# Equivalent to a header guard in C/C++
# Used to prevent the class/module from being loaded more than once
unless defined? Logging

require 'yaml'
require 'stringio'
require 'thread'

begin
  require 'lockfile'
rescue LoadError
  retry if require 'rubygems'
  raise
end

begin
  require 'syslog'
  HAVE_SYSLOG = true
rescue LoadError
  HAVE_SYSLOG = false
end

begin require 'fastthread'; rescue LoadError; end

# TODO: Windows Log Service appender

#
#
module Logging

  # :stopdoc:
  VERSION = '1.0.0'
  LIBPATH = ::File.expand_path(::File.dirname(__FILE__)) + ::File::SEPARATOR
  PATH = ::File.dirname(LIBPATH) + ::File::SEPARATOR
  WIN32 = %r/djgpp|(cyg|ms|bcc)win|mingw/ =~ RUBY_PLATFORM
  LEVELS = {}
  LNAMES = []
  # :startdoc:

  class << self

    # call-seq:
    #    Logging.configure( filename )
    #    Logging.configure { block }
    #
    # Configures the Logging framework using the configuration information
    # found in the given file. The file extension should be either '.yaml'
    # or '.yml' (XML configuration is not yet supported).
    #
    def configure( *args, &block )
      if block
        return ::Logging::Config::Configurator.process(&block)
      end

      filename = args.shift
      raise ArgumentError, 'a filename was not given' if filename.nil?

      case File.extname(filename)
      when '.yaml', '.yml'
        ::Logging::Config::YamlConfigurator.load(filename, *args)
      else raise ArgumentError, 'unknown configuration file format' end
    end

    # call-seq:
    #    Logging.logger( device, age = 7, size = 1048576 )
    #    Logging.logger( device, age = 'weekly' )
    #
    # This convenience method returns a Logger instance configured to behave
    # similarly to a core Ruby Logger instance.
    #
    # The _device_ is the logging destination. This can be a filename
    # (String) or an IO object (STDERR, STDOUT, an open File, etc.). The
    # _age_ is the number of old log files to keep or the frequency of
    # rotation (+daily+, +weekly+, or +monthly+). The _size_ is the maximum
    # logfile size and is only used when _age_ is a number.
    #
    # Using the same _device_ twice will result in the same Logger instance
    # being returned. For example, if a Logger is created using STDOUT then
    # the same Logger instance will be returned the next time STDOUT is
    # used. A new Logger instance can be obtained by closing the previous
    # logger instance.
    #
    #    log1 = Logging.logger(STDOUT)
    #    log2 = Logging.logger(STDOUT)
    #    log1.object_id == log2.object_id  #=> true
    #
    #    log1.close
    #    log2 = Logging.logger(STDOUT)
    #    log1.object_id == log2.object_id  #=> false
    #
    # The format of the log messages can be changed using a few optional
    # parameters. The <tt>:pattern</tt> can be used to change the log
    # message format. The <tt>:date_pattern</tt> can be used to change how
    # timestamps are formatted. 
    #
    #    log = Logging.logger(STDOUT,
    #              :pattern => "[%d] %-5l : %m\n",
    #              :date_pattern => "%Y-%m-%d %H:%M:%S.%s")
    #
    # See the documentation for the Logging::Layouts::Pattern class for a
    # full description of the :pattern and :date_pattern formatting strings.
    #
    def logger( *args )
      return ::Logging::Logger if args.empty?

      opts = args.pop if args.last.instance_of?(Hash)
      opts ||= Hash.new

      dev = args.shift
      keep = age = args.shift
      size = args.shift

      name = case dev
             when String; dev
             when File; dev.path
             else dev.object_id.to_s end

      repo = ::Logging::Repository.instance
      return repo[name] if repo.has_logger? name

      l_opts = {
        :pattern => "%.1l, [%d #%p] %#{::Logging::MAX_LEVEL_LENGTH}l : %m\n",
        :date_pattern => '%Y-%m-%dT%H:%M:%S.%s'
      }
      [:pattern, :date_pattern, :date_method].each do |o|
        l_opts[o] = opts.delete(o) if opts.has_key? o
      end
      layout = ::Logging::Layouts::Pattern.new(l_opts)

      a_opts = Hash.new
      a_opts[:size] = size if size.instance_of?(Fixnum)
      a_opts[:age]  = age  if age.instance_of?(String)
      a_opts[:keep] = keep if keep.instance_of?(Fixnum)
      a_opts[:filename] = dev if dev.instance_of?(String)
      a_opts[:layout] = layout
      a_opts.merge! opts

      appender =
          case dev
          when String
            ::Logging::Appenders::RollingFile.new(name, a_opts)
          else 
            ::Logging::Appenders::IO.new(name, dev, a_opts)
          end

