extends RefCounted
## Shared material library of Champions of Luneraria (first set in G2; meant for G4/G5 too).
## GLBs from the G2 Blender generators name their surfaces LN_*; `dress` swaps them for one
## shared ShaderMaterial per name. Everything that differs per building or per team (team
## colours, energy, damage, occlusion fade, rune family, banner silhouette) is a per-instance
## shader parameter with a fixed slot (see the instance_index hints in the shaders), so all
## buildings share the same few materials.

const StoneShader = preload("res://scripts/luneraria/view/materials/lune_stone.gdshader")
const MetalShader = preload("res://scripts/luneraria/view/materials/lune_metal.gdshader")
const CrystalShader = preload("res://scripts/luneraria/view/materials/lune_crystal.gdshader")
const RuneShader = preload("res://scripts/luneraria/view/materials/lune_rune.gdshader")
const ClothShader = preload("res://scripts/luneraria/view/materials/lune_cloth.gdshader")
const WaterGlowShader = preload("res://scripts/luneraria/view/materials/lune_water_glow.gdshader")
const HideShader = preload("res://scripts/luneraria/view/materials/lune_hide.gdshader")
const Limestone = preload("res://assets/materials/phase10/limestone-albedo.png")
const NEUTRAL: int = 2

## Team identity beyond colour: cool team (Blau) and warm team (Rot) differ in crystal and
## rune hue, metal (silver-steel / bronze), rune family, banner silhouette and emblem.
## Index 2 is the neutral grotto.
const TEAM_STYLE: Array[Dictionary] = [
	{"crystal": Color("78c6ff"), "rune": Color("86d2ff"), "metal": Color(.80, .85, .92), "cloth": Color("2a5aa8"),
		"emblem": Color("e8eef8"), "light": Color("8cc8ff"), "pattern": 0.0, "shape": 0.0, "name": "kühl · Mondsichel · Silber"},
	{"crystal": Color("ff7d45"), "rune": Color("ffae5a"), "metal": Color(.92, .64, .34), "cloth": Color("9a2c20"),
		"emblem": Color("f4d58c"), "light": Color("ffae72"), "pattern": 1.0, "shape": 1.0, "name": "warm · Sonnenscheibe · Bronze"},
	{"crystal": Color("b784ff"), "rune": Color("c29cff"), "metal": Color(.70, .62, .50), "cloth": Color("45305f"),
		"emblem": Color("d9c8f0"), "light": Color("b37cff"), "pattern": 2.0, "shape": 0.0, "name": "neutral · Grotte"},
]

static var _cache: Dictionary = {}

static func _shader_material(shader: Shader, params: Dictionary) -> ShaderMaterial:
	var material := ShaderMaterial.new()
	material.shader = shader
	for key: String in params:
		material.set_shader_parameter(key, params[key])
	return material

