package com.interview.qa;

import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Java8CommonProgrammingQA {

    public static void main(String[] args) {
        List<Student> studentList = Stream.of(
                new Student(1, "Rohit", 30, "Male", "Mechanical Engineering", "Mumbai", 122, Arrays.asList("+912632632782", "+1673434729929")),
                new Student(2, "Pulkit", 56, "Male", "Computer Engineering", "Delhi", 67, Arrays.asList("+912632632762", "+1673434723929")),
                new Student(3, "Ankit", 25, "Female", "Mechanical Engineering", "Kerala", 164, Arrays.asList("+912632633882", "+1673434709929")),
                new Student(4, "Satish Ray", 30, "Male", "Mechanical Engineering", "Kerala", 26, Arrays.asList("+9126325832782", "+1671434729929")),
                new Student(5, "Roshan", 23, "Male", "Biotech Engineering", "Mumbai", 12, Arrays.asList("+012632632782")),
                new Student(6, "Chetan", 24, "Male", "Mechanical Engineering", "Karnataka", 90, Arrays.asList("+9126254632782", "+16736784729929")),
                new Student(7, "Arun", 26, "Male", "Electronics Engineering", "Karnataka", 324, Arrays.asList("+912632632782", "+1671234729929")),
                new Student(8, "Nam", 31, "Male", "Computer Engineering", "Karnataka", 433, Arrays.asList("+9126326355782", "+1673434729929")),
                new Student(9, "Sonu", 27, "Female", "Computer Engineering", "Karnataka", 7, Arrays.asList("+9126398932782", "+16563434729929", "+5673434729929")),
                new Student(10, "Shubham", 26, "Male", "Instrumentation Engineering", "Mumbai", 98, Arrays.asList("+912632646482", "+16734323229929")))
                .collect(Collectors.toList());

     // 1. Find the list of students whose rank is in between 50 and 100

        List<Student> students = studentList.stream().filter(student -> student.getRank() > 50 && student.getRank() < 100)
                .collect(Collectors.toList());
       // System.out.println(students);

        //2. Find the Students who stays in Karnataka and sort them by their names

        List<Student> studentsByCity = studentList.stream().filter(student -> student.getCity().equals("Karnataka"))
                .sorted(Comparator.comparing(Student::getFirstName,Comparator.reverseOrder())).collect(Collectors.toList());
       // System.out.println(studentsByCity);

        // 3. Find all departments names

        List<String> deptNames = studentList.stream()
                .map(Student::getDept)
                .distinct()
                .collect(Collectors.toList());

        Set<String> deptNamesInSet = studentList
                .stream().map(Student::getDept)
                .collect(Collectors.toSet());

        //System.out.println(deptNames);
        //System.out.println(deptNamesInSet);

        //4.  Find all the contact numbers
        List<String> contacts = studentList.stream()
                .flatMap(student -> student.getContacts().stream())
                .distinct()
                .collect(Collectors.toList());
        System.out.println(contacts);
        //one2one-> map
        //one2many-> flatmap

        //5.  Group The Student By Department Names


        Map<String, List<Student>> studentMap = studentList.stream()
                .collect(Collectors.groupingBy(Student::getDept));
       // System.out.println(studentMap);


        //6. Find the department who is having maximum number of students
        Map.Entry<String, Long> results = studentList.stream()
                .collect(Collectors.groupingBy(Student::getDept, Collectors.counting()))
                .entrySet().stream().max(Map.Entry.comparingByValue()).get();

        System.out.println(results);

        //7. Find the average age of male and female students

        Map<String, Double> avgStudents = studentList.stream()
                .collect(Collectors
                        .groupingBy(Student::getGender,
                                Collectors.averagingInt(Student::getAge)));

        //System.out.println(avgStudents);

        //8. Find the highest rank in each department

        Map<String, Optional<Student>> stdMap = studentList.stream()
                .collect(Collectors.groupingBy(Student::getDept,
                        Collectors.minBy(Comparator.comparing(Student::getRank))));
        // System.out.println(stdMap);

         //9 .Find the student who has second rank

        Student student = studentList.stream()
                .sorted(Comparator.comparing(Student::getRank))
                .skip(2)
                .findFirst().get();
        System.out.println(student);

    }


}