import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
import au.com.bytecode.opencsv.CSVReader;



// This program reads the dataset, and the new instances.
// Note that an instance is a patient in this example.
// Then the program will compute and display the distances between the new
// instance / patient and all the instances / patients from the dataset, based on symptoms.
// The distance between two instances is defined here as the number of attribute value disparities.
// For instance the distance between two patients is 2 if one has fever and the other doesn't,
// and one has headache and the other doesn't, and all their other symptoms are the same.

public class example1 {

    //here one specifies the file containing the dataset in comma separated values format CSV

    private static final String datasetfile="diagnoses.csv";
    static String [] nextLine;
    static String[][] data= new String[100][7]; //this array will contain the dataset
    static String[]  newinstance=new String[7]; //this array will contain a new instance / new patient symptoms
    static int[] distance= new int[100];        //this array will contain the distance from the new instance to each instance in the dataset
    static int min = 0;
    static int index = 1;
    static String x,y;
    static int numberOFinstances;

    public static void KNearestNeighbour(int k){

        /*
         * K Nearest Neighbour Algorithm
         *
         */


        //loop through how many nearest neighbour's we want where k is the limit.
        for(int j=0;j<k;j++){
            //get the min value.
            min =  distance[1];
            //loop through all of the distances in the array.
        for(int i=1;i<numberOFinstances+1;i++){

            //if current value of array is less than min.
            if(distance[i]<min){

                //assign min to current array value.
                min=distance[i];

                //record index so we know where we found it.
                index=i;

            }



        }
        //Put a random high number so we don't get the same minimum
        distance[index]=999;
            //Print Distance
            System.out.println("\nDistance is "+min);
            //Print Diagnosis
            System.out.println("Diagnosis is "+data[index][6]);
            //Print patient using the index we found the minimum distance at.
            System.out.println("Close distance to Patient"+index+"\n");
        }

    }

    public static void NearestNeighbour(){

        /*
         * Nearest Neighbour Algorithm
         *
         */

        //first element of array as min.
        min =  distance[1];
        for(int k=2;k<numberOFinstances;k++){

            //if current value of array is less than min
            if(distance[k]<min){
                //assign min to current array value
                min=distance[k];
                //record index
                index=k;

            }
        }

            //Print Distance
            System.out.println("\nDistance is "+min);
            //Print Diagnosis
            System.out.println("Diagnosis is "+data[index][6]);
            //print the patient using the index we found the min value.
            System.out.println("Nearest Neighbour is Patient "+index);
    }

    public static void main(String[] args) throws IOException {

        //one declares variables and arrays to be used

        CSVReader reader = new CSVReader(new FileReader(datasetfile)); //this is used to read from CSV file


        // prepare to read the dataset in array data
        // and then to read a new instance / patient symptos from the keyboard

        int j,i=0;
        while ((nextLine = reader.readNext()) != null) { //while the line inputed is not empty do

            for(j=0;j<=6;j++)
                data[i][j]=nextLine[j];

            i++;    // this increses i with 1
        }


        //in variable i we counted the number of instances in the dataset plus 1 because
        //the attribute names were also included at the top of the dataset

         numberOFinstances = i-1;


        //this prepares a loop to input a variable number of new instances and compute thier distances
        //to the dataset instances

        Scanner in =new Scanner(System.in);  // prepare to read new instance from keyboard

        boolean finished=false;   // the next loop should execute until new instances finish

        while (!finished) {

            // Read a new instance (patient symptoms) and put it in an array called newinstance

            System.out.println();
            System.out.println("Input the new patient's 5 symptoms regarding");
            System.out.println("Sore Throat, Fever, Swollen Glands, Congestion, Headache");
            System.out.println("Input Yes or No, ONE PER LINE, CASE SENSITIVE!:");
            System.out.println();


            /*if(in.nextLine().isEmpty())
                    System.out.println("Empty: PLease enter Yes or No.");
                    System.exit(0);
             */
            for(j=1;j<=5;j++){
                String read = in.nextLine();
                if(read.isEmpty()){
                        System.err.println("Please enter either yes or no.");
                        j
                        --;
                }
                newinstance[j]=read;
            }
            // Compute the distances from the new instance to each instance in the dataset
            // For example distance[8] should contain the distance from the new instance to instance 8
            // Start with value 0 for all these distances first.

            for(i=1; i<= numberOFinstances; i++)
                distance[i]=0;

            System.out.println();

            for(i=1; i<= numberOFinstances; i++) {
                for(j=1;j<=5;j++) {
                    x=newinstance[j];
                    y=data[i][j];
                     if (x.compareTo(y)!=0)  //if x and y do not coincide
                        distance[i]++;      //then add 1 to the distance
                }

                // Now the computed distances are ready, do display them

                System.out.println("The distance between the new patient and patient"+i+" is "+distance[i]);
            }
            System.out.println("Calculating Nearest Neighbour");
            //Nearest Neighbour
            NearestNeighbour();
            System.out.println("\n Calculating K Nearest Neighbour Where K=3");
            //K Nearest Neighbour - 3 Closest Matches.
            KNearestNeighbour(3);
            // Ask user if new instances are to be inputed.
            System.out.println();
            System.out.print("Any more new patients? y/n: ");
            x=in.nextLine();

            //If the input from user is not "y" (no more new instances) then one should finish the loop.

            if (x.compareTo("y")!=0){
                finished=true;
                System.out.println();
                System.out.println("GOODBYE .........");
            }
        }
    }
}