import os

import sys

import string

from Tkinter import *

from ScrolledText import ScrolledText

from Dialog import Dialog

import signal

BUFSIZE = 512

class ShellWindow(ScrolledText):

    def __init__(self, master=None, shell=None, **cnf):

        if not shell:

            try:

                shell = os.environ['SHELL']

            except KeyError:

                shell = '/bin/sh'

            shell = shell + ' -i'

        args = string.split(shell)

        shell = args[0]

        apply(ScrolledText.__init__, (self, master), cnf)

        self.pos = '1.0'

        self.bind('<Return>', self.inputhandler)

        self.bind('<Control-c>', self.sigint)

        self.bind('<Control-t>', self.sigterm)

        self.bind('<Control-k>', self.sigkill)

        self.bind('<Control-d>', self.sendeof)

        self.pid, self.fromchild, self.tochild = spawn(shell, args)

        self.tk.createfilehandler(self.fromchild, READABLE,

                                  self.outputhandler)

    def outputhandler(self, file, mask):

        data = os.read(file, BUFSIZE)

        if not data:

            self.tk.deletefilehandler(file)

            pid, sts = os.waitpid(self.pid, 0)

            print 'pid', pid, 'status', sts

            self.pid = None

            detail = sts>>8

            cause = sts & 0xff

            if cause == 0:

                msg = "exit status %d" % detail

            else:

                msg = "killed by signal %d" % (cause & 0x7f)

                if cause & 0x80:

                    msg = msg + " -- core dumped"

            Dialog(self.master,

                   text=msg,

                   title="Exit status",

                   bitmap='warning',

                   default=0,

                   strings=('OK',))

            return

        self.insert(END, data)

        self.pos = self.index("end - 1 char")

        self.yview_pickplace(END)

    def inputhandler(self, *args):

        if not self.pid:

            self.no_process()

            return "break"

        self.insert(END, "\n")

        line = self.get(self.pos, "end - 1 char")

        self.pos = self.index(END)

        os.write(self.tochild, line)

        return "break"

    def sendeof(self, *args):

        if not self.pid:

            self.no_process()

            return "break"

        os.close(self.tochild)

        return "break"

    def sendsig(self, sig):

        if not self.pid:

            self.no_process()

            return "break"

        os.kill(self.pid, sig)

        return "break"

    def sigint(self, *args):

        return self.sendsig(signal.SIGINT)

    def sigquit(self, *args):

        return self.sendsig(signal.SIGQUIT)

    def sigterm(self, *args):

        return self.sendsig(signal.SIGTERM)

    def sigkill(self, *args):

        return self.sendsig(signal.SIGKILL)

    def no_process(self):

        Dialog(self.master,

               text="No active process",

               title="No process",

               bitmap='error',

               default=0,

               strings=('OK',))

MAXFD = 100     # Max number of file descriptors (os.getdtablesize()???)

def spawn(prog, args):

    p2cread, p2cwrite = os.pipe()

    c2pread, c2pwrite = os.pipe()

    pid = os.fork()

    if pid == 0:

        # Child

        for i in 0, 1, 2:

            try:

                os.close(i)

            except os.error:

                pass

        if os.dup(p2cread) <> 0:

            sys.stderr.write('popen2: bad read dup\n')

        if os.dup(c2pwrite) <> 1:

            sys.stderr.write('popen2: bad write dup\n')

        if os.dup(c2pwrite) <> 2:

            sys.stderr.write('popen2: bad write dup\n')

        os.closerange(3, MAXFD)

        try:

            os.execvp(prog, args)

        finally:

            sys.stderr.write('execvp failed\n')

            os._exit(1)

    os.close(p2cread)

    os.close(c2pwrite)

    return pid, c2pread, p2cwrite

def test():

    shell = string.join(sys.argv[1:])

    root = Tk()

    root.minsize(1, 1)

    if shell:

        w = ShellWindow(root, shell=shell)

    else:

        w = ShellWindow(root)

    w.pack(expand=1, fill=BOTH)

    w.focus_set()

    w.tk.mainloop()

if __name__ == '__main__':

    test()