require 'puppet/indirector/terminus'

# Store instances as files, usually serialized using some format.
class Puppet::Indirector::File < Puppet::Indirector::Terminus
    # Where do we store our data?
    def data_directory
        name = Puppet.run_mode.master? ? :server_datadir : :client_datadir

        File.join(Puppet.settings[name], self.class.indirection_name.to_s)
    end

    def file_format(path)
        path =~ /\.(\w+)$/ and return $1
    end

    def file_path(request)
        File.join(data_directory, request.key + "." + serialization_format)
    end

    def latest_path(request)
        files = Dir.glob(File.join(data_directory, request.key + ".*"))
        return nil if files.empty?

        # Return the newest file.
        files.sort { |a, b| File.stat(b).mtime <=> File.stat(a).mtime }[0]
    end

    def serialization_format
        model.default_format
    end

    # Remove files on disk.
    def destroy(request)
        begin
            removed = false
            Dir.glob(File.join(data_directory, request.key.to_s + ".*")).each do |file|
                removed = true
                File.unlink(file)
            end
        rescue => detail
            raise Puppet::Error, "Could not remove #{request.key}: #{detail}"
        end

        raise Puppet::Error, "Could not find files for #{request.key} to remove" unless removed
    end

    # Return a model instance for a given file on disk.
    def find(request)
        return nil unless path = latest_path(request)
        format = file_format(path)

        raise ArgumentError, "File format #{format} is not supported by #{self.class.indirection_name}" unless model.support_format?(format)

        begin
            return model.convert_from(format, File.read(path))
        rescue => detail
            raise Puppet::Error, "Could not convert path #{path} into a #{self.class.indirection_name}: #{detail}"
        end
    end

    # Save a new file to disk.
    def save(request)
        path = file_path(request)

        dir = File.dirname(path)

        raise Puppet::Error.new("Cannot save #{request.key}; parent directory #{dir} does not exist") unless File.directory?(dir)

        begin
            File.open(path, "w") { |f| f.print request.instance.render(serialization_format) }
        rescue => detail
            raise Puppet::Error, "Could not write #{request.key}: #{detail}" % [request.key, detail]
        end
    end

    def path(key)
        key
    end
end