require 'yaml'

# A configuration object that knows how to read options out of a file
# in <tt>~/.mailshears.conf.yml</tt>. The configuration options can be
# accessed via methods even though the internal representation is a
# hash.
#
# === Examples
#
#   >> cfg = Configuration.new()
#   >> cfg.i_mean_business()
#   => true
#
class Configuration

  # The default path to the user's configuration file.
  USERCONF_PATH = ENV['HOME'] + '/.mailshears.conf.yml'

  # The hash structure in which we store our configuration options
  # internally.
  @dict = {}


  # Initialize a {Configuration} object with the config file at *path*.
  #
  # @param path [String] the path to the configuration file to
  #   load. We check for a file named ".mailshears.conf.yml" in the
  #   user's home directory by default.
  #
  def initialize(path = USERCONF_PATH)
    cfg = default_configuration()

    # Now, load the user configuration which will override the
    # variables defined above.
    begin
      user_config = YAML.load(File.open(path))

      # Write our own update() method for Ruby 1.8.
      user_config.each do |key, value|
        cfg[key] = value
      end
    rescue Errno::ENOENT
      # If the user config file doesn't exist, whatever.
    end

    # Convert all of the keys to symbols.
    cfg = cfg.inject({}){|memo,(k,v)| memo[k.to_sym] = v; memo}

    @dict = cfg
  end


  # Replace all missing method calls with hash lookups. This lets us
  # retrieve the values in our option hash by using methods named
  # after the associated keys.
  #
  # @param sym [Symbol] the method that was called.
  #
  # @return [Object] the config file value associated with *sym*.
  #
  def method_missing(sym, *args)
    return @dict[sym]
  end


  private;


  # A default config hash.
  #
  # @return [Hash] sensible default configuration values.
  #
  def default_configuration()
    d = {}

    d['i_mean_business'] = false
    d['plugins'] = ['agendav',
                    'davical',
                    'dovecot',
                    'postfixadmin',
                    'roundcube']

    d['agendav_dbhost'] = 'localhost'
    d['agendav_dbport'] = 5432
    d['agendav_dbopts'] = ''
    d['agendav_dbtty'] = ''
    d['agendav_dbuser'] = 'postgres'
    d['agendav_dbpass'] = ''
    d['agendav_dbname'] = 'agendav'

    d['davical_dbhost'] = 'localhost'
    d['davical_dbport'] = 5432
    d['davical_dbopts'] = ''
    d['davical_dbtty'] = ''
    d['davical_dbuser'] = 'postgres'
    d['davical_dbpass'] = ''
    d['davical_dbname'] = 'davical'

    d['dovecot_mail_root'] = '/var/spool/mail/vhosts'

    d['postfixadmin_dbhost'] = 'localhost'
    d['postfixadmin_dbport'] = 5432
    d['postfixadmin_dbopts'] = ''
    d['postfixadmin_dbtty'] = ''
    d['postfixadmin_dbuser'] = 'postgres'
    d['postfixadmin_dbpass'] = ''
    d['postfixadmin_dbname'] = 'postfixadmin'

    d['roundcube_dbhost'] = 'localhost'
    d['roundcube_dbport'] = 5432
    d['roundcube_dbopts'] = ''
    d['roundcube_dbtty'] = ''
    d['roundcube_dbuser'] = 'postgres'
    d['roundcube_dbpass'] = ''
    d['roundcube_dbname'] = 'roundcube'

    return d
  end

end