#!/usr/bin/python

import sys
import getopt
import os
import commands
import re

class Instance:

  def __init__(self, root):
    self.root = root
    steps = root.replace('/', ' ').split()
    self.package = steps[-1]
    self.symlinks = {}
    self._walk(self.root)
    self.rootdirs = []
    self._checkRootDirCandidate(self.root)
    for s in self.symlinks:
      self._checkRootDirCandidate(self.symlinks[s])
    self.rootdirs = set(self.rootdirs)
    
    
  def _walk(self, dirpath):
    status, output = commands.getstatusoutput('find %s -type l -exec ls -lQ \{\} \;' % dirpath)
    if status != 0:
      print output
      sys.exit(status)
    for source, dest in re.findall('"(.*)" -> "(.*)"', output, re.M):
      self.symlinks[source] = dest
 
  def _checkRootDirCandidate(self, dir):
    i = dir.find(self.package)
    if i == -1:
      print "Package name (%s) not found in directory or file name %s" % (self.package, dir)
      sys.exit(1)
    self.rootdirs.append(dir[:i])
         
  def _targetName(self, sourceName, name):
    i = sourceName.find(self.package)
    if i == -1:
      print "Package name (%s) not found in directory or file name %s" % (self.package, sourceName)
      sys.exit(1)
    return sourceName[:i] + 'adminstance/' + self.package + '/' + name + sourceName[i + len(self.package) :]
    
  def _createSymlinks(self, name):
    for s in self.symlinks:
      i = s.find(self.package)
      linksource = self._targetName(s, name)
      linkdest = self._targetName(self.symlinks[s], name)
      print "Creating a symlink from %s to %s" % (linkdest, linksource)
      status, output = commands.getstatusoutput('rm %s' % linksource)
      status, output = commands.getstatusoutput('ln -s %s %s' % (linkdest, linksource))
      if status != 0:
        print output
        sys.exit(status)
            
  def install(self, name):
    for d in self.rootdirs:
      source = d + self.package
      dest = d + 'adminstance/' + self.package + '/' + name
      print "Copying %s to %s" % (source, dest)
      status, output = commands.getstatusoutput('mkdir -p %s' % dest)
      status, output = commands.getstatusoutput('rsync -a --delete %s/ %s/' % (source, dest))
      print output
      if status != 0:
        sys.exit(status)
    self._createSymlinks(name)

  def show(self):
    for d in self.rootdirs:
      if self.root.find(d) == 0:
        files = os.listdir(d+ 'adminstance/' + self.package)
        print "List of instances for the package %s:" % self.package 
        for f in files:
          print "\t%s" % f
        return

  def update(self, name):
    for d in self.rootdirs:
      if d.find('/usr/') == 0:
        source = d + self.package
        dest = d + 'adminstance/' + self.package + '/' + name
        print "Synchronizing %s to %s" % (source, dest)
        cmd = 'rsync -a --delete %s/ %s/' % (source, dest)
        print cmd
        status, output = commands.getstatusoutput(cmd)
        print output
        if status != 0:
          sys.exit(status)
    self._createSymlinks(name)

  def remove(self, name, purge):
    for d in self.rootdirs:
      if d.find('/usr/') == 0 or purge:
        dest = d + 'adminstance/' + self.package + '/' + name
        print "Deleting %s" % dest
        cmd = 'rm -r %s' % dest
        print cmd
        status, output = commands.getstatusoutput(cmd)
 

def usage():
  print '''

Usages:  

adminstance -h|--help
  print this message

adminstance -l|--list <root directory>
  lists the installed instances for this directory

adminstance -i|--install [-f|--force] <root directory> <instance name>
  installs an instance for a root directory
  
adminstance -u|--update [-f|--force] <root directory> <instance name>
  updates an instance for a root directory
  
adminstance -r|--remove [-f|--force] [-p|--purge] <root directory> <instance name>
  removes an instance for a root directory

Options:

  -i, --install : action = installation 
  -f, --force   : when action = install, update or remove, install
                  without prompting the user for a confirmation
  -h, --help    : prints this message
  -l, --list    : action = list 
  -p, --purge   : when action = remove, remove also files and directories
                  under /var and /etc (by default, these are preserved)
  -r, --remove  : action = remove
  -u, --update  : action = update
   
  
'''

def main(argv):         
  action = "list"
  force = False
  purge = False
  try:
    opts, args = getopt.getopt(argv, "hiurplf", ["help", "install", "update", "remove", "purge", "list", "force"])
  except getopt.GetoptError, err:
    # print help information and exit:
    print str(err) # will print something like "option -a not recognized"
    usage()
    sys.exit(2)
  for o, a in opts:
    if o in ("-l", "--list"):
      action = "list"
    elif o in ("-h", "--help"):
      usage()
      sys.exit()
    elif o in ("-i", "--install"):
      action = "install"
    elif o in ("-u", "--update"):
      action = "update"
    elif o in ("-r", "--remove"):
      action = "remove"
    elif o in ("-p", "--purge"):
      purge = True
    elif o in ("-f", "--force"):
      force = True
    else:
      assert False, "unhandled option"
  
  if len(args) < 1:
    usage()
    sys.exit(2)          

  root = args[0]
  
  if (action != 'list'):   
    if len(args) < 2:
      usage()
      sys.exit(2)          
    name = args[1]
    if not force:
      proceed = raw_input(action + ' an instance of ' + root + ' named ' + name + '? (y|N) ')
      if proceed != 'y' and proceed != 'Y':
        print "Action cancelled by user."
        sys.exit(2)

  instance = Instance(root)
  
  if (action == 'install'):
    instance.install(name)   
  elif action == 'list':
    instance.show()     
  elif action == 'update':
    instance.update(name)     
  elif action == 'remove':
    instance.remove(name, purge)     

if __name__ == '__main__':
  main(sys.argv[1:])