#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2013, Hiroaki Nakamura <hnakamur@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/>.

ANSIBLE_METADATA = {'status': ['preview'],
                    'supported_by': 'committer',
                    'version': '1.0'}

DOCUMENTATION = '''
---
module: hostname
author:
    - "Adrian Likins (@alikins)"
    - "Hideki Saito (@saito-hideki)"
version_added: "1.4"
short_description: Manage hostname
requirements: [ hostname ]
description:
    - Set system's hostname.
    - Currently implemented on Debian, Ubuntu, Fedora, RedHat, openSUSE, Linaro, ScientificLinux, Arch, CentOS, AMI, Alpine Linux.
    - Any distribution that uses systemd as their init system.
    - Note, this module does *NOT* modify /etc/hosts. You need to modify it yourself using other modules like template or replace.
options:
    name:
        required: true
        description:
            - Name of the host
'''

EXAMPLES = '''
- hostname:
    name: web01
'''

import socket
from distutils.version import LooseVersion

# import module snippets
from ansible.module_utils.basic import *
from ansible.module_utils.facts import *
from ansible.module_utils._text import to_bytes, to_native


class UnimplementedStrategy(object):
    def __init__(self, module):
        self.module = module

    def update_current_and_permanent_hostname(self):
        self.unimplemented_error()

    def update_current_hostname(self):
        self.unimplemented_error()

    def update_permanent_hostname(self):
        self.unimplemented_error()

    def get_current_hostname(self):
        self.unimplemented_error()

    def set_current_hostname(self, name):
        self.unimplemented_error()

    def get_permanent_hostname(self):
        self.unimplemented_error()

    def set_permanent_hostname(self, name):
        self.unimplemented_error()

    def unimplemented_error(self):
        platform = get_platform()
        distribution = get_distribution()
        if distribution is not None:
            msg_platform = '%s (%s)' % (platform, distribution)
        else:
            msg_platform = platform
        self.module.fail_json(
            msg='hostname module cannot be used on platform %s' % msg_platform)

class Hostname(object):
    """
    This is a generic Hostname manipulation class that is subclassed
    based on platform.

    A subclass may wish to set different strategy instance to self.strategy.

    All subclasses MUST define platform and distribution (which may be None).
    """

    platform = 'Generic'
    distribution = None
    strategy_class = UnimplementedStrategy

    def __new__(cls, *args, **kwargs):
        return load_platform_subclass(Hostname, args, kwargs)

    def __init__(self, module):
        self.module       = module
        self.name         = module.params['name']
        if self.platform == 'Linux' and Facts(module).is_systemd_managed():
            self.strategy = SystemdStrategy(module)
        else:
            self.strategy = self.strategy_class(module)

    def update_current_and_permanent_hostname(self):
        return self.strategy.update_current_and_permanent_hostname()

    def get_current_hostname(self):
        return self.strategy.get_current_hostname()

    def set_current_hostname(self, name):
        self.strategy.set_current_hostname(name)

    def get_permanent_hostname(self):
        return self.strategy.get_permanent_hostname()

    def set_permanent_hostname(self, name):
        self.strategy.set_permanent_hostname(name)

class GenericStrategy(object):
    """
    This is a generic Hostname manipulation strategy class.

    A subclass may wish to override some or all of these methods.
      - get_current_hostname()
      - get_permanent_hostname()
      - set_current_hostname(name)
      - set_permanent_hostname(name)
    """

    def __init__(self, module):
        self.module = module
        self.hostname_cmd = self.module.get_bin_path('hostname', True)
        self.changed = False

    def update_current_and_permanent_hostname(self):
        self.update_current_hostname()
        self.update_permanent_hostname()
        return self.changed

    def update_current_hostname(self):
        name = self.module.params['name']
        current_name = self.get_current_hostname()
        if current_name != name:
            self.set_current_hostname(name)
            self.changed = True

    def update_permanent_hostname(self):
        name = self.module.params['name']
        permanent_name = self.get_permanent_hostname()
        if permanent_name != name:
            self.set_permanent_hostname(name)
            self.changed = True

    def get_current_hostname(self):
        cmd = [self.hostname_cmd]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))
        return to_native(out).strip()

    def set_current_hostname(self, name):
        cmd = [self.hostname_cmd, name]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))

    def get_permanent_hostname(self):
        return None

    def set_permanent_hostname(self, name):
        pass


# ===========================================

class DebianStrategy(GenericStrategy):
    """
    This is a Debian family Hostname manipulation strategy class - it edits
    the /etc/hostname file.
    """

