using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Lab7Exc2
{
    internal class Program
    {

        static void Main(string[] args)
        {
            Graph g = null;
            int[] vertexCover = null;
            while (true)
            {
                Console.Clear();
                Console.WriteLine("1. Set graph from console");
                Console.WriteLine("2. Set graph from file");
                Console.WriteLine("3. Set vertex cover");
                Console.WriteLine("4. Export vertex cover to file");
                Console.WriteLine("5. Print graph");
                Console.WriteLine("6. Exit");

                Console.WriteLine("Example for import:");
                Console.WriteLine("4");
                Console.WriteLine("0 // the constant is always set");
                Console.WriteLine("1 3 2");
                Console.WriteLine("2 1 3");
                Console.WriteLine("3 1 2 4" );
                Console.WriteLine("4 3");
                Console.Write("Input: ");



                int choice;
                if (!int.TryParse(Console.ReadLine(), out choice) || choice < 1 || choice > 6)
                {
                    Console.WriteLine("Invalid choice, please try again");
                    Console.ReadKey();
                    continue;
                }

                switch (choice)
                {
                    case 1:
                        g = Graph.SetGraphFromConsole(false);
                        Console.ReadKey();
                        break;
                    case 2:
                        try
                        {
                            Console.Write("Enter the file name: ");
                            string fileName = Console.ReadLine();

                            g = Graph.SetGraphFromFile(fileName);

                            Console.ReadKey();
                        }
                        catch (Exception e)
                        {
                            Console.WriteLine("Error: " + e.Message);
                        }
                        break;
                    case 3:
                        try
                        {
                            if (g == null)
                            {
                                Console.WriteLine("Graph not set");
                                Console.ReadKey();
                                break;
                            }
                            vertexCover = FindVertexCover(g);
                            Console.WriteLine("Vertex cover: " + string.Join(" ", vertexCover));
                            Console.ReadKey();
                        }
                        catch (Exception e)
                        {
                            Console.WriteLine("Error: " + e.Message);
                        }
                        break;
                    case 4:
                        try
                        {
                            if (g == null)
                            {
                                Console.WriteLine("Graph not set");
                                Console.ReadKey();
                                break;
                            }
                            Console.Write("Enter the file name: ");
                            string fileName = Console.ReadLine();
                            using (StreamWriter sw = new StreamWriter(fileName))
                            {
                                vertexCover = FindVertexCover(g);
                                sw.WriteLine(string.Join(" ", vertexCover));
                            }
                            Console.ReadKey();
                        }
                        catch (Exception e)
                        {
                            Console.WriteLine("Error: " + e.Message);
                        }
                        break;
                    case 5:
                        if (vertexCover == null)
                        {
                            Console.WriteLine("Vertex cover not set");
                            Console.ReadKey();
                            break;
                        }
                        g.VisualizeVertexCover(vertexCover);
                        Console.ReadKey();
                        break;
                    case 6:
                        return;
                }
            }
        }

        public static int[] FindVertexCover(Graph g)
        {
            bool[] visited = new bool[g.NumVertices + 1];
            int[] cover = new int[g.NumVertices];
            int coverSize = 0;
            for (int i = 1; i <= g.NumVertices; i++)
            {
                if (!visited[i])
                {
                    visited[i] = true;
                    cover[coverSize++] = i;
                    var current = g.AdjList[i];
                    while (current != null)
                    {
                        visited[current.Value] = true;
                        current = current.Next;
                    }
                }
            }
            Array.Resize(ref cover, coverSize);
            return cover;
        }


    }
}