## Client P0 regression tests: guards for Bug #5 (monologue lost) and Bug #2 (camera drift).
## These must pass before any other client testing is meaningful.
##
## Bug #5: Monologue text lost when server sends snapshots faster than client
##         consumes them. Fix: carry-forward one-shot events in receive_bytes().
## Bug #2: Camera doesn't center at startup / drifts during pause. Fix: anchor
##         pattern with smoothing disabled until first snapshot applied.
##
## Spec ref: stig-round3.md Section 1 (P0 tests #1, #2).
class_name TestP0Regressions
extends GdUnitTestSuite


const MAIN_SCENE = preload("res://scenes/main.tscn")

var _instance: Node = null


func before_test() -> void:
	SimBridge.reset_test_state()
	SimBridge._last_snapshot = null
	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
	GameState.game_time = {}
	GameState.pending_recognitions = []


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


# -- Helpers -------------------------------------------------------------------

## Encode a minimal valid snapshot as MessagePack bytes.
## Protocol.decode_snapshot() requires: tick, version, entities (with kind as
## bare string for unit enum variants per rmp_serde wire format).
func _make_snapshot_bytes(overrides: Dictionary = {}) -> PackedByteArray:
	var snapshot := {
		"tick": overrides.get("tick", 1),
		"version": Protocol.PROTOCOL_VERSION,
		"entities": overrides.get("entities", [{
			"entity_id": 1,
			"x": 10.0,
			"y": 10.0,
			"z": 0,
			"kind": "Player",
			"visibility": "Forward",
		}]),
		"game_time": {
			"day": 0,
			"time_of_day": 0,
			"day_phase": "Morning",
			"tick_rate": overrides.get("tick_rate", "Full"),
		},
		"player_facing": "North",
		"player_stance": "Walk",
		"player_inventory": [],
		"visible_tiles": [],
		"nearby_interactions": [],
		"pending_recognitions": [],
	}
	# Only include current_monologue if explicitly provided (null omitted)
	if overrides.has("current_monologue"):
		snapshot["current_monologue"] = overrides["current_monologue"]
	if overrides.has("current_dialogue"):
		snapshot["current_dialogue"] = overrides["current_dialogue"]
	var result = Messagepack.encode(snapshot)
	return result.value


# -- Bug #5: Monologue carry-forward ------------------------------------------
# The server sends one-shot monologue in a snapshot. If the server sends another
# snapshot (without monologue) before the client polls, the old snapshot is
# overwritten. The carry-forward logic in receive_bytes() must preserve the
# monologue from the overwritten snapshot.

func test_monologue_not_lost_on_snapshot_overwrite() -> void:
	# Snapshot 1: server sends monologue
	var bytes_with_mono := _make_snapshot_bytes({
		"tick": 1,
		"current_monologue": {
			"id": "test_mono_001",
			"text": "Something about this manifest doesn't add up.",
			"duration_seconds": 5.0,
		},
	})
	SimBridge.receive_bytes(bytes_with_mono)

	# Snapshot 2: server sends next tick WITHOUT monologue (overwrite scenario)
	var bytes_without_mono := _make_snapshot_bytes({
		"tick": 2,
	})
	SimBridge.receive_bytes(bytes_without_mono)

	# Assert: _last_snapshot must still carry the monologue from snapshot 1.
	# This is the carry-forward fix for Bug #5.
	assert_that(SimBridge._last_snapshot).is_not_null()
	var mono: Variant = SimBridge._last_snapshot.get("current_monologue")
	assert_that(mono).is_not_null()
	assert_that(mono is Dictionary).is_true()
	assert_that(mono.get("text")).is_equal("Something about this manifest doesn't add up.")


func test_monologue_not_duplicated_after_consumption() -> void:
	# After the client consumes a carried-forward monologue, the next snapshot
	# without monologue should NOT carry forward again (it was already consumed).
	var bytes_with_mono := _make_snapshot_bytes({
		"tick": 1,
		"current_monologue": {
			"id": "test_mono_002",
			"text": "The corridors feel different at night.",
			"duration_seconds": 3.0,
		},
	})
	SimBridge.receive_bytes(bytes_with_mono)

