class_name PainterlyMeadow
extends Node3D
## Decorative flower drifts. Local seeded placement never touches simulation RNG.

const FLOWER_SCENES: Array[PackedScene] = [
	preload("res://assets/meadow/cream_daisy.glb"),
	preload("res://assets/meadow/pink_cosmos.glb"),
	preload("res://assets/meadow/yellow_buttercup.glb"),
	preload("res://assets/meadow/lavender_spire.glb"),
]
const FLOWER_SHADER := preload("res://world/jajce/materials/meadow_flowers.gdshader")
const PROFILE_DENSITY := [1.0, 0.65, 0.32]
const PROFILE_DISTANCE := [56.0, 46.0, 34.0]

@export var terrain_path := NodePath("../TerrainRoot/Terrain3D")
@export_range(0, 450, 1) var clumps_per_species := 420
@export var placement_seed := 57091
## Local x/z center, then ellipse x/z radii. Each drift favors one flower color.
@export var drifts: Array[Vector4] = [
	Vector4(7.0, 20.0, 7.0, 3.5),
	Vector4(15.0, 13.0, 2.4, 4.0),
	Vector4(-5.0, 20.0, 5.0, 3.0),
	Vector4(-18.0, -21.0, 4.5, 3.2),
	Vector4(14.0, -10.0, 3.8, 4.5),
	Vector4(-25.0, -17.0, 3.5, 4.0),
	Vector4(8.0, -20.0, 5.0, 2.5),
	Vector4(-2.0, -24.0, 6.0, 2.2),
	Vector4(17.0, 24.0, 4.0, 3.0),
	Vector4(-9.0, 21.0, 3.6, 2.5),
	Vector4(9.0, 7.2, 3.2, 1.8),
	Vector4(-16.0, 19.0, 3.0, 2.4),
]

var _terrain: Terrain3D
var _batches: Array[MultiMeshInstance3D] = []
var _material: ShaderMaterial
var _quality := 0
var _clearings: Array[Vector3] = []
var _path_strips: Array[MeshInstance3D] = []


func _ready() -> void:
	call_deferred("_build_meadow")


func apply_presentation_quality(quality: int) -> void:
	_quality = clampi(quality, 0, PROFILE_DENSITY.size() - 1)
	for batch in _batches:
		batch.multimesh.visible_instance_count = floori(
			batch.multimesh.instance_count * PROFILE_DENSITY[_quality]
		)
	if _material != null:
		_material.set_shader_parameter("fade_begin", PROFILE_DISTANCE[_quality] - 12.0)
		_material.set_shader_parameter("fade_end", PROFILE_DISTANCE[_quality])


func get_presentation_stats() -> Dictionary:
	var total := 0
	var visible_count := 0
	for batch in _batches:
		total += batch.multimesh.instance_count
		visible_count += batch.multimesh.visible_instance_count
	return {
		"flower_clump_count": total,
		"visible_flower_clump_count": visible_count,
		"multimesh_batch_count": _batches.size(),
	}


func _build_meadow() -> void:
	if not _batches.is_empty():
		return
	_terrain = get_node_or_null(terrain_path) as Terrain3D
	if _terrain == null or _terrain.data == null or drifts.is_empty():
		return
	_collect_clearings()
	_material = ShaderMaterial.new()
	_material.shader = FLOWER_SHADER
	for species in FLOWER_SCENES.size():
		var source := FLOWER_SCENES[species].instantiate()
		var mesh := _find_mesh(source)
		if mesh != null:
			_add_batch(mesh, species)
		source.free()
	apply_presentation_quality(_quality)


func _find_mesh(node: Node) -> Mesh:
	if node is MeshInstance3D:
		return (node as MeshInstance3D).mesh
	for child in node.get_children():
		var mesh := _find_mesh(child)
		if mesh != null:
			return mesh
	return null


