# frozen_string_literal: true

require 'google/apis/sheets_v4'
module SpreadsheetBackends
  class GoogleSheets
    # Hash to translate an index to a A1 notation. e.g. 1 => 'B', 27 => 'AA'
    COLUMN_INDEX_TO_LETTER = Hash.new { |hash, key| hash[key] = hash[key - 1].next }.merge({ 0 => 'A' })

    attr_accessor :form, :user

    def initialize(form)
      @form = form
      @user = form.user
    end

    def url
      "https://docs.google.com/spreadsheets/d/#{form.google_spreadsheet_id}/edit" if form.google_spreadsheet_id.present?
    end

    def append(data)
      data = data.with_indifferent_access
      check_spreadsheed_headers!(data)

      values = headers.map { |key| data[key] }
      range = "A1:A#{COLUMN_INDEX_TO_LETTER[values.length]}1"
      value_range = Google::Apis::SheetsV4::ValueRange.new(values: [values], major_dimension: 'ROWS')

      result = spreadsheet_service.append_spreadsheet_value(form.google_spreadsheet_id, range, value_range, value_input_option: 'USER_ENTERED')
      result.updates.updated_rows > 0
    end

    def create
      sheets = Google::Apis::SheetsV4::SheetsService.new
      sheets.authorization = user.google_authorization
      create_object = Google::Apis::SheetsV4::Spreadsheet.new(properties: { title: form.title })
      spreadsheet = sheets.create_spreadsheet(create_object)
      form.update(google_spreadsheet_id: spreadsheet.spreadsheet_id)
    end

    def headers
      @headers ||= begin
                           values = spreadsheet_service.get_spreadsheet_values(form.google_spreadsheet_id, 'A1:An').values
                           # if there are no headers yet, return an empty array
                           if values
                             values[0].map(&:strip)
                           else
                             []
                           end
                         end
    end

    def spreadsheet_service
      @spreadsheet_service ||= Google::Apis::SheetsV4::SheetsService.new.tap do |s|
        s.authorization = user.google_authorization
      end
    end

    def check_spreadsheed_headers!(data)
      missing_headers = data.keys.map { |k| k.to_s.strip } - headers
      append_missing_headers(missing_headers) unless missing_headers.empty?
    end

    def append_missing_headers(missing_headers)
      start_column = COLUMN_INDEX_TO_LETTER[headers.length]
      end_column = COLUMN_INDEX_TO_LETTER[headers.length + missing_headers.length]
      range = "#{start_column}1:#{end_column}1"
      value_range = Google::Apis::SheetsV4::ValueRange.new(values: [missing_headers], major_dimension: 'ROWS')
      spreadsheet_service.update_spreadsheet_value(form.google_spreadsheet_id, range, value_range, value_input_option: 'USER_ENTERED')
      @headers = nil # reset header values to refresh memoization on next access
    end
  end
end