extends Node
class_name StateSlide

## Momentum slide. Friction is a flat deceleration on level ground but gravity
## projected along the floor accelerates you downhill, so slopes are the fast
## route. The capsule stays low via the machine's crouch handling (slide counts
## as crouched); no capsule fiddling here.

var machine: MovementStateMachine
var params: MovementParams:
	get: return machine.params

var elapsed: float = 0.0
var _slide_direction: Vector3 = Vector3.ZERO


func enter(_data: Dictionary = {}) -> void:
	elapsed = 0.0
	machine.register_chain_mechanic("slide")

	if machine.player.slide_player and not machine.player.slide_player.playing:
		machine.player.slide_player.play()

	# Slide in the direction of current velocity (momentum-based)
	var hvel := Vector3(machine.player.velocity.x, 0.0, machine.player.velocity.z)
	if hvel.length_squared() > 0.01:
		_slide_direction = hvel.normalized()
	else:
		# Fallback: player forward
		_slide_direction = -machine.player.global_transform.basis.z
		_slide_direction.y = 0.0
		_slide_direction = _slide_direction.normalized()

	# Entry speed: keep momentum, add a flat boost when actually moving fast on
	# the ground (rewards slide-cancelling sprints without making crouch a brake)
	var entry_speed := hvel.length()
	if machine.player.is_on_floor() and entry_speed > params.walk_speed * 0.8:
		entry_speed += params.slide_boost
	entry_speed = maxf(entry_speed, params.slide_speed * 0.75)
	machine.player.velocity.x = _slide_direction.x * machine.get_effective_speed(entry_speed)
	machine.player.velocity.z = _slide_direction.z * machine.get_effective_speed(entry_speed)


func exit() -> void:
	machine.slide_cooldown_timer = params.slide_cooldown
	if machine.player.slide_player:
		machine.player.slide_player.stop()


func update(delta: float) -> void:
	elapsed += delta
	var player := machine.player

	if player.slide_player and not player.slide_player.playing:
		player.slide_player.play()

	var vel: Vector3 = player.velocity
	var hvel := Vector3(vel.x, 0.0, vel.z)
	var hspeed := hvel.length()

	# ── Slope physics: gravity projected along the floor plane ────────────
	var on_slope := false
	if player.is_on_floor():
		var floor_n := player.get_floor_normal()
		if floor_n.y < 0.999:
			# Downhill direction on this slope
			var downhill := (Vector3.DOWN - floor_n * Vector3.DOWN.dot(floor_n))
			if downhill.length_squared() > 0.0001:
				downhill = downhill.normalized()
				var steepness := 1.0 - floor_n.y  # 0 flat .. ~0.3 steep
				var slope_pull := downhill * params.slide_slope_accel * steepness * 8.0
				hvel += Vector3(slope_pull.x, 0.0, slope_pull.z) * delta
				on_slope = downhill.dot(_slide_direction) > 0.1

	# ── Friction: flat decel on level ground, nearly free downhill ────────
	if hspeed > 0.01:
		var friction := params.slide_friction_flat
		if on_slope:
			friction *= 0.15
		var new_speed := maxf(hvel.length() - friction * delta, 0.0)
		if hvel.length() > 0.001:
			hvel = hvel.normalized() * new_speed

	# ── Steering: bend velocity toward input without changing speed ───────
	var wish_dir := machine.wish_dir_world
	if wish_dir.length_squared() > 0.01 and hvel.length_squared() > 0.01:
		wish_dir = wish_dir.normalized()
		var speed_now := hvel.length()
		var steered := hvel.lerp(wish_dir * speed_now, params.slide_steer_rate * delta)
		if steered.length_squared() > 0.01:
			hvel = steered.normalized() * speed_now
			_slide_direction = hvel.normalized()

	vel.x = hvel.x
	vel.z = hvel.z

	# ── Gravity (for slopes / edges) ──────────────────────────────────────
	if not player.is_on_floor():
		vel.y -= params.gravity * delta
	else:
		vel.y = -2.0  # Strong floor snap

	player.velocity = vel
	player.move_and_slide()

	# ── Update ground status ──────────────────────────────────────────────
	if player.is_on_floor():
		machine.on_ground = true
		machine.current_jump_count = 0
	else:
		machine.on_ground = false

	# ── End conditions ────────────────────────────────────────────────────
	var out_speed := Vector3(player.velocity.x, 0.0, player.velocity.z).length()

	# Jump out of slide: momentum-preserving hop
	if machine.input_jump_just_pressed and machine.jump_cooldown_timer <= 0.0:
		var hv := Vector3(player.velocity.x, 0.0, player.velocity.z)
		if hv.length_squared() > 0.01:
			var dir := hv.normalized()
			var jump_speed := maxf(out_speed, minf(out_speed + params.slide_jump_speed_boost, params.bunny_hop_speed_cap))
			player.velocity.x = dir.x * jump_speed
			player.velocity.z = dir.z * jump_speed
		player.velocity.y = params.jump_velocity
		machine.current_jump_count = 1
		machine.jump_cooldown_timer = params.jump_cooldown
		machine.on_ground = false
		machine.register_chain_mechanic("slide_jump")
		machine.movement_event.emit("jump", {})
		if player.jump_player:
			player.jump_player.play()
		machine.switch_to("air")
		return

	# Slide straight onto a wall → wall run (keeps the flow going)
	if not player.is_on_floor() and machine.wall_cooldown_timer <= 0.0 and out_speed > params.slide_min_speed:
		var wall_n := machine.detect_wall_horizontal()
		if wall_n != Vector3.ZERO and abs(machine.wish_dir_world.dot(wall_n)) < 0.85:
			machine.switch_to("wall_run")
			return

	# Dash out of slide
	if machine.input_dash and machine.can_dash():
		machine.switch_to("dash")
		return

	# Slide ended: too slow
	if out_speed < params.slide_min_speed:
		machine.switch_to("ground")
		return

	# Player released crouch
	if not machine.input_crouch:
		machine.switch_to("ground")
		return

	# Fell off edge
	if not machine.on_ground and machine.coyote_timer <= 0.0:
		machine.switch_to("air")
		return