#!/usr/bin/env ruby

require 'optparse'

options = Hash.new(false)
option_parser = OptionParser.new do |opts|
    opts.banner = "Usage: bf.rb [options] <bf_file_or_string>"

    opts.on '-t', '--[no-]timing', 'Track compilation and execution time' do |v|
        options[:timing] = v
    end
    opts.on '-e', '--echo', 'Echo input file' do |v|
        options[:echo] = v
    end
    opts.on '-c', '--compiled', 'Echo generated Ruby code' do |v|
        options[:compiled] = v
    end
    opts.on '-o', '--optimize', 'Use experimental optimizations' do |v|
        options[:optimize] = v
        puts "Warning: The option --optimize is not yet supported\n"
    end
    opts.on '-d', '--debug', 'Enable debug mode' do |v|
        options[:debug] = v
    end
    opts.on '-i', '--input=INPUT', 'Use given input string instead of STDIN' do |v|
        options[:input] = v.each_byte
    end
    opts.on '--count', 'Count executed instructions' do |v|
        options[:count] = v
    end

    if ARGV.empty?
        abort(opts.help)
    end
end.parse!

begin

ic = 0 if options[:count]

t0 = Time.now if options[:timing]
input = File.exists?(ARGV[0]) ? File.open(ARGV[0], 'r').read : ARGV[0]
puts input if options[:echo]
code = 'm=Hash.new(p=0);'+input.gsub(
        /./,
        '>' => 'p+=1;' + (options[:count] ? 'ic+=1;' : ''),
        '<' => 'p-=1;' + (options[:count] ? 'ic+=1;' : ''),
        '+' => 'm[p]+=1;' + (options[:count] ? 'ic+=1;' : ''),
        '-' => 'm[p]-=1;' + (options[:count] ? 'ic+=1;' : ''),
        '[' => '(' + (options[:count] ? 'ic+=1;' : ''),
        ']' => ')while((m[p]&=255)!=0);' + (options[:count] ? 'ic+=1;' : ''),
        '.' => 'putc(m[p]&=255);' + (options[:count] ? 'ic+=1;' : ''),
        ',' => options[:input] ? 'begin m[p]=options[:input].next rescue m[p]=0 end;' : 'm[p]=STDIN.getbyte.ord if !STDIN.eof;' + (options[:count] ? 'ic+=1;' : ''),
        '#' => options[:debug] ? 'print "m="+0.upto(m.keys.max).map{|i|m[i]%256}.to_s+"; p=#{p};\n";' : '',
)
puts code if options[:compiled]
t1 = Time.now if options[:timing]
print "\n"
print "output:\n"
eval code
print "\n"
t2 = Time.now if options[:timing]
if options[:timing]
    puts "Time used:"
    puts "Compilation: " + ((t1-t0)*1000).to_s + "ms"
    puts "Execution: " + ((t2-t1)*1000).to_s + "ms"
end

puts "#{ic} instructions" if options[:count]

rescue SyntaxError => e
    abort("Syntax Error - Are there unbalanced brackets?")
rescue Interrupt => e
    abort("Interrupted")
end