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

namespace TMI_practicum
{
    internal static class Program
    {
        public static void Main(string[] args)
        {
            if (args.Length < 1)
            {
                Console.WriteLine("Please enter a file.");
                Environment.Exit(1);
            }

            if (!File.Exists(args[0]))
            {
                Console.WriteLine("File {0} not found.", args[0]);
                Environment.Exit(1);
            }

            var parsed = ParseFile(args[0]);

            IEnumerable<Intersection> solved;
            
            Stopwatch stopwatch = new Stopwatch();
            stopwatch.Start();
            
            switch (parsed.Algorithm)
            {
                case 1:
                    solved = SimpleAlgorithm.Solve(parsed.Circles);
                    break;
                case 2:
                    solved = SweepLineAlgorithm.Solve(parsed.Circles);
                    break;
                case 3:
                    solved = SweepLineEffAlgorithm.Solve(parsed.Circles);
                    break;
                default:
                    throw new ArgumentException("Algorithm with id: " + parsed.Algorithm + " is not defined!");
            }
            
            stopwatch.Stop();
            WriteOutput(solved, stopwatch.ElapsedMilliseconds);
        }


        private static (byte Algorithm, int NbCircles, IList<Circle> Circles) ParseFile(string path)
        {

            byte algorithm = 0;
            int nbCircles = 0;
            Circle[] circles = null;

            using (StreamReader file = new StreamReader(path))
            {
                try
                {
                    algorithm = byte.Parse(file.ReadLine());
                    nbCircles = int.Parse(file.ReadLine());
                    circles = new Circle[nbCircles];
                    string line;
                    int i = 0;
                    while ((line = file.ReadLine()) != null)
                    {
                        double[] parts = line.Split(' ').Select(double.Parse).ToArray();
                        circles[i++] = new Circle(parts[0], parts[1], parts[2]);
                    }
                }
                catch (Exception)
                {
                    Console.WriteLine("An error occured parsing the input file.\r\n" +
                                      "Make sure the file has all required values and consists only of numbers.");
                    Environment.Exit(1);
                }
            }
            
            return (algorithm, nbCircles, circles);
        }

        private const string OutputFile = "output.txt";

        private static void WriteOutput(IEnumerable<Intersection> intersections, double time)
        {
            if (File.Exists(OutputFile))
            {
                File.Delete(OutputFile);
            }

            using (StreamWriter sw = File.CreateText(OutputFile))
            {
                foreach (var intersection in intersections)
                {
                    sw.WriteLine("{0}\t{1}", intersection.X, intersection.Y);
                }

                sw.WriteLine("\r\n{0}", time);
            }
        }
    }
}