extends Node3D
## Weather hazards (P4, docs/PROGRESSION_DESIGN.md §5) that need more than
## the weather model:
##
## - Hard winters (weather.gd hard_winter()): a warning the day before and
##   on the day; the lake's edge freezes over (walkable ice you can't fish
##   through), on every machine since it comes from the shared clock.
## - Lightning: in a storm, every minute or so a bolt hits a tree near
##   someone, preferring tall trees near the rim. It burns for a while (a
##   fire you can warm yourself by), then falls, leaving charcoal. Decided:
##   trees only for now; buildings are never struck.
##
## Strikes and warnings happen where the game decides (single-player, a
## server); players' games are told (world_net.gd _s2c_strike).

const Weather = preload("res://scripts/world/weather.gd")

const STRIKE_MIN := 50.0
const STRIKE_MAX := 110.0
const STRIKE_RANGE := 90.0       ## trees this near someone can be struck
const BURN_SECONDS := 40.0
const CHARCOAL := 2
const ICE_IN := 0.62             ## the ice: from this x lake radius out to the shore
const ICE_OUT := 1.7

var world: Node3D
var deciding := true             ## false on a player's game online
var strikes := 0
var _strike_left := 30.0
var _rng := RandomNumberGenerator.new()
var _burning: Dictionary = {}    ## resource node -> [fire node, seconds left]
var _ice: MeshInstance3D
var _ice_body: StaticBody3D
var _warned := {}                ## day -> true

func setup(w: Node3D, decides: bool) -> void:
	world = w
	deciding = decides
	_rng.seed = w.terrain.noise_seed + 1201
	_build_ice()
	w.day_night.new_day.connect(_on_new_day)

func _physics_process(delta: float) -> void:
	step(delta)

func step(dt: float) -> void:
	_set_ice(world.weather.in_hard_winter())
	_snow_left -= dt
	if _snow_left <= 0.0:
		_snow_left = 2.0
		_update_roof_snow()
	for n in _burning.keys():
		var e: Array = _burning[n]
		e[1] = float(e[1]) - dt
		if float(e[1]) <= 0.0 or not is_instance_valid(n):
			_burn_out(n)
	if not deciding:
		return
	var w: Node = world.weather
	if w.state == "storm" and w.precip > 0.7:
		_strike_left -= dt
		if _strike_left <= 0.0:
			_strike_left = _rng.randf_range(STRIKE_MIN, STRIKE_MAX)
			var t := pick_tree()
			if t != null:
				strike(t)

# --- lightning -------------------------------------------------------------------------

## A standing tree near someone, the taller and nearer the rim the likelier.
func pick_tree() -> Node3D:
	var best: Node3D = null
	var best_s := -INF
	for n in world.props.resource_nodes.values():
		if n.kind != "tree" or n.depleted or _burning.has(n):
			continue
		var near := false
		for p in world.players():
			if (n as Node3D).global_position.distance_to(p.global_position) < STRIKE_RANGE:
				near = true
				break
		if not near:
			continue
		var pos: Vector3 = n.global_position
		var s: float = world.props._near_rim(pos.x, pos.z) * 2.0 + n.base_xf.basis.get_scale().y + _rng.randf() * 1.5
		if s > best_s:
			best_s = s
			best = n
	return best

## Lightning hits tree `n`: a flash, a crack, and it's on fire.
func strike(n: Node3D) -> void:
	strikes += 1
	show_strike(n)
	if world.server_mode:
		WorldNet.struck(n)
	for p in world.players():
		if p.global_position.distance_to(n.global_position) < 60.0:
			Actions.tell(p, "Lightning struck a tree! It's burning.")

