/*************************************************************************/
/*  test_math.cpp                                                        */
/*************************************************************************/
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/*                           GODOT ENGINE                                */
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/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "test_math.h"

#include "core/math/camera_matrix.h"
#include "core/math/delaunay_3d.h"
#include "core/math/geometry_2d.h"
#include "core/os/main_loop.h"
#include "core/os/os.h"

namespace TestMath {

class GetClassAndNamespace {
	String code;
	int idx;
	int line;
	String error_str;
	bool error;
	Variant value;

	String class_name;

	enum Token {
		TK_BRACKET_OPEN,
		TK_BRACKET_CLOSE,
		TK_CURLY_BRACKET_OPEN,
		TK_CURLY_BRACKET_CLOSE,
		TK_PERIOD,
		TK_COLON,
		TK_COMMA,
		TK_SYMBOL,
		TK_IDENTIFIER,
		TK_STRING,
		TK_NUMBER,
		TK_EOF,
		TK_ERROR
	};

	Token get_token() {
		while (true) {
			switch (code[idx]) {
				case '\n': {
					line++;
					idx++;
					break;
				};
				case 0: {
					return TK_EOF;

				} break;
				case '{': {
					idx++;
					return TK_CURLY_BRACKET_OPEN;
				};
				case '}': {
					idx++;
					return TK_CURLY_BRACKET_CLOSE;
				};
				case '[': {
					idx++;
					return TK_BRACKET_OPEN;
				};
				case ']': {
					idx++;
					return TK_BRACKET_CLOSE;
				};
				case ':': {
					idx++;
					return TK_COLON;
				};
				case ',': {
					idx++;
					return TK_COMMA;
				};
				case '.': {
					idx++;
					return TK_PERIOD;
				};
				case '#': {
					//compiler directive
					while (code[idx] != '\n' && code[idx] != 0) {
						idx++;
					}
					continue;
				} break;
				case '/': {
					switch (code[idx + 1]) {
						case '*': { // block comment

							idx += 2;
							while (true) {
								if (code[idx] == 0) {
									error_str = "Unterminated comment";
									error = true;
									return TK_ERROR;
								} else if (code[idx] == '*' && code[idx + 1] == '/') {
									idx += 2;
									break;
								} else if (code[idx] == '\n') {
									line++;
								}

								idx++;
							}

						} break;
						case '/': { // line comment skip

							while (code[idx] != '\n' && code[idx] != 0) {
								idx++;
							}

						} break;
						default: {
							value = "/";
							idx++;
							return TK_SYMBOL;
						}
					}

					continue; // a comment
				} break;
				case '\'':
				case '"': {
					char32_t begin_str = code[idx];
					idx++;
					String tk_string = String();
					while (true) {
						if (code[idx] == 0) {
							error_str = "Unterminated String";
							error = true;
							return TK_ERROR;
						} else if (code[idx] == begin_str) {
							idx++;
							break;
						} else if (code[idx] == '\\') {
							//escaped characters...
							idx++;
							char32_t next = code[idx];
							if (next == 0) {
								error_str = "Unterminated String";
								error = true;
								return TK_ERROR;
							}
							char32_t res = 0;

							switch (next) {
								case 'b':
									res = 8;
									break;
								case 't':
									res = 9;
									break;
								case 'n':
									res = 10;
									break;
								case 'f':
									res = 12;
									break;
								case 'r':
									res = 13;
									break;
								case '\"':
									res = '\"';
									break;
								case '\\':
									res = '\\';
									break;
								default: {
									res = next;
								} break;
							}

							tk_string += res;

						} else {
							if (code[idx] == '\n') {
								line++;
							}
							tk_string += code[idx];
						}
						idx++;
					}

					value = tk_string;

					return TK_STRING;

