using System;

using System.Linq;

using System.Collections.Generic;

namespace LINQ5

{

    class Employee

    {

        public string Name { get; set; }

        public int Age { get; set; }

        public List<Project> Projects { get; set; }

        public Employee(string name, int age)

        {

            Name = name;

            Age = age;

            Projects = new List<Project>();

        }

        public override string ToString()

        {

            return $"Фамилия: {Name} , Возраст: {Age}";

        }

    }

    class Project

    {

        public string Name { get; set; }

        public DateTime Date { get; set; }

        public List<Employee> Employees { get; set; }

        public Project(string name, DateTime date)

        {

            Name = name;

            Date = date;

            Employees = new List<Employee>();

        }

        public override string ToString()

        {

            return $"Проект: {Name} , Начало: {Date.ToShortDateString()}";

        }

    }

    class Company

    {

        public string Name { get; set; }

        public List<Project> Projects { get; set; }

        public List<Employee> Employees { get; set; }

​

        public Company(string name)

        {

            Name = name;

            Projects = new List<Project>();

            Employees = new List<Employee>();

        }

​

        public void AddProject(Project p, List<Employee> e)

        {

            p.Employees = e;

            foreach (var v in e)

            {

                v.Projects.Add(p);

            }

            Projects.Add(p);

        }

        public IEnumerable<Employee> GetEmployeesOnTwoOrMoreProjects()

        {

            var EmpTwoOrMorePr = Projects.SelectMany(a => a.Employees); 

            return EmpTwoOrMorePr.Where(e => e.Projects.Count() > 1).OrderBy(e => e.Name).Distinct();

        }

        public IEnumerable<Project> GetProjectsAfterDate(DateTime Date)

        {

            return Projects.Where(p => p.Date > Date).OrderByDescending(p => p.Date);

        }

        public int CountProjects()

        {

            return Projects.Where(p => p.Date >= DateTime.Today.AddYears(-1) && p.Employees.Where(e => e.Age <= 30).Count() > 0).Count();

        }

        public string GetOldEmployeeName()

        {

            var emp = Projects.SelectMany(a => a.Employees).Where(e => e.Projects.Count() == 1 && e.Projects[0].Date >= new DateTime(DateTime.Today.Year, 1, 1));

            int MaxAge = emp.Max(e => e.Age);

            return emp.First(e => e.Age == MaxAge).Name;

        }

    }

    class Program

    {

        public static void Main(string[] args)

        {

            Company company = new Company("Google");

​

            FillData(company);

​

            Console.WriteLine("Список сотрудников, работающих на двух и более проектах (в алфавитном порядке):");

            IEnumerable<Employee> employees = company.GetEmployeesOnTwoOrMoreProjects();

            foreach (Employee e in employees)

            {

                Console.WriteLine(e);

            }

            Console.WriteLine();

​

            Console.WriteLine("Список проектов, начавшихся после определенной даты(в порядке убывания даты):");

            IEnumerable<Project> projects = company.GetProjectsAfterDate(new DateTime(2010, 1, 1));

            foreach (Project p in projects)

            {

                Console.WriteLine(p);

            }

            Console.WriteLine();

​

            Console.WriteLine("Количество проектов, продолжающихся не более года, в которых, среди всех сотрудников, есть один или несколько человек, не старше 30 лет:");

            Console.WriteLine(company.CountProjects());

            Console.WriteLine();

​

            Console.WriteLine("Фамилия самого старшего сотрудника, работающего строго над одним проектом, начавшемся в этом году:");

            Console.WriteLine(company.GetOldEmployeeName());

        }

​

    public static void FillData(Company company)

    {

            Project photos = new Project("Google Photos", new DateTime(2015, 5, 28));

            Project translate = new Project("Google Translate", new DateTime(2006, 4, 28));

            Project chrome = new Project("Google Chrome", new DateTime(2008, 9, 2));

            Project gmail = new Project("Gmail", new DateTime(2004, 4, 1));

            Project calendar = new Project("Google Calendar", new DateTime(2006, 4, 13));

            Project maps = new Project("Google Maps", new DateTime(2005, 2, 8));

            Project neighbourly = new Project("Google Neighbourly", new DateTime(2020, 1, 14));

            Project reformer = new Project("Reformer", new DateTime(2020, 2, 13));

