## #507: WRONG button ring buffer tests.
## Tests the 60-tick rolling history upgrade to bug_report_dialog.gd.
## Covers ring buffer capacity, circular overwrite, JSONL format compliance,
## replay compatibility, seed file, and regression against MVP behavior.
##
## MVP baseline (must still pass): snapshot.json, render.txt, description.txt.
## New outputs: inputs.jsonl, snapshots.jsonl, seed.txt.
##
## Spec refs: D-030 (testability), D-020 (ObserverSnapshot boundary)
## Sprint 11 client.md §Notes #507
class_name TestBugReportRingBuffer
extends GdUnitTestSuite

# Expected ring buffer capacity per spec.
const EXPECTED_CAPACITY := 60

const BugReportDialogScene = preload("res://ui/bug_report_dialog.tscn")


func after_each() -> void:
	# Reset GameState fields mutated by tests to prevent cross-test leakage.
	GameState.current_tick = 0
	GameState.room_id = null
	GameState.player_stance = "Walk"
	GameState.player_facing = "South"
	GameState.player_position = Vector2.ZERO
	GameState.visible_entities = []
	GameState.visible_tiles = []
	GameState.game_time = {}
	GameState.current_monologue = null
	GameState.current_dialogue = null
	GameState.rng_seed = null


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

func _make_dialog() -> Control:
	# Instantiate via .tscn — preserves the MetaScreen runtime stack.
	# (Sprint 36 migrated bug_report_dialog.gd to extends MetaScreen; bare
	# Control.new() + set_script() no longer satisfies the base contract.)
	var dialog: Control = BugReportDialogScene.instantiate()
	auto_free(dialog)
	add_child(dialog)
	return dialog


## Create a minimal valid PlayerInput dict matching the replay.rs wire format.
## replay.rs expects: {"tick": N, "action": "MoveNorth"} or action as dict.
func _make_input(tick: int, action: String = "MoveNorth") -> Dictionary:
	return {"tick": tick, "action": action}


## Make a minimal snapshot JSON string for snapshot buffer testing.
func _make_snapshot_json(tick: int) -> String:
	return JSON.stringify({
		"tick": tick,
		"version": 23,
		"entities": [],
	})


## Check a string is valid JSON array — mirrors replay.rs line expectation.
func _is_valid_json_array(line: String) -> bool:
	if line.is_empty():
		return false
	var result = JSON.parse_string(line)
	return result != null and result is Array


# -- Ring buffer capacity ------------------------------------------------------

func test_buffer_capacity_is_60() -> void:
	# Spec: "Maintain a 60-entry circular buffer"
	var dialog = _make_dialog()
	if not dialog.has_method("_get_buffer_capacity"):
		push_warning("TestBugReportRingBuffer: _get_buffer_capacity not found — awaiting #507")
		return
	assert_that(dialog._get_buffer_capacity()).override_failure_message(
		"Ring buffer capacity must be 60 per spec"
	).is_equal(EXPECTED_CAPACITY)


func test_snapshot_buffer_capacity_is_60() -> void:
	# Parallel snapshot buffer must match input buffer capacity.
	var dialog = _make_dialog()
	if not dialog.has_method("_get_snapshot_buffer_capacity"):
		push_warning("TestBugReportRingBuffer: _get_snapshot_buffer_capacity not found — awaiting #507")
		return
	assert_that(dialog._get_snapshot_buffer_capacity()).is_equal(EXPECTED_CAPACITY)


# -- Pre-allocation -----------------------------------------------------------

func test_input_buffer_preallocated_at_ready() -> void:
	# Spec: "pre-allocate the 60-slot arrays at startup. Do not allocate on every tick."
	var dialog = _make_dialog()
	if not dialog.has_method("_get_input_buffer"):
		push_warning("TestBugReportRingBuffer: _get_input_buffer not found — awaiting #507")
		return
	var buf = dialog._get_input_buffer()
	assert_that(buf is Array).override_failure_message(
		"Input buffer must be an Array"
	).is_true()
	assert_that(buf.size()).override_failure_message(
		"Input buffer must be pre-allocated at capacity (%d slots)" % EXPECTED_CAPACITY
	).is_equal(EXPECTED_CAPACITY)


