# frozen_string_literal: true

require 'csv'

class EnrollmentLoader
  def self.load_data(filepath:)
    schools = []
    enrollments = []
    CSV.parse(File.read(filepath), headers: true) do |row|
      row = EnrollmentRowValues.new(row:)

      next unless row.school.present? && row.academic_year.present?

      schools << row.school

      enrollments << create_enrollment_entry(row:)
    end

    # It's possible that instead of updating all columns on duplicate key, we could just update the student columns and leave total_teachers alone. Right now enrollment data loads before staffing data so it works correctly.
    Respondent.import enrollments, batch_size: 1000,
                                   on_duplicate_key_update: %i[pk k one two three four five six seven eight nine ten eleven twelve total_students]

    Respondent.where.not(school: schools).destroy_all
  end

  private

  def self.create_enrollment_entry(row:)
    respondent = Respondent.find_or_initialize_by(school: row.school, academic_year: row.academic_year)
    respondent.pk = row.pk
    respondent.k = row.k
    respondent.one = row.one
    respondent.two = row.two
    respondent.three = row.three
    respondent.four = row.four
    respondent.five = row.five
    respondent.six = row.six
    respondent.seven = row.seven
    respondent.eight = row.eight
    respondent.nine = row.nine
    respondent.ten = row.ten
    respondent.eleven = row.eleven
    respondent.twelve = row.twelve
    respondent.total_students = row.total_students
    respondent
  end

  private_class_method :create_enrollment_entry
end

class EnrollmentRowValues
  attr_reader :row

  def initialize(row:)
    @row = row
  end

  def school
    @school ||= begin
      dese_id = row['DESE ID'].try(:strip).to_i
      School.find_by_dese_id(dese_id)
    end
  end

  def academic_year
    @academic_year ||= begin
      year = row['Academic Year']
      AcademicYear.find_by_range(year)
    end
  end

  def pk
    row['PK'] || row['pk']
  end

  def k
    row['K'] || row['k']
  end

  def one
    row['1']
  end

  def two
    row['2']
  end

  def three
    row['3']
  end

  def four
    row['4']
  end

  def five
    row['5']
  end

  def six
    row['6']
  end

  def seven
    row['7']
  end

  def eight
    row['8']
  end

  def nine
    row['9']
  end

  def ten
    row['10']
  end

  def eleven
    row['11']
  end

  def twelve
    row['12']
  end

  def total_students
    row['Total'].gsub(',', '').to_i
  end
end