extends "res://scripts/building/piece.gd"
## Campfire: light, warmth and cooking, while it has fuel.
##
## Starts with a little kindling. E adds wood (or sticks) from your inventory;
## it burns down in play time and goes out at zero. While lit it is a
## "campfire" station (cooking) and a heat source (warmth within ~7 m).

const MAX_FUEL := 900.0      ## 15 min
const START_FUEL := 120.0
const HEAT_RADIUS := 7.0

var fuel := START_FUEL
var _light: OmniLight3D
var _fx: Array[CPUParticles3D] = []
var _t := 0.0
var _noise := FastNoiseLite.new()
var _lit := true

func _build() -> void:
	add_to_group("station:campfire")
	add_to_group("heat")
	_noise.frequency = 2.5
	_light = OmniLight3D.new()
	_light.light_color = Color(1.0, 0.62, 0.3)
	_light.light_energy = 2.2
	_light.omni_range = 11.0
	_light.omni_attenuation = 1.4
	_light.shadow_enabled = true
	_light.position = Vector3(0, 0.7, 0)
	add_child(_light)

	_fx.append(_particles("Flames", 26, 0.55, Vector3(0, 0.12, 0), 0.5, 1.0, 0.5, 0.9, _gradient([
		[0.0, Color(1.0, 0.8, 0.35, 0.0)], [0.15, Color(1.0, 0.62, 0.2, 0.75)],
		[0.6, Color(0.95, 0.3, 0.06, 0.45)], [1.0, Color(0.5, 0.08, 0.02, 0.0)]]), true, 0.32, 0.12))
	_fx.append(_particles("Embers", 10, 2.0, Vector3(0, 0.3, 0), 0.8, 2.0, 0.5, 1.0, _gradient([
		[0.0, Color(1.0, 0.75, 0.35, 1.0)], [1.0, Color(1.0, 0.3, 0.05, 0.0)]]), true, 0.04, 0.15))
	for p in _fx:
		add_child(p)
	# TODO: smoke. Alpha-blended unshaded particles rendered as an opaque dark
	# ball whatever their ramp colour (additive flames are fine). Needs a small
	# particle shader.
	_set_lit(fuel > 0.0)

func display_name() -> String:
	return "Campfire"

func is_lit() -> bool:
	return _lit

func station_active() -> bool:
	return _lit

## 0..1 warmth this fire gives at `pos`.
func heat_at(pos: Vector3) -> float:
	if not _lit:
		return 0.0
	return 1.0 - smoothstep(1.5, HEAT_RADIUS, pos.distance_to(global_position))

func add_fuel(seconds: float) -> void:
	fuel = minf(fuel + seconds, MAX_FUEL)
	_set_lit(true)

func interact_prompt(player: Node) -> String:
	var has_fuel: bool = player.inventory.count("wood") + player.inventory.count("stick") > 0
	if _lit:
		var left := "%d:%02d" % [int(fuel) / 60, int(fuel) % 60]
		return "Campfire (%s left)%s" % [left, "  [E] Add fuel" if has_fuel else "  (add wood or sticks)"]
	return "Campfire (out)%s" % ("  [E] Add fuel to light" if has_fuel else "  (needs wood or sticks)")

func interact(player: Node) -> void:
	Actions.add_fuel(player, self)

func _process(delta: float) -> void:
	if not _lit:
		return
	fuel -= delta
	if fuel <= 0.0:
		fuel = 0.0
		_set_lit(false)
		return
	_t += delta
	var f := _noise.get_noise_1d(_t * 10.0)
	# Burns lower in its last minute.
	var strength := clampf(fuel / 60.0, 0.35, 1.0)
	_light.light_energy = (2.2 + f * 0.7) * strength
	_light.position = Vector3(f * 0.05, 0.7 + f * 0.05, 0)

func _set_lit(on: bool) -> void:
	_lit = on
	if _light != null:
		_light.visible = on
	for p in _fx:
		p.emitting = on

func save_extra() -> Dictionary:
	return {"fuel": fuel}

func load_extra(d: Dictionary) -> void:
	fuel = float(d.get("fuel", fuel))
	_set_lit(fuel > 0.0)

static func _gradient(stops: Array) -> Gradient:
	var g := Gradient.new()
	g.offsets = PackedFloat32Array(stops.map(func(s): return s[0]))
	g.colors = PackedColorArray(stops.map(func(s): return s[1]))
	return g

static func _soft_dot() -> GradientTexture2D:
	var g := Gradient.new()
	g.offsets = PackedFloat32Array([0.0, 1.0])
	g.colors = PackedColorArray([Color(1, 1, 1, 1), Color(1, 1, 1, 0)])
	var t := GradientTexture2D.new()
	t.gradient = g
	t.fill = GradientTexture2D.FILL_RADIAL
	t.fill_from = Vector2(0.5, 0.5)
	t.fill_to = Vector2(0.5, 0.0)
	t.width = 64
	t.height = 64
	return t

static func _particles(label: String, amount: int, lifetime: float, pos: Vector3, vmin: float, vmax: float,
		smin: float, smax: float, ramp: Gradient, additive: bool, quad_size: float, radius: float) -> CPUParticles3D:
	var p := CPUParticles3D.new()
	p.name = label
	p.amount = amount
	p.lifetime = lifetime
	p.position = pos
	p.direction = Vector3.UP
	p.spread = 12.0
	p.initial_velocity_min = vmin
	p.initial_velocity_max = vmax
	p.gravity = Vector3(0.15, 0.4, 0.05)
	p.emission_shape = CPUParticles3D.EMISSION_SHAPE_SPHERE
	p.emission_sphere_radius = radius
	p.scale_amount_min = smin
	p.scale_amount_max = smax
	p.color_ramp = ramp
	# Flames shrink as they rise.
	var curve := Curve.new()
	curve.add_point(Vector2(0.0, 1.0))
	curve.add_point(Vector2(1.0, 0.35))
	p.scale_amount_curve = curve
	var quad := QuadMesh.new()
	quad.size = Vector2.ONE * quad_size
	var m := StandardMaterial3D.new()
	m.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
	m.billboard_mode = BaseMaterial3D.BILLBOARD_PARTICLES
	m.vertex_color_use_as_albedo = true
	m.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
	m.blend_mode = BaseMaterial3D.BLEND_MODE_ADD if additive else BaseMaterial3D.BLEND_MODE_MIX
	m.albedo_texture = _soft_dot()
	if additive:
		m.albedo_color = Color(1.5, 1.5, 1.5)   # mildly HDR so the glow picks it up
	quad.material = m
	p.mesh = quad
	return p