## What everyone sees: the flash, and the tree alight.
func show_strike(n: Node3D) -> void:
	world.weather.flash = 1.0
	if _burning.has(n):
		return
	var fire := TreeFire.new()
	fire.name = "TreeFire"
	add_child(fire)
	fire.global_position = n.global_position
	fire.build(DisplayServer.get_name() != "headless")
	_burning[n] = [fire, BURN_SECONDS]

func burning(n: Node3D) -> bool:
	return _burning.has(n)

## Burnt through: the tree falls (where the game decides; players' games
## see it fall via world_net), leaving charcoal at its foot.
func _burn_out(n: Node3D) -> void:
	var e: Array = _burning[n]
	_burning.erase(n)
	if is_instance_valid(e[0]):
		(e[0] as Node).queue_free()
	if not deciding or not is_instance_valid(n) or n.depleted:
		return
	var top: Vector3 = n.global_position + Vector3(0, 2.0, 0)
	var from: Vector3 = n.global_position + Vector3(1, 0, 0)
	n._show_hit(0.0, top, from)
	if world.server_mode:
		WorldNet.node_hit(n, top, from)
	world.drop_item("charcoal", CHARCOAL, Transform3D(Basis(), n.global_position + Vector3(0.8, 0.3, 0.4)))

## A burning tree's fire: flames up the trunk, a light, and warmth.
class TreeFire extends Node3D:
	const RADIUS := 6.0
	func build(visual: bool) -> void:
		add_to_group("heat")
		if not visual:
			return
		var light := OmniLight3D.new()
		light.light_color = Color(1.0, 0.55, 0.25)
		light.light_energy = 3.0
		light.omni_range = 14.0
		light.position = Vector3(0, 3.0, 0)
		add_child(light)
		# The campfire's soft additive flames, bigger and up the trunk.
		var CF: Script = load("res://scripts/building/campfire.gd")
		var ramp: Gradient = CF._gradient([[0.0, Color(1.0, 0.8, 0.35, 0.0)], [0.15, Color(1.0, 0.62, 0.2, 0.8)],
			[0.6, Color(0.95, 0.3, 0.06, 0.5)], [1.0, Color(0.5, 0.08, 0.02, 0.0)]])
		for i in range(3):
			var p: CPUParticles3D = CF._particles("Flames%d" % i, 30, 1.0, Vector3(0, 1.2 + 1.6 * i, 0), 0.8, 2.0,
				0.6, 1.2, ramp, true, 0.9, 0.7 - 0.15 * i)
			add_child(p)
			p.emitting = true
	func heat_at(pos: Vector3) -> float:
		return 1.0 - smoothstep(2.0, RADIUS, pos.distance_to(global_position))

# --- hard winters ---------------------------------------------------------------------

func _on_new_day(day: int) -> void:
	if not deciding or _warned.has(day):
		return
	_warned[day] = true
	if Weather.hard_winter(day + 1) and not Weather.hard_winter(day):
		Actions.tell_all("The air has a bite to it. A hard winter is coming tomorrow: three bitter days. Stock up on food and firewood.")
	elif Weather.hard_winter(day) and not Weather.hard_winter(day - 1):
		Actions.tell_all("A hard winter has set in. The %s's edge has frozen, and the animals are holed up." % ("lake" if world.worldlet_id() == "valley" else "pond"))
	elif Weather.hard_winter(day - 1) and not Weather.hard_winter(day):
		Actions.tell_all("The hard winter is over.")