## The shared material for an LN_* surface name, or null for foreign materials.
static func get_material(key: String) -> Material:
	if _cache.has(key):
		return _cache[key]
	var material: Material = null
	match key:
		"LN_Stone_Pale":
			material = _shader_material(StoneShader, {"base_color": Color(.72, .68, .61), "stone_map": Limestone, "lichen": .22})
		"LN_Stone_Dark":
			material = _shader_material(StoneShader, {"base_color": Color(.30, .30, .33), "stone_map": Limestone, "lichen": .12,
				"course_height": .34, "block_length": .66, "roughness_base": .9})
		"LN_Stone_Grotto":
			material = _shader_material(StoneShader, {"base_color": Color(.43, .43, .46), "stone_map": Limestone, "lichen": .3,
				"course_height": .5, "block_length": .9, "tint_variation": .07})
		"LN_Rock":
			material = _shader_material(StoneShader, {"base_color": Color(.38, .38, .40), "stone_map": Limestone, "lichen": .45,
				"ashlar": false, "texture_scale": .55, "tint_variation": .05, "roughness_base": .93})
		"LN_Metal_Team":
			material = _shader_material(MetalShader, {"base_color": Color(.92, .92, .92), "roughness_base": .32, "wear": .6})
		"LN_Metal_Iron":
			material = _shader_material(MetalShader, {"base_color": Color(.24, .24, .26), "roughness_base": .52, "metallic_value": .8, "wear": .8})
		"LN_Metal_Bronze":
			material = _shader_material(MetalShader, {"base_color": Color(.66, .47, .24), "roughness_base": .42, "patina": .7})
		"LN_Crystal_Team", "LN_Crystal_Grotto":
			material = _shader_material(CrystalShader, {})
		"LN_Rune_Team", "LN_Rune_Grotto":
			material = _shader_material(RuneShader, {})
		"LN_Cloth_Team":
			material = _shader_material(ClothShader, {})
		"LN_Water_Glow":
			material = _shader_material(WaterGlowShader, {})
		# The Schlundkrone is skinned: its surfaces read their patterns from rest positions.
		"LN_Boss_Hide":
			material = _shader_material(HideShader, {})
		"LN_Boss_Bone":
			material = _shader_material(HideShader, {"base_color": Color(.74, .71, .64), "plate_color": Color(.83, .80, .72),
				"vein_amount": .25, "roughness_base": .62})
		"LN_Boss_Bronze":
			material = _shader_material(HideShader, {"base_color": Color(.42, .31, .18), "plate_color": Color(.52, .38, .21),
				"vein_amount": 0.0, "roughness_base": .42, "metallic_value": .85, "patina": .75})
		"LN_Crystal_Boss":
			material = _shader_material(CrystalShader, {"heart_radius": .02, "depth_scale": .3, "vein_scale": 3.6})
		"LN_Wood":
			var wood := StandardMaterial3D.new()
			wood.albedo_color = Color(.33, .23, .15)
			wood.roughness = .82
			wood.vertex_color_use_as_albedo = true
			material = wood
		"LN_Cave":
			var cave := StandardMaterial3D.new()
			cave.albedo_color = Color(.02, .015, .03)
			cave.roughness = 1.0
			material = cave
	if material != null:
		material.resource_name = key
	_cache[key] = material
	return material

## Swaps LN_* surface materials below root for the shared ones. Returns every geometry
## instance that carries at least one LN_* surface (the ones that take instance parameters).
static func dress(root: Node) -> Array[GeometryInstance3D]:
	var result: Array[GeometryInstance3D] = []
	_dress(root, result)
	return result

static func _dress(node: Node, result: Array[GeometryInstance3D]) -> void:
	if node is MeshInstance3D and (node as MeshInstance3D).mesh != null:
		var instance := node as MeshInstance3D
		var dressed: bool = false
		for index: int in range(instance.mesh.get_surface_count()):
			var source: Material = instance.mesh.surface_get_material(index)
			if source == null or not source.resource_name.begins_with("LN_"):
				continue
			var shared: Material = get_material(source.resource_name)
			if shared != null:
				instance.set_surface_override_material(index, shared)
				dressed = true
		if dressed:
			result.append(instance)
	for child: Node in node.get_children():
		_dress(child, result)

## Team colours and families on a set of instances. seed decorrelates buildings.
static func apply_team(instances: Array, team: int, seed_value: float) -> void:
	var style: Dictionary = TEAM_STYLE[clampi(team, 0, 2)]
	for instance: GeometryInstance3D in instances:
		instance.set_instance_shader_parameter("tint", style.crystal)
		instance.set_instance_shader_parameter("metal_tint", style.metal)
		instance.set_instance_shader_parameter("pattern", style.pattern)
		instance.set_instance_shader_parameter("cloth_color", style.cloth)
		instance.set_instance_shader_parameter("emblem_color", style.emblem)
		instance.set_instance_shader_parameter("shape", style.shape)
		instance.set_instance_shader_parameter("seed", seed_value)

## Rune surfaces use the rune hue; crystals the crystal hue. Both share the `tint` slot, so a
## mesh that only carries runes gets the rune hue.
static func apply_rune_tint(instances: Array, team: int) -> void:
	var style: Dictionary = TEAM_STYLE[clampi(team, 0, 2)]
	for instance: GeometryInstance3D in instances:
		instance.set_instance_shader_parameter("tint", style.rune)

static func set_param(instances: Array, parameter: String, value: Variant) -> void:
	for instance: GeometryInstance3D in instances:
		instance.set_instance_shader_parameter(parameter, value)

static func team_color(team: int, key: String) -> Color:
	return TEAM_STYLE[clampi(team, 0, 2)][key]