extends Node
class_name MovementStateMachine

## Generic state machine for player movement.
## Each state is a Node child; the machine switches between them.
##
## The machine owns cross-state concerns so individual states stay small:
##   - input snapshot (written by the controller each tick)
##   - jump buffering / coyote time / jump cooldown
##   - crouch capsule resizing (smoothly lerped, single owner)
##   - dash cooldown (per-instance, not shared between players)
##   - grapple hook raycast + travel
##   - wall detection helpers
##   - chain-bonus bookkeeping

signal state_changed(from_state: String, to_state: String)
signal movement_event(event_name: String, data: Dictionary)

var current_state: String = ""
var states: Dictionary = {}

var player: CharacterBody3D
var params: MovementParams

# ── Input (set by controller each physics tick) ───────────────────────────────
var input_dir: Vector2 = Vector2.ZERO
var wish_dir_world: Vector3 = Vector3.ZERO
var input_jump_pressed: bool = false
var input_jump_just_pressed: bool = false
var input_crouch: bool = false
var input_sprint: bool = false
var input_dash: bool = false
var input_grapple: bool = false
var input_grapple_just_pressed: bool = false

# Grapple state
var grapple_point: Vector3 = Vector3.ZERO
var grapple_length: float = 0.0
var grapple_travel_time: float = 0.0
var grapple_shoot_time: float = 0.0
var is_grapple_shooting: bool = false

# ── State tracking ────────────────────────────────────────────────────────────
var wall_normal: Vector3 = Vector3.ZERO
var wall_contact_point: Vector3 = Vector3.ZERO
var wall_side: float = 0.0  # -1 left, +1 right, 0 none
var on_ground: bool = false
var last_ground_time: float = 0.0
var jump_buffer_time: float = 0.0
var coyote_timer: float = 0.0
var jump_cooldown_timer: float = 0.0
var dash_charges: int = -1              # -1 = initialize from params on first tick
var dash_recharge_timer: float = 0.0
var current_jump_count: int = 0
var chain_timer: float = 0.0
var chain_count: int = 0
var current_chain_bonus: float = 0.0
var original_capsule_height: float = 1.8
var slide_cooldown_timer: float = 0.0  # Prevents instant slide re-entry
var wall_cooldown_timer: float = 0.0   # Prevents instant re-attachment after wall jump
var is_crouched: bool = false
var can_wall_climb: bool = true

# Smooth capsule crouch: the machine is the single owner of capsule height.
var _capsule_current_height: float = 0.0


func _ready() -> void:
	# Ensure grapple state is injected
	var grapple_state = Node.new()
	grapple_state.name = "state_grapple"
	grapple_state.set_script(load("res://movement/states/state_grapple.gd"))
	add_child(grapple_state)

	# Ensure wall climb state is injected
	var wall_climb_state = Node.new()
	wall_climb_state.name = "state_wall_climb"
	wall_climb_state.set_script(load("res://movement/states/state_wall_climb.gd"))
	add_child(wall_climb_state)

	for child in get_children():
		if child is Node and child.name.begins_with("state_"):
			states[child.name.replace("state_", "")] = child
			child.machine = self
	if current_state.is_empty() and not states.is_empty():
		switch_to(states.keys()[0])


func _physics_process(delta: float) -> void:
	# Client-authoritative movement: only the peer that OWNS this player
	# simulates it. Everyone else interpolates the synced transform.
	if player and not player.is_multiplayer_authority(): return

	# Update coyote time
	if on_ground:
		coyote_timer = params.coyote_time
	else:
		coyote_timer = maxf(coyote_timer - delta, 0.0)

	# Update jump buffer
	if input_jump_just_pressed:
		jump_buffer_time = params.jump_buffer
	else:
		jump_buffer_time = maxf(jump_buffer_time - delta, 0.0)

	# Update timers
	jump_cooldown_timer = maxf(jump_cooldown_timer - delta, 0.0)
	slide_cooldown_timer = maxf(slide_cooldown_timer - delta, 0.0)
	wall_cooldown_timer = maxf(wall_cooldown_timer - delta, 0.0)

	# Dash charges: regain one per dash_cooldown while below max
	if dash_charges < 0:
		dash_charges = params.dash_charges
	if dash_charges < params.dash_charges:
		dash_recharge_timer -= delta
		if dash_recharge_timer <= 0.0:
			dash_charges += 1
			dash_recharge_timer = params.dash_cooldown if dash_charges < params.dash_charges else 0.0

