#!/usr/bin/env ruby

##################################################
#= gpedit
#== SYNOPSIS
SYNOPSIS = <<-"SYNOP"
     Create or overwrite the attributes of a variable specified by
     a gtool4-type URL (Only netCDF files are supported).
SYNOP

#== HISTORY
#
#   2007/07/18  Y. Morikawa  'gpattr' is renamed to 'gpedit'
#   2006/09/29  Y. Morikawa  A value looks like numeric is treated as a numerical value
#   2005/01/09  Y. Morikawa
#   2005/01/07  D. Tsukahara
#
#==USAGE
URLFMT = "path@[varname:var_attr=...][varname|+global_attr]"
USAGE = "
        % #{File.basename(__FILE__)} [options] url

     where the format of the url is

         #{URLFMT}
"
#==EXAMPLES
EXAMPLES = "
    * Add
        % #{File.basename(__FILE__)} data.nc@temp:units=W/m
        % #{File.basename(__FILE__)} -a data.nc@temp:missing_value=-2.0e20
        % #{File.basename(__FILE__)} --add data.nc@temp+title=\"surface temperature\"

    * Delete
        % #{File.basename(__FILE__)} -d data.nc@lon:topology
        % #{File.basename(__FILE__)} --delete data.nc@lon+Conventions
"
#
##################################################
require "optparse"
require "numru/netcdf"
include NumRu

opt = OptionParser.new
OPTS = {}
ARGV.options{|opt|

  opt.summary_width = 23
  opt.summary_indent = ' '*6

  opt.on( '-a', '--add',
                             "Add attribute (default)."
         ){|v| OPTS[:add] = v}

  opt.on( '-d', '--delete',
                             "Delete attribute."
         ){|v| OPTS[:delete] = v}

  opt.on_tail('-h', '-H', '--help', 
                             "Show this help message.\n"
              ){|v| OPTS[:help] = v}

  opt.parse!
}

## help
def help(opt)
  print <<-"EOF"

#{File.basename(__FILE__)}: 
#{SYNOPSIS}
  USAGE: #{USAGE}
  OPTION: \n#{opt.to_a[1..-1].join("")}
  EXAMPLES:
    #{EXAMPLES}
  EOF
end
private :help


#####################################################

def to_appropriate_type(str)
  if str =~ /\.|e/i
    val = str.to_f
  else
    val = str.to_i
  end
  if val.to_i == 0
    unless str =~ /^0+((\.0+)?(e\d+)?)?$/i
      val = str
    end
  end
  return val
end

def url_error(msg)
  $stderr.print <<-"EOF"

  Error: invalid URL: #{msg}.
         Current URL format is 
  
           #{URLFMT}

EOF
  exit 1
end

def parse_gturl_for_attr(gturl)
  if /(.*)@(.*)/ =~ gturl
    file = $1
    var = $2
  else
    url_error "'@' between path & variable is not found"
  end
  if /(.*):(.*)/ =~ var
    var_name = var.split(":")[0]
    att =      var.split(":")[1]
    if /(.*)\=(.*)/ =~ att
      var_att =    att.split("=")[0]
      global_att = nil
      att_val  =   to_appropriate_type(var.split("=")[1])
    elsif OPTS[:delete]
      var_att =    att
      global_att = nil
      att_val =    nil
    else
      url_error "'=' between atribute name & value is not found"
    end
  elsif /(.*)\+(.*)/ =~ var
    var_name = var.split("+")[0]
    att =      var.split("+")[1]
    if /(.*)\=(.*)/ =~ att
      var_att =    nil
      global_att = att.split("=")[0]
      att_val =    to_appropriate_type(att.split("=")[1])
    elsif OPTS[:delete]
      var_att =    nil
      global_att = att
      att_val =    nil
    else
      url_error "'=' between atribute name & value is not found"
    end
  else
    url_error "':' or '+' between atribute name & value is not found"
  end
  if !(att_val) && !OPTS[:delete]
    url_error "attribute value is not found. you must point out unless delete attribute"
  end
  [file, var_name, var_att, global_att, att_val]
end
#####################################################

if OPTS[:help] || ARGV.length != 1 then
  help(opt)
  exit
end

gturl = ARGV[0]
file, var, var_att, global_att, att_val = parse_gturl_for_attr(gturl)

begin
  nc = NetCDF.new(file, "r")
  nc.close
rescue NetcdfSyserr
  $stderr.print "  Error: " + file + ": " + $!.to_s + "\n"
  exit 1
rescue NetcdfNotnc
  $stderr.print "  Error: " + file + ": " + $!.to_s + "\n"
  $stderr.print "  \"#{File.basename(__FILE__)}\" supports only netCDF files.\n"
  exit 1
end

nc = NetCDF.new(file, "a+")
if nc.var(var)
  var = nc.var(var)
elsif nc.dim(var)
  var = nc.dim(var)
end
nc.redef
if var.class.to_s == "String"
  $stderr.print "  Error: #{file}@#{var}: variable is not found.\n"
  exit 1
end
if OPTS[:delete]
  begin
    nc.att(global_att).delete       if global_att
    var.att(var_att).delete         if var_att
  rescue NoMethodError
    print "  Warning: " + gturl + " is not exist.\n"
  end
else
  nc.put_att(global_att, att_val) if global_att
  var.put_att(var_att, att_val)   if var_att
end
nc.close