extends GutTest
## Bosses that move. Movement is a property of the PHASE, so all of this is
## driven by building a BossPhase and stepping the world -- if any of it needed
## a per-boss branch in SimWorld, the boss format would have stopped being data.

var world: SimWorld
var boss: SimBoss

const ROOM := Rect2(Vector2(-300.0, -200.0), Vector2(600.0, 400.0))


func before_each() -> void:
	var map := MapGrid.new(60, 40, MapGrid.Kind.WALL)
	map.fill_rect(Rect2i(1, 1, 58, 38), MapGrid.Kind.FLOOR)
	map.centre_on_origin()
	world = SimWorld.new(3)
	world.set_map(map)


func _with_phase(phase: BossPhase, at := Vector2.ZERO) -> SimBoss:
	var def := BossDef.new()
	def.id = &"test_boss"
	def.max_hp = 1000
	def.radius = 30.0
	def.phases = [phase]
	boss = world.spawn_boss(def)
	boss.pos = at
	boss.room = ROOM
	return boss


func _static_phase() -> BossPhase:
	var p := BossPhase.new()
	p.enter_at_hp_fraction = 1.0
	p.telegraph_ticks = 0
	p.loop_ticks = 600
	return p


func _step(n: int) -> void:
	for _i in n:
		world.step()


# --- The derived "does it move" flag ----------------------------------------

func test_a_phase_with_no_mode_or_no_speed_does_not_move() -> void:
	var p := _static_phase()
	assert_false(p.moves())
	p.move = BossPhase.Move.CHASE
	assert_false(p.moves(), "a mode with no speed is still standing still")
	p.move_speed = 60.0
	assert_true(p.moves())


## Derived from the phases rather than stored, so a boss cannot claim to be
## stationary while one of its phases walks around.
func test_a_boss_moves_if_any_of_its_phases_does() -> void:
	assert_false(Content.warden().moves(), "the Warden still stands still")
	assert_true(Content.cantor().moves(), "the Cantor does not")


func test_a_static_phase_leaves_the_boss_exactly_where_it_was() -> void:
	var b := _with_phase(_static_phase(), Vector2(50.0, 20.0))
	_step(120)
	assert_eq(b.pos, Vector2(50.0, 20.0))


# --- Waypoints ---------------------------------------------------------------

func _waypoint_phase() -> BossPhase:
	var p := _static_phase()
	p.move = BossPhase.Move.WAYPOINTS
	p.move_speed = 200.0
	p.waypoint_dwell = 30
	p.waypoints = [Vector2(0.0, 0.0), Vector2(1.0, 0.0)]
	return p


func test_a_waypoint_boss_walks_to_its_first_point() -> void:
	var b := _with_phase(_waypoint_phase(), ROOM.get_center())
	var corner := ROOM.position
	var before := b.pos.distance_to(corner)
	_step(30)
	assert_lt(b.pos.distance_to(corner), before, "it should be closing")


func test_it_arrives_dwells_and_moves_on() -> void:
	var phase := _waypoint_phase()
	var b := _with_phase(phase, ROOM.position)
	_step(2)
	assert_eq(b.waypoint_index, 1, "standing on the first point advances it")
	var held := b.pos
	_step(phase.waypoint_dwell - 4)
	assert_eq(b.pos, held, "and it waits there rather than setting off at once")
	_step(60)
	assert_ne(b.pos, held, "then it goes")


## Fractions of the arena, not absolute positions -- the Warden's hall and the
## Choir Vault are different sizes, and one phase has to work in either.
func test_waypoints_are_fractions_of_the_room() -> void:
	var phase := _waypoint_phase()
	phase.waypoints = [Vector2(0.5, 0.5)]
	var b := _with_phase(phase, ROOM.position)
	_step(200)
	assert_almost_eq(b.pos.x, ROOM.get_center().x, 4.0)
	assert_almost_eq(b.pos.y, ROOM.get_center().y, 4.0)


func test_a_waypoint_phase_with_no_points_stands_still() -> void:
	var phase := _waypoint_phase()
	phase.waypoints = []
	var b := _with_phase(phase, Vector2(10.0, 10.0))
	_step(60)
	assert_eq(b.pos, Vector2(10.0, 10.0))


# --- Chase -------------------------------------------------------------------

func _chase_phase(standoff: float) -> BossPhase:
	var p := _static_phase()
	p.move = BossPhase.Move.CHASE
	p.move_speed = 180.0
	p.move_param = standoff
	return p


func test_it_closes_when_you_are_far_away() -> void:
	var b := _with_phase(_chase_phase(150.0), Vector2(-250.0, 0.0))
	var p := world.add_player(1, "bait")
	p.pos = Vector2(250.0, 0.0)
	var before := b.pos.distance_to(p.pos)
	_step(60)
	assert_lt(b.pos.distance_to(p.pos), before)


## Backs off rather than piling onto you. A boss standing on top of a player is
## a boss whose bullets cannot be read, which is the one thing this genre
## cannot afford.
func test_it_backs_off_when_you_get_too_close() -> void:
	var b := _with_phase(_chase_phase(200.0), Vector2.ZERO)
	var p := world.add_player(1, "bait")
	p.pos = Vector2(20.0, 0.0)
	_step(60)
	assert_gt(b.pos.distance_to(p.pos), 20.0)


func test_it_settles_at_the_distance_it_was_given() -> void:
	var b := _with_phase(_chase_phase(150.0), Vector2(-250.0, 0.0))
	var p := world.add_player(1, "bait")
	p.pos = Vector2(100.0, 0.0)
	_step(240)
	assert_almost_eq(b.pos.distance_to(p.pos), 150.0, 12.0)


func test_it_stands_still_with_nobody_to_chase() -> void:
	var b := _with_phase(_chase_phase(150.0), Vector2(40.0, 0.0))
	_step(60)
	assert_eq(b.pos, Vector2(40.0, 0.0))