      logger = ::Logging::Logger.new(name)
      logger.add_appenders appender
      logger.additive = false

      class << logger
        def close
          @appenders.each {|a| a.close}
          h = ::Logging::Repository.instance.instance_variable_get :@h
          h.delete(@name)
          class << self; undef :close; end
        end
      end

      logger
    end

    # Access to the layouts.
    #
    def layouts
      ::Logging::Layouts
    end

    # Access to the appenders.
    #
    def appenders
      ::Logging::Appenders
    end

    # call-seq:
    #    Logging.init( levels )
    #
    # Defines the levels available to the loggers. The _levels_ is an array
    # of strings and symbols. Each element in the array is downcased and
    # converted to a symbol; these symbols are used to create the logging
    # methods in the loggers.
    #
    # The first element in the array is the lowest logging level. Setting the
    # logging level to this value will enable all log messages. The last
    # element in the array is the highest logging level. Setting the logging
    # level to this value will disable all log messages except this highest
    # level.
    #
    # This method should only be invoked once to configure the logging
    # levels. It is automatically invoked with the default logging levels
    # when the first logger is created.
    #
    # The levels "all" and "off" are reserved and will be ignored if passed
    # to this method.
    #
    # Example:
    #
    #    Logging.init :debug, :info, :warn, :error, :fatal
    #    log = Logging::Logger['my logger']
    #    log.level = :warn
    #    log.warn 'Danger! Danger! Will Robinson'
    #    log.info 'Just FYI'                        # => not logged
    #
    # or
    #
    #    Logging.init %w(DEBUG INFO NOTICE WARNING ERR CRIT ALERT EMERG)
    #    log = Logging::Logger['syslog']
    #    log.level = :notice
    #    log.warning 'This is your first warning'
    #    log.info 'Just FYI'                        # => not logged
    #
    def init( *args )
      args = %w(debug info warn error fatal) if args.empty?

      args.flatten!
      levels = LEVELS.clear
      names = LNAMES.clear

      id = 0
      args.each do |lvl|
        lvl = levelify lvl
        unless levels.has_key?(lvl) or lvl == 'all' or lvl == 'off'
          levels[lvl] = id 
          names[id] = lvl.upcase
          id += 1
        end
      end

      longest = names.inject {|x,y| (x.length > y.length) ? x : y}
      longest = 'off' if longest.length < 3
      module_eval "MAX_LEVEL_LENGTH = #{longest.length}", __FILE__, __LINE__

      levels.keys
    end
   
    # call-seq:
    #    Logging.format_as( obj_format )
    #
    # Defines the default _obj_format_ method to use when converting objects
    # into string representations for logging. _obj_format_ can be one of
    # <tt>:string</tt>, <tt>:inspect</tt>, or <tt>:yaml</tt>. These
    # formatting commands map to the following object methods
    #
    # * :string  => to_s
    # * :inspect => inspect
    # * :yaml    => to_yaml
    #
    # An +ArgumentError+ is raised if anything other than +:string+,
    # +:inspect+, +:yaml+ is passed to this method.
    #
    def format_as( f )
      f = f.intern if f.instance_of? String

      unless [:string, :inspect, :yaml].include? f
        raise ArgumentError, "unknown object format '#{f}'"
      end

      module_eval "OBJ_FORMAT = :#{f}", __FILE__, __LINE__
    end

    # call-seq:
    #    Logging.backtrace             #=> true or false
    #    Logging.backtrace( value )    #=> true or false
    #
    # Without any arguments, returns the global exception backtrace logging
    # value. When set to +true+ backtraces will be written to the logs; when
    # set to +false+ backtraces will be suppressed.
    #
    # When an argument is given the global exception backtrace setting will
    # be changed. Value values are <tt>"on"</tt>, <tt>:on<tt> and +true+ to
    # turn on backtraces and <tt>"off"</tt>, <tt>:off</tt> and +false+ to
    # turn off backtraces.
    #
    def backtrace( b = nil )
      @backtrace = true unless defined? @backtrace
      return @backtrace if b.nil?