				} break;
				default: {
					if (code[idx] <= 32) {
						idx++;
						break;
					}

					if ((code[idx] >= 33 && code[idx] <= 47) || (code[idx] >= 58 && code[idx] <= 64) || (code[idx] >= 91 && code[idx] <= 96) || (code[idx] >= 123 && code[idx] <= 127)) {
						value = String::chr(code[idx]);
						idx++;
						return TK_SYMBOL;
					}

					if (code[idx] == '-' || (code[idx] >= '0' && code[idx] <= '9')) {
						//a number
						const char32_t *rptr;
						double number = String::to_float(&code[idx], &rptr);
						idx += (rptr - &code[idx]);
						value = number;
						return TK_NUMBER;

					} else if ((code[idx] >= 'A' && code[idx] <= 'Z') || (code[idx] >= 'a' && code[idx] <= 'z') || code[idx] > 127) {
						String id;

						while ((code[idx] >= 'A' && code[idx] <= 'Z') || (code[idx] >= 'a' && code[idx] <= 'z') || code[idx] > 127) {
							id += code[idx];
							idx++;
						}

						value = id;
						return TK_IDENTIFIER;
					} else {
						error_str = "Unexpected character.";
						error = true;
						return TK_ERROR;
					}
				}
			}
		}
	}

public:
	Error parse(const String &p_code, const String &p_known_class_name = String()) {
		code = p_code;
		idx = 0;
		line = 0;
		error_str = String();
		error = false;
		value = Variant();
		class_name = String();

		bool use_next_class = false;
		Token tk = get_token();

		Map<int, String> namespace_stack;
		int curly_stack = 0;

		while (!error || tk != TK_EOF) {
			if (tk == TK_BRACKET_OPEN) {
				tk = get_token();
				if (tk == TK_IDENTIFIER && String(value) == "ScriptClass") {
					if (get_token() == TK_BRACKET_CLOSE) {
						use_next_class = true;
					}
				}
			} else if (tk == TK_IDENTIFIER && String(value) == "class") {
				tk = get_token();
				if (tk == TK_IDENTIFIER) {
					String name = value;
					if (use_next_class || p_known_class_name == name) {
						for (const KeyValue<int, String> &E : namespace_stack) {
							class_name += E.value + ".";
						}
						class_name += String(value);
						break;
					}
				}

			} else if (tk == TK_IDENTIFIER && String(value) == "namespace") {
				String name;
				int at_level = curly_stack;
				while (true) {
					tk = get_token();
					if (tk == TK_IDENTIFIER) {
						name += String(value);
					}

					tk = get_token();
					if (tk == TK_PERIOD) {
						name += ".";
					} else if (tk == TK_CURLY_BRACKET_OPEN) {
						curly_stack++;
						break;
					} else {
						break; //whatever else
					}
				}

				if (!name.is_empty()) {
					namespace_stack[at_level] = name;
				}

			} else if (tk == TK_CURLY_BRACKET_OPEN) {
				curly_stack++;
			} else if (tk == TK_CURLY_BRACKET_CLOSE) {
				curly_stack--;
				if (namespace_stack.has(curly_stack)) {
					namespace_stack.erase(curly_stack);
				}
			}

			tk = get_token();
		}

		if (error) {
			return ERR_PARSE_ERROR;
		}

		return OK;
	}

	String get_error() {
		return error_str;
	}

	String get_class() {
		return class_name;
	}
};

void test_vec(Plane p_vec) {
	CameraMatrix cm;
	cm.set_perspective(45, 1, 0, 100);
	Plane v0 = cm.xform4(p_vec);

	print_line("out: " + v0);
	v0.normal.z = (v0.d / 100.0 * 2.0 - 1.0) * v0.d;
	print_line("out_F: " + v0);
}

uint32_t ihash(uint32_t a) {
	a = (a + 0x7ed55d16) + (a << 12);
	a = (a ^ 0xc761c23c) ^ (a >> 19);
	a = (a + 0x165667b1) + (a << 5);
	a = (a + 0xd3a2646c) ^ (a << 9);
	a = (a + 0xfd7046c5) + (a << 3);
	a = (a ^ 0xb55a4f09) ^ (a >> 16);
	return a;
}

