using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows;
using Microsoft.Phone.Controls;

namespace TranslatorByMoth //TODO replace with your namespace, so App can be resolved
{
  public static class RTL
  {
    /// <summary>
    /// Calling code can determine whether to use this class or not for the text.
    /// </summary>
    /// <param name="lang">two letter ISO code for the language, e.g. "he" or "ar"</param>
    /// <returns>true for RTL languages supported</returns>
    public static bool RequiresRTL(string lang)
    {
      return (lang == "he" || lang == "ar");
    }

    private static int MaxCharactersPerLine
    {
      get
      {
#if WINDOWS_PHONE
        if (((Application.Current as App).RootFrame.Orientation & PageOrientation.Portrait) != 0)
          return 37;
        else // Landscape
#endif
          return 50;
      }
    }

    /// <summary>
    /// Accepts a string (multi-line, line breaks, whatever) of the supported RTL languages and reverses it.
    /// </summary>
    /// <param name="translatedRtlThatIsLtr">text that needs reversing</param>
    /// <param name="breakInLines">whether to break the returned text into lines of MaxCharactersPerLine length</param>
    /// <param name="isArabic">Arabic is treated specially, due to characters having different appearence dependent on what comes before/after them</param>
    /// <param name="isFromRTL">true if the returned string is sent to a service. false if it is to be displayed to the user</param>
    /// <returns>the reversed string ready to be displayed to the user or sent to a service</returns>
    public static string ReverseLengthyMultilineText(string translatedRtlThatIsLtr, bool breakInLines, bool isArabic, bool isFromRTL)
    {
      if (translatedRtlThatIsLtr.Trim().Length < 2) //if null, let it throw
        return translatedRtlThatIsLtr;

      string[] words = translatedRtlThatIsLtr.Split(new char[] { ' ', Convert.ToChar(160), '\n' }, StringSplitOptions.RemoveEmptyEntries);

      StringBuilder result = new StringBuilder();
      int charCount = -1;
      List<String> line = new List<string>();
      int charsPerLine = breakInLines ? RTL.MaxCharactersPerLine : Int32.MaxValue;
      foreach (string w in words)
      {
        // for spaces between words.
        charCount++;

        charCount += w.Length;

        // if adding this word exceeds the chars per line then add a new line here
        // and this word will go to the next line.
        if (breakInLines && charCount > charsPerLine)
        {
          result.AppendLine(RTL.ReverseLine(line, isArabic, isFromRTL));

          // start a new line...
          line.Clear();
          charCount = w.Length;
        }

        line.Add(w);
      }

      result.Append(RTL.ReverseLine(line, isArabic, isFromRTL));

      return result.ToString();
    }

    private static string ReverseLine(List<string> words, bool isArabic, bool isFromRTL)
    {
      List<string> reversedWords = new List<string>(words.Count);

      for (int i = words.Count - 1; i > -1; i--)
        reversedWords.Add(RTL.ReverseWord(words[i], isArabic, isFromRTL));

      return String.Join(" ", reversedWords.ToArray());
    }

    /// <summary>
    /// Reverses a string that has no spaces or line breaks, taking into account to preserve order of numbers and English strings.
    /// </summary>
    /// <param name="word">the text to reverse</param>
    /// <param name="isArabic">Arabic is treated specially, due to characters having different appearence dependent on what comes before/after them</param>
    /// <param name="isFromRTL">true if the returned string is sent to a service. false if it is to displayed to the user</param>
    /// <returns>the reversed string ready to be displayed to the user or sent to a service</returns>
    public static string ReverseWord(string word, bool isArabic, bool isFromRTL)
    {
      if (word.Length < 2) //if null let it throw
        return word;

      Match m = Regex.Match(word, "[a-zA-Z0-9]+.*[a-zA-Z0-9]+");
      if (m.Success)
      {
        // English or numbers translation
        // isolate punctuation prefix and suffix. These should be reversed. The English word shouldn't be reversed.
        string prefix = word.Substring(0, m.Index);
        string actualWord = m.Value;
        string suffix = word.Substring(m.Length + m.Index);

        return RTL.ReverseWord(suffix, isArabic, isFromRTL) + actualWord + ReverseWord(prefix, isArabic, isFromRTL);
      }
      else
        // normal RTL translation        
        if (!isArabic) // regardless of TO or FROM, simple reversing works for Hebrew
          return new string(
            System.Linq.Enumerable.ToArray(
              System.Linq.Enumerable.Reverse(word.ToCharArray())));
        else
          // Arabic
          if (!isFromRTL)
            return new string(
             System.Linq.Enumerable.ToArray(
               System.Linq.Enumerable.Reverse(new Arabic.Utils.SuperString(word).DisplayText.ToCharArray())));
                //Arabic.Utils.SuperString comes from http://arabic4wp7.codeplex.com/ 
          else
            // TODO nothing here works. Can't get Arabic string and send it to Bing service and get back English :-(
            return "Sorry, not supported yet";

            // get DisplayText - doesn't work
            //return new Arabic.Utils.SuperString(word).DisplayText;
            
            // get Text - doesn't work
            //return new Arabic.Utils.SuperString(word).Text;

            // reverse first, then Text - doesn't work
            //return new Arabic.Utils.SuperString(new string(
            //  System.Linq.Enumerable.ToArray(
            //    System.Linq.Enumerable.Reverse(word.ToCharArray())))).Text;

            // reverse first, then DisplayText - doesn't work
            //return new Arabic.Utils.SuperString(new string(
            //  System.Linq.Enumerable.ToArray(
            //    System.Linq.Enumerable.Reverse(word.ToCharArray())))).DisplayText;

            // get Text then reverse - doesn't work
            //return new string(
            // System.Linq.Enumerable.ToArray(
            //   System.Linq.Enumerable.Reverse(new Arabic.Utils.SuperString(word).Text.ToCharArray())));

            // get DisplayText then reverse - doesn't work
            //return new string(
            // System.Linq.Enumerable.ToArray(
            //   System.Linq.Enumerable.Reverse(new Arabic.Utils.SuperString(word).DisplayText.ToCharArray())));

            // just reverse - doesn't work
            //return new string(
            //  System.Linq.Enumerable.ToArray(
            //    System.Linq.Enumerable.Reverse(word.ToCharArray())));
    }
  }
}