// Import the Scanner class
import java.util.Scanner;

// Import the packages from the java.util library
import java.util.ArrayList;
import java.util.Arrays;

public class Task_3 {

    public static void main(String[] args) {

        // Declare a boolean variable named 'inputStudent' with a value 'true'
        boolean inputStudent = true;

        // Place while loop's condition to check whether user inputs less than 20 students
        while (inputStudent) {

        // Prompt user to enter number of students between 1 to 20
        System.out.print("Enter number of students between 1 to 20: ");

        // Create the first Scanner object
        Scanner firstscan = new Scanner(System.in);
        int numOfStudents = firstscan.nextInt();

        // Display result
        if (numOfStudents > 20) {
            System.out.println("Please enter not more than 20 students.");
            System.out.println();

        } else {

            // Declare an integer variable named 'avg' and 'choice' with zero value
            int avg = 0;
            int choice = 0;

            // Declare a string variable named 'grade' with a value 'null'
            String grade = null;

            // Create arraylist of 'students' and 'average'
            ArrayList<String[]> students = new ArrayList<String[]>();
            ArrayList<Integer> average = new ArrayList<Integer>();

            // Create an array of 'names' and 'averageMark'
            String[] names = new String[numOfStudents];
            int[] averageMark = new int[numOfStudents];

            // Create a two-dimensional array with a given number of rows and 6 columns
            String[][] table = new String[numOfStudents][6];

            // Declare a boolean variable named 'menuLoop' with a value 'true'
            boolean menuLoop = true;

            // Insert a new line
            System.out.println();

            // Display result
            for (int n = 0; n < numOfStudents; n++) {

                // Prompt user to enter student name and 3 marks
                System.out.println("Enter the name and 3 marks for Student " + (n + 1) + ": ");

                // Create the second Scanner object
                Scanner secondscan = new Scanner(System.in);
                String studentName = secondscan.nextLine();

                // Capitalize the first letter of the names given
                studentName = studentName.toUpperCase().charAt(0) + studentName.substring(1, studentName.length());

                String mark1 = secondscan.nextLine();
                String mark2 = secondscan.nextLine();
                String mark3 = secondscan.nextLine();

                // Add elements to the array
                String[] array = {studentName, mark1, mark2, mark3};
                students.add(array);
            }

            // Display result
            System.out.println();
            System.out.println("Student" + " \tAverage" + " \tGrade");
            System.out.println("-------------------------------------");

            for (int n = 0; n < numOfStudents; n++) {

                // Calculate the average mark
                avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;

                // Calculate the grade based on average mark
                if (avg >= 90 && avg <= 100) {
                    grade = "A";
                } else if (avg >= 80 && avg <= 89) {
                    grade = "B";
                } else if (avg >= 70 && avg <= 79) {
                    grade = "C";
                } else if (avg >= 60 && avg <= 69) {
                    grade = "D";
                } else if (avg >= 0 && avg <= 59) {
                    grade = "E";
                }

                // Display result
                System.out.println(students.get(n)[0] + " \t" + " \t" + avg + " \t" + " \t" + grade);
            }

            //  Place while loop's condition to display menu
            while (menuLoop) {
                System.out.println();
                System.out.println("====================================================================================");
                System.out.println("1: Print the entire list");
                System.out.println("2: Sort and print the list alphabetically");
                System.out.println("3: Sort and print the list in descending order based on the average.");
                System.out.println("4: Ask the user to enter an average and search for the student who has that average");
                System.out.println("5: Find the student who has the minimum average");
                System.out.println("6: Print the grade distribution");
                System.out.println("0: Exit");
                System.out.println("====================================================================================");
                System.out.println();
                System.out.print("Enter your choice? ");

                // Create the third Scanner object
                Scanner thirdscan = new Scanner(System.in);
                choice = thirdscan.nextInt();