# -- Push and fill behavior ---------------------------------------------------

func test_push_fills_input_buffer() -> void:
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs"):
		push_warning("TestBugReportRingBuffer: _push_tick_inputs not found — awaiting #507")
		return
	if not dialog.has_method("_get_filled_input_count"):
		push_warning("TestBugReportRingBuffer: _get_filled_input_count not found — awaiting #507")
		return
	for i in range(10):
		dialog._push_tick_inputs(i, [_make_input(i)])
	assert_that(dialog._get_filled_input_count()).override_failure_message(
		"10 pushed ticks should produce filled count of 10"
	).is_equal(10)


func test_push_fills_snapshot_buffer() -> void:
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_snapshot"):
		push_warning("TestBugReportRingBuffer: _push_tick_snapshot not found — awaiting #507")
		return
	if not dialog.has_method("_get_filled_snapshot_count"):
		push_warning("TestBugReportRingBuffer: _get_filled_snapshot_count not found — awaiting #507")
		return
	for i in range(10):
		dialog._push_tick_snapshot(_make_snapshot_json(i))
	assert_that(dialog._get_filled_snapshot_count()).is_equal(10)


# -- Circular overwrite -------------------------------------------------------

func test_circular_overwrite_evicts_oldest() -> void:
	# After 61 pushes, filled count must be 60 (oldest evicted).
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs") or not dialog.has_method("_get_filled_input_count"):
		push_warning("TestBugReportRingBuffer: ring buffer API not found — awaiting #507")
		return
	for i in range(EXPECTED_CAPACITY + 1):
		dialog._push_tick_inputs(i, [_make_input(i)])
	assert_that(dialog._get_filled_input_count()).override_failure_message(
		"After 61 pushes, buffer must hold exactly 60 entries (oldest evicted)"
	).is_equal(EXPECTED_CAPACITY)


func test_circular_overwrite_keeps_newest_inputs() -> void:
	# After 61 pushes, the flushed JSONL must contain tick 1..60 (not tick 0).
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs") or not dialog.has_method("_format_inputs_jsonl"):
		push_warning("TestBugReportRingBuffer: ring buffer flush API not found — awaiting #507")
		return
	# Push 61 ticks. Tick 0 should be evicted; ticks 1-60 should be present.
	for i in range(EXPECTED_CAPACITY + 1):
		dialog._push_tick_inputs(i, [_make_input(i, "MoveNorth")])
	var jsonl: String = dialog._format_inputs_jsonl()
	# Tick 0 action would be at position 0, but after 61 pushes, position 0 was overwritten.
	# We check that the output has exactly 60 lines.
	var lines: PackedStringArray = jsonl.split("\n", false)
	# Filter out blank lines (PackedStringArray has no filter — convert to Array first)
	var non_blank: Array = Array(lines).filter(func(l): return not l.strip_edges().is_empty())
	assert_that(non_blank.size()).override_failure_message(
		"After 61 pushes, JSONL output must have exactly 60 non-blank lines"
	).is_equal(EXPECTED_CAPACITY)


func test_exact_60_pushes_no_eviction() -> void:
	# After exactly 60 pushes, all 60 are present.
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs") or not dialog.has_method("_get_filled_input_count"):
		push_warning("TestBugReportRingBuffer: ring buffer API not found — awaiting #507")
		return
	for i in range(EXPECTED_CAPACITY):
		dialog._push_tick_inputs(i, [_make_input(i)])
	assert_that(dialog._get_filled_input_count()).override_failure_message(
		"After exactly 60 pushes, all 60 entries should be present"
	).is_equal(EXPECTED_CAPACITY)


