## D-030 Layer 3: End-to-end connection test
## Spawns the Rust simulation server, connects via LocalBridge,
## sends a MoveNorth input, and verifies the snapshot response.
## Requires: server binary built (cargo build in server/)
class_name TestE2EConnection
extends GdUnitTestSuite

const TEST_PORT: int = 19876
const CONNECT_TIMEOUT: float = 3.0
const RESPONSE_TIMEOUT: float = 5.0

var _server_pid: int = -1
var _bridge: LocalBridge = null


func _server_binary_path() -> String:
	# Resolve path relative to the Godot project root
	var project_dir := ProjectSettings.globalize_path("res://")
	return project_dir.path_join("../server/target/debug/settled-reach-server")


func after_test() -> void:
	# Clean up regardless of test outcome
	if _bridge != null:
		_bridge.disconnect_from_server()
		_bridge = null
	if _server_pid > 0 and OS.is_process_running(_server_pid):
		OS.kill(_server_pid)
		_server_pid = -1


# -- E2E: full round-trip through server binary --------------------------------

func test_send_input_receive_snapshot() -> void:
	var server_path := _server_binary_path()
	if not FileAccess.file_exists(server_path):
		push_warning("E2E test skipped: server binary not found at %s" % server_path)
		return

	# Spawn server
	var addr := "127.0.0.1:%d" % TEST_PORT
	_server_pid = OS.create_process(server_path, [addr])
	assert_that(_server_pid).is_greater(0)

	# Connect with retries (server needs time to bind port)
	_bridge = LocalBridge.new()
	var connected := false
	var elapsed := 0.0
	while elapsed < CONNECT_TIMEOUT:
		if _bridge.get_status() == StreamPeerTCP.STATUS_NONE:
			_bridge.connect_to_server("127.0.0.1", TEST_PORT)
		_bridge.poll()
		if _bridge.get_status() == StreamPeerTCP.STATUS_CONNECTED:
			connected = true
			break
		if _bridge.get_status() == StreamPeerTCP.STATUS_ERROR:
			# Reset and retry
			_bridge.disconnect_from_server()
			_bridge.reset()
		await get_tree().create_timer(0.1).timeout
		elapsed += 0.1

	assert_bool(connected).is_true()

	# Send batch input: MoveNorth at tick 0 (matching game_loop.rs test)
	var inputs: Array = [{"tick": 0, "action_name": "MoveNorth"}]
	var encoded := Protocol.encode_player_inputs(inputs)
	assert_that(encoded.size()).is_greater(0)
	var send_err := _bridge.send_message(encoded)
	assert_that(send_err).is_equal(OK)

	# Poll for snapshot response
	var snapshot_bytes := PackedByteArray()
	elapsed = 0.0
	while elapsed < RESPONSE_TIMEOUT:
		_bridge.poll()
		snapshot_bytes = _bridge.poll_message()
		if snapshot_bytes.size() > 0:
			break
		await get_tree().create_timer(0.05).timeout
		elapsed += 0.05

	assert_that(snapshot_bytes.size()).is_greater(0)

	# Decode snapshot
	var snapshot: Variant = Protocol.decode_snapshot(snapshot_bytes)
	assert_that(snapshot).is_not_null()

	# Server starts at tick 0, snapshot reflects state after processing
	assert_that(snapshot.tick).is_equal(0)
	assert_that(snapshot.entities.size()).is_equal(1)

	# Player started at (16, 16, 0), moved north (y-1) to (16, 15, 0)
	# Render coords: tile center offset → (16.5, 15.5, 0)
	var player: Dictionary = snapshot.entities[0]
	assert_float(player.x).is_equal_approx(16.5, 0.001)
	assert_float(player.y).is_equal_approx(15.5, 0.001)
	assert_that(player.z).is_equal(0)
	assert_that(player.kind.variant).is_equal("Player")