extends SceneTree

## Asset-free M2 build-job lifecycle, FIFO, progress, engine-lifetime, source
## boundary and bounded-timing regression.

const QUEUE_SCRIPT := preload("res://src/render/m2/m2_build_queue.gd")
const QUEUE_PATH := "res://src/render/m2/m2_build_queue.gd"
const JOB_PATH := "res://src/render/m2/m2_build_job.gd"
const LOADER_PATH := "res://src/scenes/streaming/streaming_world_loader.gd"


func _initialize() -> void:
	var failures: Array[String] = []
	_verify_invalid_and_fifo_jobs(failures)
	_verify_progress_adoption(failures)
	_verify_rotation_duplicate_and_stale_keys(failures)
	_verify_erase_clear_and_engine_lifetime(failures)
	_verify_detached_sorted_diagnostics(failures)
	_verify_loader_and_engine_lifetime_boundaries(failures)
	var elapsed_milliseconds := _verify_bounded_timing(failures)
	if not failures.is_empty():
		for failure in failures:
			push_error("M2_BUILD_QUEUE: %s" % failure)
		quit(1)
		return
	print(
		"M2_BUILD_QUEUE PASS cases=13 iterations=100 elapsed_ms=%.3f"
		% elapsed_milliseconds
	)
	quit(0)


func _verify_invalid_and_fifo_jobs(failures: Array[String]) -> void:
	var queue: RefCounted = QUEUE_SCRIPT.new()
	var root := Node3D.new()
	var groups := _make_groups("world/a.m2", 2)
	_expect_false(queue.call("enqueue", "", root, groups), "empty key rejected", failures)
	_expect_false(queue.call("enqueue", "1_1", null, groups), "null root rejected", failures)
	_expect_false(queue.call("enqueue", "1_1", root, {}), "empty groups rejected", failures)
	_expect_true(queue.call("enqueue", "2_2", root, groups), "first enqueue", failures)
	_expect_true(
		queue.call("enqueue", "3_3", root, _make_groups("world/b.m2", 1)),
		"second enqueue",
		failures
	)
	_expect_string_equal(String(queue.call("front_key")), "2_2", "FIFO front", failures)
	_expect_equal(int(queue.call("pending_count")), 2, "FIFO pending count", failures)
	_expect_equal(int(queue.call("active_job_count")), 2, "active job count", failures)
	var first_job: RefCounted = queue.call("job_for", "2_2")
	_expect_string_equal(String(first_job.call("tile_key")), "2_2", "typed job key", failures)
	_expect_same(first_job.call("root"), root, "job retains root", failures)
	_expect_same(first_job.call("groups"), groups, "job retains exact groups", failures)
	_expect_string_array(first_job.call("group_keys"), ["world/a.m2"], "group-key snapshot", failures)
	queue.call("clear")
	root.free()


func _verify_progress_adoption(failures: Array[String]) -> void:
	var queue: RefCounted = QUEUE_SCRIPT.new()
	var root := Node3D.new()
	queue.call("enqueue", "4_4", root, _make_groups("world/a.m2", 2))
	_expect_equal(int(queue.call("group_index_for", "4_4")), 0, "initial group index", failures)
	_expect_equal(int(queue.call("transform_offset_for", "4_4")), 0, "initial offset", failures)
	_expect_equal(int(queue.call("batch_serial_for", "4_4")), 0, "initial serial", failures)
	_expect_true(queue.call("adopt_progress", "4_4", 7, 3, 11), "progress adopted", failures)
	_expect_equal(int(queue.call("group_index_for", "4_4")), 7, "adopted group index", failures)
	_expect_equal(int(queue.call("transform_offset_for", "4_4")), 3, "adopted offset", failures)
	_expect_equal(int(queue.call("batch_serial_for", "4_4")), 11, "adopted serial", failures)
	_expect_false(
		queue.call("adopt_progress", "missing", 1, 1, 1),
		"stale progress rejected",
		failures
	)
	queue.call("clear")
	root.free()