uint32_t ihash2(uint32_t a) {
	a = (a ^ 61) ^ (a >> 16);
	a = a + (a << 3);
	a = a ^ (a >> 4);
	a = a * 0x27d4eb2d;
	a = a ^ (a >> 15);
	return a;
}

uint32_t ihash3(uint32_t a) {
	a = (a + 0x479ab41d) + (a << 8);
	a = (a ^ 0xe4aa10ce) ^ (a >> 5);
	a = (a + 0x9942f0a6) - (a << 14);
	a = (a ^ 0x5aedd67d) ^ (a >> 3);
	a = (a + 0x17bea992) + (a << 7);
	return a;
}

MainLoop *test() {
	{
		Vector<Vector3> points;
		points.push_back(Vector3(0, 0, 0));
		points.push_back(Vector3(0, 0, 1));
		points.push_back(Vector3(0, 1, 0));
		points.push_back(Vector3(0, 1, 1));
		points.push_back(Vector3(1, 1, 0));
		points.push_back(Vector3(1, 0, 0));
		points.push_back(Vector3(1, 0, 1));
		points.push_back(Vector3(1, 1, 1));

		for (int i = 0; i < 800; i++) {
			points.push_back(Vector3(Math::randf() * 2.0 - 1.0, Math::randf() * 2.0 - 1.0, Math::randf() * 2.0 - 1.0) * Vector3(25, 30, 33));
		}

		Vector<Delaunay3D::OutputSimplex> os = Delaunay3D::tetrahedralize(points);
		print_line("simplices in the end: " + itos(os.size()));
		for (int i = 0; i < os.size(); i++) {
			print_line("Simplex " + itos(i) + ": ");
			print_line(points[os[i].points[0]]);
			print_line(points[os[i].points[1]]);
			print_line(points[os[i].points[2]]);
			print_line(points[os[i].points[3]]);
		}

		{
			FileAccessRef f = FileAccess::open("res://bsp.obj", FileAccess::WRITE);
			for (int i = 0; i < os.size(); i++) {
				f->store_line("o Simplex" + itos(i));
				for (int j = 0; j < 4; j++) {
					f->store_line(vformat("v %f %f %f", points[os[i].points[j]].x, points[os[i].points[j]].y, points[os[i].points[j]].z));
				}
				static const int face_order[4][3] = {
					{ 1, 2, 3 },
					{ 1, 3, 4 },
					{ 1, 2, 4 },
					{ 2, 3, 4 }
				};

				for (int j = 0; j < 4; j++) {
					f->store_line(vformat("f %d %d %d", 4 * i + face_order[j][0], 4 * i + face_order[j][1], 4 * i + face_order[j][2]));
				}
			}
			f->close();
		}

		return nullptr;
	}

	{
		float r = 1;
		float g = 0.5;
		float b = 0.1;

		const float pow2to9 = 512.0f;
		const float B = 15.0f;
		const float N = 9.0f;

		float sharedexp = 65408.000f;

		float cRed = MAX(0.0f, MIN(sharedexp, r));
		float cGreen = MAX(0.0f, MIN(sharedexp, g));
		float cBlue = MAX(0.0f, MIN(sharedexp, b));

		float cMax = MAX(cRed, MAX(cGreen, cBlue));

		float expp = MAX(-B - 1.0f, floor(Math::log(cMax) / Math_LN2)) + 1.0f + B;

		float sMax = (float)floor((cMax / Math::pow(2.0f, expp - B - N)) + 0.5f);

		float exps = expp + 1.0f;