    HOSTNAME_FILE = '/etc/hostname'

    def get_permanent_hostname(self):
        if not os.path.isfile(self.HOSTNAME_FILE):
            try:
                open(self.HOSTNAME_FILE, "a").write("")
            except IOError:
                err = get_exception()
                self.module.fail_json(msg="failed to write file: %s" %
                    str(err))
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to read hostname: %s" %
                str(err))

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to update hostname: %s" %
                str(err))

# ===========================================

class SLESStrategy(GenericStrategy):
    """
    This is a SLES Hostname strategy class - it edits the
    /etc/HOSTNAME file.
    """
    HOSTNAME_FILE = '/etc/HOSTNAME'

    def get_permanent_hostname(self):
        if not os.path.isfile(self.HOSTNAME_FILE):
            try:
                open(self.HOSTNAME_FILE, "a").write("")
            except IOError:
                err = get_exception()
                self.module.fail_json(msg="failed to write file: %s" %
                    str(err))
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to read hostname: %s" %
                str(err))

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to update hostname: %s" %
                str(err))

# ===========================================

class RedHatStrategy(GenericStrategy):
    """
    This is a Redhat Hostname strategy class - it edits the
    /etc/sysconfig/network file.
    """
    NETWORK_FILE = '/etc/sysconfig/network'

    def get_permanent_hostname(self):
        try:
            f = open(self.NETWORK_FILE, 'rb')
            try:
                for line in f.readlines():
                    if line.startswith('HOSTNAME'):
                        k, v = line.split('=')
                        return v.strip()
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to read hostname: %s" %
                str(err))

    def set_permanent_hostname(self, name):
        try:
            lines = []
            found = False
            f = open(self.NETWORK_FILE, 'rb')
            try:
                for line in f.readlines():
                    if line.startswith('HOSTNAME'):
                        lines.append("HOSTNAME=%s\n" % name)
                        found = True
                    else:
                        lines.append(line)
            finally:
                f.close()
            if not found:
                lines.append("HOSTNAME=%s\n" % name)
            f = open(self.NETWORK_FILE, 'w+')
            try:
                f.writelines(lines)
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to update hostname: %s" %
                str(err))

# ===========================================

class AlpineStrategy(GenericStrategy):
    """
    This is a Alpine Linux Hostname manipulation strategy class - it edits
    the /etc/hostname file then run hostname -F /etc/hostname.
    """

    HOSTNAME_FILE = '/etc/hostname'

    def update_current_and_permanent_hostname(self):
        self.update_permanent_hostname()
        self.update_current_hostname()
        return self.changed

    def get_permanent_hostname(self):
        if not os.path.isfile(self.HOSTNAME_FILE):
            try:
                open(self.HOSTNAME_FILE, "a").write("")
            except IOError:
                err = get_exception()
                self.module.fail_json(msg="failed to write file: %s" %
                    str(err))
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to read hostname: %s" %
                str(err))

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to update hostname: %s" %
                str(err))

    def set_current_hostname(self, name):
        cmd = [self.hostname_cmd, '-F', self.HOSTNAME_FILE]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))


# ===========================================

class SystemdStrategy(GenericStrategy):
    """
    This is a Systemd hostname manipulation strategy class - it uses
    the hostnamectl command.
    """

    def get_current_hostname(self):
        cmd = ['hostname']
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))
        return to_native(out).strip()

    def set_current_hostname(self, name):
        if len(name) > 64:
            self.module.fail_json(msg="name cannot be longer than 64 characters on systemd servers, try a shorter name")
        cmd = ['hostnamectl', '--transient', 'set-hostname', name]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))

    def get_permanent_hostname(self):
        cmd = ['hostnamectl', '--static', 'status']
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))
        return to_native(out).strip()

    def set_permanent_hostname(self, name):
        if len(name) > 64:
            self.module.fail_json(msg="name cannot be longer than 64 characters on systemd servers, try a shorter name")
        cmd = ['hostnamectl', '--pretty', 'set-hostname', name]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))
        cmd = ['hostnamectl', '--static', 'set-hostname', name]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))