func _add_batch(mesh: Mesh, species: int) -> void:
	var rng := RandomNumberGenerator.new()
	rng.seed = placement_seed + species * 173
	var transforms: Array[Transform3D] = []
	var variations: Array[Color] = []
	for _attempt in clumps_per_species * 18:
		if transforms.size() >= clumps_per_species:
			break
		var drift_index := rng.randi_range(0, drifts.size() - 1)
		# Broad color masses with a few companion flowers at the edges.
		if drift_index % FLOWER_SCENES.size() != species and rng.randf() > 0.12:
			continue
		var drift := drifts[drift_index]
		var angle := rng.randf_range(0.0, TAU)
		var radius := pow(rng.randf(), 0.7) * (0.9 + 0.12 * sin(angle * 3.0 + drift_index))
		var offset := Vector3(
			drift.x + cos(angle) * radius * drift.z, 0.0, drift.y + sin(angle) * radius * drift.w
		)
		var world_sample := to_global(offset)
		if _is_cleared(world_sample):
			continue
		var height := _terrain.data.get_height(world_sample)
		if is_nan(height):
			continue
		var nearby := _terrain.data.get_height(world_sample + Vector3(0.35, 0.0, 0.35))
		if is_nan(nearby) or absf(height - nearby) > 0.32:
			continue
		var local_position := to_local(Vector3(world_sample.x, height - 0.018, world_sample.z))
		var scale_variation := rng.randf_range(0.80, 1.28)
		var basis := Basis(Vector3.UP, rng.randf_range(0.0, TAU)).scaled(
			Vector3.ONE * scale_variation
		)
		transforms.append(Transform3D(basis, local_position))
		variations.append(Color(rng.randf(), 0.0, 0.0, 1.0))
	var multimesh := MultiMesh.new()
	multimesh.transform_format = MultiMesh.TRANSFORM_3D
	# Compatibility needs an explicit neutral color alongside the custom buffer
	# to preserve the GLB's painted vertex colors.
	multimesh.use_colors = true
	multimesh.use_custom_data = true
	multimesh.mesh = mesh
	multimesh.instance_count = transforms.size()
	for index in transforms.size():
		multimesh.set_instance_transform(index, transforms[index])
		multimesh.set_instance_color(index, Color.WHITE)
		multimesh.set_instance_custom_data(index, variations[index])
	var batch := MultiMeshInstance3D.new()
	batch.name = "FlowerDrifts_%d" % species
	batch.multimesh = multimesh
	batch.material_override = _material
	batch.cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_OFF
	batch.extra_cull_margin = 0.4
	add_child(batch)
	_batches.append(batch)


func _collect_clearings() -> void:
	var village := get_node_or_null("../VillageRoot")
	if village != null:
		for child in village.get_children():
			if child is MeshInstance3D and str(child.name).begins_with("Path_"):
				_path_strips.append(child)
			elif child is Node3D:
				var radius := 4.3 if str(child.name).begins_with("House_") else 4.5
				_add_clearing(child, radius)
	var fortress := get_node_or_null("../FortressBlockout") as Node3D
	if fortress != null:
		_add_clearing(fortress, 11.0)
	for root_path in [
		"../WorldObjects/ResourceNodes",
		"../WorldObjects/StorageSites",
		"../WorldObjects/ActivitySites",
		"../WorldObjects/AnimalHabitats",
	]:
		var root := get_node_or_null(root_path)
		if root != null:
			for child in root.get_children():
				if child is Node3D:
					_add_worksite_clearing(child)
	var clusters := get_node_or_null("../WorldObjects/ResourceClusters")
	if clusters != null:
		for cluster in clusters.get_children():
			var anchors := cluster.get_node_or_null("ResourceAnchors")
			if anchors == null:
				continue
			for anchor in anchors.get_children():
				if anchor is Node3D:
					_add_worksite_clearing(anchor)


func _add_worksite_clearing(node: Node3D) -> void:
	_add_clearing(node, 2.0)
	var interaction := node.get_node_or_null("InteractionPoint") as Node3D
	if interaction != null:
		_add_clearing(interaction, 1.2)


func _add_clearing(node: Node3D, radius: float) -> void:
	_clearings.append(Vector3(node.global_position.x, node.global_position.z, radius))


func _is_cleared(point: Vector3) -> bool:
	var flat := Vector2(point.x, point.z)
	for clearing in _clearings:
		if flat.distance_squared_to(Vector2(clearing.x, clearing.y)) < clearing.z * clearing.z:
			return true
	for strip in _path_strips:
		var box := strip.mesh as BoxMesh
		if box == null:
			continue
		var local := strip.to_local(point)
		var half_width := box.size.x * 0.5 + 0.35 / strip.global_basis.x.length()
		if absf(local.x) < half_width and absf(local.z) < box.size.z * 0.5 + 0.08:
			return true
	var river_distance := absf(point.x - JajceWatercourse.downstream_center_x(point.z))
	return (
		point.z >= JajceWatercourse.DOWNSTREAM_START_Z - 3.0
		and point.z <= JajceWatercourse.DOWNSTREAM_END_Z
		and river_distance < JajceWatercourse.downstream_half_width(point.z) + 1.7
	)