#include <stdio.h>
#include "futil.c"

typedef enum EIdent
{
	EI_MAG0 = 0, //Magic number position zero - three.
	EI_MAG1 = 1,
	EI_MAG2 = 2,
	EI_MAG3 = 3,
	EI_CLASS = 4,
	EI_DATA = 5,
	EI_VERSION = 6,
	EI_OSABI = 7,
	EI_ABIVERSION = 8,
	EI_PAD = 9,
	EI_NIDENT = 16 //End of reserved 16 bytes for the header.
} EIdent;

typedef enum EIClass
{
	ELFClassNone = 0,
	ELFClass32 = 1,
	ELFClass64 = 2
} EIClass;

typedef enum EI_Data
{
	ELFDataNone = 0,
	ELFDataLSB = 1,
	ELFDataMSB = 2
} EIData;

typedef enum ELFType{
	ET_None = 0,		//No file type
	ET_Rel = 1,			//Relocatable file
	ET_Exec = 2,		//Executable file
	ET_Dyn = 3,			//Shared object file
	ET_Core = 4,		//Core file
	ET_LOProc = 0xff00, //Processor
	ET_HIProc = 0xffff  //Specific
} ELFType;

typedef enum ELFMachine
{
	EM_None = 0,
	EM_M32 = 1, //AT&T WE 32100
	EM_Sparc = 2,
	EM_386 = 3,
	EM_68k = 4,
	EM_88k = 5,
	EM_860 = 7,
	EM_MIPS = 8,
	EM_X86_64 = 62
} ELFMachine;

typedef enum ELFOSABI
{
	ELFOSABI_SYSTEMV = 0,
	ELFOSABI_HPUX = 1,
	ELFOSABI_NETBSD = 2,
	ELFOSABI_GNU = 3,
	ELFOSABI_LINUX = 3,
	ELFOSABI_SOLARIS = 6,
	ELFOSABI_AIX,
	ELFOSABI_IRIX,
	ELFOSABI_FREEBSD,
	ELFOSABI_TRU64,
	ELFOSABI_MODESTO,
	ELFOSABI_OPENBSD,
	ELFOSABI_OPENVMS,
	ELFOSABI_NSK,
	ELFOSABI_AROS,
	ELFOSABI_FENIXOS,
	ELFOSABI_CLOUDABI,
	ELFOSABI_OPENVOS
} ELFOSABI;

int main(int argc, char** argv)
{
	char* bytes;
	size_t size;

	if (argc != 2)
	{
		printf("No argcs\n");
		return 0;
	}

	if (!ReadAllString(argv[1], &bytes, &size)) return 0;

	char magic[5] = { bytes[EI_MAG0], bytes[EI_MAG1], bytes[EI_MAG2], bytes[EI_MAG3], '\0' };

	if (strcmp(magic, "\x7f""ELF") != 0) 
	{
		fprintf(stderr, "Failed to find ELF magic number in file header.\n");

		return 0;
	}

	printf("Magic: ");

	for(int i = 0; i < EI_NIDENT; i++)
	{
		printf("%02X ", bytes[i]);
	}

	printf("\n");

	switch(bytes[EI_CLASS])
	{
		case ELFClass32:
			printf("Class: 32-bit object\n");
			break;
		case ELFClass64:
			printf("Class: 64-bit object\n");
			break;
		default:
			printf("Class: Invalid\n");
			return 1;
	}

	switch(bytes[EI_DATA])
	{
		case ELFDataLSB:
			printf("Data: 2's complement, little endian.\n");
			break;
		case ELFDataMSB:
			printf("Data: 2's complement, big endian.\n");
			break;
		default:
			printf("Data: Unknown byte order\n");
			return 1;
	}

	if (bytes[EI_VERSION] == 1) printf("Version: 1 (Current)\n");
	else printf("Version: 0 (Invalid)\n");

	printf("OS/ABI: ");

	switch(bytes[EI_OSABI])
	{
		case ELFOSABI_SYSTEMV:
			printf("System V ABI\n");
			break;
		case ELFOSABI_HPUX:
			printf("Hewlett-Packard HP-UX ABI\n");
			break;
		case ELFOSABI_NETBSD:
			printf("NetBSD ABI\n");
			break;
		case ELFOSABI_LINUX:
			printf("GNU ABI\n");
			break;
		case ELFOSABI_SOLARIS:
			printf("Sun Solaris ABI\n");
			break;
		case ELFOSABI_AIX:
			printf("AIX ABI\n");
			break;
		case ELFOSABI_IRIX:
			printf("IRIX ABI\n");
			break;
		case ELFOSABI_FREEBSD:
			printf("FreeBSd ABI\n");
			break;
		case ELFOSABI_TRU64:
			printf("Compaq TRU64 UNIX ABI\n");
			break;
		case ELFOSABI_MODESTO:
			printf("Novell Modesto ABI\n");
			break;
		case ELFOSABI_OPENBSD:
			printf("OpenBSD ABI\n");
			break;
		case ELFOSABI_OPENVMS:
			printf("Open VMS ABI\n");
			break;
		case ELFOSABI_NSK:
			printf("Hewlett-Packard Non-Stop Kernel ABI\n");
			break;
		case ELFOSABI_AROS:
			printf("Amiga Research OS ABI\n");
			break;
		case ELFOSABI_FENIXOS:
			printf("The FenixOS highly scalable multi-core OS ABI\n");
			break;
		case ELFOSABI_CLOUDABI:
			printf("Nuxi CloudABI ABI\n");
			break;
		case ELFOSABI_OPENVOS:
			printf("Stratus Technologies OpenVOS ABI\n");
			break;
		default:
			printf("Reserved ABI (%d)\n", bytes[EI_ABIVERSION]);
			break;
	}

	printf("ABI Version: %d\n", bytes[EI_ABIVERSION]);

	printf("Type: ");

	switch(bytes[EI_NIDENT] + bytes[EI_NIDENT + 1])
	{
		case ET_None:
			printf("None\n");
			break;
		case ET_Rel:
			printf("Rel\n");
			break;
		case ET_Exec:
			printf("Exec\n");
			break;
		case ET_Dyn:
			printf("DYN (Position-Independent Executable file)\n");
			break;
		case ET_Core:
			printf("Core\n");
			break;
		case ET_LOProc:
			printf("LO\n");
			break;
		case ET_HIProc:
			printf("HI\n");
			break;
		default:
			fprintf(stderr, "Unknown file type\n");
			return 1;
	}

	printf("Machine: ");

	switch (bytes[EI_NIDENT + 2] + bytes[EI_NIDENT + 3]) {
		case EM_860:
			printf("Intel 80860\n");
			break;
		case EM_X86_64:
			printf("AMD x86-64 architecture\n");
			break;
		default:
			fprintf(stderr, "Failed to identify machine type\n");
			return 1;
	}

	printf("Read %ld bytes from file '%s'\n", size, argv[1]);
}