# ===========================================

class OpenRCStrategy(GenericStrategy):
    """
    This is a Gentoo (OpenRC) Hostname manipulation strategy class - it edits
    the /etc/conf.d/hostname file.
    """

    HOSTNAME_FILE = '/etc/conf.d/hostname'

    def get_permanent_hostname(self):
        try:
            try:
                f = open(self.HOSTNAME_FILE, 'r')
                for line in f:
                    line = line.strip()
                    if line.startswith('hostname='):
                        return line[10:].strip('"')
            except Exception:
                err = get_exception()
                self.module.fail_json(msg="failed to read hostname: %s" % str(err))
        finally:
            f.close()

        return None

    def set_permanent_hostname(self, name):
        try:
            try:
                f = open(self.HOSTNAME_FILE, 'r')
                lines = [x.strip() for x in f]

                for i, line in enumerate(lines):
                    if line.startswith('hostname='):
                        lines[i] = 'hostname="%s"' % name
                        break
                f.close()

                f = open(self.HOSTNAME_FILE, 'w')
                f.write('\n'.join(lines) + '\n')
            except Exception:
                err = get_exception()
                self.module.fail_json(msg="failed to update hostname: %s" % str(err))
        finally:
            f.close()

# ===========================================

class OpenBSDStrategy(GenericStrategy):
    """
    This is a OpenBSD family Hostname manipulation strategy class - it edits
    the /etc/myname file.
    """

    HOSTNAME_FILE = '/etc/myname'

    def get_permanent_hostname(self):
        if not os.path.isfile(self.HOSTNAME_FILE):
            try:
                open(self.HOSTNAME_FILE, "a").write("")
            except IOError:
                err = get_exception()
                self.module.fail_json(msg="failed to write file: %s" %
                    str(err))
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to read hostname: %s" %
                str(err))

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception:
            err = get_exception()
            self.module.fail_json(msg="failed to update hostname: %s" %
                str(err))

# ===========================================

class SolarisStrategy(GenericStrategy):
    """
    This is a Solaris11 or later Hostname manipulation strategy class - it
    execute hostname command.
    """

    def set_current_hostname(self, name):
        cmd_option = '-t'
        cmd = [self.hostname_cmd, cmd_option, name]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))

    def get_permanent_hostname(self):
        fmri = 'svc:/system/identity:node'
        pattern = 'config/nodename'
        cmd = '/usr/sbin/svccfg -s %s listprop -o value %s' % (fmri, pattern)
        rc, out, err = self.module.run_command(cmd, use_unsafe_shell=True)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))
        return to_native(out).strip()

    def set_permanent_hostname(self, name):
        cmd = [self.hostname_cmd, name]
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
                (rc, out, err))

# ===========================================

class FreeBSDStrategy(GenericStrategy):
    """
    This is a FreeBSD hostname manipulation strategy class - it edits
    the /etc/rc.conf.d/hostname file.
    """

    HOSTNAME_FILE = '/etc/rc.conf.d/hostname'

    def get_permanent_hostname(self):

        if not os.path.isfile(self.HOSTNAME_FILE):
            try:
                open(self.HOSTNAME_FILE, "a").write("hostname=temporarystub\n")
            except IOError:
                err = get_exception()
                self.module.fail_json(msg="failed to write file: %s" %
                    str(err))
        try:
            try:
                f = open(self.HOSTNAME_FILE, 'r')
                for line in f:
                    line = line.strip()
                    if line.startswith('hostname='):
                        return line[10:].strip('"')
            except Exception:
                err = get_exception()
                self.module.fail_json(msg="failed to read hostname: %s" % str(err))
        finally:
            f.close()

        return None

    def set_permanent_hostname(self, name):
        try:
            try:
                f = open(self.HOSTNAME_FILE, 'r')
                lines = [x.strip() for x in f]

                for i, line in enumerate(lines):
                    if line.startswith('hostname='):
                        lines[i] = 'hostname="%s"' % name
                        break
                f.close()

                f = open(self.HOSTNAME_FILE, 'w')
                f.write('\n'.join(lines) + '\n')
            except Exception:
                err = get_exception()
                self.module.fail_json(msg="failed to update hostname: %s" % str(err))
        finally:
            f.close()

