class_name ShipCameraRig
extends Node3D

# Third-person camera for a Ship. Ball Cam keeps the ship between the camera
# and the ball; Ship Cam chases behind the ship. The game mode spawns this
# rig and assigns `target` after spawning the player's ship — ships
# themselves are camera-free (a headless/AI ship never needs one).

signal camera_mode_changed(is_ball_cam: bool)
signal impact_feedback(intensity: float)

@export var camera_distance := 8.0
@export var camera_height := 3.0
@export var camera_smoothing := 10.0
@export var orbit_smoothing := 6.0   # How fast the camera swings around the ship in ball cam
@export var look_smoothing := 20.0   # How fast the camera re-centres its look target
@export var min_camera_height := 1.0 # Keeps the camera from dipping through the arena floor
@export_group("Speed Feel")
@export var base_fov := 70.0
@export var speed_fov_add := 11.0
@export var turbo_fov_kick := 7.0
@export var turbo_distance_kick := 0.9
@export var feel_smoothing := 7.0
@export_group("Impact Shake")
@export var max_shake_offset := 0.32
@export var shake_decay := 8.0
@export_group("Impact Punch")
# Replaces Engine.time_scale hit-stop / goal slow-mo (see game_mode.gd):
# a camera-only FOV kick + PostFX flash that decays over real time, so it
# works identically for hit-stop and goal moments without touching global
# simulation speed — which a networked client could never do to a shared sim.
@export var punch_fov_kick := 9.0
@export var punch_vignette_kick := 0.28
@export var punch_chroma_kick := 0.012
@export var punch_decay := 5.0

var target: Ship:
	set(value):
		if target == value:
			return
		if is_instance_valid(target) and target.ball_contact.is_connected(_on_target_ball_contact):
			target.ball_contact.disconnect(_on_target_ball_contact)
		target = value
		_connect_target()
		# Priming: a freshly assigned target's Visual has no interpolation
		# history yet (or is about to be reparented mid-spawn), and the rig
		# itself would otherwise lerp in from wherever it was previously
		# (world origin on first spawn, the old target on a Spectate switch)
		# over camera_smoothing seconds. Both read as a visible swoop/smear;
		# neither is a real camera move.
		if is_instance_valid(target) and is_instance_valid(target.visual):
			target.visual.reset_physics_interpolation()
		if is_inside_tree():
			snap_to_target()
var ball_cam_enabled := true

@onready var camera: Camera3D = $Camera3D
@onready var post_material: ShaderMaterial = $PostProcess/PostFX.material as ShaderMaterial

var _ball: Node3D
# Smoothed horizontal direction from ball to ship; the ball-cam orbits along
# this so the camera swings smoothly around the ship instead of chasing a
# raw position (which whips when ball and ship are close together).
var _orbit_dir := Vector3.BACK
var _turbo_blend := 0.0
var _speed_blend := 0.0
var _effective_distance := 8.0
var _shake_strength := 0.0
var _shake_noise := FastNoiseLite.new()
var _shake_time := 0.0
var _last_shake_offset := Vector3.ZERO
var _punch_strength := 0.0
var _goal_cut_active := false
var _goal_cut_position := Vector3.ZERO
var _goal_cut_look_at := Vector3.ZERO

const SHAKE_UPDATE_HZ := 60.0


func _ready():
	# Group lets the HUD discover the rig for the camera-mode instrument
	add_to_group("ship_camera")
	# The rig moves itself every rendered frame in _process now (task 0.16),
	# not on the physics tick — Godot's built-in physics interpolation would
	# otherwise smooth between _physics_process-era transforms this rig no
	# longer writes, fighting the manual smoothing below.
	physics_interpolation_mode = Node.PHYSICS_INTERPOLATION_MODE_OFF
	camera.fov = base_fov
	_effective_distance = camera_distance
	_shake_noise.noise_type = FastNoiseLite.TYPE_SIMPLEX_SMOOTH
	_shake_noise.frequency = 2.5
	_connect_target()


func _connect_target() -> void:
	if not is_inside_tree() or not is_instance_valid(target):
		return
	if not target.ball_contact.is_connected(_on_target_ball_contact):
		target.ball_contact.connect(_on_target_ball_contact)
	if not target.wall_contact.is_connected(_on_target_wall_contact):
		target.wall_contact.connect(_on_target_wall_contact)


