using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace MarkovGrams
{
	class MainClass
	{
		public static int Main(string[] args)
		{
			if(args.Length < 1)
			{
				Console.WriteLine("Usage:");
				Console.WriteLine("    ./MarkovGrams.exe <command>");
				Console.WriteLine();
				Console.WriteLine("Available commands:");
				Console.WriteLine("    markov:");
				Console.WriteLine("        Generate new words using a markov chain.");
				Console.WriteLine("    ngrams:");
				Console.WriteLine("        Generate raw unique n-grams");
				Console.WriteLine();
				Console.WriteLine("Type just ./MarovGrams.exe <command> to see command-specific help.");
				return 1;
			}

			string mode = args[0];
			string wordlistFilename;
			int order;
			IEnumerable<string> words, ngrams;

			switch(mode)
			{
				case "markov":
					if(args.Length != 5)
					{
						Console.WriteLine("markov command usage:");
						Console.WriteLine("    ./MarkovGrams.exe markov <wordlist.txt> <order> <length> <count>");
						Console.WriteLine();
						Console.WriteLine("<wordlist.txt>  The path to the wordlist to read from.");
						Console.WriteLine("<order>         The order of the n-grams to use.");
						Console.WriteLine("<length>        The length of word to generate.");
						Console.WriteLine("<count>         The number of words to generate.");
						Console.WriteLine();
						return 1;
					}
					wordlistFilename = args[1];
					order = int.Parse(args[2]);
					int desiredStringLength = int.Parse(args[3]);
					int count = int.Parse(args[4]);

					words = File.ReadLines(wordlistFilename).SelectMany(word => word.Trim().Split(' '));
					ngrams = NGrams.GenerateFlat(words, order);

					UnweightedMarkovChain chain = new UnweightedMarkovChain(ngrams);

					for(int i = 0; i < count; i++)
						Console.WriteLine(chain.Generate(desiredStringLength));
					break;
					
				case "ngrams":
					if(args.Length != 3)
					{
						Console.WriteLine("ngrams command usage:");
						Console.WriteLine("    ./MarkovGrams.exe <wordlist.txt> <order>");
						Console.WriteLine();
						Console.WriteLine("<wordlist.txt>  The path to the wordlist to read from.");
						Console.WriteLine("<order>         The order of n-grams to generate.");
						Console.WriteLine();
						return 1;
					}

					wordlistFilename = args[1];
					order = int.Parse(args[2]);
					words = File.ReadLines(wordlistFilename).SelectMany(word => word.Trim().Split(' '));
					ngrams = NGrams.GenerateFlat(words, order);

					foreach(string ngram in ngrams)
						Console.WriteLine(ngram);

					break;
				default:
					Console.WriteLine("Unknown command {0}.");
					Console.WriteLine("Available commands:");
					Console.WriteLine("    markov  Generate words with a markov chain");
					Console.WriteLine("    ngrams  Generate unique ngrams from wordlists");
					Console.WriteLine();
					return 1;
			}

			return 0;
		}
	}
}