func _verify_rotation_duplicate_and_stale_keys(failures: Array[String]) -> void:
	var queue: RefCounted = QUEUE_SCRIPT.new()
	var first_root := Node3D.new()
	var second_root := Node3D.new()
	var groups := _make_groups("world/a.m2", 1)
	queue.call("enqueue", "5_5", first_root, groups)
	queue.call("enqueue", "6_6", first_root, groups)
	_expect_true(queue.call("rotate_front"), "front rotates", failures)
	_expect_string_equal(String(queue.call("front_key")), "6_6", "rotated FIFO front", failures)
	queue.call("enqueue", "6_6", second_root, groups)
	_expect_equal(int(queue.call("pending_count")), 3, "duplicate appends FIFO key", failures)
	_expect_equal(int(queue.call("active_job_count")), 2, "duplicate replaces keyed job", failures)
	_expect_same(queue.call("root_for", "6_6"), second_root, "duplicate latest root wins", failures)
	_expect_true(queue.call("erase_job", "6_6"), "job erased", failures)
	_expect_equal(int(queue.call("pending_count")), 3, "erase preserves FIFO keys", failures)
	_expect_false(queue.call("has_job", "6_6"), "front key becomes stale", failures)
	_expect_string_equal(String(queue.call("pop_front")), "6_6", "stale front popped", failures)
	queue.call("clear")
	first_root.free()
	second_root.free()


func _verify_erase_clear_and_engine_lifetime(failures: Array[String]) -> void:
	var queue: RefCounted = QUEUE_SCRIPT.new()
	var root := Node3D.new()
	queue.call("enqueue", "7_7", root, _make_groups("world/a.m2", 1))
	_expect_false(queue.call("erase_job", "missing"), "unknown erase rejected", failures)
	_expect_true(queue.call("erase_job", "7_7"), "known job erased", failures)
	_expect_true(is_instance_valid(root), "erase keeps root valid", failures)
	_expect_equal(int(queue.call("pending_count")), 1, "erase leaves stale key", failures)
	queue.call("clear")
	queue.call("clear")
	_expect_equal(int(queue.call("pending_count")), 0, "clear idempotent", failures)
	_expect_true(is_instance_valid(root), "clear keeps root valid", failures)
	root.free()


func _verify_detached_sorted_diagnostics(failures: Array[String]) -> void:
	var queue: RefCounted = QUEUE_SCRIPT.new()
	var root := Node3D.new()
	queue.call("enqueue", "20_20", root, _make_groups("world/a.m2", 1))
	queue.call("enqueue", "10_10", root, _make_groups("world/b.m2", 2))
	queue.call("adopt_progress", "10_10", 1, 2, 3)
	var snapshot: Dictionary = queue.call("diagnostic_snapshot")
	_expect_string_array(
		snapshot["queued_tile_keys"],
		["20_20", "10_10"],
		"diagnostic FIFO order",
		failures
	)
	var jobs: Array = snapshot["jobs"]
	_expect_string_equal(String(jobs[0]["tile_key"]), "10_10", "diagnostic job sort", failures)
	_expect_equal(int(jobs[0]["batch_serial"]), 3, "diagnostic progress", failures)
	(snapshot["queued_tile_keys"] as Array).append("mutated")
	jobs[0]["batch_serial"] = 99
	var fresh_snapshot: Dictionary = queue.call("diagnostic_snapshot")
	_expect_string_array(
		fresh_snapshot["queued_tile_keys"],
		["20_20", "10_10"],
		"diagnostic FIFO detached",
		failures
	)
	_expect_equal(
		int((fresh_snapshot["jobs"] as Array)[0]["batch_serial"]),
		3,
		"job diagnostic detached",
		failures
	)
	queue.call("clear")
	root.free()


