extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_waves_attack_buildings.gd
# Forgejo #101 (#97c): "Waves tries to attack built buildings."
#
# Before this every enemy component asked one question - which player SHIP
# is nearest - so a structure was scenery they flew straight through. A
# Building is also a plain Node2D, so there was nothing to collide with even
# if one had tried.
#
# Covers:
#   A. an enemy with no ship anywhere near it goes for a building
#   B. a ship in its face still wins: the fleet must be able to defend a
#      structure by interposing itself, and an enemy that ignored the
#      vessels shooting it to reach a depot slightly closer reads as broken
#   C. a chaser that reaches a building damages it, and spends itself doing
#      so - the same bargain it makes ramming a vessel
#   D. an enemy parked on a structure keeps hurting it, rather than landing
#      one hit on entry and then sitting there harmlessly
#   E. an enemy projectile damages a structure
#   F. enough of it levels the building, and the node goes with the record

var game_state: Node
var main: Node
var fleet: Node
var field: Node
var chaser: Node2D
var sniper: Node2D
var target_building: Node2D
# Held separately: the node is freed when the building comes down, and the
# last stage still has to ask GameState about the record it left behind.
var target_id: int = 0
var stage: int = 0
var elapsed: float = 0.0
var hp_watermark: int = 0
var destroyed_fired: bool = false


func _initialize() -> void:
	# GameState is an autoload: a bare GameState.<instance member> does not
	# compile in a SceneTree script, so the node is fetched by name instead.
	game_state = root.get_node("GameState")
	game_state.buildings.clear()
	game_state.extractors.clear()
	game_state.transporters.clear()
	game_state.reset_progression()
	game_state.reset_waves()
	game_state.rocks = 5000
	main = load("res://world/Main.tscn").instantiate()
	root.add_child(main)
	current_scene = main
	fleet = main.get_node("Fleet")
	field = main.get_node("BuildingField")


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


func _spawn_enemy(enemy_id: String, at: Vector2) -> Node2D:
	var enemy: Node2D = load("res://enemies/Enemy.tscn").instantiate()
	enemy.enemy_id = enemy_id
	enemy.position = at
	main.add_child(enemy)
	return enemy


func _building_of(type: String) -> Node2D:
	for b in field.spawned:
		if is_instance_valid(b) and not b.is_queued_for_deletion() and b.building_type == type:
			return b
	return null


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			if elapsed < 0.3:
				return false
			main.get_node("EnemySpawner").set_process(false)
			main.get_node("AsteroidField").set_process(false)
			for hazard in get_nodes_in_group("asteroids") + get_nodes_in_group("enemies"):
				if is_instance_valid(hazard):
					hazard.queue_free()
			# The fleet is parked far away for A, C and D. It comes back for B.
			fleet.spawn_ships(1, Vector2(-9000.0, 0.0),
				PackedStringArray([GameState.VESSEL_INTERCEPTOR]))
			fleet.ships[0].move_target = fleet.ships[0].position
			field.place(GameState.BUILDING_SHIP_CRAFTER, Vector2(0.0, 0.0))
			elapsed = 0.0
			stage = 1
			return false
		1:
			if elapsed < 0.2:
				return false
			target_building = _building_of(GameState.BUILDING_SHIP_CRAFTER)
			if target_building == null:
				return _fail("no crafter was placed")
			target_id = int(target_building.building_id)

			# --- A. with no ship near, a building is the target ----------
			var targets: Script = load("res://enemies/EnemyTargets.gd")
			var from: Vector2 = Vector2(600.0, 0.0)
			var picked: Node2D = targets.nearest_target(main, from)
			if picked != target_building:
				return _fail("an enemy 600px from a crafter and 9600px from the fleet picked %s" \
					% ("nothing" if picked == null else str(picked.name)))
			print("with the fleet 9600px away, the crafter is the target")

			# --- B. a ship in its face still wins ------------------------
			# Deliberately FURTHER from the enemy than the building is: the
			# rule is not "nearest thing", it is "the fleet you are fighting".
			var guard: Node2D = fleet.ships[0]
			guard.position = from + Vector2(0.0, 500.0)
			guard.move_target = guard.position
			var defended: Node2D = targets.nearest_target(main, from)
			if defended != guard:
				return _fail("a vessel 500px away lost priority to a building 600px away - the fleet cannot screen anything")
			guard.position = Vector2(-9000.0, 0.0)
			guard.move_target = guard.position
			print("a vessel inside %.0fpx outranks a nearer building" % targets.SHIP_PRIORITY_RANGE)

			# --- C. a chaser spends itself on the structure --------------
			hp_watermark = game_state.building_hp(target_id)
			chaser = _spawn_enemy("chaser", target_building.global_position)
			chaser.destroyed.connect(func(): destroyed_fired = true)
			elapsed = 0.0
			stage = 2
			return false
		2:
			if elapsed < 1.2:
				return false
			var now: int = game_state.building_hp(target_id)
			if now >= hp_watermark:
				return _fail("a chaser sat on the crafter and it took no damage")
			if is_instance_valid(chaser) and not chaser.is_queued_for_deletion():
				return _fail("the chaser survived ramming a structure")
			if not destroyed_fired:
				return _fail("the chaser vanished without firing `destroyed`")
			print("a chaser took the crafter from %d to %d hp and died doing it" % [hp_watermark, now])

			# --- D. a besieger keeps working ----------------------------
			sniper = _spawn_enemy("sniper", target_building.global_position)
			sniper.speed = 0.0
			hp_watermark = game_state.building_hp(target_id)
			elapsed = 0.0
			stage = 3
			return false
		3:
			if elapsed < 2.5:
				return false
			var now: int = game_state.building_hp(target_id)
			var strikes: int = hp_watermark - now
			if not is_instance_valid(sniper):
				return _fail("the sniper died on contact - it is not marked dies_on_contact")
			if strikes <= sniper.definition.contact_damage:
				return _fail("%.1fs of siege did %d damage - that is one hit on entry, not a siege" \
					% [elapsed, strikes])
			print("%.1fs parked on the crafter cost it %d hp" % [elapsed, strikes])
			sniper.queue_free()

			# --- E. a projectile hits a structure ------------------------
			hp_watermark = game_state.building_hp(target_id)
			var projectile: Area2D = load("res://enemies/EnemyProjectile.tscn").instantiate()
			projectile.position = target_building.global_position + Vector2(0.0, -140.0)
			projectile.damage = 3
			root.add_child(projectile)
			projectile.launch(Vector2(0.0, 1.0))
			elapsed = 0.0
			stage = 4
			return false
		4:
			if elapsed < 1.2:
				return false
			var now: int = game_state.building_hp(target_id)
			if now >= hp_watermark:
				return _fail("an enemy bolt passed straight through the crafter")
			print("an enemy bolt took %d hp off the crafter" % (hp_watermark - now))

			# --- F. enough of it levels the place ------------------------
			game_state.damage_building(target_id,
				game_state.building_hp(target_id) - 1)
			var last: Node2D = _spawn_enemy("chaser", target_building.global_position)
			last.speed = 0.0
			elapsed = 0.0
			stage = 5
			return false
		5:
			if elapsed < 1.2:
				return false
			if not game_state.find_building(target_id).is_empty():
				return _fail("the crafter survived on its last hit point")
			if _building_of(GameState.BUILDING_SHIP_CRAFTER) != null:
				return _fail("the crafter node outlived the record")
			print("the crafter came down, and its node went with it")

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