# -- JSONL format compliance (replay.rs contract) ----------------------------

func test_inputs_jsonl_each_line_is_json_array() -> void:
	# replay.rs: "Each line is a JSON array of PlayerInput for one tick."
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs") or not dialog.has_method("_format_inputs_jsonl"):
		push_warning("TestBugReportRingBuffer: JSONL API not found — awaiting #507")
		return
	for i in range(3):
		dialog._push_tick_inputs(i, [_make_input(i)])
	var jsonl: String = dialog._format_inputs_jsonl()
	var lines: PackedStringArray = jsonl.split("\n", false)
	var non_blank: Array = Array(lines).filter(func(l): return not l.strip_edges().is_empty())
	for line in non_blank:
		assert_that(_is_valid_json_array(line)).override_failure_message(
			"Each JSONL line must be a valid JSON array, got: %s" % line
		).is_true()


func test_inputs_jsonl_idle_tick_is_empty_array() -> void:
	# replay.rs: "Empty array = idle tick (no input sent)."
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs") or not dialog.has_method("_format_inputs_jsonl"):
		push_warning("TestBugReportRingBuffer: JSONL API not found — awaiting #507")
		return
	dialog._push_tick_inputs(0, [])  # Idle tick: no inputs
	var jsonl: String = dialog._format_inputs_jsonl()
	var lines: PackedStringArray = jsonl.split("\n", false)
	var non_blank: Array = Array(lines).filter(func(l): return not l.strip_edges().is_empty())
	assert_that(non_blank.size()).override_failure_message(
		"One idle tick should produce exactly 1 JSONL line"
	).is_equal(1)
	assert_that(non_blank[0].strip_edges()).override_failure_message(
		"Idle tick line must be an empty JSON array '[]'"
	).is_equal("[]")


func test_inputs_jsonl_has_tick_field() -> void:
	# replay.rs PlayerInput expects {"tick": N, "action": "..."}
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs") or not dialog.has_method("_format_inputs_jsonl"):
		push_warning("TestBugReportRingBuffer: JSONL API not found — awaiting #507")
		return
	dialog._push_tick_inputs(42, [_make_input(42, "MoveEast")])
	var jsonl: String = dialog._format_inputs_jsonl()
	# Parse the first line and verify structure
	var lines: PackedStringArray = jsonl.split("\n", false)
	var non_blank: Array = Array(lines).filter(func(l): return not l.strip_edges().is_empty())
	assert_that(non_blank.size()).is_greater(0)
	var arr = JSON.parse_string(non_blank[0])
	assert_that(arr is Array).is_true()
	assert_that(arr.size() > 0).is_true()
	var first_input: Dictionary = arr[0]
	assert_that(first_input.has("tick")).override_failure_message(
		"Each PlayerInput in JSONL must have 'tick' field"
	).is_true()
	assert_that(first_input.has("action")).override_failure_message(
		"Each PlayerInput in JSONL must have 'action' field"
	).is_true()


func test_inputs_jsonl_multiple_actions_per_tick() -> void:
	# replay.rs supports multiple PlayerInput per tick (one array entry per action).
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_inputs") or not dialog.has_method("_format_inputs_jsonl"):
		push_warning("TestBugReportRingBuffer: JSONL API not found — awaiting #507")
		return
	dialog._push_tick_inputs(0, [
		_make_input(0, "MoveNorth"),
		_make_input(0, "Pause"),
	])
	var jsonl: String = dialog._format_inputs_jsonl()
	var lines: PackedStringArray = jsonl.split("\n", false)
	var non_blank: Array = Array(lines).filter(func(l): return not l.strip_edges().is_empty())
	assert_that(non_blank.size()).is_equal(1)
	var arr = JSON.parse_string(non_blank[0])
	assert_that(arr is Array).is_true()
	assert_that(arr.size()).override_failure_message(
		"Tick with 2 actions must have 2 entries in the JSONL array"
	).is_equal(2)


