import os
import subprocess

def public_keys( keyhome ):
	cmd = '/usr/bin/gpg --homedir %s --list-keys --with-colons' % keyhome
	p = subprocess.Popen( cmd.split(' '), stdin=None, stdout=subprocess.PIPE, stderr=subprocess.PIPE )
	p.wait()
	keys = list()
	for line in p.stdout.readlines():
		if line[0:3] == 'uid' or line[0:3] == 'pub':
			if ('<' not in line or '>' not in line):
				continue
			key = line.split('<')[1].split('>')[0]
			if keys.count(key) == 0:
				keys.append(key)
	return keys

class GPGEncryptor:
	def __init__(self, keyhome, recipients = None, charset = None):
		self._keyhome = keyhome
		self._message = ''
		self._recipients = list()
		self._charset = charset		
		if recipients != None:
			self._recipients.extend(recipients)

	def update(self, message):
		self._message += message

	def encrypt(self):
		p = subprocess.Popen( self._command(), stdin=subprocess.PIPE, stdout=subprocess.PIPE,stderr=subprocess.PIPE )
		encdata = p.communicate(input=self._message)[0]
		return encdata

	def _command(self):
		cmd = ["/usr/bin/gpg", "--trust-model", "always", "--homedir", self._keyhome, "--batch", "--yes", "--pgp7", "--no-secmem-warning", "-a", "-e"]
		
		# add recipients
		for recipient in self._recipients:
			cmd.append("-r")
			cmd.append(recipient)
		
		# add on the charset, if set
		if self._charset:
			cmd.append("--comment")
			cmd.append('Charset: ' + self._charset)
		
		return cmd