## D-030 Layer 1: Fixture-based tests for snapshot parsing
## Validates that GameState correctly parses ObserverSnapshot data
class_name TestSnapshotParsing
extends GdUnitTestSuite

# Valid snapshot fixture
var _valid_snapshot: Dictionary = {
	"tick": 1,
	"player": {
		"position": [10, 15],
		"health": 85
	},
	"entities": [
		{"id": 1, "type": "npc", "position": [12, 8], "name": "Test NPC"},
		{"id": 2, "type": "npc", "position": [5, 20], "name": "Second NPC"},
	],
	"fog": {"radius": 8},
	"hud": {"perception_mode": "baseline", "time": "14:30"}
}

func test_apply_valid_snapshot() -> void:
	GameState.apply_snapshot(_valid_snapshot)

	assert_that(GameState.player_position).is_equal(Vector2(10, 15))
	assert_that(GameState.visible_entities.size()).is_equal(2)
	assert_that(GameState.fog_state).is_equal({"radius": 8})
	assert_that(GameState.hud_data).is_equal({"perception_mode": "baseline", "time": "14:30"})

func test_empty_snapshot_no_crash() -> void:
	# Reset state
	GameState.player_position = Vector2.ZERO
	GameState.visible_entities = []

	GameState.apply_snapshot({})

	# State should remain at defaults
	assert_that(GameState.player_position).is_equal(Vector2.ZERO)
	assert_that(GameState.visible_entities.size()).is_equal(0)

func test_malformed_position_no_crash() -> void:
	var bad_snapshot: Dictionary = {
		"player": {"position": "not_an_array"},
	}
	# Reset
	GameState.player_position = Vector2.ZERO

	# Should not crash — logs warning instead
	GameState.apply_snapshot(bad_snapshot)
	assert_that(GameState.player_position).is_equal(Vector2.ZERO)

func test_missing_fields_partial_update() -> void:
	# First apply valid snapshot
	GameState.apply_snapshot(_valid_snapshot)
	assert_that(GameState.player_position).is_equal(Vector2(10, 15))

	# Apply snapshot with only HUD data — player position unchanged
	GameState.apply_snapshot({"hud": {"perception_mode": "thermal", "time": "22:00"}})
	assert_that(GameState.player_position).is_equal(Vector2(10, 15))
	assert_that(GameState.hud_data.perception_mode).is_equal("thermal")

func test_sim_bridge_test_snapshot_deterministic() -> void:
	SimBridge._test_tick = 0
	var snap1 = SimBridge._test_snapshot()
	var snap2 = SimBridge._test_snapshot()

	assert_that(snap1.tick).is_equal(1)
	assert_that(snap2.tick).is_equal(2)
	# Snapshot structure is stable
	assert_that(snap1.has("player")).is_true()
	assert_that(snap1.has("entities")).is_true()
	assert_that(snap1.has("fog")).is_true()
	assert_that(snap1.has("hud")).is_true()