using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _01.Class_Student
{
    class Problems1to12
    {

        static void Main(string[] args)
        {
            //Problem 1.    Class Student
            var students = new List<Student>
        {
            new Student("Ivan", "Atanaschev",30,870020915,"+359 2 1122334455","kosta@abv.bg",new List<int> {2, 4, 5, 6},1,"ATHENS"),
            new Student("Victor", "Benov",30,881020915,"02 96969696","rotkiv@abv.bg",new List<int> {5, 6, 5, 6},1, "SOFIA"),
            new Student("Ivan", "Agitanski",17,891020915,"+359 474747474","john.p@abv.bg",new List<int> {6, 2, 6, 2},2,"VIENNA"),
            new Student("Nasko", "Rusev",24,894020915,"+454564643","ata.nas@gmail.com",new List<int> {2, 6, 6, 6},2, "VIENNA"),
            new Student("Lili", "Baba",21,894030914,"+359 979695959","lilski@yahoo.com",new List<int> {2, 6, 6, 6},1, "ATHENS"),
            new Student("Salami", "Salambo",25,894050915,"+359 4463924957","salami@abv.bg",new List<int> {4, 2, 6, 6},2,"SOFIA"),
            new Student("Resto", "Pesto",22,894056914,"+359 65986857","pesto@hotmail.com",new List<int> {6, 6, 6, 6},3,"ROME"),
        };

            Console.WriteLine("Problem 2.   Students by Group");
            var groupTwoStudents =
                from st in students
                where st.GroupNumber == 2
                orderby st.FirstName
                select st;
            var group2 = students.Where(st => st.GroupNumber == 2).OrderBy(st => st.FirstName);
            PrintCollection(group2);
            Console.WriteLine();

            Console.WriteLine("Problem 3.   Students by First and Last Name");
            var studentsFirstAndLastName =
               from st in students
               where st.FirstName.CompareTo(st.LastName) < 0
               select st;
            var studentsNameOrder = students.Where(x => x.FirstName.CompareTo(x.LastName) < 0);
            PrintCollection(studentsNameOrder);
            Console.WriteLine();

            Console.WriteLine("Problem 4.   Students by Age");
            var studentsByAge =
                from st in students
                where (st.Age >= 18 && st.Age <= 24)
                select new { st.FirstName, st.LastName, st.Age };
            var studentAgeAnnonymos =
                students.Where(st => st.Age >= 18 && st.Age <= 24).Select(st => new { st.FirstName, st.LastName, st.Age });
            PrintCollection(studentAgeAnnonymos);
            Console.WriteLine();

            Console.WriteLine("Problem 5.   Sort Students");
            var sortStudentsLINQquery =
                from st in students
                orderby st.FirstName descending, st.LastName descending
                select st;
            var studentsLinqExtMethods = students.OrderByDescending(x => x.FirstName).ThenByDescending(x => x.LastName);
            PrintCollection(studentsLinqExtMethods);
            Console.WriteLine();

            Console.WriteLine("Problem 6.   Filter Students by Email Domain");
            var studentsByEmails =
               from st in students
               where st.Email.Contains("@abv.bg")
               select st;
            var studentsABV = students.Where(st => st.Email.Contains("abv.bg")).Select(st => new { st.FirstName, st.LastName, st.Email });
            PrintCollection(studentsABV);
            Console.WriteLine();

            Console.WriteLine("Problem 7.   Filter Students by Phone");
            var studentsPhoneSofia =
                from st in students
                where (st.Phone.StartsWith("02") || st.Phone.StartsWith("+3592") || st.Phone.StartsWith("+359 2"))
                select st;
            var phoneSofia =
                students.Where(
                    st => st.Phone.StartsWith("02") || st.Phone.StartsWith("+3592") || st.Phone.StartsWith("+359 2"));
            PrintCollection(phoneSofia);
            Console.WriteLine();

            Console.WriteLine("Problem 8.   Excellent Students");
            var excellentStudents =
               from st in students
               where (st.Marks.Max() == 6)
               select new { Fullname = string.Join(" ", st.FirstName, st.LastName), Marks = string.Join(" ", st.Marks) };
            var studentsHas6 =
                students.Where(st => st.Marks.Max() == 6).Select(st => new { Fullname = string.Join(" ", st.FirstName, st.LastName), Marks = string.Join(" ", st.Marks) });
            PrintCollection(studentsHas6);
            Console.WriteLine();

            Console.WriteLine("Problem 9.   Weak Students");
            var weakStudents = students.Where(st => st.Marks.Count(x => x == 2) == 2);
            PrintCollection(weakStudents);
            Console.WriteLine();

            Console.WriteLine("Problem 10.  Students Enrolled in 2014");
            var enroledIn2014 =
                from st in students
                where (st.FacultyNumber % 100 == 14)
                select st;
            var joned2014 =
                students.Where(st => st.FacultyNumber % 100 == 14)
                    .Select(st => new { st.FirstName, st.LastName, st.FacultyNumber });
            PrintCollection(joned2014);
            Console.WriteLine();

            Console.WriteLine("Problem 11.  * Students by Groups");
            var studentsByGroups =
                from st in students
                group st by st.GroupName;
            var studentsGropuNames = students.Select(st => new { st.FirstName, st.LastName, st.GroupName }).GroupBy(st => st.GroupName);
            foreach (var group in studentsGropuNames)
            {
                Console.WriteLine(group.Key);
                PrintCollection(group);
            }
            Console.WriteLine();

            Console.WriteLine("Problem 12.  * Students Joined to Specialties");
            var specialitiesFacNums = new List<StudentSpecialties>
                                    {
                                        new StudentSpecialties("Web Developer",900020915),
                                        new StudentSpecialties("Web Developer",901020915),
                                        new StudentSpecialties("PHP Developer",921020915),
                                        new StudentSpecialties("PHP Developer",924020915),
                                        new StudentSpecialties("QA Engineer",924030914),
                                        new StudentSpecialties("QA Engineer",924050915),
                                        new StudentSpecialties("Web Developer", 024056914)
                                    };
            var jonedData =
                from student in students
                orderby student.FirstName ascending, student.LastName ascending
                join speciality in specialitiesFacNums on student.FacultyNumber equals speciality.FacultyNumber
                select new { student.FirstName, student.LastName, student.FacultyNumber, speciality.Speciality };
            var jonedDataLinqExtMtd =
                students.OrderBy(st => st.FirstName)
                    .ThenBy(st => st.LastName)
                    .Join(specialitiesFacNums, st => st.FacultyNumber, sp => sp.FacultyNumber,
                        (student, speciality) =>
                            new { student.FirstName, student.LastName, student.FacultyNumber, speciality.Speciality });
            PrintCollection(jonedDataLinqExtMtd);
            Console.WriteLine();
        }

        static void PrintCollection(IEnumerable collection)
        {
            foreach (var item in collection)
            {
                Console.WriteLine(item);
            }
        }
    }
}