#include "libfat.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"

os_u32 loaded_fat_segment[512];
os_u8 mbr_buffer[512];

os_u32 readRoutine(os_u32 amount, void* buffer, void* user_data) {
	if (user_data == 0) {
		return 0;
	}
	FILE** f = (FILE**)user_data;

	os_u32 read_bytes = fread(buffer, 1, amount, *f);
	return read_bytes;
}

os_u32 writeRoutine(os_u32 amount, void* buffer, void* user_data) {
	if (user_data == 0) {
		return 0;
	}

	FILE** f = (FILE**)user_data;

	os_u32 written_bytes = fwrite(buffer, 1, amount, *f);
	return written_bytes;
}

os_bool seekRoutine(os_u32 offset, os_u32 direction, void* user_data) {
	if (user_data == 0) {
		return OS_FALSE;
	}

	FILE** f = (FILE**)user_data;
	int seek_dir = SEEK_SET;
	switch(direction) {
		case LIBFAT_SEEK_ORIGIN:
			seek_dir = SEEK_SET;
			break;
		case LIBFAT_SEEK_CURRENT:
			seek_dir = SEEK_CUR;
			break;
		case LIBFAT_SEEK_END:
			seek_dir = SEEK_END;
			break;
	}

	int result = fseek(*f, offset, seek_dir);
	return result == 0 ? OS_TRUE : OS_FALSE;
}

os_u32 tellRoutine(void* user_data) {
	if (user_data == 0) {
		return 0;
	}

	FILE** f = (FILE**)user_data;

	os_u32 result = ftell(*f);
	return result;
}

void printRoutine(os_s8* data, os_u16 size) {
	if (size == 0) {
		printf("%s\n", data);
		return;
	}

	for(os_u16 s = 0; s < size; s++) {
		printf("%c", *data);
		data++;
	}
	printf("\n");
}

void printNumber(os_u32 number) {
	printf("%#x\n", number);
}

int main(int argc, char** argv) {
	if (argc < 3) {
		printf("No files provided\n");
		return 1;
	}

	FILE* f = fopen(argv[1], "rb+");

	LFFileHandle h;
	h.read = readRoutine;
	h.write = writeRoutine;
	h.seek = seekRoutine;
	h.tell = tellRoutine;
	h.user_data = (void*)&f;

	LFControlBlock fat;
	if(libfat_init(h, loaded_fat_segment, 512 * sizeof(os_u32), &fat) != OS_TRUE) {
		fprintf(stderr, "libfat_init failed.\n");
		return 1;
	}

	FILE* f2 = fopen(argv[2], "rb");

	LFFileHandle mbrHandle;
	mbrHandle.read = readRoutine;
	mbrHandle.write = writeRoutine;
	mbrHandle.seek = seekRoutine;
	mbrHandle.tell = tellRoutine;
	mbrHandle.user_data = (void*)&f2;

	if(libfat_test_mbr(&mbrHandle) != OS_TRUE) {
		printf("Failed to test MBR...\n");
		return 1;
	}

	printf("FAT Ok.\n");

	FatHeader_32 header = fat.header;
	fseek(f2, 0, SEEK_SET);

	os_u32 read = fread(mbr_buffer, 1, 512, f2);
	if (read < 512) {
		fprintf(stderr, "MBR size is incorrect: %d\n", read);
		return 1;
	}

	if (*(os_u16*)(mbr_buffer + 510) != 0xAA55) {
		fprintf(stderr, "MBR boot signature is missing: %#x\n", *(os_u16*)(mbr_buffer + 510));
		return 1;
	}

	printf("MBR Ok.\n");

	memcpy(mbr_buffer + 3, ((char*)&header) + 3, sizeof(FatHeader_32) - 3);

	fseek(f, 0, SEEK_SET);
	fwrite(mbr_buffer, 1, 512, f);

	fclose(f);
	fclose(f2);
	printf("MBR Written on FAT.\n");

	return 0;
}