extends GutTest
## Generator properties. The important one is reachability: a map where the
## boss cannot be walked to is a run that cannot be finished, and it would show
## up as a player wandering confused rather than as an error.


func _flood_reachable(grid: MapGrid, from: Vector2i) -> Dictionary:
	var seen := {}
	var queue: Array[Vector2i] = [from]
	seen[from] = true
	while not queue.is_empty():
		var t: Vector2i = queue.pop_back()
		for d in [Vector2i(1, 0), Vector2i(-1, 0), Vector2i(0, 1), Vector2i(0, -1)]:
			var n: Vector2i = t + d
			if seen.has(n) or not grid.in_bounds(n.x, n.y):
				continue
			if grid.blocks_move(n.x, n.y):
				continue
			seen[n] = true
			queue.append(n)
	return seen


func test_the_boss_is_always_reachable_from_the_spawn() -> void:
	# Many seeds, because "usually connected" is the failure mode that survives
	# a single-seed test and ruins one run in twenty.
	for s in range(1, 40):
		var m := MapGen.generate(s * 7919, 1 + (s % 5))
		var grid: MapGrid = m["grid"]
		var spawn_tile := grid.to_tile(m["spawn"])
		var boss_tile := grid.to_tile(m["boss_pos"])
		var reachable := _flood_reachable(grid, spawn_tile)
		assert_true(reachable.has(boss_tile),
			"seed %d: the boss room is walled off from the spawn" % s)


func test_generation_is_deterministic() -> void:
	var a := MapGen.generate(12345, 3)
	var b := MapGen.generate(12345, 3)
	assert_eq((a["grid"] as MapGrid).tiles, (b["grid"] as MapGrid).tiles,
		"same seed and depth must give the same map, or the server cannot " +
		"just send two numbers")
	assert_eq(a["spawn"], b["spawn"])
	assert_eq(a["boss_pos"], b["boss_pos"])


func test_different_seeds_give_different_maps() -> void:
	var a := MapGen.generate(1, 2)
	var b := MapGen.generate(2, 2)
	assert_ne((a["grid"] as MapGrid).tiles, (b["grid"] as MapGrid).tiles)


func test_maps_grow_with_depth() -> void:
	var shallow: MapGrid = MapGen.generate(99, 1)["grid"]
	var deep: MapGrid = MapGen.generate(99, 6)["grid"]
	assert_gt(deep.width, shallow.width)
	assert_gt(deep.height, shallow.height)


func test_the_map_is_sealed_at_its_border() -> void:
	var grid: MapGrid = MapGen.generate(4242, 2)["grid"]
	for x in grid.width:
		assert_true(grid.blocks_move(x, 0), "top border leaks at x=%d" % x)
		assert_true(grid.blocks_move(x, grid.height - 1), "bottom border leaks at x=%d" % x)
	for y in grid.height:
		assert_true(grid.blocks_move(0, y), "left border leaks at y=%d" % y)
		assert_true(grid.blocks_move(grid.width - 1, y), "right border leaks at y=%d" % y)


func test_spawn_and_boss_stand_on_open_ground() -> void:
	for s in range(1, 20):
		var m := MapGen.generate(s * 104729, 1 + (s % 4))
		var grid: MapGrid = m["grid"]
		assert_false(grid.circle_blocked(m["spawn"], SimConfig.PLAYER_RADIUS),
			"seed %d: player spawns inside geometry" % s)
		assert_false(grid.circle_blocked(m["boss_pos"], 40.0),
			"seed %d: boss spawns inside geometry" % s)


func test_rooms_do_not_overlap() -> void:
	var rooms: Array = MapGen.generate(777, 4)["rooms"]
	for i in rooms.size():
		for j in range(i + 1, rooms.size()):
			assert_false((rooms[i] as Rect2i).intersects(rooms[j]),
				"rooms %d and %d overlap" % [i, j])


# --- Tunnels ----------------------------------------------------------------

func _inside_any(rooms: Array, x: int, y: int) -> bool:
	for r: Rect2i in rooms:
		if r.has_point(Vector2i(x, y)):
			return true
	return false


## Whether (x, y) is a corner of at least one 2x2 square of open floor. A
## passage one tile wide has no such square anywhere along it.
func _in_open_square(g: MapGrid, x: int, y: int) -> bool:
	for dy in [-1, 0]:
		for dx in [-1, 0]:
			var ok := true
			for oy in 2:
				for ox in 2:
					if g.at(x + dx + ox, y + dy + oy) != MapGrid.Kind.FLOOR:
						ok = false
			if ok:
				return true
	return false


func test_no_tunnel_is_a_single_file_squeeze() -> void:
	# A one-tile corridor in a bullet hell is a shooting gallery: there is no
	# side to step to. Every corridor tile has to sit in open ground at least
	# two wide in some direction. Rooms and the authored arena are left out --
	# the arena's door is drawn one tile wide on purpose.
	for s in range(1, 40):
		var m := MapGen.generate(s * 7919, 1 + (s % 5))
		var g: MapGrid = m["grid"]
		var rooms: Array = m["rooms"]
		var arena: Rect2i = m["boss_room"]
		var squeezes := 0
		for y in g.height:
			for x in g.width:
				if g.at(x, y) != MapGrid.Kind.FLOOR:
					continue
				if _inside_any(rooms, x, y) or arena.has_point(Vector2i(x, y)):
					continue
				if not _in_open_square(g, x, y):
					squeezes += 1
		assert_eq(squeezes, 0,
			"seed %d: %d corridor tile(s) in a passage one tile wide" % [s, squeezes])


func test_tunnel_widths_vary_and_never_go_below_two() -> void:
	var seen := {}
	for s in range(1, 40):
		var widths: PackedInt32Array = MapGen.generate(s * 7919, 1 + (s % 5))["corridor_widths"]
		assert_false(widths.is_empty(), "seed %d carved no tunnels at all" % s)
		for w in widths:
			assert_between(w, MapGen.CORRIDOR_MIN_WIDTH, MapGen.CORRIDOR_MAX_WIDTH)
			seen[w] = true
	assert_eq(seen.size(), MapGen.CORRIDOR_MAX_WIDTH - MapGen.CORRIDOR_MIN_WIDTH + 1,
		"every width in the range turns up somewhere; got %s" % [seen.keys()])


func test_the_arena_keeps_every_wall_it_was_drawn_with() -> void:
	# The corridor to the door used to aim at the door tile itself, which sits
	# ON the arena's west wall. An L that bent the other way ran its second leg
	# down that wall column, and 45% of generated arenas had a slit carved in
	# an authored room. A wide tunnel makes the same mistake wider.
	for arena in [&"warden_hall", &"choir_vault"]:
		var stamp := Rooms.warden_hall() if arena == &"warden_hall" else Rooms.choir_vault()
		for s in range(1, 60):
			var m := MapGen.generate(s * 7919, 1 + (s % 5), arena)
			var g: MapGrid = m["grid"]
			var room: Rect2i = m["boss_room"]
			var carved := 0
			for y in stamp.size():
				for x in stamp[y].length():
					if stamp[y][x] != "#":
						continue
					if g.at(room.position.x + x, room.position.y + y) != MapGrid.Kind.WALL:
						carved += 1
			assert_eq(carved, 0,
				"seed %d %s: %d of the arena's own wall tiles were carved open"
					% [s * 7919, arena, carved])