using System;
using System.IO;
using System.Diagnostics;

namespace OSProgram3
{
    class Program
    {
        static int Main(string[] args)
        {

            
            if (args.Length < 1)
            {
                Console.WriteLine("No input file specified in command line arguments.");
                Console.ReadLine();
                return 1;
            }

            string filename1 = args[0];

            int numRows = GetRows(filename1);
            Console.WriteLine("Returned Rows = " + numRows);

            int numCols = GetCols(filename1);
            Console.WriteLine("Returned Cols = " + numCols);

            Console.WriteLine("Getting Process Array.");
            int[,] procArr = GetProcArr(filename1, numRows, numCols);
            PrintProcArr(procArr, numRows, numCols);

            //now implement FCFS scehduling on 1 CPU
            GoFCFS(procArr);


            Console.WriteLine("Press Enter to Exit Program.");
            Console.ReadLine();
            return 0;
        } //end main


        //take filename and return number of rows (processes)
        static int GetRows(string filename)
        {

            int rows = 0;

            StreamReader sr = new StreamReader(filename);

            while (sr.ReadLine() != null)
            {
                rows++;
                //Console.WriteLine(rows);
            }

            //Console.WriteLine("\nRows = " + rows);

            sr.Close();

            return rows;

        }

        //take filename and return number of columns (process attributes)
        static int GetCols(string filename)
        {

            int cols = 1;
            StreamReader sr = new StreamReader(filename);
            string line = sr.ReadLine();

            for (int i=0; i<line.Length; i++)
            {
                if (line[i] == ',' )
                {
                    cols++;
                } 
            }

            sr.Close();

            return cols;

        }

        //take filename, numRows, numCols, and return the processArray for that file
        static int[,] GetProcArr(string filename, int numRows, int numCols)
        {

            int[,] procArr = new int[numRows, numCols];
            StreamReader sr = new StreamReader(filename);
            int col = 0;
            string line = "";
            string output = "";

            for (int i=0; i<numRows; i++)
            {
                line = sr.ReadLine();
                output = "";
                col = 0;

                for (int j=0; j<line.Length; j++)
                {
                    if (line[j] == ',')
                    {

                        procArr[i,col] = Int32.Parse(output);
                        output = "";
                        col++;

                    } else if (j == line.Length - 1)
                    {

                        output += line[j];
                        procArr[i, col] = Int32.Parse(output);
                        output = "";
                        col++;

                    } else
                    {

                        output += line[j];
                        
                    }

                } //end line for loop

            } //end rows for loop

            return procArr;

        } //end GetProcArr()

        static void PrintProcArr(int [,] arr, int numRows, int numCols)
        {

            for (int i=0; i<numRows; i++)
            {

                for (int j=0; j<numCols; j++)
                {
                    Console.Write(arr[i, j] + " " );
                }

                Console.Write("\n");

            }


        } //end PrintProcArr()

        //FCFS scheduler
        static void GoFCFS(int[,] procArr)
        {

            int numRows = procArr.GetLength(0);
            int numCols = procArr.GetLength(1);
            int row = 0;

            //result array [proc][wait, turnaround]
            long[,] resArr = new long[numRows, numCols-1];

            Console.WriteLine("Rows (Procs): " + numRows);
            Console.WriteLine("Result Cols: " + resArr.GetLength(1) );

            Stopwatch stw = new Stopwatch();
            stw.Start();

            while (row < numRows)
            {

                if (stw.ElapsedMilliseconds > procArr[row, 1])
                {
                    Console.WriteLine("Doing Process #" + (row+1) );
                    resArr[row, 0] = stw.ElapsedMilliseconds - procArr[row, 1];
                    resArr[row, 1] = DoBusyWork(procArr[row, 2], stw) + resArr[row, 0];
                    row++;
                }

                //else wait for submission time (go to next iteration, check time again)

            } //end while

            stw.Stop();
            Console.WriteLine("Done Scheduling FCFS.");

            //now analyze the results
            AnalyzeRes(resArr, "FCFS");

        } //end GoFCFS()

        //Busy work method to simulate process
        static long DoBusyWork(int time, Stopwatch stw)
        {

            long burstStart = stw.ElapsedMilliseconds;

            while ( (stw.ElapsedMilliseconds - burstStart) < time)
            {
                //waste time
                //Console.WriteLine("Wasting time.");
            }

            return (stw.ElapsedMilliseconds - burstStart);

        } //end DoBusyWork()

        //Analyze a results array
        static void AnalyzeRes(long[,] resArr, string alg)
        {

            long totalWait = 0;
            long totalTurn = 0;
            int numProcs = resArr.GetLength(0);

            Console.WriteLine("Analyzing " + alg);

            for (int i=0; i<numProcs; i++)
            {
                Console.WriteLine("Process #" + (i + 1) + " Wait Time=" + resArr[i, 0] + "ms Tunrnaround=" + resArr[i, 1] + "ms");

                totalWait += resArr[i, 0];
                totalTurn += resArr[i, 1];
                
            }

            Console.WriteLine("Average Wait Time = " + (totalWait /numProcs) + "ms");
            Console.WriteLine("Average Turnaround Time = " + (totalTurn / numProcs) + "ms");

        } //end AnalyzeRes()


        
    } //end Program class

} // end OSProgram3 namespace