module ShnaiderCode
    class StudentListFormat
        attr_private_accessor :students
        attr_accessor :formater

        def initialize(formater)
            self.formater = formater
        end

        def read_from(filename)
            self.students = formater.read_from(filename)
        end

        def write_to(filename)
            formater.write_to(filename, self.students)
        end

        def get_student(id)
            self.students.detect { |x|
                x.id == id .to_s
            }
        end

        def add_student(student)
            self.students << student
        end

        def delete_student(id)
            index = students.index(students.detect { |x| x.id == id.to_s })
            self.students.delete_at(index)
        end

        def replace_student(id, student)
            self.students.map! { |x| x.id == id.to_s ? student : x }
        end

        def get_students_slice(k, count)
            from = [k * count, self.students.count].min
            to = [self.students.count, from + count].min
        end

        def count()
            self.students.count
        end

        def sort()
            self.students.sort_by(&:fio_info)
        end
    end
end