build.rb

require 'json'
require 'open-uri'
require 'tmpdir'
require 'fileutils'
require 'roo'
require 'nkf'

CODE_FILE_URL = 'https://www.soumu.go.jp/main_content/000730858.xlsx'.freeze
API_DIR = 'api/v1/'.freeze

def conv_katakana(str)
  NKF.nkf('--katakana -w', str)
end

def load_xlsx
  cities = []
  designated_cities = []

  xlsx = Roo::Excelx.new(CODE_FILE_URL)
  xlsx.sheet(0).parse.each { |row| cities << [row[0].to_i, row[1], row[2], conv_katakana(row[3].to_s), conv_katakana(row[4].to_s)] }
  xlsx.sheet(1).parse.each { |row| designated_cities << [row[0].to_i, row[2], conv_katakana(row[4])] }

  [cities, designated_cities]
end

def make_pref_table(cities)
  prefs = {}
  cities.each do |row|
    code_with_checksum = row[0].to_i
    code = code_with_checksum / 10
    prefs[make_pref_dir(code / 1000)] = [row[1], row[3]] if code % 1000 == 0 && code != 0
  end
  prefs
end

def merge_pref(designated_cities, prefs)
  rows = designated_cities.map do |row|
    code = format('%06d', row[0])
    pref_name, pref_kana = prefs[code[0, 2]]
    [row[0], pref_name, row[1], pref_kana, row[2]]
  end
  rows
end

def merge_data(cities, designated_cities)
  city_data = {}
  prefs = make_pref_table(cities)
  d_cities = merge_pref(designated_cities, prefs)
  (cities + d_cities).sort { |a, b| a[0] <=> b[0] }.each do |row|
    code_str = format('%06d', row[0])
    next if code_str[0, 5] == '00000'
    next if code_str[2, 3] == '000'

    city_data[code_str] = {
      'prefecture' => row[1],
      'city' => row[2],
      'prefecture_kana' => row[3],
      'city_kana' => row[4]
    }
  end
  city_data
end

def write_json(city_data, api_dir = API_DIR)
  bulk_prepare = Hash.new { |h, k| h[k] = {} }
  (1..47).each do |pref_code|
    pref_path = File.join(api_dir, make_pref_dir(pref_code))
    FileUtils.mkdir_p(pref_path)
  end
  File.open(File.join(api_dir, 'all.json'), 'wb') do |f|
    f.write JSON.dump(city_data)
  end
  city_data.each do |code, data|
    code35 = code[2, 3]
    code36 = code[2, 4]
    code05 = code[0, 5]
    pref_code = code[0, 2].to_i
    data_ext = data.dup
    data_ext['code'] = code
    data_ext['code5'] = code05
    pref_dir = make_pref_dir(pref_code)
    File.open(File.join(api_dir, pref_dir, code35 + '.json'), 'wb') do |f|
      f.write JSON.dump(data_ext)
    end
    File.open(File.join(api_dir, pref_dir, code36 + '.json'), 'wb') do |f|
      f.write JSON.dump(data_ext)
    end
    bulk_prepare[pref_dir][code] = data
    bulk_prepare[pref_dir][code05] = data
  end
  # create bulk json
  (1..47).each do |pref_code|
    pref_dir = make_pref_dir(pref_code)
    File.open(File.join(api_dir, pref_dir + '.json'), 'wb') do |f|
      f.write JSON.dump(bulk_prepare[pref_dir])
    end
  end
end

def make_pref_dir(pref_code)
  format('%02d', pref_code)
end

def main
  cities, ordinance_designated_cities = load_xlsx
  city_data = merge_data(cities, ordinance_designated_cities)
  write_json(city_data)
end

main if __FILE__ == $0