## A ring of ice round the lake, at the water line: it shows (and you can
## walk on it) wherever the water is, from the shore out to ICE_IN of the
## lake's radius. Off except in a hard winter.
func _build_ice() -> void:
	var t: Node3D = world.terrain
	var c: Vector2 = t.lake_center
	var r0: float = t.lake_radius * ICE_IN
	var r1: float = t.lake_radius * ICE_OUT
	var y: float = t.water_level + 0.04
	var segs := 64
	var st := SurfaceTool.new()
	st.begin(Mesh.PRIMITIVE_TRIANGLES)
	var faces := PackedVector3Array()
	var nz := FastNoiseLite.new()
	nz.seed = t.noise_seed + 1202
	for i in range(segs):
		var a0 := TAU * i / segs
		var a1 := TAU * (i + 1) / segs
		var k0 := 1.0 + 0.12 * nz.get_noise_1d(i * 7.0)
		var k1 := 1.0 + 0.12 * nz.get_noise_1d((i + 1) * 7.0)
		var p := [Vector3(c.x + cos(a0) * r0 * k0, y, c.y + sin(a0) * r0 * k0), Vector3(c.x + cos(a0) * r1, y, c.y + sin(a0) * r1),
			Vector3(c.x + cos(a1) * r1, y, c.y + sin(a1) * r1), Vector3(c.x + cos(a1) * r0 * k1, y, c.y + sin(a1) * r0 * k1)]
		for tri in [[p[0], p[2], p[1]], [p[0], p[3], p[2]]]:
			for v in tri:
				st.set_normal(Vector3.UP)
				st.add_vertex(v)
				faces.append(v)
	_ice = MeshInstance3D.new()
	_ice.name = "LakeIce"
	_ice.mesh = st.commit()
	var m := StandardMaterial3D.new()
	m.albedo_color = Color(0.86, 0.93, 0.98, 0.96)
	m.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
	m.roughness = 0.35
	m.metallic_specular = 0.8
	_ice.material_override = m
	_ice.visible = false
	add_child(_ice)
	_ice_body = StaticBody3D.new()
	_ice_body.name = "IceBody"
	var cs := CollisionShape3D.new()
	var shape := ConcavePolygonShape3D.new()
	shape.set_faces(faces)
	shape.backface_collision = true
	cs.shape = shape
	_ice_body.add_child(cs)
	_ice_body.collision_layer = 0
	add_child(_ice_body)

func _set_ice(on: bool) -> void:
	if _ice.visible == on:
		return
	_ice.visible = on
	_ice_body.collision_layer = 1 if on else 0

# --- snow on roofs ----------------------------------------------------------------------

var _snow_left := 0.0
var _snow_mat: StandardMaterial3D
var _snow_mesh: BoxMesh

## Snow piles up on roofs as it settles (weather.gd snow_cover), and melts
## off with it. Just a look: a white layer on each roof piece, thicker the
## more has settled. (Visual only, so not on a headless server.)
func _update_roof_snow() -> void:
	if DisplayServer.get_name() == "headless":
		return
	var cover: float = world.weather.snow_cover
	if _snow_mesh == null:
		var BP: Script = load("res://scripts/building/build_piece.gd")
		_snow_mesh = BoxMesh.new()
		_snow_mesh.size = Vector3(2.04, 0.12, sqrt(5.0) + 0.25)
		_snow_mat = StandardMaterial3D.new()
		_snow_mat.albedo_color = Color(0.93, 0.95, 0.98)
		_snow_mat.roughness = 0.9
		_snow_mesh.material = _snow_mat
		_snow_angle = BP.ROOF_ANGLE
		_snow_t = BP.ROOF_T
	for p in world.build.build_pieces():
		if p.kind != "roof":
			continue
		var s: MeshInstance3D = p.get_node_or_null("Snow")
		if cover < 0.2:
			if s != null:
				s.visible = false
			continue
		if s == null:
			s = MeshInstance3D.new()
			s.name = "Snow"
			s.mesh = _snow_mesh
			p.add_child(s)
		var k := clampf((cover - 0.2) / 0.8, 0.0, 1.0)
		var n := Vector3(0, cos(_snow_angle), sin(_snow_angle))
		var along := Vector3(0, sin(_snow_angle), -cos(_snow_angle))
		s.visible = true
		s.transform = Transform3D(Basis(Vector3.RIGHT, _snow_angle).scaled(Vector3(1.0, maxf(k, 0.15), 1.0)),
			along * (sqrt(5.0) * 0.5 - 0.1) + n * (_snow_t + 0.11 + 0.06 * k))

var _snow_angle := 0.4636476
var _snow_t := 0.12

## How many roofs have snow on them right now (tests).
func snowy_roofs() -> int:
	var n := 0
	for p in world.build.build_pieces():
		var s: Node = p.get_node_or_null("Snow")
		if s != null and s.visible:
			n += 1
	return n

func lake_frozen() -> bool:
	return _ice.visible

## Frozen over at (x, z): ice, not open water.
func iced(x: float, z: float) -> bool:
	if not lake_frozen():
		return false
	var c: Vector2 = world.terrain.lake_center
	return Vector2(x - c.x, z - c.y).length() > world.terrain.lake_radius * ICE_IN * 0.9