using System;

using System.Collections.Specialized;

using System.Linq;

using System.Web;



namespace Trentacular.SharePoint.Util

{

    public static class UrlUtils

    {

        public static string AppendQueryString(string url, NameValueCollection queryString)

        {

            var query = StringUtils.Delimit(queryString.AllKeys.Select(k => string.Format("{0}={1}",

                HttpUtility.UrlEncode(k),

                HttpUtility.UrlEncode(queryString[k]))

                ),

                "&");



            if (string.IsNullOrEmpty(query))

                return url;



            string delimiter = url.Contains("?") ? "&" : "?";

            return string.Format("{0}{1}{2}", url, delimiter, query);

        }



        public static string AppendQueryStringPair(string url, string key, string value)

        {

            string delimiter = url.Contains("?") ? "&" : "?";



            return string.Format("{0}{1}{2}={3}",

                url,

                delimiter,

                HttpUtility.UrlEncode(key),

                HttpUtility.UrlEncode(value));

        }



        public static string StripQueryAndHash(string url)

        {

            int queryIndex = url.IndexOf('?');

            if (queryIndex >= 0)

                url = url.Remove(queryIndex);



            int hashIndex = url.IndexOf('#');

            if (hashIndex >= 0)

                url = url.Remove(hashIndex);



            return url;

        }



        public static string GetVirtualUrl(this HttpRequest request)

        {

            string virtualUrl = request.RawUrl.Substring(request.ApplicationPath.Length);

            if (virtualUrl[0] != '/')

                virtualUrl = virtualUrl.Insert(0, "~/");

            else

                virtualUrl = virtualUrl.Insert(0, "~");

            return virtualUrl;

        }



        public static string GetAbsoluteApplicationPath(this HttpRequest request)

        {

            return string.Format("{0}://{1}{2}", request.Url.Scheme, request.Url.Host, request.ApplicationPath.TrimEnd('/'));

        }



        public static Uri GetOriginalUri(this HttpRequest request)

        {

            return new Uri(request.Url, request.RawUrl);

        }



        public static NameValueCollection GenerateQueryStringCollection(string url)

        {

            NameValueCollection queryString = new NameValueCollection();



            int queryIndex = url.IndexOf('?');

            if (queryIndex < 0)

                return queryString;



            string query = url.Substring(queryIndex + 1);

            int hashIndex = query.IndexOf('#');

            if (hashIndex >= 0)

                query = query.Substring(0, hashIndex);



            int chars = query.Length;

            for (int i = 0; i < chars; i++)

            {

                int startIndex = i;

                int sepIndex = -1;

                while (i < chars)

                {

                    char ch = query[i];

                    if (ch == '=')

                    {

                        if (sepIndex < 0)

                        {

                            sepIndex = i;

                        }

                    }

                    else if (ch == '&')

                    {

                        break;

                    }

                    i++;

                }



                string name = null;

                string value = null;

                if (sepIndex >= 0)

                {

                    name = query.Substring(startIndex, sepIndex - startIndex);

                    value = query.Substring(sepIndex + 1, (i - sepIndex) - 1);

                }

                else

                {

                    value = query.Substring(startIndex, i - startIndex);

                }



                queryString.Add(HttpUtility.UrlDecode(name), HttpUtility.UrlDecode(value));



                if ((i == (chars - 1)) && (query[i] == '&'))

                {

                    queryString.Add(null, string.Empty);

                }

            }



            return queryString;

        }



        public static string EncodeSpaces(string url)

        {

            return url.Replace(" ", "%20");

        }



        public static StringDictionary UrlSpecialCharacters;

        static UrlUtils()

        {

            UrlSpecialCharacters = new StringDictionary();

            UrlSpecialCharacters.Add("$", "%24");

            UrlSpecialCharacters.Add("&", "%26");

            UrlSpecialCharacters.Add("+", "%2B");

            UrlSpecialCharacters.Add(",", "%2C");

            UrlSpecialCharacters.Add("/", "%2F");

            UrlSpecialCharacters.Add(":", "%3A");

            UrlSpecialCharacters.Add(";", "%3B");

            UrlSpecialCharacters.Add("=", "%3D");

            UrlSpecialCharacters.Add("?", "%3F");

            UrlSpecialCharacters.Add("@", "%40");

            UrlSpecialCharacters.Add(" ", "%20");

            UrlSpecialCharacters.Add("\"", "%22");

            UrlSpecialCharacters.Add("<", "%3C");

            UrlSpecialCharacters.Add(">", "%3E");

            UrlSpecialCharacters.Add("#", "%23");

            UrlSpecialCharacters.Add("%", "%25");

            UrlSpecialCharacters.Add("{", "%7B");

            UrlSpecialCharacters.Add("}", "%7D");

            UrlSpecialCharacters.Add("|", "%2C");

            UrlSpecialCharacters.Add("\\", "%5C");

            UrlSpecialCharacters.Add("^", "%5E");

            UrlSpecialCharacters.Add("~", "%7E");

            UrlSpecialCharacters.Add("[", "%5B");

            UrlSpecialCharacters.Add("]", "%5D");

            UrlSpecialCharacters.Add("`", "%60");

        }



        public static string ToUrlSafeString(string text)

        {

            foreach (string specialChar in UrlSpecialCharacters.Keys)

            {

                text = text.Replace(specialChar, UrlSpecialCharacters[specialChar]);

            }

            return text;

        }



        public static string FromUrlSafeString(string text)

        {

            foreach (string specialChar in UrlSpecialCharacters.Keys)

            {

                text = text.Replace(UrlSpecialCharacters[specialChar], specialChar);

            }

            return text;

        }



        public static string ToUrlSafeBase64String(byte[] data)

        {

            return Convert.ToBase64String(data)

                .Replace('+', '-')

                .Replace('/', '_')

                .Replace('=', ',');

        }



        public static byte[] FromUrlSafeBase64String(string text)

        {

            return Convert.FromBase64String(text

                    .Replace('-', '+')

                    .Replace('_', '/')

                    .Replace(',', '=')

                );

        }



        public static bool IsVirtualPath(string path)

        {

            return path.StartsWith("~");

        }

    }

}