# --- Orbit -------------------------------------------------------------------

func _orbit_phase() -> BossPhase:
	var p := _static_phase()
	p.move = BossPhase.Move.ORBIT
	p.move_speed = 160.0
	p.move_param = 120.0
	return p


## ORBIT computes an absolute destination, so without the shared speed clamp it
## would snap onto its circle on the very first tick.
func test_orbiting_never_teleports_onto_the_circle() -> void:
	var phase := _orbit_phase()
	var b := _with_phase(phase, ROOM.get_center() + Vector2(280.0, 0.0))
	var before := b.pos
	world.step()
	assert_lte(b.pos.distance_to(before), phase.move_speed * SimConfig.TICK_DELTA + 0.5,
		"one tick may move it at most one tick's worth")


func test_orbiting_ends_up_on_the_circle_and_keeps_going() -> void:
	var phase := _orbit_phase()
	var b := _with_phase(phase, ROOM.get_center())
	_step(300)
	var centre := ROOM.get_center()
	assert_almost_eq(b.pos.distance_to(centre), phase.move_param, 25.0)
	var somewhere := b.pos
	_step(90)
	assert_gt(b.pos.distance_to(somewhere), 20.0, "and it is still travelling")


# --- The invariants movement had to not break --------------------------------

## Boss rooms deliberately do not lock: a player can always walk out. That only
## works as an escape if the boss cannot follow.
func test_a_moving_boss_never_leaves_its_arena() -> void:
	var phase := _chase_phase(0.0)
	phase.move_speed = 400.0
	var b := _with_phase(phase, ROOM.get_center())
	var p := world.add_player(1, "bait")
	for step_index in 400:
		# Drag the bait right out of the room and around the map.
		p.pos = Vector2(900.0, 500.0).rotated(float(step_index) * 0.05)
		world.step()
		assert_true(ROOM.has_point(b.pos) or ROOM.abs().grow(1.0).has_point(b.pos),
			"the boss left its arena at %s" % b.pos)


## A single pillar proves nothing -- the boss would end up at its quarry either
## way, and only the final position was ever checked. A wall it cannot go round
## is the test: if movement ignores geometry the boss simply appears on the far
## side of it.
func test_a_moving_boss_does_not_walk_through_geometry() -> void:
	var wall_x := world.map.to_tile(Vector2.ZERO).x
	for ty in range(world.map.to_tile(Vector2(0.0, -260.0)).y,
			world.map.to_tile(Vector2(0.0, 260.0)).y + 1):
		world.map.set_tile(wall_x, ty, MapGrid.Kind.WALL)

	var b := _with_phase(_chase_phase(0.0), Vector2(-200.0, 0.0))
	var p := world.add_player(1, "bait")
	p.pos = Vector2(200.0, 0.0)
	for _i in 300:
		world.step()
		assert_false(world.map.circle_blocked(b.pos, 2.0),
			"the boss stepped inside solid geometry at %s" % b.pos)
	assert_lt(b.pos.x, 0.0,
		"the wall spans the arena, so the boss must still be on its own side")


## The replica draws bosses from snapshots. If it moved one itself, the drawn
## boss and the authoritative one would drift apart with nothing to correct it.
func test_a_replica_never_moves_a_boss() -> void:
	var replica := SimWorld.new(3)
	replica.authoritative = false
	var def := BossDef.new()
	def.max_hp = 1000
	def.radius = 30.0
	def.phases = [_waypoint_phase()]
	var b := replica.spawn_boss(def)
	b.pos = Vector2(77.0, -33.0)
	b.room = ROOM
	for _i in 200:
		replica.step()
	assert_eq(b.pos, Vector2(77.0, -33.0))


# --- The real fight ---------------------------------------------------------

## Drives the actual Cantor through every phase in its own arena. Nothing here
## asserts a specific pattern -- the point is that a boss which moves, walks a
## circuit, chases, orbits and telegraphs runs for thousands of ticks without
## leaving its room, standing in a wall, or firing nothing.
func test_the_cantor_survives_its_own_fight() -> void:
	var inst := Instance.make_dungeon(2, 9183, 1)
	assert_eq(inst.boss_id, Content.BOSS_CANTOR, "setup: an odd seed is the vault")
	var b := inst.world.boss
	var bait := inst.world.add_player(1, "bait")
	bait.pos = b.pos + Vector2(180.0, 0.0)
	bait.spawn_grace = 1000000          # watching, not fighting

	var phases_seen := {}
	var telegraphs := 0
	var full := b.def.max_hp
	for stage in b.def.phases.size():
		# Set health to each phase's own threshold rather than to fractions
		# picked by hand -- guessing them missed the last phase entirely, and
		# would go stale the moment the fight was retuned.
		b.hp = maxi(roundi(float(full) * b.def.phases[stage].enter_at_hp_fraction), 1)
		for _i in 600:
			inst.step()
			phases_seen[b.phase_index] = true
			assert_true(b.room.grow(1.0).has_point(b.pos),
				"the Cantor left its arena at %s" % b.pos)
			assert_false(inst.world.map.circle_blocked(b.pos, 2.0),
				"the Cantor stood inside geometry at %s" % b.pos)
			for ev in inst.world.events:
				if int(ev["t"]) == SimEvent.Type.TELEGRAPH:
					telegraphs += 1
			inst.world.drain_events()

	assert_eq(phases_seen.size(), b.def.phases.size(), "every phase ran")
	assert_gt(telegraphs, 0, "and it warned before striking at least once")
	assert_gt(inst.world.pool.live_count, 0, "and it is actually shooting")