      @backtrace = case b
          when :on, 'on', true;    true
          when :off, 'off', false; false
          else
            raise ArgumentError, "backtrace must be true or false"
          end
    end

    # Returns the version string for the library.
    #
    def version
      VERSION
    end

    # Returns the library path for the module. If any arguments are given,
    # they will be joined to the end of the libray path using
    # <tt>File.join</tt>.
    #
    def libpath( *args )
      args.empty? ? LIBPATH : ::File.join(LIBPATH, args.flatten)
    end

    # Returns the lpath for the module. If any arguments are given,
    # they will be joined to the end of the path using
    # <tt>File.join</tt>.
    #
    def path( *args )
      args.empty? ? PATH : ::File.join(PATH, args.flatten)
    end

    # call-seq:
    #    show_configuration( io = STDOUT, logger = 'root' )
    #
    # This method is used to show the configuration of the logging
    # framework. The information is written to the given _io_ stream
    # (defaulting to stdout). Normally the configuration is dumped starting
    # with the root logger, but any logger name can be given.
    #
    # Each line contains information for a single logger and it's appenders.
    # A child logger is indented two spaces from it's parent logger. Each
    # line contains the logger name, level, additivity, and trace settings.
    # Here is a brief example:
    #
    #    root  ...........................   *info      -T
    #      LoggerA  ......................    info  +A  -T
    #        LoggerA::LoggerB  ...........    info  +A  -T
    #        LoggerA::LoggerC  ...........  *debug  +A  -T
    #      LoggerD  ......................   *warn  -A  +T
    #
    # The lines can be deciphered as follows:
    #
    #    1) name       - the name of the logger
    #
    #    2) level      - the logger level; if it is preceeded by an
    #                    asterisk then the level was explicitly set for that
    #                    logger (as opposed to being inherited from the parent
    #                    logger)
    #
    #    3) additivity - a "+A" shows the logger is additive, and log events
    #                    will be passed up to the parent logger; "-A" shows
    #                    that the logger will *not* pass log events up to the
    #                    parent logger
    #
    #    4) trace      - a "+T" shows that the logger will include trace
    #                    information in generated log events (this includes
    #                    filename and line number of the log message; "-T"
    #                    shows that the logger does not include trace
    #                    information in the log events)
    #
    # If a logger has appenders then they are listed, on per line,
    # immediately below the logger. Appender lines are pre-pended with a
    # single dash:
    #
    #    root  ...........................   *info      -T
    #    - <Appenders::Stdout:0x8b02a4 name="stdout">
    #      LoggerA  ......................    info  +A  -T
    #        LoggerA::LoggerB  ...........    info  +A  -T
    #        LoggerA::LoggerC  ...........  *debug  +A  -T
    #      LoggerD  ......................   *warn  -A  +T
    #      - <Appenders::Stderr:0x8b04ca name="stderr">
    #
    # We can see in this configuration dump that all the loggers will append
    # to stdout via the Stdout appender configured in the root logger. All
    # the loggers are additive, and so their generated log events will be
    # passed up to the root logger.
    #
    # The exception in this configuration is LoggerD. Its additivity is set
    # to false. It uses its own appender to send messages to stderr.
    #
    def show_configuration( io = STDOUT, logger = 'root', indent = 0 )
      logger = ::Logging::Logger[logger] unless ::Logging::Logger === logger

      logger._dump_configuration(io, indent)

      indent += 2
      children = ::Logging::Repository.instance.children(logger.name)
      children.sort {|a,b| a.name <=> b.name}.each do |child|
        ::Logging.show_configuration(io, child, indent)
      end

      nil
    end

    # :stopdoc:
    # Convert the given level into a connaconical form - a lowercase string.
    def levelify( level )
      case level
      when String; level.downcase
      when Symbol; level.to_s.downcase
      else raise ArgumentError, "levels must be a String or Symbol" end
    end

    # Convert the given level into a level number.
    def level_num( level )
      l = levelify level
      case l
      when 'all'; 0
      when 'off'; LEVELS.length
      else begin; Integer(l); rescue ArgumentError; LEVELS[l] end end
    end

    # Internal logging method for use by the framework.
    def log_internal( level = 1, &block )
      ::Logging::Logger[::Logging].__send__(levelify(LNAMES[level]), &block)
    end
    # :startdoc:
  end
end  # module Logging


require Logging.libpath(%w[logging utils])
require Logging.libpath(%w[logging appender])
require Logging.libpath(%w[logging layout])
require Logging.libpath(%w[logging log_event])
require Logging.libpath(%w[logging logger])
require Logging.libpath(%w[logging repository])
require Logging.libpath(%w[logging root_logger])
require Logging.libpath(%w[logging stats])
require Logging.libpath(%w[logging appenders])
require Logging.libpath(%w[logging layouts])

require Logging.libpath(%w[logging config configurator])
require Logging.libpath(%w[logging config yaml_configurator])


# This exit handler will close all the appenders that exist in the system.
# This is needed for closing IO streams and connections to the syslog server
# or e-mail servers, etc.
#
at_exit {
  Logging.log_internal {'at_exit hook called - closing all appenders'}
  Logging::Appenders.each {|appender| appender.close}
}

end  # unless defined?

# EOF