                // Place switch statement
                switch (choice) {

                // Place case statement
                case 1:
                    System.out.println();
                    System.out.println("Student" + " \t" + "Mark 1" + " \t" + " \t" + "Mark 2" + " \t" + " \t" + "Mark 3" + " \t" + " \t" + "Average" + " \t" + "Grade");
                    System.out.println("----------------------------------------------------------------------------------------------");

                    for (int n = 0; n < numOfStudents; n++) {
                        avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;

                        if (avg >= 90 && avg <= 100) {
                            grade = "A";
                        } else if (avg >= 80 && avg <= 89) {
                            grade = "B";
                        } else if (avg >= 70 && avg <= 79) {
                            grade = "C";
                        } else if (avg >= 60 && avg <= 69) {
                            grade = "D";
                        } else if (avg >= 0 && avg <= 59) {
                            grade = "E";
                        }

                        // Display result
                        System.out.println(students.get(n)[0] + "\t" + "\t" + students.get(n)[1] + "\t" + "\t" + students.get(n)[2] + "\t" + "\t" + students.get(n)[3] + "\t" + "\t" + avg + "\t" + "\t" + grade);
                    }
                    break;

                case 2:
                    System.out.println();
                    System.out.println("Student" + " \t" + "Mark 1" + " \t" + " \t" + "Mark 2" + " \t" + " \t" + "Mark 3" + " \t" + " \t" + "Average" + " \t" + "Grade");
                    System.out.println("----------------------------------------------------------------------------------------------");

                    for (int n = 0; n < numOfStudents; n++) {
                        names[n] = students.get(n)[0];
                    }

                    // Implement Selection Sort
                    for (int j = 0; j < names.length-1; j++) {
                        int min = j;

                        for (int k = j+1; k < names.length; k++)
                        if (names[k].compareTo(names[min]) < 0 ) min = k;

                      String temp = names[j];
                      names[j] = names[min];
                      names[min] = temp;

                    }
                    for (String value : names) {
                        for (int n = 0; n < numOfStudents; n++) {
                            avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;

                            if (avg >= 90 && avg <= 100) {
                                grade = "A";
                            } else if (avg >= 80 && avg <= 89) {
                                grade = "B";
                            } else if (avg >= 70 && avg <= 79) {
                                grade = "C";
                            } else if (avg >= 60 && avg <= 69) {
                                grade = "D";
                            } else if (avg >= 0 && avg <= 59) {
                                grade = "E";
                            }

                            // Display result
                            if (students.get(n)[0] == value) {
                                System.out.println(students.get(n)[0] + "\t" + "\t" + students.get(n)[1] + "\t" + "\t" + students.get(n)[2] + "\t" + "\t" + students.get(n)[3] + "\t" + "\t" + avg + "\t" + "\t" + grade);
                            }
                        }
                    }
                    break;

                case 3:
                    System.out.println();
                    System.out.println("Student" + " \t" + "Mark 1" + " \t" + " \t" + "Mark 2" + " \t" + " \t" + "Mark 3" + " \t" + " \t" + "Average" + " \t" + "Grade");
                    System.out.println("----------------------------------------------------------------------------------------------");

                    for (int n = 0; n < numOfStudents; n++) {
                        avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;

                        if (avg >= 90 && avg <= 100) {
                            grade = "A";
                        } else if (avg >= 80 && avg <= 89) {
                            grade = "B";
                        } else if (avg >= 70 && avg <= 79) {
                            grade = "C";
                        } else if (avg >= 60 && avg <= 69) {
                            grade = "D";
                        } else if (avg >= 0 && avg <= 59) {
                            grade = "E";
                        }

                        // Fill in the rows and columns of the two-dimensional array with elements
                        table[n][0] = students.get(n)[0];
                        table[n][1] = students.get(n)[1];
                        table[n][2] = students.get(n)[2];
                        table[n][3] = students.get(n)[3];
                        table[n][4] = Integer.toString(avg);
                        table[n][5] = grade;
                    }

                    for (int n = 0; n < numOfStudents; n++) {
                        avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;

                        // Adding object in average arraylist
                        average.add(avg);
                    }