		if (0.0 <= sMax && sMax < pow2to9) {
			exps = expp;
		}

		float sRed = Math::floor((cRed / pow(2.0f, exps - B - N)) + 0.5f);
		float sGreen = Math::floor((cGreen / pow(2.0f, exps - B - N)) + 0.5f);
		float sBlue = Math::floor((cBlue / pow(2.0f, exps - B - N)) + 0.5f);

		print_line("R: " + rtos(sRed) + " G: " + rtos(sGreen) + " B: " + rtos(sBlue) + " EXP: " + rtos(exps));

		uint32_t rgbe = (Math::fast_ftoi(sRed) & 0x1FF) | ((Math::fast_ftoi(sGreen) & 0x1FF) << 9) | ((Math::fast_ftoi(sBlue) & 0x1FF) << 18) | ((Math::fast_ftoi(exps) & 0x1F) << 27);

		float rb = rgbe & 0x1ff;
		float gb = (rgbe >> 9) & 0x1ff;
		float bb = (rgbe >> 18) & 0x1ff;
		float eb = (rgbe >> 27);
		float mb = Math::pow(2.0, eb - 15.0 - 9.0);
		float rd = rb * mb;
		float gd = gb * mb;
		float bd = bb * mb;

		print_line("RGBE: " + Color(rd, gd, bd));
	}

	Vector<int> ints;
	ints.resize(20);

	{
		int *w;
		w = ints.ptrw();
		for (int i = 0; i < ints.size(); i++) {
			w[i] = i;
		}
	}

	Vector<int> posho = ints;

	{
		const int *r = posho.ptr();
		for (int i = 0; i < posho.size(); i++) {
			print_line(itos(i) + " : " + itos(r[i]));
		}
	}

	List<String> cmdlargs = OS::get_singleton()->get_cmdline_args();

	if (cmdlargs.is_empty()) {
		//try editor!
		return nullptr;
	}

	String test = cmdlargs.back()->get();
	if (test == "math") {
		// Not a file name but the test name, abort.
		// FIXME: This test is ugly as heck, needs fixing :)
		return nullptr;
	}

	FileAccess *fa = FileAccess::open(test, FileAccess::READ);
	ERR_FAIL_COND_V_MSG(!fa, nullptr, "Could not open file: " + test);

	Vector<uint8_t> buf;
	uint64_t flen = fa->get_length();
	buf.resize(fa->get_length() + 1);
	fa->get_buffer(buf.ptrw(), flen);
	buf.write[flen] = 0;

	String code;
	code.parse_utf8((const char *)&buf[0]);

	GetClassAndNamespace getclass;
	if (getclass.parse(code)) {
		print_line("Parse error: " + getclass.get_error());
	} else {
		print_line("Found class: " + getclass.get_class());
	}

	{
		Vector<int> hashes;
		List<StringName> tl;
		ClassDB::get_class_list(&tl);

		for (const StringName &E : tl) {
			Vector<uint8_t> m5b = E.operator String().md5_buffer();
			hashes.push_back(hashes.size());
		}

		for (int i = nearest_shift(hashes.size()); i < 20; i++) {
			bool success = true;
			for (int s = 0; s < 10000; s++) {
				Set<uint32_t> existing;
				success = true;

				for (int j = 0; j < hashes.size(); j++) {
					uint32_t eh = ihash2(ihash3(hashes[j] + ihash(s) + s)) & ((1 << i) - 1);
					if (existing.has(eh)) {
						success = false;
						break;
					}
					existing.insert(eh);
				}

				if (success) {
					print_line("success at " + itos(i) + "/" + itos(nearest_shift(hashes.size())) + " shift " + itos(s));
					break;
				}
			}
			if (success) {
				break;
			}
		}

		print_line("DONE");
	}

	{
		print_line("NUM: " + itos(-128));
	}

	{
		Vector3 v(1, 2, 3);
		v.normalize();
		real_t a = 0.3;

		Basis m(v, a);

		Vector3 v2(7, 3, 1);
		v2.normalize();
		real_t a2 = 0.8;

