package module5;

import java.lang.reflect.Array;
import java.util.Arrays;

public class Matrix {

    // Instance variable to store matrix contents
    private double[][] contents;

    // Constructor
    public Matrix(double[][] m){
        this.contents = m; // Set the contents variable to constructor's argument
    }

    // Number of rows - Non static
    public int nRows(){
        return this.contents.length;
    }

    // Number of columns (in first row) - Non static
    public int nCols(){
        return this.contents[0].length;
    }

    // Is current matrix square? - Non static
    public boolean isSquare(){
        if(nRows() == nCols()){
            return true;
        } else {
            return false;
        }
    }

    // Create a new matrix containing diagonal elements of original - Non static
    public Matrix diagonal() throws Exception{
        // Determine if matrix is square or not
        if (!this.isSquare()){
            throw new Exception("Matrix is not square");
        } else {
            // Create a new array to store the diagonal values
            double[][] a1 = new double[nCols()][nRows()];

            for(int i = 0; i < nCols(); i++){
                // Step through the diagonal elements only
                a1[i][i] = this.contents[i][i];
            }

            System.out.println(Arrays.deepToString(a1)); // Seems to work
            return new Matrix(a1); // How would i print this? System.out.println(Matrix(a1))???
        }
    }

    // Add two matrices - Non static
    public Matrix add(Matrix m2) throws Exception {
        if(this.nCols() != m2.nCols()){
            throw new Exception("Number of coloumns do not match");
        } else if(this.nRows() != m2.nRows()) {
            throw new Exception("Number of rows do not match");
        } else {
            // Create a new array to store the addition
            double[][] m3 = new double[nCols()][nRows()];

            // Cycle over each row
            for(int x = 0; x < nRows(); x++){
                // Within each row, cycle over each column
                for(int y = 0; y < nCols(); y++){
                    m3[x][y] = this.contents[x][y] + m2[x][y]; // m2 - The type of the expression must be an array type but it resolved to Matrix
                }
            }

            System.out.println(Arrays.deepToString(m3));
            return new Matrix(m3);
        }
    }

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

        // Define the contents of an array
        double[][] contents = {
            {1.0,2.1,3.2,4.3},
            {11.5,12.6,13.7,14.8},
            {11.9,12.0,13.1,14.2},
            {11.9,12.0,13.1,14.2}
        };

        // Create a new Matrix object with contents
        Matrix m1 = new Matrix(contents);

        //System.out.println(m1.nRows());
        //System.out.println(m1.nCols());
        //System.out.println(m1.isSquare());
        System.out.println(m1.diagonal());

    }

}