extends "res://tests/test_case.gd"

# §6.1 match lifecycle state machine (task 5.1). The table is pure data, so
# it can be checked exhaustively rather than by example — which is the point
# of keeping it out of NetworkedMatch.

const MatchStateScript = preload("res://scripts/match_state.gd")


func test_wire_values_are_stable() -> void:
	# These integers ARE the snapshot's match_state byte. Renumbering an
	# existing state silently reinterprets every packet from an older peer,
	# so pin them: this test failing means a protocol break, not a typo.
	assert_eq(MatchStateScript.State.LOBBY, 0, "LOBBY")
	assert_eq(MatchStateScript.State.LOADING, 1, "LOADING")
	assert_eq(MatchStateScript.State.WARMUP, 2, "WARMUP")
	assert_eq(MatchStateScript.State.PLAYING, 3, "PLAYING")
	assert_eq(MatchStateScript.State.GOAL_PAUSE, 4, "GOAL_PAUSE")
	assert_eq(MatchStateScript.State.FULL_TIME, 5, "FULL_TIME")
	assert_eq(MatchStateScript.State.OVERTIME_WARMUP, 6, "OVERTIME_WARMUP")
	assert_eq(MatchStateScript.State.OVERTIME, 7, "OVERTIME")
	assert_eq(MatchStateScript.State.RESULTS, 8, "RESULTS")


func test_every_state_fits_in_the_wire_byte() -> void:
	for value in MatchStateScript.State.values():
		assert_true(value >= 0 and value <= 255, "state %d must fit a u8" % value)


func test_the_documented_happy_path_is_walkable() -> void:
	# §6.1's own diagram, start to finish, including the goal loop.
	var path := [
		MatchStateScript.State.LOBBY, MatchStateScript.State.LOADING,
		MatchStateScript.State.WARMUP, MatchStateScript.State.PLAYING,
		MatchStateScript.State.GOAL_PAUSE, MatchStateScript.State.WARMUP,
		MatchStateScript.State.PLAYING, MatchStateScript.State.FULL_TIME,
		MatchStateScript.State.OVERTIME_WARMUP, MatchStateScript.State.OVERTIME,
		MatchStateScript.State.RESULTS, MatchStateScript.State.LOBBY,
	]
	for i in path.size() - 1:
		assert_true(
			MatchStateScript.can_transition(path[i], path[i + 1]),
			"%s -> %s must be legal" % [MatchStateScript.to_name(path[i]), MatchStateScript.to_name(path[i + 1])]
		)


func test_illegal_shortcuts_are_rejected() -> void:
	var illegal := [
		[MatchStateScript.State.LOBBY, MatchStateScript.State.PLAYING],       # must load first
		[MatchStateScript.State.LOADING, MatchStateScript.State.PLAYING],     # must warm up first
		[MatchStateScript.State.WARMUP, MatchStateScript.State.GOAL_PAUSE],   # cannot score before play
		[MatchStateScript.State.PLAYING, MatchStateScript.State.RESULTS],     # must pass full time
		[MatchStateScript.State.RESULTS, MatchStateScript.State.PLAYING],     # match is over
		[MatchStateScript.State.FULL_TIME, MatchStateScript.State.PLAYING],   # regulation cannot resume
	]
	for pair in illegal:
		assert_true(
			not MatchStateScript.can_transition(pair[0], pair[1]),
			"%s -> %s must be rejected" % [MatchStateScript.to_name(pair[0]), MatchStateScript.to_name(pair[1])]
		)


func test_abort_to_lobby_is_reachable_from_anywhere_but_lobby() -> void:
	# §6.4: "if the last human leaves, abort to LOBBY" can fire at any point.
	for state in MatchStateScript.State.values():
		if state == MatchStateScript.State.LOBBY:
			assert_true(not MatchStateScript.can_transition(state, state), "LOBBY -> LOBBY is not a transition")
			continue
		assert_true(
			MatchStateScript.can_transition(state, MatchStateScript.State.LOBBY),
			"%s must be able to abort to LOBBY" % MatchStateScript.to_name(state)
		)


func test_no_state_transitions_to_itself() -> void:
	for state in MatchStateScript.State.values():
		assert_true(not MatchStateScript.can_transition(state, state), "%s -> itself" % MatchStateScript.to_name(state))


func test_every_state_is_reachable_and_can_make_progress() -> void:
	# Guards against a state being added to the enum and forgotten in the
	# table — an orphan would be broadcastable but a dead end, or unreachable
	# but present on the wire.
	for state in MatchStateScript.State.values():
		var has_exit := false
		var has_entry := false
		for other in MatchStateScript.State.values():
			if other != state and MatchStateScript.can_transition(state, other):
				has_exit = true
			if other != state and MatchStateScript.can_transition(other, state):
				has_entry = true
		assert_true(has_exit, "%s has no legal exit" % MatchStateScript.to_name(state))
		assert_true(has_entry, "%s is unreachable" % MatchStateScript.to_name(state))


func test_only_playing_and_overtime_are_live() -> void:
	# is_live() gates simulation in tasks 5.3/5.4; a warmup or a goal pause
	# must never read as live.
	assert_true(MatchStateScript.is_live(MatchStateScript.State.PLAYING), "PLAYING is live")
	assert_true(MatchStateScript.is_live(MatchStateScript.State.OVERTIME), "OVERTIME is live")
	for state in [
		MatchStateScript.State.LOBBY, MatchStateScript.State.LOADING, MatchStateScript.State.WARMUP,
		MatchStateScript.State.GOAL_PAUSE, MatchStateScript.State.FULL_TIME,
		MatchStateScript.State.OVERTIME_WARMUP, MatchStateScript.State.RESULTS,
	]:
		assert_true(not MatchStateScript.is_live(state), "%s must not be live" % MatchStateScript.to_name(state))


func test_unknown_values_are_rejected_rather_than_coerced() -> void:
	# A newer server can legitimately send a state this build has never heard
	# of; it must be refused, not clamped into a neighbouring valid state.
	for bogus in [-1, 9, 42, 255]:
		assert_true(not MatchStateScript.is_valid(bogus), "%d is not a valid state" % bogus)
		assert_true(not MatchStateScript.can_transition(MatchStateScript.State.PLAYING, bogus), "cannot enter %d" % bogus)
		assert_true(not MatchStateScript.can_transition(bogus, MatchStateScript.State.PLAYING), "cannot leave %d" % bogus)