# ===========================================

class FedoraHostname(Hostname):
    platform = 'Linux'
    distribution = 'Fedora'
    strategy_class = SystemdStrategy

class SLESHostname(Hostname):
    platform = 'Linux'
    distribution = 'Suse linux enterprise server '
    distribution_version = get_distribution_version()
    if distribution_version and LooseVersion("10") <= LooseVersion(distribution_version) <= LooseVersion("12"):
        strategy_class = SLESStrategy
    else:
        strategy_class = UnimplementedStrategy

class OpenSUSEHostname(Hostname):
    platform = 'Linux'
    distribution = 'Opensuse '
    strategy_class = SystemdStrategy

class ArchHostname(Hostname):
    platform = 'Linux'
    distribution = 'Arch'
    strategy_class = SystemdStrategy

class RedHat5Hostname(Hostname):
    platform = 'Linux'
    distribution = 'Redhat'
    strategy_class = RedHatStrategy

class RedHatServerHostname(Hostname):
    platform = 'Linux'
    distribution = 'Red hat enterprise linux server'
    strategy_class = RedHatStrategy

class RedHatWorkstationHostname(Hostname):
    platform = 'Linux'
    distribution = 'Red hat enterprise linux workstation'
    strategy_class = RedHatStrategy

class CentOSHostname(Hostname):
    platform = 'Linux'
    distribution = 'Centos'
    strategy_class = RedHatStrategy

class CentOSLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Centos linux'
    strategy_class = RedHatStrategy

class ScientificHostname(Hostname):
    platform = 'Linux'
    distribution = 'Scientific'
    strategy_class = RedHatStrategy

class ScientificLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Scientific linux'
    strategy_class = RedHatStrategy

class ScientificLinuxCERNHostname(Hostname):
    platform = 'Linux'
    distribution = 'Scientific linux cern slc'
    strategy_class = RedHatStrategy

class OracleLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Oracle linux server'
    strategy_class = RedHatStrategy

class AmazonLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Amazon'
    strategy_class = RedHatStrategy

class DebianHostname(Hostname):
    platform = 'Linux'
    distribution = 'Debian'
    strategy_class = DebianStrategy

class KaliHostname(Hostname):
    platform = 'Linux'
    distribution = 'Kali'
    strategy_class = DebianStrategy

class UbuntuHostname(Hostname):
    platform = 'Linux'
    distribution = 'Ubuntu'
    strategy_class = DebianStrategy

class LinuxmintHostname(Hostname):
    platform = 'Linux'
    distribution = 'Linuxmint'
    strategy_class = DebianStrategy

class LinaroHostname(Hostname):
    platform = 'Linux'
    distribution = 'Linaro'
    strategy_class = DebianStrategy

class GentooHostname(Hostname):
    platform = 'Linux'
    distribution = 'Gentoo base system'
    strategy_class = OpenRCStrategy

class ALTLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Altlinux'
    strategy_class = RedHatStrategy

class AlpineLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Alpine'
    strategy_class = AlpineStrategy

class OpenBSDHostname(Hostname):
    platform = 'OpenBSD'
    distribution = None
    strategy_class = OpenBSDStrategy

class SolarisHostname(Hostname):
    platform = 'SunOS'
    distribution = None
    strategy_class = SolarisStrategy

class FreeBSDHostname(Hostname):
    platform = 'FreeBSD'
    distribution = None
    strategy_class = FreeBSDStrategy


# ===========================================

def main():
    module = AnsibleModule(
        argument_spec = dict(
            name=dict(required=True)
        )
    )

    hostname = Hostname(module)
    name = module.params['name']
    changed = hostname.update_current_and_permanent_hostname()

    module.exit_json(changed=changed, name=name,
                     ansible_facts=dict(ansible_hostname=name.split('.')[0],
                                        ansible_nodename=name,
                                        ansible_fqdn=socket.getfqdn(),
                                        ansible_domain='.'.join(socket.getfqdn().split('.')[1:])))

if __name__ == '__main__':
    main()