#pragma once

#include <assert.h>
#include <chrono>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <fstream>
#include <glm/glm.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/mat4x4.hpp>
#include <map>
#include <stack>
#include <stdbool.h>
#include <utilities/glutils.h>
#include <utilities/shader.hpp>
#include <utilities/material.hpp>
#include <vector>

using glm::vec2;
using glm::vec3;
using glm::vec4;
using glm::mat4;
using std::map;
using std::vector;
typedef unsigned int uint;

enum SceneNodeType {
	GEOMETRY,
	POINT_LIGHT,
	SPOT_LIGHT,
};

struct SceneNode {
	SceneNode(SceneNodeType type = GEOMETRY) {
        nodeType = type;
	}
	
	void setMesh(const Mesh* mesh) {
		static map<const Mesh*, int> cache;

		if (cache.find(mesh) == cache.end())
			cache[mesh] = generateBuffer(*mesh, isNormalMapped || isDisplacementMapped);

		vertexArrayObjectID = cache[mesh];
		VAOIndexCount = mesh->indices.size();
		isVertexColored = ! mesh->colors.empty();
	}
	void setTexture(
				const PNGImage* diffuse,
				const PNGImage* normal=nullptr,
				const PNGImage* displacement=nullptr,
				const PNGImage* reflection=nullptr,
				bool texture_reset=true) {
		static map<const PNGImage*, int> cache;
		if (texture_reset){
			isTextured = false;
			isNormalMapped = false;
			isDisplacementMapped = false;
		}

		if (diffuse) {
			if (cache.find(diffuse) == cache.end())
				cache[diffuse] = generateTexture(*diffuse);
			diffuseTextureID = cache[diffuse];
			isTextured = true;
		}
		
		if (normal) {
			if (cache.find(normal) == cache.end())
				cache[normal] = generateTexture(*normal);
			normalTextureID = cache[normal];
			isNormalMapped  = true;
		}
		
		if (displacement) {
			if (cache.find(displacement) == cache.end())
				cache[displacement] = generateTexture(*displacement);
			displacementTextureID = cache[displacement];
			isDisplacementMapped  = true;
		}
	}
	void setMaterial(const Material& mat, bool recursive=false) {
		if (!mat.ignore_diffuse)  diffuse_color  = mat.diffuse_color;
		if (!mat.ignore_emissive) emissive_color = mat.emissive_color;
		if (!mat.ignore_specular) specular_color = mat.specular_color;
		if (!mat.ignore_specular) shininess      = mat.shininess;
		setTexture(
			mat.diffuse_texture,
			mat.normal_texture,
			mat.displacement_texture,
			mat.reflection_texture,
			mat.texture_reset
		);
		if (recursive) for (SceneNode* child : children)
			child->setMaterial(mat, true);
	}
	
	// this node
	SceneNodeType nodeType;
	vector<SceneNode*> children;

	// light specific:
	uint lightID = -1;
	vec3 light_color = vec3(1.0);
	vec3 attenuation = vec3(1.0, 0.0, 0.001); // 1 / (x + y*l + z*l*l)
	vec3 spot_direction = vec3(0.0); // in MV space, must be normalized
	float spot_cuttof_cos = glm::cos(glm::radians(1.5));
	SceneNode* targeted_by  = nullptr; // spot will follow this node

	// The node's position and rotation relative to its parent
	vec3 position = vec3(0, 0, 0);
	vec3 rotation = vec3(0, 0, 0); // also used as spot-target
	vec3 scale    = vec3(1, 1, 1);
	vec3 referencePoint = vec3(0, 0, 0); // center of rotation, in model space

	// VAO IDs refering to a loaded Mesh and its length
	int vertexArrayObjectID = -1;
	uint VAOIndexCount = 0;

	// textures and materials
	float opacity = 1.0;
	float shininess = 1.0; // specular power
	vec3 diffuse_color  = vec3(1.0);
	vec3 emissive_color = vec3(0.5);
	vec3 specular_color = vec3(0.2);
	vec2 uvOffset = vec2(0.0, 0.0); // specular power
	uint diffuseTextureID;
	uint normalTextureID;
	uint displacementTextureID;
	float displacementCoefficient = 0.1; // in units

	// shader flags
	bool isTextured = false;
	bool isVertexColored = false;
	bool isNormalMapped = false;
	bool isDisplacementMapped = false;
	bool isIlluminated = true;
	bool isInverted = false;

	// rendering
	Gloom::Shader* shader = nullptr;
	mat4 MVP; // MVP
	mat4 MV; // MV
	mat4 MVnormal; // transpose(inverse(MV))

};

// Struct for keeping track of 2D coordinates

SceneNode* createSceneNode();
SceneNode* createSceneNode(SceneNodeType type);
void addChild(SceneNode* parent, SceneNode* child);
void printNode(SceneNode* node);