	# Update chain timer
	if chain_timer > 0.0 and on_ground:
		chain_timer -= delta
		if chain_timer <= 0.0:
			chain_count = 0
			current_chain_bonus = 0.0

	# Global grapple check: if just pressed, raycast from camera
	if input_grapple_just_pressed and current_state != "grapple" and not is_grapple_shooting:
		_try_start_grapple()

	if is_grapple_shooting:
		if not input_grapple:
			is_grapple_shooting = false
		else:
			grapple_shoot_time += delta
			if grapple_shoot_time >= grapple_travel_time:
				is_grapple_shooting = false
				movement_event.emit("grapple_latch", {})
				switch_to("grapple")

	# Manage global crouch state (slide keeps the capsule low)
	is_crouched = input_crouch or current_state == "slide"
	_update_crouch_capsule(delta)

	if current_state.is_empty():
		return
	if not states.has(current_state):
		return
	var state_node = states[current_state]
	if state_node.has_method("update"):
		state_node.update(delta)


func switch_to(new_state_name: String, data: Dictionary = {}) -> void:
	if new_state_name == current_state:
		return
	if not states.has(new_state_name):
		push_warning("MovementStateMachine: state '%s' not found" % new_state_name)
		return
	var prev = current_state
	# Exit only the current state
	if states.has(prev):
		var old_state = states[prev]
		if old_state.has_method("exit"):
			old_state.exit()
	# Enter the new state
	current_state = new_state_name
	var new_state = states[new_state_name]
	if new_state.has_method("enter"):
		new_state.enter(data)
	state_changed.emit(prev, new_state_name)


## Called by states when the player touches down. Emits the landing event so
## camera/audio/animation can react proportionally to impact speed.
func notify_landed(fall_speed: float) -> void:
	on_ground = true
	current_jump_count = 0
	can_wall_climb = true
	if fall_speed > params.land_soft_speed:
		movement_event.emit("land", {
			"fall_speed": fall_speed,
			"heavy": fall_speed >= params.land_heavy_speed,
		})


## Shared jump executed from ground-like states. Keeps horizontal momentum.
func do_jump(extra_boost: float = 0.0) -> void:
	player.velocity.y = params.jump_velocity + extra_boost
	current_jump_count = 1
	on_ground = false
	coyote_timer = 0.0
	jump_buffer_time = 0.0
	jump_cooldown_timer = params.jump_cooldown
	register_chain_mechanic("jump")
	movement_event.emit("jump", {})
	if player.jump_player:
		player.jump_player.play()


func _try_start_grapple() -> void:
	if not player or not player.camera:
		return
	var camera: Camera3D = player.camera
	var space_state := player.get_world_3d().direct_space_state
	var origin := camera.global_position
	var end := origin - camera.global_transform.basis.z * params.grapple_range
	var ray := PhysicsRayQueryParameters3D.create(origin, end)
	ray.exclude = [player.get_rid()]
	var hit := space_state.intersect_ray(ray)
	if not hit.is_empty():
		grapple_point = hit.position
		grapple_length = origin.distance_to(grapple_point)
		grapple_travel_time = grapple_length / params.grapple_shoot_speed
		grapple_shoot_time = 0.0
		is_grapple_shooting = true
		movement_event.emit("grapple_shoot", {})


func register_chain_mechanic(_mechanic_name: String) -> void:
	if chain_timer > 0.0 and chain_count > 0:
		chain_count += 1
	else:
		chain_count = 1

	# Shrink the chain window as the chain gets longer to make it increasingly punishing
	# Drops by 0.05 seconds per successful chain, down to a minimum of 0.4 seconds
	var current_window = maxf(0.4, params.chain_window - (float(chain_count) * 0.05))
	chain_timer = current_window

	var raw_bonus = float(chain_count) * params.chain_bonus_per_success
	if raw_bonus <= params.chain_bonus_cap:
		current_chain_bonus = raw_bonus
	else:
		# Soft cap: diminishing returns past the cap
		var over_bonus = raw_bonus - params.chain_bonus_cap
		current_chain_bonus = params.chain_bonus_cap + (over_bonus / (1.0 + over_bonus * 3.0))

	movement_event.emit("chain_updated", {
		"count": chain_count,
		"bonus": current_chain_bonus
	})


func get_effective_speed(base_speed: float) -> float:
	return base_speed * (1.0 + current_chain_bonus)


