package com.gitblit.utils;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.List;

import org.tautua.markdownpapers.Markdown;
import org.tautua.markdownpapers.parser.ParseException;

public class StringUtils {

	public static boolean isEmpty(String value) {
		return value == null || value.trim().length() == 0;
	}

	public static String breakLinesForHtml(String string) {
		return string.replace("\r\n", "<br/>").replace("\r", "<br/>").replace("\n", "<br/>");
	}

	public static String escapeForHtml(String inStr, boolean changeSpace) {
		StringBuffer retStr = new StringBuffer();
		int i = 0;
		while (i < inStr.length()) {
			if (inStr.charAt(i) == '&') {
				retStr.append("&amp;");
			} else if (inStr.charAt(i) == '<') {
				retStr.append("&lt;");
			} else if (inStr.charAt(i) == '>') {
				retStr.append("&gt;");
			} else if (inStr.charAt(i) == '\"') {
				retStr.append("&quot;");
			} else if (changeSpace && inStr.charAt(i) == ' ') {
				retStr.append("&nbsp;");
			} else if (changeSpace && inStr.charAt(i) == '\t') {
				retStr.append(" &nbsp; &nbsp;");
			} else
				retStr.append(inStr.charAt(i));
			i++;
		}
		return retStr.toString();
	}

	public static String flattenStrings(List<String> values) {
		StringBuilder sb = new StringBuilder();
		for (String value : values) {
			sb.append(value).append(" ");
		}
		return sb.toString().trim();
	}

	public static String trimString(String value, int max) {
		if (value.length() <= max) {
			return value;
		}
		return value.substring(0, max - 3) + "...";
	}

	public static String trimShortLog(String string) {
		return trimString(string, 60);
	}

	public static String leftPad(String input, int length, char pad) {
		if (input.length() < length) {
			StringBuilder sb = new StringBuilder();
			for (int i = 0, len = length - input.length(); i < len; i++) {
				sb.append(pad);
			}
			sb.append(input);
			return sb.toString();
		}
		return input;
	}

	public static String rightPad(String input, int length, char pad) {
		if (input.length() < length) {
			StringBuilder sb = new StringBuilder();
			sb.append(input);
			for (int i = 0, len = length - input.length(); i < len; i++) {
				sb.append(pad);
			}
			return sb.toString();
		}
		return input;
	}

	public static String getSHA1(String text) {
		try {
			byte[] bytes = text.getBytes("iso-8859-1");
			return getSHA1(bytes);
		} catch (UnsupportedEncodingException u) {
			throw new RuntimeException(u);
		}
	}

	public static String getSHA1(byte[] bytes) {
		try {
			MessageDigest md = MessageDigest.getInstance("SHA-1");
			md.update(bytes, 0, bytes.length);
			byte[] sha1hash = md.digest();
			StringBuilder sb = new StringBuilder(sha1hash.length * 2);
			for (int i = 0; i < sha1hash.length; i++) {
				if (((int) sha1hash[i] & 0xff) < 0x10)
					sb.append("0");
				sb.append(Long.toString((int) sha1hash[i] & 0xff, 16));
			}
			return sb.toString();
		} catch (NoSuchAlgorithmException t) {
			throw new RuntimeException(t);
		}
	}

	public static String transformMarkdown(String markdown) throws java.text.ParseException {
		// Read raw markdown content and transform it to html		
		StringReader reader = new StringReader(markdown);
		StringWriter writer = new StringWriter();
		try {
			Markdown md = new Markdown();
			md.transform(reader, writer);
			return writer.toString();
		} catch (ParseException p) {			
			throw new java.text.ParseException(p.getMessage(), 0);
		} finally {
			reader.close();
			try {
				writer.close();
			} catch (IOException e) {
			}
		}
	}
	
	public static String transformMarkdown(Reader markdownReader) throws java.text.ParseException {
		// Read raw markdown content and transform it to html				
		StringWriter writer = new StringWriter();
		try {
			Markdown md = new Markdown();
			md.transform(markdownReader, writer);
			return writer.toString();
		} catch (ParseException p) {			
			throw new java.text.ParseException(p.getMessage(), 0);
		} finally {
			try {
				markdownReader.close();
			} catch (IOException e) {
			}
			try {
				writer.close();
			} catch (IOException e) {
			}
		}
	}
}