#!/usr/bin/python2.4

import os, sys
import cryptobox.web.sites
from cryptobox.core.exceptions import *
from optparse import OptionParser

try:
	import cherrypy
except: 
	print "Could not import the cherrypy module! Try 'apt-get install python-cherrypy'."
	sys.exit(1)


# TODO: change this for the release version
SERVER_ENVIRONMENT = "development"

class CryptoBoxWebserver:
	'''this class starts the cherryp webserver and serves the single sites'''

	def __init__(self, opts):
		## check conffile
		if not os.access(opts.conffile, os.R_OK) or not os.path.isfile(opts.conffile):
			sys.stderr.write("Error: could not read configuration file (%s)\n" % opts.conffile)
			sys.exit(1)
		## store the absolute path as we will chdir later (for daemons)
		self.conffile = os.path.realpath(opts.conffile)
		## initialize site class
		try:
			cherrypy.root = cryptobox.web.sites.WebInterfaceSites(self.conffile)
		except (CBConfigError,CBEnvironmentError), errMsg:
			sys.stderr.write("Error: the CryptoBox is misconfigured - please fix it!\n")
			sys.stderr.write("%s\n" % str(errMsg))
			sys.exit(1)
		#expose static content:
		#I currently have no idea how to cleanly extract the stylesheet path from 
		#the config object without an extra cryptobox.core.main.CryptoBoxProps instance.
		#perhaps put config handling into a separate class in CryptoBox.py?
		#
		# the following manual mapping is necessary, as we may not use relative
		# paths in the config file
		cherrypy.config.update({
			"global": {
				"server.socket_port" : int(opts.port),
				"server.socket_host" : opts.host,
				"server.log_to_screen" : not opts.background and opts.verbose,
				"server.log_tracebacks" : opts.verbose,
				"server.environment": SERVER_ENVIRONMENT,
				"server.log_file" : opts.logfile },
			"/cryptobox-misc": { 
					"staticFilter.on" : True, 
					"staticFilter.dir": os.path.realpath(opts.datadir)}
			})
		
	def start(self):
		cherrypy.server.start()


def fork_to_background():
	## this is just copy'n'pasted from http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/278731
	## check the original for exhaustive comments
	try:
		pid = os.fork()
	except OSError, errMsg:
		sys.stderr.write("Error: failed to fork cryptobox daemon process!\n")
		sys.stderr.write("%s\n" % errMsg)
		sys.exit(1)
	if pid == 0:	# the first child
		os.setsid()
		try:
			pid = os.fork()
		except OSError, errMsg:
			sys.stderr.write("Error: failed to fork second cryptobox daemon process!\n")
			sys.stderr.write("%s\n" % errMsg)
			sys.exit(1)
		if pid == 0:	# the second child
			## we do not change the directory - otherwise there seems to be a race condition with the python interpreter loading this script file
			#os.chdir(os.path.sep)
			os.umask(0)
		else:
			os._exit(0)
	else:
		os._exit(0)


def close_open_files():
	"""this is only necessary if we want to go into background"""
	import resource		# Resource usage information.
	maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
	if (maxfd == resource.RLIM_INFINITY):
		maxfd = 1024
	for fd in range(0, maxfd):
		try:
			os.close(fd)
		except OSError:		# ERROR, fd wasn't open to begin with (ignored)
			pass
	os.open(os.devnull, os.O_RDWR)		# standard input (0)
	os.dup2(0, 1)			# standard output (1)
	os.dup2(0, 2)			# standard error (2)


def write_pid_file(pid_file):
	try:
		pidf = open(pid_file,"w")
		pidf.write(str(os.getpid()))
		pidf.close()
	except (IOError, OSError), errMsg:
		sys.stderr.write("Warning: failed to write pid file (%s): %s\n" % (pid_file, errMsg))
		## it is just a warning - no need to break


def parseOptions():
	version = "%prog" + cryptobox.core.main.VERSION
	parser = OptionParser(version=version)
	parser.set_defaults(conffile="/etc/cryptobox/webserver.conf",
		pidfile="/var/run/cryptobox/webserver.pid",
		background=False,
		datadir="/usr/share/cryptobox/html",
		logfile="/var/log/cryptobox/webserver.log",
		port="8080",
		host="",
		verbose=True)
	parser.add_option("-c", "--config", dest="conffile",
		help="read configuration from FILE", metavar="FILE")
	parser.add_option("","--pidfile", dest="pidfile",
		help="write process id to FILE", metavar="FILE")
	parser.add_option("-B","", dest="background", action="store_true",
		help="run webserver in background (as daemon)")
	parser.add_option("-q","", dest="verbose", action="store_false",
		help="output only errors")
	parser.add_option("","--datadir", dest="datadir", metavar="DIR",
		help="set data directory to DIR")
	parser.add_option("-p","--port", dest="port", metavar="PORT",
		help="listen on PORT")
	parser.add_option("-l","--logfile", dest="logfile", metavar="FILE",
		help="write webserver log to FILE")
	parser.add_option("","--host", dest="host", metavar="HOST",
		help="attach to HOST")
	(options, args) = parser.parse_args()
	## we do not expect any remaining arguments
	if len(args) != 0:
		parser.error("unknown argument: %s" % str(args[0]))
	if not os.path.isdir(options.datadir) or not os.access(options.datadir,os.X_OK):
		parser.error("could not access the data directory (%s)" % options.datadir)
	try:
		if (int(options.port) < 0) or (int(options.port) > 65535):
			parser.error("invalid port number: %s" % str(options.port))
	except ValueError:
		parser.error("invalid port specified (%s) - it must be a number" % (options.port))
	return options


if __name__ == "__main__":
	## process arguments
	options = parseOptions()
	## initialize the webserver class (before forking to get some error messages)
	cbw = CryptoBoxWebserver(options)
	## run the webserver as a daemon process
	if options.background: fork_to_background()
	## write pid file
	write_pid_file(options.pidfile)
	## close open files to allow background execution
	if options.background: close_open_files()
	## start the webserver
	try:
		cbw.start()
	except CBError, errMsg:
		sys.stderr.write("Failed to start the CryptoBox webserver!\n")
		sys.stderr.write("%s\n" % str(errMsg))
		sys.stderr.write("Check the log file for details.\n")
		sys.exit(1)
	sys.exit(0)