require 'net/http'
require 'net/https'
require 'uri'


require 'custodian/protocoltest/tcp.rb'
require 'custodian/protocoltest/dns.rb'
require 'custodian/protocoltest/ftp.rb'
require 'custodian/protocoltest/http.rb'
require 'custodian/protocoltest/jabber.rb'
require 'custodian/protocoltest/ldap.rb'
require 'custodian/protocoltest/ping.rb'
require 'custodian/protocoltest/rsync.rb'
require 'custodian/protocoltest/ssh.rb'
require 'custodian/protocoltest/smtp.rb'
require 'custodian/testfactory'






#
# This is a simple class which will parse a sentinel configuration file.
#
# Unlike Sentinel it is not built using a real parser, instead it peels off lines
# via a small number of very simple regular expressions - this should be flaky,
# but in practice it manages to successfully parse each of the configuration
# files that we currently maintain @ Bytemark.
#
# If there are any lines which are not recognized the class will raise an exception.
#
# Steve
# --
#
class MonitorConfig

  #
  # A hash of macros we found.
  #
  attr_reader :MACROS

  #
  # The filename that we're going to parse.
  #
  attr_reader :filename

  #
  # Timeout period, in seconds, that we encode into test objects.
  #
  attr_reader :timeout

  #
  # An array of test-objects, which are subclasses of our test-factory.
  #
  attr_reader :jobs



  #
  # Constructor
  #
  def initialize( filename )


    @MACROS  = Hash.new()
    @jobs    = Array.new()
    @file    = filename
    @timeout = 60

    raise ArgumentError, "Missing configuration file!" if ( @file.nil? )
    raise ArgumentError, "File not found: #{@file}" unless ( File.exists?( @file) )
  end




  #
  # Retrieve a HTTP page from the web - this is used for macro-expansion
  #
  # NOTE:  This came from sentinel.
  #
  def getURL (uri_str)
    begin
      uri_str = 'http://' + uri_str unless uri_str.match(/^http/)
      url = URI.parse(uri_str)
      http = Net::HTTP.new(url.host, url.port)
      http.open_timeout = @timeout
      http.read_timeout = @timeout

      if (url.scheme == "https")
        http.use_ssl = true
        http.verify_mode = OpenSSL::SSL::VERIFY_NONE
      end

      response = nil

      if nil == url.query
        response = http.start { http.get(url.path) }
      else
        response = http.start { http.get("#{url.path}?#{url.query}") }
      end


      if ( response.code.to_i != 200 )
        puts "Status code of #{uri_str} was #{response.code}"
        puts "ABORTING"
        exit( 0 )
      end

      case response
      when Net::HTTPRedirection
      then
        newURL = response['location'].match(/^http/)?
        response['Location']:uri_str+response['Location']
        return( getURL(newURL) )
      else
        return response.body
      end

    rescue Errno::EHOSTUNREACH => ex
      raise ex, "no route to host"
    rescue Timeout::Error => ex
      raise ex, "timeout"
    rescue Errno::ECONNREFUSED => ex
      raise ex, "connection refused"
    end
  end



  #
  #  Define a macro, from the configuration file.
  #
  def define_macro( line )
    name = nil
    val  = Array.new

    #
    #  Get the name of the macro.
    #
    name = $1.dup if ( line =~ /^([0-9A-Z_]+)\s+/ )


    #
    #  Get the value
    #
    if ( line =~ /fetched\s+from\s+(.*)[\r\n\.]*$/ )

      #
      #  HTTP-fetch
      #
      uri = $1.dup.chomp(".")

      text = getURL(uri)
      text.split( /[\r\n]/ ).each do |line|
        val.push( line ) if ( line.length() > 0)
      end

    elsif ( line =~ /\s(is|are)\s+(.*)\.+$/ )

      #
      #  Literal list of hosts
      #
      hosts = $2.dup

      #
      #  If there is " and " then tokenize
      #
      if ( hosts =~ /\s+and\s+/ )
        tmp = hosts.split( /\s+and\s+/ )
        tmp.each do |entry|
          val.push( entry )
        end
      else
        #
        # Otherwise a single host
        #
        val.push( hosts )
      end
    end

    if ( is_macro?( name ) )
      raise ArgumentError, "The macro #{name} is already defined"
    end

