#!/usr/bin/env ruby
### wxbaddata --- Utility checking for bad data in Open3600 files.
## Copyright 2006 by Dave Pearson <davep@davep.org>
## $Revision: 1.2 $
##
## wxbaddata is free software distributed under the terms of the GNU General
## Public Licence, version 2. For details see the file COPYING.

# We're going to use long options.
require "getoptlong"

# Set the default parameters.
$params = {
  :field      => 18,
  :help       => false,
  :licence    => false,
  :maxdiff    => 5,
}

# Print the help screen.
def printHelp
  print "wxbaddata v#{/(\d+\.\d+)/.match( '$Revision: 1.2 $' )[ 1 ]}
Copyright 2006 by Dave Pearson <davep@davep.org>
http://www.davep.org/

Supported command line options:

  -f --field <field>       Specify which field to average.
                           (default is 18 -- the pressure field).
  -m --maxdiff <diff>      Specify the maximum difference allowed.
                           (default is 5).
  -h --help                Display this help.
"
end

# Print the licence.
def printLicence
  print "wxbaddata - Utility checking for bad data in Open3600 files.
Copyright (C) 2006 Dave Pearson <davep@davep.org>

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option)
any later version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 675 Mass
Ave, Cambridge, MA 02139, USA.

"
end

# Get the arguments from the command line.
begin
  GetoptLong.new().set_options(
                               [ "--field",      "-f", GetoptLong::REQUIRED_ARGUMENT ],
                               [ "--maxdiff",    "-m", GetoptLong::REQUIRED_ARGUMENT ],
                               [ "--help",       "-h", GetoptLong::NO_ARGUMENT       ]
                               ).each {|name, value| $params[ name.gsub( /^--/, "" ).intern ] = value }
rescue GetoptLong::Error
  printHelp()
  exit 1
end

# The need for help overrides everything else
if $params[ :help ]
  printHelp()
elsif $params[ :licence ]
  # As does the need for the legal mumbojumbo
  printLicence()
else
  
  # Ensure the numeric parameters are numeric.
  $params[ :maxdiff ] = $params[ :maxdiff ].to_f
  $params[ :field ]   = $params[ :field ].to_i
  
  # For each file given on the command line (or from stdin if no files were
  # given)...
  ( ARGV.length == 0 ? ( "-" ) : ARGV ).each do |file|

    # Init the previous value.
    prev_value = -1
    
    # Process the file. Note that "-" means process stdin.
    ( file == "-" ? $stdin : File.open( file ) ).each  do |line|

      # Split the line into fields.
      fields = line.chomp.split( " " )

      # Does the field we're after exist?
      if fields.length >= $params[ :field ]

        # Get the value.
        value = fields[ $params[ :field ] - 1 ].to_f
        
        # Not got previous value?
        if prev_value == -1 then prev_value = value end
        
        # Does it differ too much?
        if ( value - prev_value ).abs() > $params[ :maxdiff ]
          puts line
        else
          prev_value = value
        end
        
      end

    end

  end

end

# All's well that ends well.
exit 0

### wxbaddata ends here