#! /usr/bin/env python3

from __future__ import print_function

import os, re, string, sys, getopt, signal


def version():
    print ("Generic Colouriser 1.13")
    sys.exit()

def help():
    print("""Generic Colouriser 1.13
grc [options] command [args]
Options:
-e --stderr    redirect stderr. If this option is selected,
               do not automatically redirect stdout
-s --stdout    redirect stdout, even if -e is selected
-c name --config=name    use name as configuration file for grcat
--colour=word  word is one of: on, off, auto
--pty          run command in pseudoterminal (experimental)
""")
    sys.exit()


def catch_signal(signum, frame):
    "catch signal sent to grc and forward it to the original application"
    global pidp
    try:
        os.kill(pidp, signum)
    except OSError: # if the subprocess already died
        pass

try:
    optlist, args = getopt.getopt(sys.argv[1:], "sec:", ["stdout", "stderr", "config=", "colour=", "pty"] )
except:
    help()

if not args:
    help()

stdoutf = 0
stderrf = 0

# configure file for grcat
cfile = ""

colour = sys.stdout.isatty()
use_pty = 0

for i in optlist:
    if i[0] in ["--stderr", "-e"]:
        # redirect stderr
        stderrf = 1
    elif i[0] in ["--stdout", "-s"]:
        # redirect stdout
        stdoutf = 1
    elif i[0] in ["--config", "-c"]:
        cfile = i[1]
    elif i[0] == "--colour":
        if i[1] == "on":
            colour = 1
        elif i[1] == "off":
            colour = 0
        elif i[1] == "auto":
            colour = sys.stdout.isatty()
        else:
            help()
    elif i[0] == '--pty':
        use_pty = 1

stdoutff = 1
stderrff = 0
if stderrf == 1:
    stdoutff = 0
    stderrff = 1
if stdoutf == 1:
    stdoutff = 1

if use_pty:
    import pty

if cfile == "":
    home = os.environ.get('HOME')
    xdg  = os.environ.get('XDG_CONFIG_HOME')
    if not xdg and home:
        xdg = home + '/.config'

    conffilenames = ['/etc/grc.conf', '/usr/local/etc/grc.conf']
    if xdg:
        conffilenames += [xdg + '/grc/grc.conf']
    if home:
        conffilenames += [home + '/.grc/grc.conf']

    for conffile in conffilenames:
        # test if conffile exists, it can be also a pipe
        if os.path.exists(conffile) and not os.path.isdir(conffile):
            f = open(conffile, "r")
            while 1:
                l = f.readline()
                if l == "":
                    break
                if l[0] == "#" or l[0] == '\012':
                    continue
                regexp = l.strip()
                if re.search(regexp, ' '.join(args)):
                    cfile = f.readline().strip()
                    break


signal.signal(signal.SIGINT, catch_signal)


if cfile != "" and colour:
    if stdoutff:
        choo, chio = os.pipe()
    if stderrff:
        choe, chie = os.pipe()
    if use_pty:
        pidp, pty_fd = pty.fork()
    else:
        pidp = os.fork()
    if pidp == 0: # child, command to run
        if stdoutff:
            # connect child (this) stdout to pipe write end
            if not use_pty:
                os.dup2(chio, 1)
                os.close(choo)
                os.close(chio)
        if stderrff:
                os.dup2(chie, 2)
                os.close(choe)
                os.close(chie)
        try:
            os.execvp(args[0], args)
        except OSError as e:
            sys.stderr.write('grc: %s: %s\n' % (args[0], e.strerror))
            sys.exit(1)


    if stdoutff:
        pido = os.fork()
        if pido == 0: # child, grcat
            # connect grcat's stdin to pipe read end, or pty master
            if use_pty:
                os.dup2(pty_fd, 0)
            else:
                os.dup2(choo, 0)
            os.close(choo)
            os.close(chio)
            if stderrff:
                os.close(choe)
                os.close(chie)
            os.execvp("grcat", ["grcat", cfile])

    if stderrff:
        pide = os.fork()
        if pide == 0: # child
            os.dup2(choe, 0)
            os.dup2(2, 1)
            os.close(choe)
            os.close(chie)
            if stdoutff:
                os.close(choo)
                os.close(chio)
            os.execvp("grcat", ["grcat", cfile])
    try:
        status = os.waitpid(pidp, 0)[1]
    except OSError: # interrupted system call
        status = None
        pass # this is probably not correct
#    except KeyboardInterrupt: # catching SIGINT does not work when using pty...
#        status = None
#        os.kill(pidp, signal.SIGINT)
#        pass
    if stderrff:
        os.close(chie)
        os.waitpid(pide, 0)
        os.close(choe)
    if stdoutff:
        os.close(chio)
        os.waitpid(pido, 0)
        os.close(choo)
    sys.exit(status and os.WEXITSTATUS(status))

else:
    pidp = os.fork()
    if pidp == 0:
        try:
            os.execvp(args[0], args)
        except OSError as e:
            sys.stderr.write('grc: %s: %s\n' % (args[0], e.strerror))
            sys.exit(1)
    try:
        status = os.wait()[1]
    except OSError: # interrupted system call
        status = None
        pass # this is probably not correct

sys.exit(status and os.WEXITSTATUS(status))