## Utility: detect wall to left or right of player using horizontal raycasts.
## Returns the wall normal and sets wall_side. Returns Vector3.ZERO if no wall.
func detect_wall_horizontal() -> Vector3:
	if not player:
		return Vector3.ZERO
	var origin := player.global_position + Vector3.UP * params.wall_ray_up_height
	var right_dir := player.global_transform.basis.x.normalized()
	var space_state := player.get_world_3d().direct_space_state

	# Cast two rays: one left, one right
	for side_data in [{"dir": right_dir, "side": 1.0}, {"dir": -right_dir, "side": -1.0}]:
		var ray_end: Vector3 = origin + side_data["dir"] * params.wall_detect_distance
		var ray := PhysicsRayQueryParameters3D.create(origin, ray_end)
		ray.exclude = [player.get_rid()]
		var hit := space_state.intersect_ray(ray)
		if not hit.is_empty():
			var collider = hit.get("collider")
			if collider is PlayerMovementController or collider is CharacterBody3D or collider.has_method("take_damage"):
				continue
			var n: Vector3 = hit.get("normal", Vector3.ZERO)
			# Wall must be roughly vertical (normal mostly horizontal)
			if abs(n.y) < 0.3 and n.length_squared() > 0.0:
				wall_normal = n.normalized()
				wall_contact_point = hit.get("position", origin)
				wall_side = side_data["side"]
				return wall_normal

	# Also cast along movement direction for head-on walls
	var hvel := Vector3(player.velocity.x, 0.0, player.velocity.z)
	if hvel.length_squared() > 0.1:
		var move_dir := hvel.normalized()
		var perp := move_dir.cross(Vector3.UP).normalized()
		for side_data in [{"dir": perp, "side": 1.0}, {"dir": -perp, "side": -1.0}]:
			var ray_end: Vector3 = origin + side_data["dir"] * params.wall_detect_distance
			var ray := PhysicsRayQueryParameters3D.create(origin, ray_end)
			ray.exclude = [player.get_rid()]
			var hit := space_state.intersect_ray(ray)
			if not hit.is_empty():
				var collider = hit.get("collider")
				if collider is PlayerMovementController or collider is CharacterBody3D or collider.has_method("take_damage"):
					continue
				var n: Vector3 = hit.get("normal", Vector3.ZERO)
				if abs(n.y) < 0.3 and n.length_squared() > 0.0:
					wall_normal = n.normalized()
					wall_contact_point = hit.get("position", origin)
					wall_side = side_data["side"]
					return wall_normal

	wall_normal = Vector3.ZERO
	wall_contact_point = Vector3.ZERO
	wall_side = 0.0
	return Vector3.ZERO

## Utility: detect wall directly in front of the player.
## Useful for wall climbing and vaulting over short walls.
func detect_wall_forward() -> Dictionary:
	if not player:
		return {"hit": false, "normal": Vector3.ZERO, "is_short": false}

	var move_dir := -player.global_transform.basis.z
	move_dir.y = 0.0
	if move_dir.length_squared() > 0.01:
		move_dir = move_dir.normalized()
	else:
		return {"hit": false, "normal": Vector3.ZERO, "is_short": false}

	var space_state := player.get_world_3d().direct_space_state
	var dist := 1.2 # Increased to reliably detect walls at an angle

	# Lower ray (feet/knees)
	var origin_low := player.global_position + Vector3.UP * params.wall_ray_down_height
	var ray_low := PhysicsRayQueryParameters3D.create(origin_low, origin_low + move_dir * dist)
	ray_low.exclude = [player.get_rid()]
	var hit_low := space_state.intersect_ray(ray_low)

	# Mid ray (chest/head)
	var origin_mid := player.global_position + Vector3.UP * params.wall_ray_up_height
	var ray_mid := PhysicsRayQueryParameters3D.create(origin_mid, origin_mid + move_dir * dist)
	ray_mid.exclude = [player.get_rid()]
	var hit_mid := space_state.intersect_ray(ray_mid)

	# If both lower rays miss, there is no wall directly in front
	if hit_low.is_empty() and hit_mid.is_empty():
		return {"hit": false, "normal": Vector3.ZERO, "is_short": false}

	# Get the normal from the highest point we hit, or the lowest if we only hit low
	var best_hit = hit_mid if not hit_mid.is_empty() else hit_low
	var collider = best_hit.get("collider")
	if collider is PlayerMovementController or collider is CharacterBody3D or collider.has_method("take_damage"):
		return {"hit": false, "normal": Vector3.ZERO, "is_short": false}

	var normal: Vector3 = best_hit.get("normal", Vector3.ZERO)
	if abs(normal.y) >= 0.3:
		return {"hit": false, "normal": Vector3.ZERO, "is_short": false} # Not a vertical wall