func _exit_tree() -> void:
	AudioManager.stop_engine()
	if is_instance_valid(target) and target.ball_contact.is_connected(_on_target_ball_contact):
		target.ball_contact.disconnect(_on_target_ball_contact)
	if is_instance_valid(target) and target.wall_contact.is_connected(_on_target_wall_contact):
		target.wall_contact.disconnect(_on_target_wall_contact)


func _input(event):
	if event.is_action_pressed("ui_accept"):  # Enter key
		ball_cam_enabled = !ball_cam_enabled
		camera_mode_changed.emit(ball_cam_enabled)


func _process(delta):
	# Camera position smoothing operates on the unshaken chase position. Remove
	# last frame's presentation-only offset first so shake never accumulates or
	# exceeds its configured amplitude during a low-time-scale hit-stop.
	camera.global_position -= _last_shake_offset
	_last_shake_offset = Vector3.ZERO
	if not is_instance_valid(target):
		return
	if _goal_cut_active:
		_smooth_look_at(_goal_cut_look_at, delta)
		# The cinematic cut freezes camera position, but leftover shake from
		# an impact right before the goal must still bleed off in real time —
		# otherwise it resumes at full pre-cut magnitude when play returns.
		_decay_shake(delta)
		return
	_update_speed_feel(delta)
	var ball := _get_ball()
	if ball_cam_enabled and ball:
		_update_ball_cam(delta, ball)
	else:
		_update_ship_cam(delta)
	_apply_punch(delta)


func _get_ball() -> Node3D:
	if not is_instance_valid(_ball):
		_ball = get_tree().get_first_node_in_group("ball")
	return _ball


func _update_ball_cam(delta, ball: Node3D):
	# Ball cam keeps the ship between the camera and the ball: the camera sits
	# on the ball→ship line (horizontal component only), looking at the ball,
	# so the ship stays low-centre in frame and the ball stays centred.
	# Reads target.visual, not target itself: once prediction correction
	# (task 0.14) lands, the body can be offset from what's on screen — the
	# camera must always frame what the player sees, not the collider.
	# get_global_transform_interpolated() (not global_transform) because this
	# now runs in _process: the physics body only moves once per 60Hz tick,
	# so sampling its raw transform every rendered frame at 240fps would
	# repeat the same value 4 times in a row and read as stutter.
	var ship_pos: Vector3 = target.visual.get_global_transform_interpolated().origin
	var ball_pos: Vector3 = ball.global_transform.origin

	# Smooth the orbit direction in angle space rather than lerping the camera
	# position directly — when ball and ship pass close to each other the raw
	# direction flips instantly, and slerping the direction turns that into a
	# controlled swing around the ship. The vertical component is dropped so
	# a ball flying overhead pitches the camera up instead of shoving it into
	# the floor or the sky.
	var flat := Vector3(ship_pos.x - ball_pos.x, 0.0, ship_pos.z - ball_pos.z)
	if flat.length() > 0.25:
		var t := 1.0 - exp(-orbit_smoothing * delta)  # frame-rate independent
		# Both directions are horizontal, so swing about the exact UP axis.
		# (Vector3.slerp derives its axis from the cross product, which
		# degenerates when the directions are nearly parallel — the common
		# case here — and spams normalization errors every frame.)
		var swing := _orbit_dir.signed_angle_to(flat.normalized(), Vector3.UP)
		_orbit_dir = _orbit_dir.rotated(Vector3.UP, swing * t).normalized()

	var camera_target_pos := ship_pos + _orbit_dir * _effective_distance + Vector3.UP * camera_height
	camera_target_pos.y = maxf(camera_target_pos.y, min_camera_height)

	var pos_t := 1.0 - exp(-camera_smoothing * delta)
	camera.global_position = camera.global_position.lerp(camera_target_pos, pos_t)
	_apply_shake(delta)

	# Look slightly above the ball's centre; look smoothing is faster than
	# position smoothing so the ball never drifts out of frame while the
	# camera is still swinging into place.
	_smooth_look_at(ball_pos + Vector3.UP * 0.5, delta)


func _update_ship_cam(delta):
	# In ship cam, camera follows and looks in the same direction as the ship.
	# Reads target.visual, not target itself, via the interpolated transform —
	# see _update_ball_cam.
	var visual_xform := target.visual.get_global_transform_interpolated()
	var ship_pos: Vector3 = visual_xform.origin
	var ship_forward: Vector3 = -visual_xform.basis.z

