class Gmail

# File lib/gmail.rb, line 25
def self.authorization_url
  authorizer.get_authorization_url(base_url: OOB_URI)
end

# File lib/gmail.rb, line 16
def self.authorized?
  !service.nil? && !service.authorization.nil?
end

# File lib/gmail.rb, line 20
def self.credentials_from_code(code)
  authorizer.get_and_store_credentials_from_code(
  user_id: USER_ID, code: code, base_url: OOB_URI)
end

# File lib/gmail.rb, line 29
def self.find_mail(query)
  ids = service.list_user_messages('me', q: query)

  return [] unless ids.messages
  ids.messages.map do |message|
    find_mail_by_id(message.id)
  end
end

# File lib/gmail.rb, line 38
def self.send_message(mail)
  message = Google::Apis::GmailV1::Message.new(raw: mail.to_s )
  result = service.send_user_message('me', message)
end

# File lib/gmail.rb, line 56
def self.authorizer
  return @authorizer unless @authorizer.nil?

  @service = Google::Apis::GmailV1::GmailService.new
  @service.client_options.application_name = APPLICATION_NAME

  FileUtils.mkdir_p(File.dirname(CREDENTIALS_PATH))

  client_id = Google::Auth::ClientId.from_file(CLIENT_SECRETS_PATH)
  token_store = Google::Auth::Stores::FileTokenStore.new(
    file: CREDENTIALS_PATH)
  @authorizer = Google::Auth::UserAuthorizer.new(
    client_id, SCOPE, token_store)
end

# File lib/gmail.rb, line 71
def self.find_mail_by_id(id)
  results = @service.get_user_message('me', id)

  body = results.payload.parts ?
    results.payload.parts.first.body.data :
    results.payload.body.data
  headers = results.payload.headers

  {
    subject: headers.select { |e| e.name == 'Subject'}.first.value,
    from: headers.select { |e| e.name == 'From'}.first.value,
    date: Time.parse(headers.select { |e| e.name == 'Date'}.first.value),
    body: body.force_encoding('utf-8'),
  }
end

# File lib/gmail.rb, line 44
def self.service
  return @service if !@service.nil? && !@service.authorization.nil?

  credentials = authorizer.get_credentials(USER_ID)
  if credentials
    @service.authorization = credentials
    return @service
  end

  return @service
end