/* Copyright (c) Citrix Systems Inc. 
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
 * that the following conditions are met: 
 * 
 * *   Redistributions of source code must retain the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer. 
 * *   Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer in the documentation and/or other 
 *     materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace XenAdmin.Core
{
    public static class StringUtility
    {
        /// <summary>
        /// Parses strings of the form "hostname:port" 
        /// </summary>
        /// <param name="s"></param>
        /// <param name="hostname"></param>
        /// <param name="port"></param>
        /// <returns></returns>
        public static bool TryParseHostname(string s, int defaultPort, out string hostname, out int port)
        {
            try
            {
                int i = s.IndexOf(':');
                if (i != -1)
                {
                    hostname = s.Substring(0, i).Trim();
                    port = int.Parse(s.Substring(i + 1).Trim());
                }
                else
                {
                    hostname = s;
                    port = defaultPort; // Program.DEFAULT_XEN_PORT;
                }
                return true;
            }
            catch (Exception)
            {
                hostname = null;
                port = 0;
                return false;
            }
        }

        public static int NaturalCompare(string s1, string s2)
        {
            if (string.Compare(s1, s2, StringComparison.CurrentCultureIgnoreCase) == 0)
            {
                // Strings are identical
                return 0;
            }

            if (s1 == null)
                return -1;
            if (s2 == null)
                return 1;

            char[] chars1 = s1.ToCharArray();
            char[] chars2 = s2.ToCharArray();

            // Compare strings char by char
            int min = Math.Min(chars1.Length, chars2.Length);
            for (int i = 0; i < min; i++)
            {
                char c1 = chars1[i];
                char c2 = chars2[i];

                bool c1IsDigit = char.IsDigit(c1);
                bool c2IsDigit = char.IsDigit(c2);

                if (!c1IsDigit && !c2IsDigit)
                {
                    // Two non-digits. Do a string (i.e. alphabetical) comparison.
                    int tmp = String.Compare(s1.Substring(i, 1), s2.Substring(i, 1), StringComparison.CurrentCultureIgnoreCase);
                    if (tmp == 0)
                        continue;  // Identical non-digits. Move onto next character.
                    else
                        return tmp;
                }
                else if (c1IsDigit && c2IsDigit)
                {
                    // See how many digits there are in a row in each string.
                    int j = 1;
                    while (i + j < chars1.Length && char.IsDigit(chars1[i + j]))
                        j++;
                    int k = 1;
                    while (i + k < chars2.Length && char.IsDigit(chars2[i + k]))
                        k++;

                    // A number that is shorter in decimal places must be smaller.
                    if (j < k)
                    {
                        return -1;
                    }
                    else if (k < j)
                    {
                        return 1;
                    }

                    // The two integers have the same number of digits. Compare them digit by digit.
                    for (int m = i; m < i + j; m++)
                    {
                        if (chars1[m] != chars2[m])
                            return chars1[m] - chars2[m];
                    }

                    // Skip the characters we've already compared, so we don't have to do them again. (CA-50738)
                    // (It's only j-1, not j, because we get one more in the loop increment).
                    i += j - 1;
                    continue;
                }
                else
                {
                    // We're comparing a digit to a non-digit.
                    return String.Compare(s1.Substring(i, 1), s2.Substring(i, 1), StringComparison.CurrentCultureIgnoreCase);
                }
            }
            // The shorter string comes first.
            return chars1.Length - chars2.Length;
        }

        private static readonly Regex IPRegex = new Regex(@"^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$");
        private static readonly Regex IPRegex0 = new Regex(@"^([0]{1,3})\.([0]{1,3})\.([0]{1,3})\.([0]{1,3})$");

        public static bool IsIPAddress(string s)
        {
            if (string.IsNullOrEmpty(s))
                return false;

            // check the general form is ok
            Match m = IPRegex.Match(s);
            if (!m.Success)
                return false;

            // check the individual numbers are in range, easier to do this as a parse than with the regex
            for (int i = 1; i < 3; i++)
            {
                int v;
                if (!int.TryParse(m.Groups[i].Value, out v))
                    return false;

                if (v > 255)
                    return false;
            }

            Match m2 = IPRegex0.Match(s);
            if (m2.Success)
                return false;

            return true;
        }
    }
}