	# Client polls and consumes the monologue.
	# In live mode, poll_snapshot() returns _last_snapshot and sets it to null.
	# In test mode, poll_snapshot() returns _test_snapshot() instead, so we
	# simulate the live-mode consumption path directly.
	var snapshot = SimBridge._last_snapshot
	SimBridge._last_snapshot = null
	assert_that(snapshot).is_not_null()
	GameState.apply_snapshot(snapshot)
	# apply_snapshot sets current_monologue, then main._consume_monologue() clears it.
	# Simulate consumption:
	GameState.current_monologue = null

	# Next snapshot arrives without monologue — _last_snapshot was null after poll,
	# so no carry-forward should happen.
	var bytes_next := _make_snapshot_bytes({"tick": 2})
	SimBridge.receive_bytes(bytes_next)

	var mono: Variant = SimBridge._last_snapshot.get("current_monologue")
	assert_that(mono).is_null()


func test_monologue_carry_forward_preserves_newest() -> void:
	# If two snapshots both have monologue, the second one wins (no accumulation).
	var bytes_mono1 := _make_snapshot_bytes({
		"tick": 1,
		"current_monologue": {
			"id": "first",
			"text": "First thought.",
			"duration_seconds": 3.0,
		},
	})
	SimBridge.receive_bytes(bytes_mono1)

	var bytes_mono2 := _make_snapshot_bytes({
		"tick": 2,
		"current_monologue": {
			"id": "second",
			"text": "Second thought.",
			"duration_seconds": 3.0,
		},
	})
	SimBridge.receive_bytes(bytes_mono2)

	# Second monologue should win — latest snapshot takes precedence.
	var mono: Variant = SimBridge._last_snapshot.get("current_monologue")
	assert_that(mono).is_not_null()
	assert_that(mono.get("text")).is_equal("Second thought.")


# -- Bug #2: Camera static during pause ---------------------------------------
# During pause, the server sends snapshots with unchanged player position.
# The camera must remain at the same position — no drift, no snap to origin.

func test_camera_static_during_pause() -> void:
	# 1. Instantiate main scene — camera anchors at test mode player position
	var scene := MAIN_SCENE
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	var camera: Camera2D = _instance.get_node("Camera2D")
	var expected_pos := Vector2(10, 10) * Constants.TILE_SIZE  # (320, 320)

	# 2. Verify camera is anchored at expected position
	assert_that(camera.global_position).is_equal(expected_pos)
	assert_that(_instance._camera_anchored).is_true()

	# 3. Set game state to Paused
	GameState.game_time = {
		"day": 0,
		"time_of_day": 0,
		"day_phase": "Morning",
		"tick_rate": "Paused",
	}

	# 4. Process a frame — in test mode, poll_snapshot returns same position
	#    (no movement inputs queued), simulating server pause behavior
	_instance._process(0.016)

	# 5. Camera must remain at the same position (no drift)
	assert_that(camera.global_position).is_equal(expected_pos)


func test_camera_anchored_after_pause_unpause() -> void:
	# Verify camera stays properly anchored through a pause → unpause cycle.
	var scene := MAIN_SCENE
	_instance = scene.instantiate()
	auto_free(_instance)
	add_child(_instance)

	var camera: Camera2D = _instance.get_node("Camera2D")
	var expected_pos := Vector2(10, 10) * Constants.TILE_SIZE

	# Process several frames with Paused tick rate
	GameState.game_time.tick_rate = "Paused"
	for i in 5:
		_instance._process(0.016)

	assert_that(camera.global_position).is_equal(expected_pos)
	assert_that(_instance._camera_anchored).is_true()

	# Unpause and process — camera should track the (potentially moved) player
	GameState.game_time.tick_rate = "Full"
	_instance._process(0.016)

	# Camera still tracking player (position may have changed due to test_snapshot)
	var player_pos := GameState.player_position * Constants.TILE_SIZE
	assert_that(camera.global_position).is_equal(player_pos)