#
# sort.rb
# Sorts an input text file and writes output to a file or stdout.
#
# Author:: David Muir <david.muir@rockstarnorth.com>
# Date:: 11 March 2008
#
# == Example Usage
#
# From a command line:
#
#    sort.rb -a file1.txt file2.txt
#

#-----------------------------------------------------------------------------
# Uses
#-----------------------------------------------------------------------------

require 'pipeline/os/getopt'
require 'pipeline/os/path'
include Pipeline

#-----------------------------------------------------------------------------
# Constants
#-----------------------------------------------------------------------------

SORT_VERSION = '0.9.0'
OPTIONS = [
		[ '--version', '-v', Getopt::BOOLEAN, 'show version information.' ],
		[ '--help', '-h', Getopt::BOOLEAN, 'show this help information.' ],
		[ '--output', '-o', Getopt::REQUIRED, 'write sorted output to file.' ],
		[ '--ascending', '-a', Getopt::BOOLEAN, 'sort in ascending order.' ],
		[ '--descending', '-d', Getopt::BOOLEAN, 'sort in descending order.' ]		
	]

#-----------------------------------------------------------------------------
# Functions
#-----------------------------------------------------------------------------

def print_usage
	usage_message = OS::Getopt::usage( OPTIONS, 
		{ 'files' => 'List of files to sort.' } )
	puts usage_message
end

def print_version
	puts "\nsort.rb Version #{SORT_VERSION}"
end

def process_sort( opts, files )
	
	# Read all files into an unsorted array ...
	unsorted_input = Array.new
	files.each do |filename|
		
		File.open( filename ) do |fp|
			begin
				unsorted_input += fp.readlines
			ensure
				fp.close
			end
		end	
	end
	
	sorted_output = nil
	if ( opts['descending'] or opts['d'] ) then
		sorted_output = unsorted_input.sort do |x,y| y <=> x; end
	else
		sorted_output = unsorted_input.sort
	end
	
	write_sorted_output( sorted_output, opts['output'] ) if opts['output']
	sorted_output.each do |item|
		puts item
	end unless opts['output']
end

def write_sorted_output( output, filename )
	
	File.open( filename, 'w' ) do |out|
	
		output.each do |value|
			out.write( "#{value}\n" )
		end
	end
end

#-----------------------------------------------------------------------------
# Entry
#-----------------------------------------------------------------------------

begin
	opts, targs = OS::Getopt.getopts( OPTIONS )
	
	if ( opts['version'] or opts['help'] )
	
		print_version() if opts['version']
		print_usage() if opts['help']
	elsif targs.size > 0
	
		process_sort( opts, targs )
	else
	
		print_usage() if opts['help']
	end
	
rescue OS::Getopt::Error => ex
	puts "Error parsing command line arguments: #{ex.message}"
	print_usage()
	
rescue Exception => ex
	puts "Unhandled exception: #{ex.message}"
	puts "\tStacktrace: #{ex.backtrace.join('\n\r')}"	
end

# End of sort.rb