## Tests for camera anchor behavior — the camera must show the player's
## position from the very first rendered frame, with no visible drift from (0,0).
##
## These tests verify the full pipeline: SimBridge → GameState → Camera2D.
## The player starts at (10,10) in test mode, so the expected camera position
## is (10,10) * TILE_SIZE = (320, 320).
class_name TestCameraAnchor
extends GdUnitTestSuite

const EXPECTED_PLAYER_POS := Vector2(10, 10)
const EXPECTED_CAMERA_POS := Vector2(320, 320)  # 10 * 32, 10 * 32

var _instance: Node = null


func before_test() -> void:
	SimBridge.reset_test_state()
	GameState.current_tick = 0
	GameState.player_position = Vector2.ZERO
	GameState.visible_entities = []
	GameState.visible_tiles = []
	GameState.visible_positions = {}
	GameState.current_monologue = null
	GameState.current_dialogue = null


func after_test() -> void:
	if _instance and is_instance_valid(_instance):
		_instance.queue_free()
		_instance = null


# --- Pipeline precondition tests ---

func test_simbridge_connected_in_test_mode() -> void:
	SimBridge.state = SimBridge.ConnectionState.DISCONNECTED
	SimBridge.connect_to_sim()
	assert_that(SimBridge.state).is_equal(SimBridge.ConnectionState.CONNECTED)


func test_poll_snapshot_returns_data_when_connected() -> void:
	SimBridge.connect_to_sim()
	var snapshot: Variant = SimBridge.poll_snapshot()
	assert_that(snapshot).is_not_null()
	assert_that(snapshot is Dictionary).is_true()


func test_snapshot_has_player_at_10_10() -> void:
	var snap := SimBridge._test_snapshot()
	var player_x: float = -1.0
	var player_y: float = -1.0
	for entity in snap.entities:
		if entity.kind.variant == "Player":
			player_x = entity.x
			player_y = entity.y
			break
	assert_that(player_x).is_equal(10.0)
	assert_that(player_y).is_equal(10.0)


func test_apply_snapshot_sets_player_position() -> void:
	var snap := SimBridge._test_snapshot()
	GameState.apply_snapshot(snap)
	assert_that(GameState.player_position).is_equal(EXPECTED_PLAYER_POS)


# --- Camera anchor after _ready() ---

func test_camera_position_after_ready() -> void:
	var scene := load("res://scenes/main.tscn")
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	var camera: Camera2D = _instance.get_node("Camera2D")
	assert_that(camera.global_position).is_equal(EXPECTED_CAMERA_POS)


func test_camera_anchored_flag_after_ready() -> void:
	var scene := load("res://scenes/main.tscn")
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	assert_that(_instance._camera_anchored).is_true()


func test_camera_smoothing_off_after_ready() -> void:
	# Camera smoothing must be disabled during init to prevent lerp from (0,0).
	# If this test fails, the camera will visibly drift from origin to player.
	var scene := load("res://scenes/main.tscn")
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	var camera: Camera2D = _instance.get_node("Camera2D")
	assert_that(camera.position_smoothing_enabled).is_false()


func test_camera_smoothing_stays_off_with_manual_lerp() -> void:
	# #117: Manual lerp approach — Godot's built-in smoothing must stay OFF always.
	# CAMERA_SMOOTHING_SPEED is used as the lerp weight, not Godot's position_smoothing_speed.
	var scene := load("res://scenes/main.tscn")
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	_instance._process(0.016)

	var camera: Camera2D = _instance.get_node("Camera2D")
	assert_that(camera.position_smoothing_enabled).is_false()


# --- Camera behavior across frames ---

func test_camera_tracks_player_after_process() -> void:
	var scene := load("res://scenes/main.tscn")
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	# Simulate one game frame
	_instance._process(0.016)

	var camera: Camera2D = _instance.get_node("Camera2D")
	var expected := GameState.player_position * Constants.TILE_SIZE
	assert_that(camera.global_position).is_equal(expected)


func test_camera_lerps_toward_player_movement() -> void:
	# #117: With manual lerp, camera moves TOWARD player position (not snapping).
	# After one 16ms frame the camera should be partway between old and new position.
	var scene := load("res://scenes/main.tscn")
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	var camera: Camera2D = _instance.get_node("Camera2D")
	var initial_pos := camera.global_position  # anchored at (320, 320)

	# Move player north via SimBridge test mode
	SimBridge._test_input_queue.append("MoveNorth")
	_instance._process(0.016)

	var new_target := GameState.player_position * Constants.TILE_SIZE  # (320, 288)
	# Camera should have moved north (lower y) but NOT reached the target yet
	assert_that(camera.global_position.y).is_less(initial_pos.y)
	assert_that(camera.global_position.y).is_greater(new_target.y)