	# Position camera behind and above the ship
	var camera_target_pos := ship_pos - ship_forward * _effective_distance + Vector3.UP * camera_height
	camera_target_pos.y = maxf(camera_target_pos.y, min_camera_height)

	var pos_t := 1.0 - exp(-camera_smoothing * delta)
	camera.global_position = camera.global_position.lerp(camera_target_pos, pos_t)
	_apply_shake(delta)

	# Look ahead of the ship
	_smooth_look_at(ship_pos + ship_forward * 10.0, delta)


func _smooth_look_at(point: Vector3, delta: float) -> void:
	var to_point := point - camera.global_position
	if to_point.length() < 0.1:
		return
	var dir := to_point.normalized()
	if absf(dir.dot(Vector3.UP)) > 0.99:
		return  # Nearly vertical: looking_at would be degenerate, keep last frame
	var look_basis := Basis.looking_at(dir, Vector3.UP)
	var look_t := 1.0 - exp(-look_smoothing * delta)
	camera.global_basis = camera.global_basis.slerp(look_basis, look_t).orthonormalized()


func _update_speed_feel(delta: float) -> void:
	var feel_t := 1.0 - exp(-feel_smoothing * delta)
	var turbo_target := 1.0 if target.is_turbo_active() else 0.0
	var engine_action := target.get_current_action_copy()
	AudioManager.set_engine_state(maxf(engine_action.thrust.z, 0.0), turbo_target > 0.5)
	_turbo_blend = lerpf(_turbo_blend, turbo_target, feel_t)
	_speed_blend = lerpf(_speed_blend, target.get_speed_ratio(), feel_t)
	var target_fov := base_fov + _speed_blend * speed_fov_add + _turbo_blend * turbo_fov_kick
	camera.fov = lerpf(camera.fov, target_fov, feel_t)
	_effective_distance = lerpf(
		_effective_distance, camera_distance + _turbo_blend * turbo_distance_kick, feel_t
	)
	post_material.set_shader_parameter("chromatic_aberration", _turbo_blend * 0.007)
	post_material.set_shader_parameter("vignette_strength", 0.22 + _turbo_blend * 0.16)


func _on_target_ball_contact(intensity: float, _world_position: Vector3) -> void:
	_shake_strength = maxf(_shake_strength, clampf(intensity, 0.0, 1.0))
	_punch_strength = maxf(_punch_strength, clampf(intensity, 0.0, 1.0))
	for device in Input.get_connected_joypads():
		Input.start_joy_vibration(
			device, lerpf(0.18, 0.65, intensity), lerpf(0.32, 1.0, intensity),
			lerpf(0.08, 0.2, intensity)
		)
	impact_feedback.emit(intensity)


func _on_target_wall_contact(intensity: float) -> void:
	AudioManager.play_wall_scrape(intensity)


func _apply_shake(delta: float) -> void:
	if _shake_strength <= 0.001:
		_shake_strength = 0.0
		return
	_shake_time += delta
	# Quantized to a fixed 60Hz cadence rather than sampled once per rendered
	# frame. The noise domain's total distance travelled per second is the
	# same either way, but that's not what "reads the same" means here: at
	# 60fps, consecutive samples are frequency (2.5) domain-units apart —
	# far enough that FastNoiseLite's simplex correlation has decayed, so it
	# reads as sharp, uncorrelated jitter. At 240fps the same per-second
	# distance is split across 4x the samples, so consecutive samples are
	# ~4x closer together and highly correlated — a completely different,
	# much gentler wobble. Freezing the domain input to whole 60Hz ticks
	# makes every render frame within one tick reuse the exact same sample,
	# so the perceived shake texture is identical at any frame rate.
	var tick: float = floori(_shake_time * SHAKE_UPDATE_HZ)
	var amplitude := max_shake_offset * _shake_strength * _shake_strength
	var noise := Vector2(
		_shake_noise.get_noise_1d(tick),
		_shake_noise.get_noise_1d(tick + 100.0)
	).limit_length(1.0) * amplitude
	_last_shake_offset = camera.global_basis.x * noise.x + camera.global_basis.y * noise.y
	camera.global_position += _last_shake_offset
	_decay_shake(delta)


func _decay_shake(delta: float) -> void:
	_shake_strength = move_toward(_shake_strength, 0.0, shake_decay * delta)


