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

namespace CrosswordSolver
{
    class Program
    {
        static void Main(string[] args)
        {
            int c = 0;
            //User input
            //NOTE: Use * to represent characters unknown 
            string userWord = "a****";
            int wordLength = userWord.Length;

            //Assign directory location of the csv file containing the collection of words to a variable
            string projectFolder = Directory.GetParent(Directory.GetCurrentDirectory()).Parent.FullName;
            string file = Path.Combine(projectFolder, "words.csv");

            //Display dictionary location in console
            Console.WriteLine("Dictionary location: " + file);

            var dictionary = new List<string>();
            using (var rd = new StreamReader(file))

            //Pull file column into dictionary list without cleaning
            //{
            //    while (!rd.EndOfStream)
            //    {
            //        var splits = rd.ReadLine().Split(',');
            //        dictionary.Add(splits[0]);
            //    }
            //}

            //Pull file column into dictionary list while cleaning
            {
                while (!rd.EndOfStream)
                {
                    var splits = rd.ReadLine().Split(',');
                    //string clean is done with Regex
                    dictionary.Add(Regex.Replace(splits[0], "[^A-Za-z0-9 ]", ""));
                }
            }

            //Test that dictionary has been read into memory
            //Console.WriteLine("The dictionary contains the following words:");
            //foreach (var element in dictionary)
            //Console.WriteLine(element);

            //Remove duplicate word entries
            //c = dictionary.Count;
            //Console.WriteLine("The dictionary contains " + c + " words");
            dictionary = dictionary.Distinct().ToList();
            //c = dictionary.Count;
            //Console.WriteLine("The dictionary contains " + c + " words");

            // Count the elements in the List and display test parameters
            c = dictionary.Count;
            Console.WriteLine("The dictionary contains " + c + " words");
            Console.WriteLine("User entered the string: " + userWord);
            Console.WriteLine(userWord + " has " + wordLength + " characters");
            userWord = userWord.ToLower();

            //Reduce the dataset size based on number of characters in string
            IEnumerable<string> query =
                dictionary.Where(word => word.Length == wordLength);

            var subSet = new List<string>();
            foreach (var word in query)
                subSet.Add(word);

            //Order List
            subSet = subSet.OrderBy(x => x).ToList();

            c = subSet.Count;
            if (c != 0)
            {
                Console.WriteLine("The dictionary contains " + c + " words that are " + wordLength + " characters in length");

                //Begin character and position match check
                var result = new List<string>();
                foreach (var word in subSet)

                {
                    for (int i = 0; i <= wordLength - 1; i++)
                    {

                        if ((word.ToLower()[i] == userWord[i]) | (userWord[i] == '*'))
                        {

                            //Test letter comparison (Letters match)
                            //Console.WriteLine(
                            //"Letter " + i + ", which is " + "\"" + word[i] + "\"" + ", of the word " + "\"" + word + "\"" +
                            //" matches letter " + i + ", which is " + "\"" + userWord[i] + "\"" + ", of the user input " + "\"" + userWord + "\""
                            //);

                            if (i == wordLength - 1)
                            { result.Add(word); }

                        }
                        else
                        {
                            //Test letter comparison (Letters do not match)
                            //Console.WriteLine(
                            //"Letter " + i + ", which is " + "\"" + word[i] + "\"" + ", of the word " + "\"" + word + "\"" +
                            //" does not match letter " + i + ", which is " + "\"" + userWord[i] + "\"" + ", of the user input " + "\"" + userWord + "\""
                            //);

                            break;
                        }
                    }
                }

                //Test words that do not match
                //foreach (var word in subSetToRemove)
                //Console.WriteLine(word);

                bool isEmpty = !result.Any();
                if (isEmpty)
                {
                    Console.WriteLine("No matches found");
                }
                else
                {
                    c = result.Count();
                    Console.WriteLine("Potential matches found: " + c);
                    foreach (var word in result)
                        Console.WriteLine(word);
                }
            }
            else
            {
                Console.WriteLine("No words of " + wordLength + " characters long found");
            }
            Console.ReadKey();
        }
    }
}