using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;

namespace RoboticsClub
{
    /*
     * PersonalPage represents all information for a
     * http://www.personal.psu.edu/
     */

    class PersonalPage
    {
        // Internal error string
        private bool _ErrorBool = false;
        public bool ErrorBool
        {
            get { return _ErrorBool; }
            set { _ErrorBool = value; }
        }

        private String _ErrorString;
        public String ErrorString
        {
            get { return _ErrorString; }
            set { _ErrorString = value; }
        }

        private String _FullName;
        public String FullName
        {
            get { return _FullName; }
            set { _FullName = value; }
        }

        private String _ID;
        public String ID
        {
            get { return _ID; }
            set { _ID = value; }
        }

        private String _EMail;
        public String EMail
        {
            get { return _EMail; }
            set { _EMail = value; }
        }

        private String _Major;
        public String Major
        {
            get { return _Major; }
            set { _Major = value; }
        }

        private String _Year;
        public String Year
        {
            get { return _Year; }
            set { _Year = value; }
        }

        private static int MAX_LENGTH = 128;

        // Constructor: Takes a persons student ID
        public PersonalPage(String UserID)
        {
            // Save user id
            ID = (String)UserID.Clone();

            // Load page into internal link
            String page = LoadPage(UserID);

            // Parse the page only if it's valid
            if (page.Length > 500)
                ParsePage(page);
            else
                ErrorBool = true;
        }

        // Load user data, returns new page
        private String LoadPage(String UserID)
        {
            // Load page into internal string
            WebClient Client = new WebClient();
            String ReturnedPage = "";
            Client.Headers.Add("Content-Type", "application/x-www-form-urlencoded");

            // Attempt to load a page
            try
            {
                // Set the target address for the search engine
                Uri Address = new Uri("http://www.psu.edu/cgi-bin/ldap/ldap_query.cgi");

                // Post target search parameters
                string PostData = "sn=&cn=&uid=" + UserID + "&mail=&full=0&submit=Search+Directory";
                ReturnedPage = Client.UploadString(Address, PostData);
            }
            catch (System.Net.WebException Error)
            {
                // Post the error
                ErrorBool = true;
                ErrorString = Error.Message;
            }

            // Return the loaded page
            return ReturnedPage;
        }

        // Parse a given page into user data
        private void ParsePage(String Page)
        {
            // Find the name
            FullName = CutOut(Page, "</td>\n<td width=59%>\n", "\n<br>\n</td>");
            if (FullName.Length > MAX_LENGTH)
                FullName = "No name found";

            // Find the email
            EMail = CutOut(Page, "@psu.edu\">", "</a><br>");
            if (EMail.Length > MAX_LENGTH)
                EMail = "No email found";

            // Find the major
            Major = CutOut(Page, "Curriculum:\n</b>\n</td>\n<td width=59%>\n", "\n<br>");
            if (Major.Length > MAX_LENGTH)
                Major = "No major found";

            // Find the year
            Year = CutOut(Page, "Title:\n</b>\n</td>\n<td width=59%>\n", "\n<br>");
            if (Year.Length > MAX_LENGTH)
                Year = "No year found";
        }

        // Returns text between two specific strings of text
        private String CutOut(String Text, String BeforeTag, String AfterTag)
        {
            int StartLoc = Text.IndexOf(BeforeTag) + BeforeTag.Length;
            int EndLoc = Text.IndexOf(AfterTag, StartLoc);

            // Return the substring
            return Text.Substring(StartLoc, EndLoc - StartLoc);
        }
    }
}