    @MACROS[name] = val

    true
  end




  #
  #  Return a hash of our current macro-definitions.
  #
  #  This is used only by the test-suite.
  #
  def macros
    @MACROS
  end




  #
  # Is the given string of text a macro?
  #
  def is_macro?( name )
    !(@MACROS[name]).nil?
  end



  #
  # Return an array of hosts if the given string was a macro identifier.
  #
  def get_macro_targets( name )
    @MACROS[name]
  end



  #
  #  Return multiple copies of a line for each macro-target
  #
  def expand_macro( input )

    r = Array.new()

    if ( input =~ /^(\S+)\s+(.*)$/ )
      macro=$1.dup
      rest=$2.dup
    end


    if ( is_macro?( macro ) )
      get_macro_targets(macro).each do |host|
        r.push( "#{host} #{rest}" )
      end
    else
      r.push( input )
    end

    r
  end


  #
  # Parse a single line from the configuration file.
  #
  def parse_line( line )

    line.chomp! if ( !line.nil? )

    #
    # A blank line, or a comment may be skipped.
    #
    return nil if ( ( line.nil? ) || ( line =~ /^#/ ) || ( line.length < 1 ) )

    #
    # The specification of mauve-server to which we should raise our alerts to.
    #
    return nil if ( line =~ /Mauve\s+server(.*)source/ )


    #
    #  Look for macro definitions, inline
    #
    if ( line =~ /^([0-9A-Z]_+)\s+are\s+fetched\s+from\s+([^\s]+)\.?/ )
      define_macro( line )

    elsif ( line =~ /^([0-9A-Z_]+)\s+(is|are)\s+/ )
      define_macro( line )

    elsif ( line =~ /^(\S+)\s+must\s+ping(.*)/ )
      #
      #  Ping is a special case because the configuration file entry
      # would read:
      #
      #  $FOO must ping otherwise ...
      #
      #  All other tests are of the form:
      #
      #  $FOO must run XXX ... otherwise ...
      #
      #  If we clevery rewrite the line into:
      #
      #  ... must run ping ...
      #
      #  We can avoid duplicating the macro-expansion, etc.
      #
      pre  = $1.dup
      post = $2.dup
      new_line = "#{pre} must run ping #{post}"
      return( parse_line( new_line ) )

    elsif ( line =~ /^\S+\s+must\s+run\s+([^\s]+)(\s+|\.|$)/i )

      #
      # Expand the macro if we should
      #
      tests = expand_macro( line )

      #
      # The array of objects we will return to the caller.
      #
      ret = Array.new()

      #
      # For each host in our possibly-macro-expanded list:
      #
      tests.each do |macro_expanded|

        job = nil

        begin
          job = Custodian::TestFactory.create( macro_expanded )
          ret.push( job )
        rescue => ex
          puts "ERROR: #{ex}"
          return nil
        end
      end

      ret
    else
      raise ArgumentError, "Unknown line: '#{line}'"
    end
  end




  #
  # Parse the configuration file which was named in our constructor.
  #
  # This updates our @jobs array with the tests - and optionally
  # invokes our callback.
  #
  def parse_file( &callback )

    #
    #  Parse the configuration file on the command line
    #
    File.open( @file, "r").each_line do |line|

      ret = parse_line( line)

      #
      #  The return value from the parse_line method
      # is either:
      #
      #  Array -> An array of test-objects.
      #
      #  nil   -> The line was a macro.
      #         or
      #           The line was a comment.
      #
      #
      if ( ret.kind_of?( Array ) )
        ret.each do |probe|
          @jobs.push( probe )
        end
      end

      #
      # If there was an optional callback then invoke it
      # with the newly added job/jobs.
      #
      if ( block_given? )
        if ( ret.kind_of?( Array ) )
          ret.each do |probe|
            yield probe.to_s
          end
        end
      end
    end
  end


end