	# Check if wall is short (ledge check) using a top ray
	var origin_high := player.global_position + Vector3.UP * (params.wall_ray_up_height + params.wall_climb_vault_height_check)
	var ray_high := PhysicsRayQueryParameters3D.create(origin_high, origin_high + move_dir * dist)
	ray_high.exclude = [player.get_rid()]
	var hit_high := space_state.intersect_ray(ray_high)

	return {"hit": true, "normal": normal.normalized(), "is_short": hit_high.is_empty()}


## Perform an instant vault over a short wall: forward+up impulse, camera kick
## via the rig, cooldown so we don't immediately re-detect the same wall.
func do_vault() -> void:
	var look_dir := -player.global_transform.basis.z
	var h_look := Vector3(look_dir.x, 0.0, look_dir.z)
	if h_look.length_squared() > 0.01:
		h_look = h_look.normalized()
	player.velocity = h_look * params.wall_climb_vault_forward
	player.velocity.y = params.wall_climb_vault_up
	if player.vault_player:
		player.vault_player.play()
	movement_event.emit("vault", {})
	var rig = player.get_node_or_null("HeadPivot")
	if rig and rig.has_method("add_pitch_impulse"):
		rig.add_pitch_impulse(6.0)
	wall_cooldown_timer = 0.3
	register_chain_mechanic("vault")


## Smoothly lerp the collision capsule toward the crouch/stand height and keep
## the capsule's bottom anchored so shrinking doesn't lift the player off the
## floor. Standing back up is blocked while there's no headroom.
func _update_crouch_capsule(delta: float) -> void:
	var shape_node: CollisionShape3D = null
	for child in player.get_children():
		if child is CollisionShape3D and child.shape is CapsuleShape3D:
			shape_node = child
			break
	if not shape_node:
		return
	var shape = shape_node.shape as CapsuleShape3D
	if _capsule_current_height <= 0.0:
		_capsule_current_height = shape.height

	var target_height := original_capsule_height * (0.5 if is_crouched else 1.0)

	# Don't stand up into a ceiling
	if not is_crouched and target_height > _capsule_current_height + 0.01:
		var space_state := player.get_world_3d().direct_space_state
		var from := player.global_position + Vector3.UP * (_capsule_current_height * 0.5)
		var to := player.global_position + Vector3.UP * (original_capsule_height * 0.55)
		var ray := PhysicsRayQueryParameters3D.create(from, to)
		ray.exclude = [player.get_rid()]
		if not space_state.intersect_ray(ray).is_empty():
			target_height = _capsule_current_height  # hold until clear

	var t := 1.0 - exp(-params.crouch_transition_speed * delta)
	_capsule_current_height = lerpf(_capsule_current_height, target_height, t)
	if absf(_capsule_current_height - target_height) < 0.005:
		_capsule_current_height = target_height

	shape.height = _capsule_current_height
	# Keep feet planted: offset the shape down by half the height loss.
	shape_node.position.y = -(original_capsule_height - _capsule_current_height) * 0.5


## 0 (standing) → 1 (fully crouched); used by the camera rig for eye height.
func get_crouch_factor() -> float:
	if original_capsule_height <= 0.0 or _capsule_current_height <= 0.0:
		return 0.0
	return clampf((original_capsule_height - _capsule_current_height)
		/ (original_capsule_height * 0.5), 0.0, 1.0)


func can_dash() -> bool:
	return dash_charges != 0  # -1 (uninitialized) counts as ready


## Spend one dash charge and start the recharge clock if it isn't running.
func consume_dash_charge() -> void:
	if dash_charges < 0:
		dash_charges = params.dash_charges
	dash_charges = maxi(dash_charges - 1, 0)
	if dash_recharge_timer <= 0.0:
		dash_recharge_timer = params.dash_cooldown


## Seconds until the NEXT dash is available (0 when a charge is banked).
## HUDs also read get_dash_charges() to draw pips.
func get_dash_cooldown_remaining() -> float:
	if dash_charges != 0:
		return 0.0
	return maxf(dash_recharge_timer, 0.0)


func get_dash_charges() -> int:
	return dash_charges if dash_charges >= 0 else params.dash_charges