func _verify_loader_and_engine_lifetime_boundaries(failures: Array[String]) -> void:
	var loader_source := FileAccess.get_file_as_string(LOADER_PATH)
	var queue_source := FileAccess.get_file_as_string(QUEUE_PATH)
	var job_source := FileAccess.get_file_as_string(JOB_PATH)
	_expect_true(
		loader_source.contains("M2_BUILD_QUEUE_SCRIPT.new()"),
		"loader composes queue",
		failures
	)
	for delegated_call in [
		"_m2_build_queue_state.enqueue(",
		"_m2_build_queue_state.has_job(",
		"_m2_build_queue_state.root_for(",
		"_m2_build_queue_state.rotate_front()",
		"_m2_build_queue_state.adopt_progress(",
		"_m2_build_queue_state.erase_job(",
		"_m2_build_queue_state.clear()",
	]:
		_expect_true(
			loader_source.contains(delegated_call),
			"loader delegates %s" % delegated_call,
			failures
		)
	_expect_false(
		loader_source.contains("var _m2_build_jobs"),
		"legacy job Dictionary removed",
		failures
	)
	_expect_false(
		loader_source.contains("var _m2_build_queue: Array"),
		"legacy FIFO Array removed",
		failures
	)
	_expect_true(
		loader_source.contains("_queue_free_streamed_node(root)")
		and loader_source.contains("_m2_static_batch_materializer.materialize_batch(")
		and loader_source.contains("_m2_animated_instance_materializer.materialize_batch(")
		and loader_source.contains("try_consume_permit("),
		"loader retains destruction, materialization and permits",
		failures
	)
	for forbidden_token in [
		"queue_free",
		"RenderingServer",
		"RID",
		"MeshInstance3D",
		"MultiMesh",
		"ResourceLoader",
		"FileAccess",
		"WorkerThreadPool",
		"Thread",
		"Mutex",
	]:
		_expect_false(
			queue_source.contains(forbidden_token) or job_source.contains(forbidden_token),
			"queue/job omit %s ownership" % forbidden_token,
			failures
		)


func _verify_bounded_timing(failures: Array[String]) -> float:
	var queue: RefCounted = QUEUE_SCRIPT.new()
	var root := Node3D.new()
	var groups := _make_groups("world/timing.m2", 4)
	var started_microseconds := Time.get_ticks_usec()
	for _iteration in range(100):
		for job_index in range(256):
			queue.call("enqueue", "%d_%d" % [job_index, job_index], root, groups)
		for _job_index in range(256):
			queue.call("rotate_front")
		for job_index in range(256):
			queue.call("erase_job", "%d_%d" % [job_index, job_index])
		queue.call("clear")
	var elapsed_milliseconds := float(Time.get_ticks_usec() - started_microseconds) / 1000.0
	_expect_true(elapsed_milliseconds < 1000.0, "100 queue cycles remain bounded", failures)
	root.free()
	return elapsed_milliseconds


func _make_groups(relative_path: String, transform_count: int) -> Dictionary:
	var transforms: Array = []
	for transform_index in transform_count:
		transforms.append(
			Transform3D(Basis.IDENTITY, Vector3(float(transform_index), 0.0, 0.0))
		)
	return {relative_path: transforms}


func _expect_equal(actual: int, expected: int, label: String, failures: Array[String]) -> void:
	if actual != expected:
		failures.append("%s expected=%d actual=%d" % [label, expected, actual])


func _expect_string_equal(
	actual: String,
	expected: String,
	label: String,
	failures: Array[String]
) -> void:
	if actual != expected:
		failures.append("%s expected=%s actual=%s" % [label, expected, actual])


func _expect_string_array(
	actual: Array,
	expected: Array,
	label: String,
	failures: Array[String]
) -> void:
	if actual != expected:
		failures.append("%s expected=%s actual=%s" % [label, expected, actual])


func _expect_same(
	actual: Variant,
	expected: Variant,
	label: String,
	failures: Array[String]
) -> void:
	if not is_same(actual, expected):
		failures.append(label)


func _expect_true(condition: bool, label: String, failures: Array[String]) -> void:
	if not condition:
		failures.append(label)


func _expect_false(condition: bool, label: String, failures: Array[String]) -> void:
	_expect_true(not condition, label, failures)