# This class contains the logic to find the user's credentials from a
# configuration file. By default, the file is `~/.sumo_creds`.
class Sumo::Config
  include Sumo::Error

  attr_reader :config_file

  # Given an optional `String`, sets and freezes the `@config_file` instance
  # variable, as long as it's a valid file path.
  def initialize(config_file = Sumo::CONFIG_FILE)
    @config_file = File.expand_path(config_file).freeze
  end

  # Load the credentials, raising an any errors that occur.
  def load_creds!
    @creds ||= load_file[cred_key].tap do |creds|
      raise NoCredsFound, "#{cred_key} not found in #{config_file}" if !creds
    end
  end

  # Load the credentials, returning nil if an error occurs.
  def load_creds
    load_creds! rescue nil
  end

  # Get the credentials from the environment.
  def cred_key
    @cred_key = ENV['SUMO_CREDENTIAL'] || 'default'
  end
  private :cred_key

  # Get the credentials from the configuration file.
  def load_file
    if File.exists?(config_file)
      parse_file
    else
      raise NoCredsFound, bad_config_file("#{config_file} does not exist.")
    end
  end
  private :load_file

  # Parse the configuration file, raising an error if it is invalid YAML.
  def parse_file
    YAML.load_file(config_file).tap { |creds| raise unless creds.is_a?(Hash) }
  rescue
    raise NoCredsFound, bad_config_file("#{config_file} is not valid YAML.")
  end
  private :parse_file

  def bad_config_file(message)
    <<-EOS.gsub(/^\s+\|/, '')
      |#{message}
      |
      |sumo-search now expects its config file (located at #{config_file}) to
      |be valid YAML. Below is an example of a valid config file:
      |
      |backend:
      |  email: backend@example.com
      |  password: trustno1
      |frontend:
      |  email: frontend@example.com
      |  password: test-pass-1
      |
      |By default, the 'default' credential in #{config_file} will be used. To
      |change this behavior, set the $SUMO_CREDENTIAL environment varibale
      |to the credential you would like to use. In the above example, setting
      |$SUMO_CREDENTIAL to 'frontend' would allow you to access the account with
      |email 'frontend@example.com' and password 'test-pass-1'.
    EOS
  end
  private :bad_config_file
end