package envoy.client.util;

import java.util.regex.Pattern;

import envoy.event.IssueProposal;

/**
 * Provides methods to handle outgoing issues.
 *
 * @author Leon Hofmeister
 * @author Kai S. K. Engelbart
 * @since Envoy Client v0.2-beta
 */
public final class IssueUtil {

	private static final Pattern	removeBackslashes	= Pattern.compile("\\\\");
	private static final Pattern	escapeQuotes		= Pattern.compile("\"");

	private IssueUtil() {}

	/**
	 * Creates a new {@code IssueProposal} from the given data.
	 *
	 * @param title       the proposed title of the issue
	 * @param description the proposed description of the issue
	 * @param username    the user who submitted the issue. Should be
	 *                    {@code null} if he does not want to be named. * @param
	 *                    isBug
	 * @param isBug       whether this issue is a bug or a feature
	 * @return a sanitized IssueProposal that should not fail to be sent
	 * @since Envoy Client v0.2-beta
	 */
	public static IssueProposal createIssueProposal(String title, String description, String username, boolean isBug) {
		title		= sanitizeIssueTitle(title);
		description	= sanitizeIssueDescription(description, username);
		return new IssueProposal(title, description, isBug);

	}

	/**
	 * Escapes quotes and removes backslashes for a suggested issue title.
	 *
	 * @param title the title to sanitize
	 * @return the sanitized title
	 * @since Envoy Client v0.2-beta
	 */
	private static String sanitizeIssueTitle(String title) {

		// Remove ALL backslashes as they are only error prone
		title = removeBackslashes.matcher(title).replaceAll("");

		// Escape quotes
		title = escapeQuotes.matcher(title).replaceAll("\\\\\"");
		return title;
	}

	/**
	 * Normalizes line breaks, <br>
	 * removes all backslashes, <br>
	 * escapes quotes and<br>
	 * appends the user name to the issue description if requested.
	 *
	 * @param description the description to sanitize
	 * @param username    the user who submitted the issue. Should be
	 *                    {@code null} if he does not want to be named.
	 * @return the sanitized description
	 * @since Envoy Client v0.2-beta
	 * @apiNote the String returned might not be sanitized in case multiple
	 *          backslashes are preceding a quote.
	 */
	public static String sanitizeIssueDescription(String description, String username) {

		// Trim and replace line breaks by <br> tags
		description = description.trim().replaceAll(System.getProperty("line.separator"), "<br>");

		// Append user name if requested
		if (username != null) description += String.format("<br>Submitted by user %s.", username);

		// Remove ALL backslashes as they are only error prone
		description = removeBackslashes.matcher(description).replaceAll("");

		// Escape all quotes to avoid prematurely ending the string
		description = escapeQuotes.matcher(description).replaceAll("\\\\\"");
		return description;
	}
}