using System;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
    class WordCountProgram
    {
        static void Main(String[] args)
        {
            var operatorSet = new Tuple<String, Func<String, String>>[]
            { Tuple.Create<String, Func<String, String>>("w", i => String.Join(" ",i.Split(Estring.seperators, StringSplitOptions.RemoveEmptyEntries)) )
            , Tuple.Create<String, Func<String, String>>("r", i => i.Reverse()                                                                         )
            , Tuple.Create<String, Func<String, String>>("u", i => i.ToUpper()                                                                         )
            , Tuple.Create<String, Func<String, String>>("h", i => helpMessage                                                                         )
            };
            operatorSet.filter(i=>IsGivenInArgs(i.Item1,args)).foldl(GetStringFromArgs(args),(b,f) => f.Item2(b)).ShowScreen();
        }
        static bool IsGivenInArgs(string command,string[] options )
        {
            Regex regex = new Regex(@"^-(\w)*" + command + @"(\w)*");
            return Array.Exists(options, (s) => regex.IsMatch(s));
        }
        static string GetStringFromArgs(string[] options)
        {
            Regex regex = new Regex(@"^-(\w)*");
            return Array.Find(options, (s) => !regex.IsMatch(s));
        }
        static string helpMessage = "用法: DealSentenct [-w] [-r] [-u] <\"a sentence\">\n\n"
                                  + "其中 [] 表示可选参数项,句子串以双引号引出\n"
                                  + "-w 分解出单词并分行输出\n"
                                  + "-r 将原句子字串反向输出（若同时又-w选项，按单词分行反向输出)\n"
                                  + "-u 处理结果以大写字母输出\n"
                                  + "-h 输出此帮助信息\n";
    }

    static class Estring
    {
        static public String Reverse(this String s)
        {
            Char[] t = s.ToCharArray();
            Array.Reverse(t);
            return new String(t);
        }
        // print the object to console
        static public Boolean ShowScreen<T>(this T m)
        {
            try   { Console.WriteLine(m.ToString());}
            catch { return false; }
            return true;
        }
        static public Char[] seperators = { ' ', '\n', '\t', '.', '\"', ';', ',', '!', '?', '(', ')', '<', '>', '[', ']' };
    }


    /* ------------------------------------------------------------------------------------
    *  The Generic Extention to T[]
    *  Making the original function side-effect-less(Reference Tranparent)
    *  ------------------------------------------------------------------------------------
    */
    static class XList
    {
        //take head of the array or throw an error
        static public T head<T>(this T[] x)
        {
            return x[0];
        }
        //take all elements of the array except its head
        static public T[] tails<T> (this T[] x)
            {
                  int n = x.Length;
                  if (n == 0)
                  {
                        return x;
                  }
                  else
                  {
                        T[] y = new T[n-1];
                        for (int i = 0; i < (n-1); i++)
                        {
                              y[i] = x[i+1];
                        }
                        return y;
                  }
            }
            //let f acts on every element (Functor Map)
            static public T2 [] map<T1, T2> (this T1[] x, Func<T1,T2> f)
            {
                  if (x.Length == 0)
                  {
                        return new T2 [] {};
                  }
                  else
                  {
                        return f(x.head()).con(x.tails().map(f));
                  }
            }
        //the elements become the head of an array
        static public T[] con<T>(this T a, T[] x)
        {
            var y = new T[x.Length + 1];
            x.CopyTo(y, 1);
            y[0] = a;
            return y;
        }
        //applied to a predicate and a list, returns the list of those elements that satisfy the predicate;
        static public T[] filter<T>(this T[] xs, Func<T,Boolean> p)
        {
            if (xs.Length == 0)
            {
                return new T[] {};
            }
            else
            {
                if (p(xs.head()))
                {
                    return xs.head().con(xs.tails().filter(p));
                }
                else
                {
                    return xs.tails().filter(p);
                }
            }
        }
        //applied to a binary operator, a starting value (typically the left-identity of the operator), and a list, reduces the list using the binary operator, from left to right:
        static public T2 foldl<T1,T2>(this T1[] xs,T2 b, Func<T2,T1,T2> f)
        {
            if (xs.Length == 0)
            {
                return b;
            }
            else
            {
                return xs.tails().foldl(f(b,xs.head()), f);
            }
        }
    }
}