/* Project #1 - Interval Scheduling
 * AUTHOR: Uyen Nguyen
 * CLASS: COMP496ALG
 * PROFESSOR: John Noga
 * DATE: 04/24/2015
 */

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.Arrays;
import java.util.Comparator;

public class IntervalScheduling {

    public static void main(String args[]){
        IntervalScheduling ie = new IntervalScheduling();
        ie.run();
    }

    public void run() {
        int[][] jobs;

        System.out.println("Project 1: Machine Scheduling with Deadlines");
        System.out.println("Reading jobs.txt");
        jobs = getJobs();

        // Sort by the 2nd column
        Arrays.sort(jobs, new Comparator<int[]>(){
            @Override
            public int compare(int[] n1, int[] n2) {
                return Integer.compare(n1[1], n2[1]);
            }
        });

        System.out.println("The best order to schedule the jobs is:");
        for (int i = 0; i < jobs.length; i++) {
            System.out.println("(" + jobs[i][0] + ", " + jobs[i][1] + ")");
        }

        int time = 0;
        int lateness = 0;
        for (int i = 0; i < jobs.length; i++) {
            time += jobs[i][0];
            if (time > jobs[i][1]) lateness += time - jobs[i][1];
        }
        System.out.println("It has a total lateness of " + lateness + ".");
    }

    private int[][] getJobs() {
        int[][] jobs = null;

        BufferedReader br;
        BufferedReader c;
        try {
            String line = "";
            int numJobs = 0;

            // Count jobs
            c = new BufferedReader(new FileReader("src/jobs.txt"));
            while ((line = c.readLine()) != null) {
                line = line.trim();
                if (line.length() != 0) numJobs++;
            }
            System.out.println("Number of jobs: " + numJobs);
            c.close();

            // Allocate array based on number of jobs found in .txt file
            jobs = new int[numJobs][2];

            // Parse jobs into jobs array
            br = new BufferedReader(new FileReader("src/jobs.txt"));
            line = "";
            int counter = 0;
            while((line = br.readLine()) != null && counter < numJobs) {
                line = line.trim();
                if (line.length() != 0) {
                    String [] str = line.split(" ");
                    if (isInt(str[0]) && isInt(str[1])) {
                        jobs[counter][0] = Integer.parseInt(str[0]);
                        jobs[counter][1] = Integer.parseInt(str[1]);
                        counter++;
                    }
                }
            }
            br.close();
        } catch(Exception e) {System.out.println("Failed to open file.");}
        return jobs;
    }

    private boolean isInt(String s) {
        try {
            Integer.parseInt(s);
            return true;
        } catch(Exception e) {}
        return false;
    }
}