struct CMDS {
	const char* name;
	char len;
};

struct CMDS comm[] = { {"CONNECT", 7}, {"CONNECT_OK", 10}, {"GET_VER", 7}, {"GET_DATA", 8}, {"GET_FILE", 8}, {"GET_COMMAND", 11}, {"GET_B64", 7}, {"DISCONNECT", 10}, {"VERSION ", 8}, {"B64: ", 5}, {"DISCONNECT_OK", 13} };

enum PreviousMess { WRONG, RIGHT };
char dataValid[127] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0 };
char b64Valid[127] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, };

char CheckDirection(int* state, enum Direction direct);
char CheckState(int* prevState, int* state, enum Direction direct, enum PreviousMess* message, char* str, char** cmd);
void Mistake(messagePtr, statePtr, prevStatePtr);
void True(messagePtr, statePtr, prevStatePtr);
char CheckCMD(char* str, char** cmd);
char CheckVer(char* str);
char CheckB64(char* str);

int state = 1;
int prevState = 1;
enum PreviousMess message = WRONG;
char* cmd[12];
char* prevComm[20];

int* statePtr = &state;
int* prevStatePtr = &prevState;
enum PreviousMess* messagePtr = &message;
char** cmdPtr = &cmd;
char** prevCommPtr = &prevComm;

enum test_status validate_message( struct Message *msg ) {

    // TODO: Implement me
	if (!CheckState(prevStatePtr, statePtr, msg->direction, messagePtr, cmdPtr, prevCommPtr))
		return MESSAGE_INVALID;
    return MESSAGE_VALID;
}

char CheckDirection(int* state, enum Direction direct) {
	switch (*state) {
	case 1: {
		if (direct != A_TO_B)
			return 0;
		break;
	}
	case 2: {
		if (direct != B_TO_A)
			return 0;
		break;
	}
	case 3: {
		if (direct != A_TO_B)
			return 0;
		break;
	}
	case 4: {
		if (direct != B_TO_A)
			return 0;
		break;
	}
	case 5: {
		if (direct != B_TO_A)
			return 0;
		break;
	}
	case 6: {
		if (direct != B_TO_A)
			return 0;
		break;
	}
	case 7: {
		if (direct != B_TO_A)
			return 0;
		break;
	}
	default: return 0;
	}

	return 1;
}

void Mistake(messagePtr, statePtr, prevStatePtr) {
	messagePtr = WRONG;
	prevStatePtr = statePtr;
	statePtr = 1;
}

void True(messagePtr, statePtr, prevStatePtr) {
	messagePtr = RIGHT;
	prevStatePtr = statePtr;
}

char CheckVer(char* str) {
	int len = strlen(str);

	if (len <= 8)
		return 0;

	char* tmp = malloc(10);

	strncpy_s(tmp, 0, str, 7);
	if (strcmp(tmp, comm[8].name)) {
		free(tmp);
		return 0;
	}

	tmp = "";

	strncpy_s(tmp, 8, str, len - 1);

	int k = atoi(tmp);

	if (k <= 0) {
		free(tmp);
		return 0;
	}

	return 1;
}

char CheckB64(char* str) {
	int len = strlen(str);

	if (len <= 5)
		return 0;

	char* tmp = malloc(10);

	strncpy_s(tmp, 0, str, 4);
	if (strcmp(tmp, comm[9].name)) {
		free(tmp);
		return 0;
	}

	free(tmp);

	for (int i = 5; i < len - 2; i++) {
		if (!b64Valid[str[i]])
			return 0;
	}

	if ((str[len - 2] != '=' && !b64Valid[str[len - 2]])
		|| (str[len - 1] != '=' && !b64Valid[str[len - 1]]))
		return 0;

	return 1;
}

char CheckCMD(char* str, char** cmd) {
	int len = strlen(str);
	int len2 = strlen(*cmd);

	if (len <= len2 * 2 + 2)
		return 0;

	char* tmp = malloc(len2 + 2);

	strncpy_s(tmp, 0, str, len2);

	if (strcmp(tmp, *cmd) != 0) {
		free(tmp);
		return 0;
	}

	if (str[len2] != ' ' || str[len - len2 - 1] != ' ') {
		free(tmp);
		return 0;
	}

	for (int i = len2 + 1; i < len - len2 - 1; i++) {
		if ((!dataValid[str[i]])) {
			free(tmp);
			return 0;
		}
	}

	strncpy_s(tmp, len - len2, str, len - 1);

	if (strcmp(tmp, *cmd) != 0) {
		free(tmp);
		return 0;
	}

	free(tmp);

	return 1;
}

char CheckState(int* prevState, int* state, enum Direction direct, enum PreviousMess* message, char* str, char** cmd) {
	if (!CheckDirection(statePtr, direct)) {
		Mistake(messagePtr, statePtr, prevStatePtr);
		return 0;
	}

	switch (*state) {

	case 1: {
		if (strcmp(str, comm[0].name) != 0 || *message != WRONG && prevState != 7) {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}

		True(messagePtr, statePtr, prevStatePtr);
		*state = 2;

		return 1;
	}

	case 2: {
		if (strcmp(str, comm[1].name) != 0 || *message != WRONG && prevState != 1) {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}

		True(messagePtr, statePtr, prevStatePtr);
		*state = 3;

		return 1;
	}

	case 3: {
		if (*message == WRONG || (prevState != 4
			&& prevState != 5 && prevState != 7)) {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}

		if (strcmp(str, comm[2].name) == 0)
			*state = 4;
		else  if (strcmp(str, comm[3].name) == 0
			|| strcmp(str, comm[4].name) == 0 || strcmp(str, comm[5].name) == 0)
			*state = 5;
		else if (strcmp(str, comm[6].name) == 0)
			*state = 6;
		else if (strcmp(str, comm[7].name) == 0)
			*state = 7;
		else {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}
		True(messagePtr, statePtr, prevStatePtr);
		*state = 3;

		return 1;
	}


	case 4: {
		if (strcmp(*cmd, comm[8].name) != 0 || *message == WRONG
			|| !CheckVer(str) || prevState != 3) {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}

		True(messagePtr, statePtr, prevStatePtr);
		*state = 3;

		return 1;
	}

	case 5: {
		if ( *message == WRONG || !CheckCMD(str, prevCommPtr)
			|| prevState != 3) {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}

		True(messagePtr, statePtr, prevStatePtr);
		*state = 3;

		return 1;
	}

	case 6: {
		if (strcmp(*cmd, comm[9].name) != 0 || !CheckB64(str)
			|| *message == WRONG || prevState != 3) {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}

		True(messagePtr, statePtr, prevStatePtr);
		*state = 3;

		return 1;
	}

	case 7: {
		if (strcmp(str, comm[10].name) != 0 || *message == WRONG || prevState != 3) {
			Mistake(messagePtr, statePtr, prevStatePtr);
			return 0;
		}

		True(messagePtr, statePtr, prevStatePtr);
		*state = 1;

		return 1;
	}

	default: return 0;
	}
}