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package gov.samhsa.consent2share.service.account;

import gov.samhsa.consent2share.common.UniqueValueGenerator;
import gov.samhsa.consent2share.domain.patient.PatientRepository;

import org.apache.commons.lang.RandomStringUtils;

/**
 * The Class MrnServiceImpl.
 */
public class MrnServiceImpl implements MrnService {

	/** The Constant RANDOM_STRING_LENGTH. */
	private static final int RANDOM_STRING_LENGTH = 6;

	/** The prefix. */
	private String prefix;

	/** The patient repository. */
	private PatientRepository patientRepository;

	/**
	 * Instantiates a new mrn service impl.
	 *
	 * @param prefix
	 *            the prefix
	 * @param patientRepository
	 *            the patient repository
	 */
	public MrnServiceImpl(String prefix, PatientRepository patientRepository) {
		super();
		this.prefix = prefix;
		this.patientRepository = patientRepository;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see gov.samhsa.consent2share.service.account.MrnService#generateMrn()
	 */
	@Override
	public String generateMrn() {
		final short iterationLimit = 3;
		return UniqueValueGenerator
				.generateUniqueValue(this::generateRandomMrn,
						generatedValue -> patientRepository
								.findAllByMedicalRecordNumber(generatedValue)
								.size() == 0, iterationLimit);
	}

	/**
	 * Generate random mrn.
	 *
	 * @return the string
	 */
	private String generateRandomMrn() {
		StringBuilder localIdIdBuilder = new StringBuilder();
		if (null != prefix) {
			localIdIdBuilder.append(new String(prefix));
			localIdIdBuilder.append(".");
		}
		localIdIdBuilder.append(RandomStringUtils
				.randomAlphanumeric((RANDOM_STRING_LENGTH)));
		return localIdIdBuilder.toString().toUpperCase();
	}
}