#!/usr/bin/env ruby
# lrep [-z] [-t SECS] [FILES...] - literate read-eval-print

# -*- ruby -*-
require 'pty'
require 'io/console'
require 'optparse'

params = ARGV.getopts("t:z")

zap = params["z"]
$timeout = params["t"] ? params["t"].to_f : 0.04

# TODO keep each session keyed by ps1?

output = input = pid = nil

trap(:SIGCHLD) { input = output = nil }

def readp(output, ps, timeout=$timeout)
  return "[DEAD]"  if output == nil

  o = ps ? output.readpartial(1024) : ""
# p [:READ, o]
  timedout = true
  loop {
    if o.split("\r\n").last =~ ps
      timedout = false
      break
    end
    if IO.select([output],[],[],timeout)
      begin
	x=output.readpartial(1024)
      # p [:READ, x]
	o << x
      rescue Errno::EIO
	# eof
	break
      end
    else
      break
    end
  }

  o = "[TIMEOUT]\r\n" + o  if timedout && ps

  l = o.split("\r\n")

  if ps && l[-1]
    l[-1].gsub!(ps, "")
    l.pop  if l[-1].empty?
  end
  o = l.join("\n")

  o
end

def ind(txt)
  txt.split("\n").map { |l| "\t#{l}\n" }.join
end

ps = nil

while line = gets
  if line =~ /^\t!(.*?)(?:!(.*?))?!(.*)/
    puts line
    begin
      if $1.empty? && $2.empty?
	output = input = pid = nil
        next  if zap
	print ind(`#{$3}`)
      else
	if $1.empty?
	  ps = nil
	  psl = /^\t.*#{Regexp.quote $2}(.*)/
	else
	  ps = /.*?#{Regexp.union [$1,$2].compact}$/
	  psl = /^\t.*?#{Regexp.union [$1,$2].compact}(.*)/
	end
        next  if zap

        cmd = $3
        silent = cmd.gsub!(/>-$/, '')

	output, input, pid = PTY.spawn cmd
	input.echo = false
        # more timeout to launch program
        o = readp(output, ps, $timeout*20)
	print ind(o)  unless silent
      end
    rescue
      print ind("ERROR: #{$!.message}")
    end
  elsif line =~ psl
    puts line
    next  if zap
    if input
      cmd = $1
      silent = cmd.gsub!(/>-$/, '')

#     p [:WRITE, cmd + "\n"]
      input.write cmd + "\n"
      o = readp(output, ps)
      print ind(o)  unless silent
    end
  elsif line =~ /^\t/
    # old output, remove
  else
    puts line
  end
end

if pid
  n = 0
  until Process.waitpid(pid, Process::WNOHANG)
    Process.kill(n > 10 ? "KILL" : "TERM", pid)
    sleep 0.1
    n += 1
  end
end