            Project search = new Project("Google Search", new DateTime(1997, 5, 12));

            Project oneToday = new Project("Google One Today", new DateTime(2020, 3, 11));

​

            Employee employee1 = new Employee("Смирнов", 26);

            Employee employee2 = new Employee("Иванов", 43);

            Employee employee3 = new Employee("Кузнецов", 54);

            Employee employee4 = new Employee("Соколов", 24);

            Employee employee5 = new Employee("Попов", 34);

            Employee employee6 = new Employee("Лебедев", 28);

            Employee employee7 = new Employee("Козлов", 22);

            Employee employee8 = new Employee("Новиков", 55);

            Employee employee9 = new Employee("Морозов", 42);

            Employee employee10 = new Employee("Петров", 27);

            Employee employee11 = new Employee("Волков", 32);

            Employee employee12 = new Employee("Соловьёв", 38);

            Employee employee13 = new Employee("Васильев", 43);

            Employee employee14 = new Employee("Зайцев", 21);

            Employee employee15 = new Employee("Павлов", 33);

            Employee employee16 = new Employee("Семёнов", 56);

            Employee employee17 = new Employee("Голубев", 45);

            Employee employee18 = new Employee("Виноградов", 44);

            Employee employee19 = new Employee("Богданов", 27);

            Employee employee20 = new Employee("Воробьёв", 21);

            Employee employee21 = new Employee("Фёдоров", 62);

            Employee employee22 = new Employee("Михайлов", 37);

            Employee employee23 = new Employee("Беляев", 38);

            Employee employee24 = new Employee("Тарасов", 39);

            Employee employee25 = new Employee("Белов", 40);

            Employee employee26 = new Employee("Комаров", 41);

            Employee employee27 = new Employee("Орлов", 42);

            Employee employee28 = new Employee("Киселёв", 33);

            Employee employee29 = new Employee("Макаров", 34);

            Employee employee30 = new Employee("Андреев", 35);

            Employee employee31 = new Employee("Ковалёв", 36);

            Employee employee32 = new Employee("Ильин", 31);

            Employee employee33 = new Employee("Гусев", 37);

            Employee employee34 = new Employee("Титов", 38);

            Employee employee35 = new Employee("Кузьмин", 39);

            Employee employee36 = new Employee("Кудрявцев", 40);

            Employee employee37 = new Employee("Баранов", 21);

            Employee employee38 = new Employee("Куликов", 25);

            Employee employee39 = new Employee("Алексеев", 27);

            Employee employee40 = new Employee("Степанов", 29);

            Employee employee41 = new Employee("Яковлев", 37);

            Employee employee42 = new Employee("Сорокин", 44);

            Employee employee43 = new Employee("Сергеев", 48);

            Employee employee44 = new Employee("Романов", 53);

            Employee employee45 = new Employee("Захаров", 25);

            Employee employee46 = new Employee("Борисов", 37);

            Employee employee47 = new Employee("Королёв", 47);

            Employee employee48 = new Employee("Герасимов", 41);

            Employee employee49 = new Employee("Пономарёв", 40);

            Employee employee50 = new Employee("Григорьев", 30);

​

            company.AddProject(photos, new List<Employee> { employee1, employee2, employee3, employee4, employee5, employee6 });

            company.AddProject(translate, new List<Employee> { employee10, employee11, employee12, employee13, employee14, employee15 });

            company.AddProject(chrome, new List<Employee> { employee20, employee21, employee22, employee23, employee24, employee25 });

            company.AddProject(gmail, new List<Employee> { employee30, employee31, employee32, employee33, employee34, employee35 });

            company.AddProject(calendar, new List<Employee> { employee40, employee41, employee42, employee43, employee44, employee45 });

            company.AddProject(maps, new List<Employee> { employee46, employee47, employee48, employee49, employee50, employee45 });

            company.AddProject(neighbourly, new List<Employee> { employee36, employee37, employee38, employee39, employee6, employee7 });

            company.AddProject(reformer, new List<Employee> { employee26, employee27, employee28, employee29, employee15, employee16 });

            company.AddProject(search, new List<Employee> { employee8, employee9, employee17, employee29, employee15, employee3 });

            company.AddProject(oneToday, new List<Employee> { employee18, employee19, employee31, employee27, employee15, employee46 });

        }

    }

​

}