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')
		for i in range(3, MAXFD):
			try:
				os.close(i)
			except:
				pass
		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()