# (c) 2012, Michael DeHaan <michael.dehaan@gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
#

################################################

import paramiko
import traceback
import os
import time
import random
from ansible import errors

################################################

class Connection(object):
    ''' Handles abstract connections to remote hosts '''

    def __init__(self, runner, transport):
        self.runner = runner
        self.transport = transport

    def connect(self, host):
        conn = None
        if self.transport == 'paramiko':
            conn = ParamikoConnection(self.runner, host)
        if conn is None:
            raise Exception("unsupported connection type")
        return conn.connect()

################################################
# want to implement another connection type?
# follow duck-typing of ParamikoConnection
# you may wish to read config files in __init__
# if you have any.  Paramiko does not need any.

class ParamikoConnection(object):
    ''' SSH based connections with Paramiko '''

    def __init__(self, runner, host):
        self.ssh = None
        self.runner = runner
        self.host = host

    def _get_conn(self):
        ssh = paramiko.SSHClient()
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())

        try:
            ssh.connect(
                self.host, username=self.runner.remote_user,
                allow_agent=True, look_for_keys=True, password=self.runner.remote_pass,
                timeout=self.runner.timeout, port=self.runner.remote_port
            )
        except Exception, e:
            if str(e).find("PID check failed") != -1:
                raise errors.AnsibleError("paramiko version issue, please upgrade paramiko on the machine running ansible")
            else:
                raise errors.AnsibleConnectionFailed(str(e))

        return ssh


    def connect(self):
        ''' connect to the remote host '''

        self.ssh = self._get_conn()
        return self

    def exec_command(self, cmd, tmp_path, sudoable=False):
        ''' run a command on the remote host '''
        if not self.runner.sudo or not sudoable: 
            stdin, stdout, stderr = self.ssh.exec_command(cmd)
            return (stdin, stdout, stderr)
        else:
            # percalculated tmp_path is ONLY required for sudo usage
            if tmp_path is None:
                raise Exception("expecting tmp_path")
            r = random.randint(0,99999)
            
            # invoke command using a new connection over sudo
            result_file = os.path.join(tmp_path, "sudo_result.%s" % r)
            self.ssh.close()
            ssh_sudo = self._get_conn()
            sudo_chan = ssh_sudo.invoke_shell()
            sudo_chan.send("sudo -s\n")

            # to avoid ssh expect logic, redirect output to file and move the
            # file when we are done with it...
            sudo_chan.send("(%s >%s_pre 2>/dev/null ; mv %s_pre %s) &\n" % (cmd, result_file, result_file, result_file))
            time.sleep(1)
            sudo_chan.close()
            self.ssh = self._get_conn()

            # now load the results of the JSON execution...
            # FIXME: really need some timeout logic here
            sftp = self.ssh.open_sftp()
            while True:
                # print "waiting on %s" % result_file
                time.sleep(1)
                try:
                    sftp.stat(result_file)
                    break
                except IOError:
                    pass
            sftp.close()
            # TODO: see if there's a SFTP way to just get the file contents w/o saving
            # to disk vs this hack...
            stdin, stdout, stderr = self.ssh.exec_command("cat %s" % result_file)
            return (stdin, stdout, stderr)

    def put_file(self, in_path, out_path):
        ''' transfer a file from local to remote '''
        if not os.path.exists(in_path):
            raise errors.AnsibleFileNotFound("file or module does not exist: %s" % in_path)
        sftp = self.ssh.open_sftp()
        try:
            sftp.put(in_path, out_path)
        except IOError:
            traceback.print_exc()
            raise errors.AnsibleError("failed to transfer file to %s" % out_path)
        sftp.close()

    def close(self):
        ''' terminate the connection '''

        self.ssh.close()

############################################
# add other connection types here