		Basis m2(v2, a2);

		Quaternion q = m;
		Quaternion q2 = m2;

		Basis m3 = m.inverse() * m2;
		Quaternion q3 = (q.inverse() * q2); //.normalized();

		print_line(Quaternion(m3));
		print_line(q3);

		print_line("before v: " + v + " a: " + rtos(a));
		q.get_axis_angle(v, a);
		print_line("after v: " + v + " a: " + rtos(a));
	}

	String ret;

	List<String> args;
	args.push_back("-l");
	Error err = OS::get_singleton()->execute("/bin/ls", args, &ret);
	print_line("error: " + itos(err));
	print_line(ret);

	Basis m3;
	m3.rotate(Vector3(1, 0, 0), 0.2);
	m3.rotate(Vector3(0, 1, 0), 1.77);
	m3.rotate(Vector3(0, 0, 1), 212);
	Basis m32;
	m32.set_euler(m3.get_euler());
	print_line("ELEULEEEEEEEEEEEEEEEEEER: " + m3.get_euler() + " vs " + m32.get_euler());

	{
		Dictionary d;
		d["momo"] = 1;
		Dictionary b = d;
		b["44"] = 4;
	}

	print_line("inters: " + rtos(Geometry2D::segment_intersects_circle(Vector2(-5, 0), Vector2(-2, 0), Vector2(), 1.0)));

	print_line("cross: " + Vector3(1, 2, 3).cross(Vector3(4, 5, 7)));
	print_line("dot: " + rtos(Vector3(1, 2, 3).dot(Vector3(4, 5, 7))));
	print_line("abs: " + Vector3(-1, 2, -3).abs());
	print_line("distance_to: " + rtos(Vector3(1, 2, 3).distance_to(Vector3(4, 5, 7))));
	print_line("distance_squared_to: " + rtos(Vector3(1, 2, 3).distance_squared_to(Vector3(4, 5, 7))));
	print_line("plus: " + (Vector3(1, 2, 3) + Vector3(Vector3(4, 5, 7))));
	print_line("minus: " + (Vector3(1, 2, 3) - Vector3(Vector3(4, 5, 7))));
	print_line("mul: " + (Vector3(1, 2, 3) * Vector3(Vector3(4, 5, 7))));
	print_line("div: " + (Vector3(1, 2, 3) / Vector3(Vector3(4, 5, 7))));
	print_line("mul scalar: " + (Vector3(1, 2, 3) * 2.0));
	print_line("premul scalar: " + (2.0 * Vector3(1, 2, 3)));
	print_line("div scalar: " + (Vector3(1, 2, 3) / 3.0));
	print_line("length: " + rtos(Vector3(1, 2, 3).length()));
	print_line("length squared: " + rtos(Vector3(1, 2, 3).length_squared()));
	print_line("normalized: " + Vector3(1, 2, 3).normalized());
	print_line("inverse: " + Vector3(1, 2, 3).inverse());

	{
		Vector3 v(4, 5, 7);
		v.normalize();
		print_line("normalize: " + v);
	}

	{
		Vector3 v(4, 5, 7);
		v += Vector3(1, 2, 3);
		print_line("+=: " + v);
	}

	{
		Vector3 v(4, 5, 7);
		v -= Vector3(1, 2, 3);
		print_line("-=: " + v);
	}

	{
		Vector3 v(4, 5, 7);
		v *= Vector3(1, 2, 3);
		print_line("*=: " + v);
	}

	{
		Vector3 v(4, 5, 7);
		v /= Vector3(1, 2, 3);
		print_line("/=: " + v);
	}

	{
		Vector3 v(4, 5, 7);
		v *= 2.0;
		print_line("scalar *=: " + v);
	}

	{
		Vector3 v(4, 5, 7);
		v /= 2.0;
		print_line("scalar /=: " + v);
	}

	return nullptr;
}
} // namespace TestMath