# Additive FOV kick + PostFX flash on top of _update_speed_feel's base
# values, decaying over real time. Replaces the weight that Engine.time_scale
# hit-stop used to sell on ball impact — see the Impact Punch export group.
func _apply_punch(delta: float) -> void:
	if _punch_strength <= 0.001:
		_punch_strength = 0.0
		return
	camera.fov += punch_fov_kick * _punch_strength
	var chroma: float = post_material.get_shader_parameter("chromatic_aberration")
	var vignette: float = post_material.get_shader_parameter("vignette_strength")
	post_material.set_shader_parameter("chromatic_aberration", chroma + punch_chroma_kick * _punch_strength)
	post_material.set_shader_parameter("vignette_strength", vignette + punch_vignette_kick * _punch_strength)
	_punch_strength = move_toward(_punch_strength, 0.0, punch_decay * delta)


# Places the camera at its resting chase position instantly, bypassing
# camera_smoothing/orbit_smoothing/look_smoothing entirely. Used whenever the
# thing being framed just teleported (kickoff, target reassignment) — without
# this the rig would lerp smoothly across the whole arena over
# camera_smoothing seconds, which reads as an unintended camera move rather
# than a reset.
func snap_to_target() -> void:
	if not is_instance_valid(target) or not is_instance_valid(camera):
		return
	_shake_strength = 0.0
	camera.global_position -= _last_shake_offset
	_last_shake_offset = Vector3.ZERO
	var visual_xform := target.visual.get_global_transform_interpolated()
	var ship_pos: Vector3 = visual_xform.origin
	var ball := _get_ball()
	if ball_cam_enabled and ball:
		var ball_pos: Vector3 = ball.global_transform.origin
		var flat := Vector3(ship_pos.x - ball_pos.x, 0.0, ship_pos.z - ball_pos.z)
		_orbit_dir = flat.normalized() if flat.length() > 0.01 else Vector3.BACK
		camera.global_position = ship_pos + _orbit_dir * _effective_distance + Vector3.UP * camera_height
		camera.global_position.y = maxf(camera.global_position.y, min_camera_height)
		camera.look_at(ball_pos + Vector3.UP * 0.5, Vector3.UP)
	else:
		var ship_forward: Vector3 = -visual_xform.basis.z
		camera.global_position = ship_pos - ship_forward * _effective_distance + Vector3.UP * camera_height
		camera.global_position.y = maxf(camera.global_position.y, min_camera_height)
		camera.look_at(ship_pos + ship_forward * 10.0, Vector3.UP)


func begin_goal_cut(goal_position: Vector3) -> void:
	_goal_cut_active = true
	# The hard cut replaces the chase camera's presentation offset entirely;
	# don't let the next physics frame subtract a pre-cut shake sample from the
	# new cinematic position.
	camera.global_position -= _last_shake_offset
	_last_shake_offset = Vector3.ZERO
	var inward := Vector3(-goal_position.x, 0.0, -goal_position.z)
	if inward.length_squared() < 0.01:
		inward = Vector3.BACK
	else:
		inward = inward.normalized()
	_goal_cut_position = goal_position + inward * 10.5 + Vector3.UP * 5.5
	_goal_cut_look_at = goal_position + Vector3.UP * 0.8
	camera.global_position = _goal_cut_position
	camera.fov = 58.0
	camera.look_at(_goal_cut_look_at, Vector3.UP)
	# A hard, stationary cinematic camera must not inherit the scoring frame's
	# turbo chroma; keep only a deliberate cinematic edge.
	post_material.set_shader_parameter("chromatic_aberration", 0.0)
	post_material.set_shader_parameter("vignette_strength", 0.3)


func end_goal_cut() -> void:
	_goal_cut_active = false
	_speed_blend = 0.0
	_turbo_blend = 0.0
	post_material.set_shader_parameter("chromatic_aberration", 0.0)
	post_material.set_shader_parameter("vignette_strength", 0.22)