import java.util.Map;
import java.sql.SQLException;

/**
 * Static methods to verify certain user inputs are valid.
 */
public class InputChecker
{
	public static final int USER_ID_LENGTH = 9;
	public static final int PASSWORD_LENGTH = 6;

	/**
	 * Checks to see if a Banner user id and password are "valid".  This validation
	 * only checks to see if the lengths of the strings are correct, nothing more.  True
	 * validation is done by Banner itself.
	 * @param userId the user id to check.
	 * @param password the password to check.
	 * @return a non-null user-friendly String if an error occurs, or null if everything was ok.
	 */
	public static String isLoginOk(String userId, String password)
	{
		if(userId == null || password == null)		
		{
			throw new RuntimeException(
				"User Id or Password was null.");
		}

		StringBuffer errorBuffer = new StringBuffer();
		boolean foundError = false;

		if(userId.length() != USER_ID_LENGTH)
		{
			errorBuffer.append("User Id must be " + USER_ID_LENGTH + " characters long.");			
			foundError = true;
		}

		if(password.length() != PASSWORD_LENGTH)
		{
			if(foundError) errorBuffer.append("<BR>");
			errorBuffer.append("Password must be " + PASSWORD_LENGTH + " characters long.");
			foundError = true;
		}
		
		return foundError ? errorBuffer.toString() : null;
	}

	/**
	 * Ensures the input map passed into the processor contains the correct entries and that
	 * these entries contain valid values.
	 * @param map the map containing values to check prior to invoking the processor.
	 * @return a non-null user-friendly String if an error occurs, or null if everything was ok.
	 * @exception SQLException if an error occurs while connecting to the SAS database.
	 */
	public static String isInputMapOk(Map map) throws SQLException
	{
		if(map == null)
		{
			throw new RuntimeException(
				"The map was null.");
		}

		String majorStr = (String) map.get("major");
		String minorStr = (String) map.get("minor");
		String secondMajorStr = (String) map.get("secondmajor");

		StringBuffer errorBuffer = new StringBuffer();
		boolean foundError = false;

		if(majorStr.equals("none"))
		{
			errorBuffer.append("You must specify a major in your preferences.");
			foundError = true;
		}

		if(minorStr.equals("none"))
		{
			if(foundError) errorBuffer.append("<BR>");
			errorBuffer.append("You must specify a minor in your preferences.");
			foundError = true;
		}

		if(majorStr.equals(minorStr))
		{
			if(foundError) errorBuffer.append("<BR>");
			errorBuffer.append("You must specify a different major and minor in your preferences.");
			foundError = true;
		}

		if(majorStr.equals(secondMajorStr))
		{
			if(foundError) errorBuffer.append("<BR>");
			errorBuffer.append("You must specify a different major and second major in your preferences.");
			foundError = true;
		}

		if(minorStr.equals(secondMajorStr))
		{
			if(foundError) errorBuffer.append("<BR>");
			errorBuffer.append("You must specify a different minor and second major in your preferences.");
			foundError = true;
		}

		if(!foundError && !RetrieverUtils.isMajorOkWithMinor(majorStr, minorStr))
		{
			if(foundError) errorBuffer.append("<BR>");
			errorBuffer.append("Selected major and minor cannot be chosen together.");
			foundError = true;
		}

		if(!foundError && !secondMajorStr.equals("-1") && 
			!RetrieverUtils.isMajorOkWithMinor(secondMajorStr, minorStr))
		{
			if(foundError) errorBuffer.append("<BR>");
			errorBuffer.append("Selected second major and minor cannot be chosen together.");
			foundError = true;
		}

		String coreNeededStr = (String) map.get("coreneeded");

		if(coreNeededStr.length() > 0)
		{
			int coreNeededInt = 0;

			try
			{
				coreNeededInt = Integer.parseInt(
					coreNeededStr);

				if(coreNeededInt < 0)
				{
					if(foundError) errorBuffer.append("<BR>");

					errorBuffer.append(
						"You must specify a number of CORE credits needed that is not negative." +
						"  If you are not a transfer student, leave this field blank.");

					foundError = true;
				}
			}
			catch(NumberFormatException e)
			{
				if(foundError) errorBuffer.append("<BR>");
				
				errorBuffer.append(
					"The number of CORE credits you entered was invalid.");

				foundError = true;				
			}
		}
		else map.put("coreneeded", "no");

		return foundError ? errorBuffer.toString() : null;
	}
}