extends Node

# Autoload singleton - the one thing that survives change_scene_to_file()
# scene swaps between space (Main.tscn) and a planet's surface
# (PlanetSurface.tscn). Everything else in either scene gets torn down
# and rebuilt from scratch on each swap, so anything that needs to
# survive the trip has to live here instead.

var has_return_position: bool = false
var surviving_ship_count: int = 5
var return_world_position: Vector2 = Vector2.ZERO
var return_camera_zoom: float = 1.0

var planet_name: String = ""
var planet_type: String = ""

# Explored-chunk history for the world map's fog-of-war reveal. Lives
# here (not on ExplorationTracker, which gets destroyed and recreated on
# every scene swap) so exploration progress isn't lost every time the
# player lands on and leaves a planet.
var explored_chunks: Dictionary = {}

# --- Resources -------------------------------------------------------------

# Rocks mined from asteroid-planet surfaces, spent on buildings and ships.
# Starts stocked for play-testing so buildings can be tried without mining
# first - drop this back to 0 for a real playthrough.
var rocks: int = 500

const MOTHERSHIP_COST: int = 20
const SHIP_CRAFTER_COST: int = 12
const SHIP_COST: int = 6

# --- Buildings -------------------------------------------------------------

# Player-placed structures, as [{"type": String, "position": Vector2}].
# Buildings exist only in space (Main.tscn) but are stored here so they
# survive the scene swap to a planet's surface and back.
const BUILDING_MOTHERSHIP: String = "mothership"
const BUILDING_SHIP_CRAFTER: String = "ship_crafter"
const BUILDING_COMMAND_CENTER: String = "command_center"
# Extractors are not placed in space like the others - they are built ON a
# planet's surface and tracked separately (see `extractors`).
const BUILDING_EXTRACTOR: String = "extractor"

const COMMAND_CENTER_COST: int = 15
const EXTRACTOR_COST: int = 25

var buildings: Array = []


func add_building(type: String, at_position: Vector2) -> void:
	buildings.append({"type": type, "position": at_position})


func has_mothership() -> bool:
	return get_mothership_position() != null


func remove_buildings_of_type(type: String) -> int:
	var kept: Array = []
	var removed: int = 0
	for b in buildings:
		if b.type == type:
			removed += 1
		else:
			kept.append(b)
	buildings = kept
	return removed


func get_mothership_position() -> Variant:
	# Where a wiped-out fleet gets rebuilt. Returns null when no mothership
	# has been built yet, so the caller can fall back to the world origin.
	for b in buildings:
		if b.type == BUILDING_MOTHERSHIP:
			return b.position
	return null


# --- Fleet formation -------------------------------------------------------

# Where each vessel sits relative to the fleet centre, editable at a command
# centre. Lives here (not as a const on Fleet) so a layout the player has
# arranged survives the trip to a planet's surface and back, and so a
# rebuilt fleet keeps their arrangement.
const DEFAULT_FORMATION: Array = [
	Vector2(0, -48), Vector2(-30, -8), Vector2(30, -8), Vector2(-60, 32), Vector2(60, 32),
]

var formation: Array = DEFAULT_FORMATION.duplicate()


func reset_formation() -> void:
	formation = DEFAULT_FORMATION.duplicate()


func rotate_formation(radians: float) -> void:
	# Pivots every slot about the fleet centre, keeping the shape intact
	# and only changing which way it faces.
	for i in range(formation.size()):
		formation[i] = formation[i].rotated(radians)


# --- Extractors and their haulers -----------------------------------------

# An extractor sits on a planet and runs a single automated hauler back and
# forth to the mothership, delivering ore on each arrival.
#
# The round trip is SIMULATED HERE, in the autoload, rather than by any
# node: it advances whether the player is in space, on a planet's surface,
# or far enough away that nothing about the route is loaded. `progress` is
# a fraction of one full there-and-back cycle, so a hauler's drawn position
# is derived from the same number that decides when ore is delivered - the
# visual arrival and the payout cannot drift apart, because they are the
# same event.
#
# Entries are {"position": Vector2 (the planet's position in SPACE),
# "planet_name": String, "progress": float}.
const HAULER_SPEED: float = 260.0
const HAULER_YIELD: int = 4
# Progress value at which the hauler reaches the mothership: exactly half
# way through the cycle, the outbound leg being the first half.
const HAULER_ARRIVAL: float = 0.5

var extractors: Array = []


func has_extractor_at(planet_name: String) -> bool:
	for e in extractors:
		if e.planet_name == planet_name:
			return true
	return false


func add_extractor(planet_name: String, at_position: Vector2) -> void:
	extractors.append({
		"position": at_position,
		"planet_name": planet_name,
		"progress": 0.0,
	})


func get_hauler_route_time(extractor: Dictionary) -> float:
	# Full cycle: out to the mothership and back again.
	var mothership: Variant = get_mothership_position()
	if mothership == null:
		return 0.0
	var distance: float = extractor.position.distance_to(mothership)
	if distance < 1.0:
		return 0.0
	return (distance * 2.0) / HAULER_SPEED


func get_hauler_position(extractor: Dictionary) -> Variant:
	# Where the hauler is right now, derived purely from `progress`. Returns
	# null when there is no route (no mothership built yet).
	var mothership: Variant = get_mothership_position()
	if mothership == null:
		return null
	var t: float = extractor.progress
	if t <= HAULER_ARRIVAL:
		return extractor.position.lerp(mothership, t / HAULER_ARRIVAL)
	return mothership.lerp(extractor.position, (t - HAULER_ARRIVAL) / (1.0 - HAULER_ARRIVAL))


func _process(delta: float) -> void:
	# Runs in the autoload, so extraction keeps earning while the player is
	# on a planet's surface or nowhere near the route.
	if extractors.is_empty():
		return
	for e in extractors:
		var cycle: float = get_hauler_route_time(e)
		if cycle <= 0.0:
			continue  # nothing to deliver to yet
		var before: float = e.progress
		e.progress += delta / cycle
		# Ore lands the instant the hauler reaches the mothership - the same
		# instant get_hauler_position() puts it there.
		if before < HAULER_ARRIVAL and e.progress >= HAULER_ARRIVAL:
			rocks += HAULER_YIELD
		while e.progress >= 1.0:
			e.progress -= 1.0


func can_afford(cost: int) -> bool:
	return rocks >= cost


func spend(cost: int) -> bool:
	if not can_afford(cost):
		return false
	rocks -= cost
	return true