extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_fleet_growth.gd
# A new game opens with a SINGLE vessel and three slots, and the fleet grows
# from there through the doctrine branch of the skill tree.
#
# BASE_FLEET_SIZE used to be both "how many slots exist" and "how many ships
# you start with", which forced a new game to open with a full fleet - there
# was nowhere to put a vessel until a doctrine was researched, so the first
# ship crafter had nothing to do. The two are now separate constants, and
# this test pins the distinction.
#
# Covers:
#   A. a new game starts with one vessel and three slots
#   B. the fleet really spawns one ship, and can be grown into its slots
#   C. every doctrine raises the ceiling by its own stated bonus
#   D. the doctrine branch is a chain, in increasing cost order
#   E. the tree cannot promise a slot the formation has no room for - the
#      invariant that made extra doctrines silently worthless

const DOCTRINE_CHAIN: Array = ["wing", "squadron", "armada", "battlegroup", "grand_fleet"]

var game_state: Node
var scene: Node
var fleet: Node
var stage: int = 0
var elapsed: float = 0.0


func _initialize() -> void:
	game_state = root.get_node("GameState")
	game_state.reset_new_game()


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			# --- A. the opening position ---------------------------------
			if GameState.STARTING_SHIP_COUNT != 1:
				return _fail("a new game starts with %d vessels, expected 1" % GameState.STARTING_SHIP_COUNT)
			if GameState.BASE_FLEET_SIZE != 3:
				return _fail("the fleet has %d slots by default, expected 3" % GameState.BASE_FLEET_SIZE)
			if game_state.surviving_ship_count != GameState.STARTING_SHIP_COUNT:
				return _fail("reset_new_game left %d surviving ships" % game_state.surviving_ship_count)
			if game_state.max_fleet_size() != GameState.BASE_FLEET_SIZE:
				return _fail("an unresearched fleet caps at %d, expected %d" \
					% [game_state.max_fleet_size(), GameState.BASE_FLEET_SIZE])
			print("new game: %d vessel, %d slots" % [GameState.STARTING_SHIP_COUNT, GameState.BASE_FLEET_SIZE])

			# --- C + D. the doctrine chain -------------------------------
			var expected: int = GameState.BASE_FLEET_SIZE
			var previous_cost: int = -1
			var previous_points: int = -1
			var previous_id: String = "coordination"
			for id in DOCTRINE_CHAIN:
				var node: Dictionary = game_state.skill_node(id)
				if node.is_empty():
					return _fail("no skill node '%s' - the doctrine chain is broken" % id)
				var bonus: int = int(node.get("fleet_bonus", 0))
				if bonus <= 0:
					return _fail("'%s' is in the doctrine chain but grants no fleet_bonus" % id)
				if String(node.get("requires", "")) != previous_id:
					return _fail("'%s' requires '%s', expected it to follow '%s' - the branch is not one chain" \
						% [id, node.get("requires", ""), previous_id])
				# Later tiers must not be cheaper than earlier ones, or the
				# order the player meets them stops matching what they cost.
				var cost: int = int(node.get("cost", 0))
				var points: int = int(node.get("research_points", 0))
				if cost <= previous_cost:
					return _fail("'%s' costs %d ore, not more than the tier before it (%d)" % [id, cost, previous_cost])
				if points < previous_points:
					return _fail("'%s' costs %d research points, fewer than the tier before it (%d)" \
						% [id, points, previous_points])
				previous_cost = cost
				previous_points = points
				previous_id = id

				game_state.unlocked.append(id)
				expected += bonus
				if game_state.max_fleet_size() != expected:
					return _fail("after researching '%s' the fleet caps at %d, expected %d" \
						% [id, game_state.max_fleet_size(), expected])
				print("  %-12s +%d -> %2d slots (%d ore, %d research)" % [id, bonus, expected, cost, points])

			# --- E. no doctrine may be swallowed by the formation ---------
			# max_fleet_size() clamps to the formation's length, so a doctrine
			# added without extending DEFAULT_FORMATION would cost the player
			# real resources and grant nothing.
			if expected > GameState.DEFAULT_FORMATION.size():
				return _fail("the doctrines promise %d slots but DEFAULT_FORMATION only defines %d - the last ones buy nothing" \
					% [expected, GameState.DEFAULT_FORMATION.size()])
			print("full doctrine chain reaches %d slots, with %d formation positions defined" \
				% [expected, GameState.DEFAULT_FORMATION.size()])

			# --- B. what actually flies ----------------------------------
			game_state.reset_new_game()
			scene = load("res://Main.tscn").instantiate()
			root.add_child(scene)
			fleet = scene.get_node("Fleet")
			elapsed = 0.0
			stage = 1
			return false
		1:
			if elapsed < 0.3:
				return false
			scene.get_node("AsteroidField").set_process(false)
			scene.get_node("EnemySpawner").set_process(false)
			if fleet.ships.size() != GameState.STARTING_SHIP_COUNT:
				return _fail("a fresh scene spawned %d vessels, expected %d" \
					% [fleet.ships.size(), GameState.STARTING_SHIP_COUNT])
			print("a fresh game really flies %d vessel" % fleet.ships.size())

			# The two empty slots are what the opening is for, so they have to
			# be fillable without researching anything.
			for i in range(GameState.BASE_FLEET_SIZE - GameState.STARTING_SHIP_COUNT):
				if not fleet.add_ship(GameState.VESSEL_INTERCEPTOR):
					return _fail("could not crew slot %d of the starting fleet" % (i + 2))
			if fleet.ships.size() != GameState.BASE_FLEET_SIZE:
				return _fail("the fleet holds %d after filling its slots, expected %d" \
					% [fleet.ships.size(), GameState.BASE_FLEET_SIZE])
			# And the cap has to actually bite past that.
			if fleet.add_ship(GameState.VESSEL_INTERCEPTOR):
				return _fail("a %dth vessel joined an unresearched fleet of %d slots" \
					% [fleet.ships.size(), GameState.BASE_FLEET_SIZE])
			print("the starting slots fill to %d and refuse a %dth" \
				% [GameState.BASE_FLEET_SIZE, GameState.BASE_FLEET_SIZE + 1])

			print("TEST_FLEET_GROWTH: PASS")
			quit(0)
			return true
	return false


func _fail(message: String) -> bool:
	print("TEST_FLEET_GROWTH: FAIL (%s)" % message)
	quit(1)
	return true