                    // Implement Insertion Sort
                    InsertionSort is = new InsertionSort(average);
                    is.sortGivenArray();
                    for (int i : InsertionSort.getInputArray()) {

                        for (int n = 0; n < numOfStudents; n++) {
                            if (Integer.parseInt(table[n][4]) == i) {
                                System.out.println(table[n][0] + "\t" + "\t" + table[n][1] + "\t" + "\t" + table[n][2] + "\t" + "\t" + table[n][3] + "\t" + "\t" + table[n][4] + "\t" + "\t" + table[n][5]);
                            }
                        }
                    }
                    break;

                case 4:
                    for (int n = 0; n < numOfStudents; n++) {
                        avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;
                        averageMark[n] = avg;
                    }

                    // Prompt user to enter an average
                    System.out.println();
                    System.out.print("Enter an average: ");

                    // Create the fourth Scanner object
                    Scanner fourthscanner = new Scanner(System.in);
                    int key = fourthscanner.nextInt();

                    // Perform a Binary Search on the given average
                    int result = Arrays.binarySearch(averageMark, key);

                    // Display result
                    if (result < 0) {
                        System.out.println();
                        System.out.println("There is no student with that average.");
                    } else {
                        System.out.println();
                        System.out.println("Student" + " \t" + "Average");
                        System.out.println("-----------------------");

                    for (int n = 0; n < numOfStudents; n++) {
                        avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;

                        table[n][0] = students.get(n)[0];
                        table[n][1] = Integer.toString(avg);

                        if (Integer.parseInt(table[n][1]) == key) {
                            System.out.println(table[n][0] + "\t" + "\t" + table[n][1]);
                        }
                    }
                    }
                    break;

                case 5:
                    for (int n = 0; n < numOfStudents; n++) {
                        avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;
                        averageMark[n] = avg;
                        table[n][0] = students.get(n)[0];
                        table[n][1] = Integer.toString(avg);
                    }

                    // Perform a Sequential Search to find the minimum average
                    int minvalue = averageMark[0];
                    for (int i = 0; i < averageMark.length; i++) {
                        if (averageMark[i] < minvalue) {
                            minvalue = averageMark[i];
                        }
                    }

                    // Display result
                    for (int n = 0; n < numOfStudents; n++) {
                        if (Integer.parseInt(table[n][1]) == minvalue) {
                            System.out.println();
                            System.out.println("Student with the mininum average is: ");
                            System.out.println();
                            System.out.println("Student" + " \t" + "Average");
                            System.out.println("-----------------------");
                            System.out.println(table[n][0] + "\t" + "\t" + minvalue);
                        }
                    }
                    break;

                case 6:

                    // Declare integer variables with zero value
                    int a = 0, b = 0, c = 0, d = 0, e = 0;

                    for (int n = 0; n < numOfStudents; n++) {
                        avg = (Integer.parseInt(students.get(n)[1]) + Integer.parseInt(students.get(n)[2]) + Integer.parseInt(students.get(n)[3])) / 3;

                        if (avg >= 90 && avg <= 100) {
                            grade = "A";
                            a++;
                        } else if (avg >= 80 && avg <= 89) {
                            grade = "B";
                            b++;
                        } else if (avg >= 70 && avg <= 79) {
                            grade = "C";
                            c++;
                        } else if (avg >= 60 && avg <= 69) {
                            grade = "D";
                            d++;
                        } else if (avg >= 0 && avg <= 59) {
                            grade = "E";
                            e++;
                        }
                    }

                    // Display result
                    System.out.println();
                    System.out.println("Grade distribution: ");
                    System.out.println("A = " + a + "\t B = " + b + " \t C = " + c + "\t D = " + d + " \t E = " + e);
                    break;

                case 0:
                    System.out.println();
                    System.out.println("This is the end of the program. Thank you.");

                    // Terminate the program
                    System.exit(0);
                    break;

                // Set a default statement for when user inputs invalid menu choice
                default:
                    System.out.println();
                    System.out.println("This is not a valid menu choice. Please select another!");
                    break;

                }

                }

            }

        }
    }

}