))
	return ship


func _on_garrison_lost(outpost_id: int, vessel_type: String) -> void:
	var crew: Array = GameState.garrison_crew(outpost_id)
	var index: int = crew.find(vessel_type)
	if index >= 0:
		crew.remove_at(index)