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require_relative '../student'
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require_relative '../student_short'
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require_relative '../data_list_student_short'
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require_relative '../data_table'
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class StudentsList
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attr_reader :students
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def initialize(filename, persistence_strategy)
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@filename = filename
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@persistence_strategy = persistence_strategy
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@students = []
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end
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# Загрузка студентов через выбранную стратегию.
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def load
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@students = @persistence_strategy.load(@filename)
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self
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end
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# Сохранение студентов через выбранную стратегию.
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def save
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@persistence_strategy.save(@filename, @students)
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self
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end
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# Получить объект Student по ID.
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def get_student_by_id(id)
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@students.find { |s| s.id.to_s == id.to_s }
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end
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# Получить список из k студентов (страница n) в виде объекта DataList.
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def get_k_n_student_short_list(k, n, data_list = nil)
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start_index = (n - 1) * k
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sorted_students = @students.sort_by { |s| s.surname_initials }
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selected_students = sorted_students[start_index, k] || []
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short_objects = selected_students.map { |s| StudentShort.from_student(s) }
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if data_list && data_list.is_a?(DataList)
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if data_list.respond_to?(:items=)
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data_list.items = short_objects
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else
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data_list = DataListStudentShort.new(short_objects)
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end
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data_list
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else
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DataListStudentShort.new(short_objects)
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end
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end
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# Сортировка студентов по фамилии и инициалам.
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def sort_students!
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@students.sort_by! { |s| s.surname_initials }
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end
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# Добавление студента с автоматическим присвоением нового ID.
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def add_student(student)
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new_id = if @students.empty?
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1
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else
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max_id = @students.map { |s| s.id.to_i }.max
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max_id + 1
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end
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student.id = new_id.to_s
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@students << student
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student
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end
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# Обновление студента по ID.
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def update_student_by_id(id, new_student)
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index = @students.find_index { |s| s.id.to_s == id.to_s }
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if index
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new_student.id = @students[index].id
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@students[index] = new_student
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true
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else
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false
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end
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end
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# Удаление студента по ID.
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def delete_student_by_id(id)
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initial_count = @students.size
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@students.reject! { |s| s.id.to_s == id.to_s }
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initial_count != @students.size
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end
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# Получить количество студентов.
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def get_student_short_count
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@students.size
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end
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end
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