/*
	Programming 111
	Program 04 (BookCode Validator)
	Coded by Blake Imsland

	--
	This program; given a string or book code; will check the validity of said code
	and inform the user of any errors.
	--

	File: program04.cpp
	Date: 2006/11/18
*/

/* include required headers */
#include <iostream>
#include <string>
using namespace std;

/* define constants */
#define NOS 10			// length for short code
#define NOD 3			// number of dashes in long code

/* prototype functions */
void directions();
bool validate(string &);

/* main program */
int main() {

	/* prototype variables */
	string bookCode;

	/* print directions */
	directions();

	/* main program loop */
	while (1) {

		/* get code from user */
		cout << "\nCode entry: ";
		cin >> bookCode;

		/* check for quit */
		if (bookCode == "q" || bookCode == "Q") {
			break;
		}

		/* validate code */
		if (validate(bookCode)) {
			cout << "Valid code entered;\n";
		}
	}

	/* quit */
	return 0;
}

/* print directions for user */
void directions()
{
	cout << "Welcome to the Graysville library catalog!\n"
		<< "Enter a book code of length 13 (with dashes) or 10 (without dashes).\n"
		<< "The program will check the validity of the code before querying the catalog.\n";
}

/* takes a string/code and checks the validity */
/* returns true if code is valid, false if not */
bool validate(string &bookCode)
{
	/* prototype variables */
	int i;
	bool valid = true;

	/* convert string to char array */
	int c[bookCode.length()];
	for (i=0;i<bookCode.length();i++) {
		c[i] = bookCode.at(i);
	}

	/* get length of array */
	int length = sizeof(c)/sizeof(int);

	/* if code is short */
	if (length == NOS) {

		/* check first and middle digits */
		for (i=0;i<length-1;i++) {
			if (c[i] < '0' || c[i] > '9') {
				cout << "Invalid digit at position " << i+1 << ";\n";
				valid = false;
			}
		}

		/* check last digit */
		if ((c[length-1] < '0' || c[length-1] > '9') && c[length-1] != 'X') {
			cout << "Invalid digit at position " << NOS << ";\n";
			valid = false;
		}
	}

	/* if code is long */
	else if (length == (NOS + NOD)) {

		/* null dash count to 0 */
		int dashes = 0;

		/* check first digit */
		if (c[0] < '0' || c[0] > '9') {
			if (c[0] == '-') {
				cout << "Invalid dash at position 1;\n";
				dashes++;
				valid = false;
			} else {
				cout << "Invalid digit at position 1;\n";
				valid = false;
			}
		}

		/* check whether middle digits are valid */
		for (i=1;i<length-1;i++) {
			if (c[i] == '-') {
				if ((i<length-1 && c[i+1] == '-') || (i>0 && c[i-1] == '-')) {
					cout << "Invalid sequential dash at position " << i+1 << ";\n";
					valid = false;
				}
				dashes++;
			}
			else if (c[i] < '0' || c[i] > '9') {
				cout << "Invalid digit at position " << i+1 << ";\n";
				valid = false;
			}
		}

		/* check last digit */
		if ((c[length-1] < '0' || c[length-1] > '9') && c[length-1] != 'X') {
			if (c[length-1] == '-') {
				cout << "Invalid dash at position " << length << ";\n";
				dashes++;
				valid = false;
			}
			else {
				cout << "Invalid digit at position " << length << ";\n";
				valid = false;
			}
		}

		/* check dash count */
		if (dashes != NOD) {
			cout << "Invalid number of dashes " << dashes << ";\n";
			valid = false;
		}
	}

	/* if code is neither */
	else {
		cout << "Invalid code length of " << length << ";\n";
		valid = false;
	}
	return valid;
}