#
# Author:: Christian Reiniger <creinig@dotsrc.org>
# License:: GNU GPL v2 or later, as described in the accompanying LICENSE file
# Homepage: http://dsadmin.dotsrc.org/
#
# ----
# Last change:
#
# CVS User:: $Author: creinig $
# Date:: $Date: 2006-10-24 10:29:33 +0200 (Tue, 24 Oct 2006) $
# Revision:: $Revision: 110 $
#

require 'thread'

require 'dsadmin/contractor'
require 'dsadmin/system'
require 'dsadmin/email'

module Dsadmin
  
  
  # Collection of output handlers for the logging subsystem
  module LogWriters
    
    # Abstract base class for all output handlers
    class LogWriter
      include Dsadmin::Contractor
      
      # OVERRIDE
      def write(message, formatted_record)
        assertNotReachable
      end

      # Returns the "kind" of writer the object represents (:file, :stream, :email, ...)
      # OVERRIDE
      def kind
        assertNotReachable
      end
      
      # override if necessary
      def shutdown
      end  
    end
    
    
    
    
    
    # Output handler for filesystem entities (plain files, named pipes etc)
    class FileWriter < LogWriter
      
      def write(message, formatted_record)
        @mutex.synchronize {
          @dest << formatted_record
        }
      end
      
      def shutdown
        @dest.close if @dest
        @dest = nil
      end
      
      
      def stream
        @dest
      end
      
      def filename
        @destname
      end

      def kind
        :file
      end      
      
      
      private
      
      # Constructor
      #
      # Accepts parameterized filenames (printf-style):
      #  * '%d' => current date (YYYY-MM-DD),
      #  * '%p' => current process id,
      #  * '%h' => hostname,
      #  * '%i' => instance ID (only when running in an admind context),
      #  * '%t' => current time (%H:%M:%S)
      def initialize(aFilename, config_manager)
        @sys = System.instance
        
        @destname    = expandFilename(aFilename, config_manager)
        @dest = File.new(@destname, "a")
        @dest.sync = true
        
        @mutex = Mutex.new
      end
      
      # Generates a proper filename from the given one by replacing parameters
      # (%d, %p, ...) with their actual values
      def expandFilename(aFilename, config_manager)
        date_s = Date.today.to_s
        time_s = System.instance.now.strftime('%H:%M:%S')
        pid_s  = Process.pid.to_s
        
        res = aFilename.gsub(/%d/, date_s)
        res = res.gsub(/%p/, pid_s)
        res = res.gsub(/%h/, Socket.gethostname)
        res = res.gsub(/%i/, config_manager.instanceid) if(config_manager.respond_to?(:instanceid))
        res = res.gsub(/%t/, time_s)
        return config_manager.localpath(res)
      end # expandFilename
      
    end
    
    
    
    
    
    # Output handler for raw streams ($stdout, $stderr, pre-opened files or sockets, ...) or, 
    # in fact, anything that responds to "<<" (like an array or a ring buffer).
    # The given stream is *not* automatically closed at handler shutdown.
    class StreamWriter < LogWriter
      
      def write(message, formatted_record)
        @stream << formatted_record
      end

      def kind
        :stream
      end      
            
      attr_reader :stream
      
      private
      
      def initialize(stream)
        assertRespondTo(stream, "<<")
        @stream = stream
      end
    end
    
    
    
    
    
    # Output handler for email messages (one per log message).
    # Use only for low-frequency messages (bug reports etc)
    # FIXME: Implement queueing and bundling of messages to avoid flooding
    class EmailWriter < LogWriter
      def write(message, formatted_record)
        mail = Email.new(@facility)
        mail.subject = message.to_s
        mail.text = formatted_record
        mail.send
      end
      
      def kind
        :email
      end
      
      private # ---------------------------------------------------------- private
      
      # Constructor
      def initialize(mail_facility)
        # Try if the mail facility exists
        tmp = Email.new(mail_facility)
        
        @facility = mail_facility
      end
    end
    
    
  end # module LogWriters
end # module Dsadmin