module Geocoder::MaxmindDatabase

def archive_edition(package)
  {
    geolite_country_csv: "GeoLite2-Country-CSV",
    geolite_city_csv: "GeoLite2-City-CSV",
    geolite_asn_csv: "GeoLite2-ASN-CSV"
  }[package]
end

def archive_filename(package)
  p = archive_url_path(package)
  s = !(pos = p.rindex('/')).nil? && pos + 1 || 0
  p[s..-1]
end

def archive_url(package)
  base_url + archive_url_path(package)
end

def base_url(edition)
  "https://download.maxmind.com/app/geoip_download?edition_id=#{edition}&license_key=#{ENV['LICENSE_KEY']}&suffix=zip"
end

def data_files(package, dir = "tmp")
  case package
  when :geolite_city_csv
    # use the last two in case multiple versions exist
    files = Dir.glob(File.join(dir, "GeoLiteCity_*/*.csv"))[-2..-1].sort
    Hash[*files.zip(["maxmind_geolite_city_blocks", "maxmind_geolite_city_location"]).flatten]
  when :geolite_country_csv
    {File.join(dir, "GeoIPCountryWhois.csv") => "maxmind_geolite_country"}
  end
end

def download(package, dir = "tmp")
  filepath = File.expand_path(File.join(dir, "#{archive_edition(package)}.zip"))
  open(filepath, 'wb') do |file|
    uri = URI.parse(base_url(package))
    Net::HTTP.start(uri.host, uri.port) do |http|
      http.request_get(uri.path) do |resp|
        # TODO: show progress
        resp.read_body do |segment|
          file.write(segment)
        end
      end
    end
  end
end

def insert(package, dir = "tmp")
  data_files(package, dir).each do |filepath,table|
    print "Resetting table #{table}..."
    ActiveRecord::Base.connection.execute("DELETE FROM #{table}")
    puts "done"
    insert_into_table(table, filepath)
  end
end

def insert_into_table(table, filepath)
  start_time = Time.now
  print "Loading data for table #{table}"
  rows = []
  columns = table_columns(table)
  CSV.foreach(filepath, encoding: "ISO-8859-1") do |line|
    # Some files have header rows.
    # skip if starts with "Copyright" or "locId" or "startIpNum"
    next if line.first.match(/[A-z]/)
    rows << line.to_a
    if rows.size == 10000
      insert_rows(table, columns, rows)
      rows = []
      print "."
    end
  end
  insert_rows(table, columns, rows) if rows.size > 0
  puts "done (#{Time.now - start_time} seconds)"
end

def insert_rows(table, headers, rows)
  value_strings = rows.map do |row|
    "(" + row.map{ |col| sql_escaped_value(col) }.join(',') + ")"
  end
  q = "INSERT INTO #{table} (#{headers.join(',')}) " +
    "VALUES #{value_strings.join(',')}"
  ActiveRecord::Base.connection.execute(q)
end

def sql_escaped_value(value)
  value.to_i.to_s == value ? value :
    ActiveRecord::Base.connection.quote(value)
end

def table_columns(table_name)
  {
    maxmind_geolite_city_blocks: %w[start_ip_num end_ip_num loc_id],
    maxmind_geolite_city_location: %w[loc_id country region city postal_code latitude longitude metro_code area_code],
    maxmind_geolite_country: %w[start_ip end_ip start_ip_num end_ip_num country_code country]
  }[table_name.to_sym]
end