class Inspec::Resources::Postgres

def cluster_from_dir(dir)
  # Main is the default cluster name on debian use it if it
  # exists.
  if inspec.directory("#{dir}/main").exist?
    'main'
  else
    dirs = inspec.command("ls -d #{dir}/*/").stdout.lines
    first = dirs.first.chomp.split('/').last
    if dirs.count > 1
      warn "Multiple postgresql clusters configured or incorrect base dir #{dir}"
      warn "Using the first directory found: #{first}"
    end
    first
  end
end

def dir_to_version(dir)
  dir.chomp.split('/').last
end

def initialize
  os = inspec.os
  if os.debian?
    #
    # https://wiki.debian.org/PostgreSql
    #
    # Debian allows multiple versions of postgresql to be
    # installed as well as multiple "clusters" to be configured.
    #
    version = version_from_dir('/etc/postgresql')
    cluster = cluster_from_dir("/etc/postgresql/#{version}")
    @conf_dir = "/etc/postgresql/#{version}/#{cluster}"
    @data_dir = "/var/lib/postgresql/#{version}/#{cluster}"
  elsif os.redhat?
    #
    # /var/lib/pgsql/data is the default data directory on RHEL6
    # and RHEL7. However, PR #824 explicitly added version-based
    # directories. Thus, we call #version_from_dir unless it looks
    # like we are using unversioned directories.
    #
    # TODO(ssd): This has the potential to be noisy because of the
    # warning in version_from_dir. We should determine which case
    # is more common and only warn in the less common case.
    #
    version = if inspec.directory('/var/lib/pgsql/data').exist?
                warn 'Found /var/lib/pgsql/data. Assuming postgresql install uses un-versioned directories.'
                nil
              else
                version_from_dir('/var/lib/pgsql/')
              end
    @data_dir = File.join('/var/lib/pgsql/', version.to_s, 'data')
  elsif os[:name] == 'arch'
    #
    # https://wiki.archlinux.org/index.php/PostgreSQL
    #
    # The archlinux wiki points to /var/lib/postgresql/data as the
    # main data directory.
    #
    @data_dir = '/var/lib/postgres/data'
  else
    #
    # According to https://www.postgresql.org/docs/9.5/static/creating-cluster.html
    #
    # > There is no default, although locations such as
    # > /usr/local/pgsql/data or /var/lib/pgsql/data are popular.
    #
    @data_dir = '/var/lib/pgsql/data'
  end
  @service = 'postgresql'
  @conf_dir ||= @data_dir
  verify_dirs
  @conf_path = File.join @conf_dir, 'postgresql.conf'
end

def to_s
  'PostgreSQL'
end

def verify_dirs
  if !inspec.directory(@conf_dir).exist?
    warn "Default postgresql configuration directory: #{@conf_dir} does not exist. Postgresql may not be installed or we've misidentified the configuration directory."
  end
  if !inspec.directory(@data_dir).exist?
    warn "Default postgresql data directory: #{@data_dir} does not exist. Postgresql may not be installed or we've misidentified the data directory."
  end
end

def version_from_dir(dir)
  dirs = inspec.command("ls -d #{dir}/*/").stdout
  entries = dirs.lines.count
  case entries
  when 0
    warn "Could not determine version of installed postgresql by inspecting #{dir}"
    nil
  when 1
    warn "Using #{dirs}: #{dir_to_version(dirs)}"
    dir_to_version(dirs)
  else
    warn "Multiple versions of postgresql installed or incorrect base dir #{dir}"
    first = dir_to_version(dirs.lines.first)
    warn "Using the first version found: #{first}"
    first
  end
end