func test_snapshots_jsonl_each_line_is_valid_json() -> void:
	# Each snapshot line should be valid JSON (parsed snapshot).
	var dialog = _make_dialog()
	if not dialog.has_method("_push_tick_snapshot") or not dialog.has_method("_format_snapshots_jsonl"):
		push_warning("TestBugReportRingBuffer: snapshots JSONL API not found — awaiting #507")
		return
	for i in range(3):
		dialog._push_tick_snapshot(_make_snapshot_json(i))
	var jsonl: String = dialog._format_snapshots_jsonl()
	var lines: PackedStringArray = jsonl.split("\n", false)
	var non_blank: Array = Array(lines).filter(func(l): return not l.strip_edges().is_empty())
	assert_that(non_blank.size()).is_equal(3)
	for line in non_blank:
		var parsed = JSON.parse_string(line)
		assert_that(parsed != null).override_failure_message(
			"Each snapshot line must be valid JSON, got: %s" % line
		).is_true()
		assert_that(parsed is Dictionary).override_failure_message(
			"Each snapshot line must parse to a Dictionary"
		).is_true()


# -- Seed file ----------------------------------------------------------------

func test_seed_written_on_capture() -> void:
	# Spec: "Include the server's current RNG seed... Output as seed.txt"
	# We can't easily verify file output in headless mode, but we verify
	# the dialog has the method to produce the seed value.
	var dialog = _make_dialog()
	if not dialog.has_method("_get_current_seed"):
		push_warning("TestBugReportRingBuffer: _get_current_seed not found — awaiting #507")
		return
	# Should return some Variant (int or String) without crashing
	var seed_val = dialog._get_current_seed()
	assert_that(seed_val != null).override_failure_message(
		"_get_current_seed() must not return null (use 0 or 'unavailable' if seed unavailable)"
	).is_true()


# -- Room metadata regression -------------------------------------------------

func test_description_txt_still_contains_room_id() -> void:
	# Regression: MVP description.txt must still include room metadata.
	GameState.current_tick = 5
	GameState.room_id = "warehouse_01"
	GameState.player_stance = "Walk"
	GameState.player_facing = "North"
	GameState.player_position = Vector2(10.0, 10.0)
	GameState.visible_entities = []
	GameState.visible_tiles = []
	GameState.game_time = {}
	GameState.current_monologue = null
	GameState.current_dialogue = null
	var dialog = _make_dialog()
	# Call the render text method to verify room shows up in render output
	# (description.txt itself writes via FileAccess, difficult in headless — test the render path)
	if dialog.has_method("_render_snapshot_text"):
		# The text render is for render.txt, but description.txt room comes from GameState.room_id
		# We indirectly verify by checking that the game state has the right fields.
		assert_that(GameState.room_id).is_equal("warehouse_01")
	GameState.room_id = null


# -- MVP regression -----------------------------------------------------------

func test_render_snapshot_text_still_works() -> void:
	# Regression: MVP _render_snapshot_text() must still work after upgrade.
	GameState.current_tick = 10
	GameState.player_position = Vector2(5.0, 5.0)
	GameState.player_facing = "East"
	GameState.player_stance = "Careful"
	GameState.visible_entities = []
	GameState.visible_tiles = []
	GameState.game_time = {}
	GameState.current_monologue = null
	GameState.current_dialogue = null
	var dialog = _make_dialog()
	if not dialog.has_method("_render_snapshot_text"):
		push_warning("TestBugReportRingBuffer: _render_snapshot_text missing — regression risk")
		return
	var text: String = dialog._render_snapshot_text()
	assert_that(text.length() > 0).is_true()
	assert_that(text.contains("t10")).is_true()


func test_dialog_is_active_api_unchanged() -> void:
	# Regression: public API from MVP must be unchanged.
	var dialog = _make_dialog()
	assert_that(dialog.has_method("start_capture")).override_failure_message(
		"start_capture() must still be present (MVP regression)"
	).is_true()
	assert_that(dialog.has_method("is_active")).override_failure_message(
		"is_active() must still be present (MVP regression)"
	).is_true()