package org.csstudio.sds.util;

import java.util.regex.Pattern;

/**
 * Utility for color and font conversions.
 * 
 * @author Sven Wende
 * 
 */
public class ColorAndFontUtil {
	private static final Pattern COLOR_SYNTAX_PATTERN = Pattern.compile("#[0123456789abcdefABCDEF]{6}");
	private static final Pattern VARIABLE_SYNTAX_PATTERN = Pattern.compile("\\$\\{[a-zA-Z0-9.-]+\\}");

	public static String toFontString(String font, int size) {
		return toFontString(font, size, false, false);

	}

	public static String toFontString(String font, boolean bold, boolean italic) {
		return toFontString(font, -1, bold, italic);
	}

	public static String toFontString(String font, int size, boolean bold, boolean italic) {
		StringBuffer sb = new StringBuffer();
		sb.append(font);

		if (size > 0) {
			sb.append(", ");
			sb.append(size);
		}

		if (bold) {
			sb.append(", bold");
		}

		if (italic) {
			sb.append(", italic");
		}

		return sb.toString();
	}

	/**
	 * Converts the specified rgb values to a hexadecimal representation.
	 * 
	 * @param r
	 *            red
	 * @param g
	 *            green
	 * @param b
	 *            blue
	 * @return hexadecimal representation of the color
	 */
	public static String toHex(int r, int g, int b) {
		return "#" + number2hex(r) + number2hex(g) + number2hex(b);
	}

	/**
	 * Returns true, if the specified String is a hexadecimal color
	 * representation, like #FF0000.
	 * 
	 * @param hex
	 *            the raw String
	 * 
	 * @return true if the specified raw String is a hexadecimal color
	 *         representation
	 */
	public static boolean isHex(String hex) {
		if (hex != null) {
			return COLOR_SYNTAX_PATTERN.matcher(hex).matches();
		} else {
			return false;
		}
	}

	/**
	 * Returns true if the specified String is a variable that can be used for
	 * colors or fonts, like ${colorId}.
	 * 
	 * @param s
	 *            the raw String
	 * 
	 * @return true if the specified String is a variable that can be used for
	 *         colors or fonts
	 */
	public static boolean isVariable(String s) {
		return VARIABLE_SYNTAX_PATTERN.matcher(s).matches();
	}

	private static String number2hex(int nr) {
		String hex = Integer.toHexString(nr);

		String result = hex;

		while (result.length() < 2) {
			result = '0' + result;
		}

		return result;
	}
}