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

# Copyright: (c) 2013, Hiroaki Nakamura <hnakamur@gmail.com>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function
__metaclass__ = type

ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['preview'],
                    'supported_by': 'community'}

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, supports most OSs/Distributions, including those using systemd.
    - Note, this module does *NOT* modify C(/etc/hosts). You need to modify it yourself using other modules like template or replace.
    - Windows, HP-UX and AIX are not currently supported.
options:
    name:
        description:
            - Name of the host
        required: true
    use:
        description:
            - Which strategy to use to update the hostname.
            - If not set we try to autodetect, but this can be problematic, specially with containers as they can present misleading information.
        choices: ['generic', 'debian','sles', 'redhat', 'alpine', 'systemd', 'openrc', 'openbsd', 'solaris', 'freebsd']
        version_added: '2.9'
'''

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

import os
import socket
import traceback

from ansible.module_utils.basic import (
    AnsibleModule,
    get_distribution,
    get_distribution_version,
    get_platform,
    load_platform_subclass,
)
from ansible.module_utils.facts.system.service_mgr import ServiceMgrFactCollector
from ansible.module_utils._text import to_native

STRATS = {'generic': 'Generic', 'debian': 'Debian', 'sles': 'SLES', 'redhat': 'RedHat', 'alpine': 'Alpine',
          'systemd': 'Systemd', 'openrc': 'OpenRC', 'openbsd': 'OpenBSD', 'solaris': 'Solaris', 'freebsd': 'FreeBSD'}


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']
        self.use = module.params['use']

        if self.use is not None:
            strat = globals()['%sStrategy' % STRATS[self.use]]
            self.strategy = strat(module)
        elif self.platform == 'Linux' and ServiceMgrFactCollector.is_systemd_managed(module):
            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:
            if not self.module.check_mode:
                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:
            if not self.module.check_mode:
                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 'UNKNOWN'

    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 as e:
                self.module.fail_json(msg="failed to write file: %s" %
                                          to_native(e), exception=traceback.format_exc())
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to read hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to update hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())


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 as e:
                self.module.fail_json(msg="failed to write file: %s" %
                                          to_native(e), exception=traceback.format_exc())
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to read hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to update hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())


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 as e:
            self.module.fail_json(msg="failed to read hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())

    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 as e:
            self.module.fail_json(msg="failed to update hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())


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 as e:
                self.module.fail_json(msg="failed to write file: %s" %
                                          to_native(e), exception=traceback.format_exc())
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to read hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to update hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())

    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):
        name = 'UNKNOWN'
        try:
            try:
                f = open(self.HOSTNAME_FILE, 'r')
                for line in f:
                    line = line.strip()
                    if line.startswith('hostname='):
                        name = line[10:].strip('"')
                        break
            except Exception as e:
                self.module.fail_json(msg="failed to read hostname: %s" %
                                          to_native(e), exception=traceback.format_exc())
        finally:
            f.close()

        return name

    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 as e:
                self.module.fail_json(msg="failed to update hostname: %s" %
                                          to_native(e), exception=traceback.format_exc())
        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 as e:
                self.module.fail_json(msg="failed to write file: %s" %
                                          to_native(e), exception=traceback.format_exc())
        try:
            f = open(self.HOSTNAME_FILE)
            try:
                return f.read().strip()
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to read hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())

    def set_permanent_hostname(self, name):
        try:
            f = open(self.HOSTNAME_FILE, 'w+')
            try:
                f.write("%s\n" % name)
            finally:
                f.close()
        except Exception as e:
            self.module.fail_json(msg="failed to update hostname: %s" %
                                      to_native(e), exception=traceback.format_exc())


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):

        name = 'UNKNOWN'
        if not os.path.isfile(self.HOSTNAME_FILE):
            try:
                open(self.HOSTNAME_FILE, "a").write("hostname=temporarystub\n")
            except IOError as e:
                self.module.fail_json(msg="failed to write file: %s" %
                                          to_native(e), exception=traceback.format_exc())
        try:
            try:
                f = open(self.HOSTNAME_FILE, 'r')
                for line in f:
                    line = line.strip()
                    if line.startswith('hostname='):
                        name = line[10:].strip('"')
                        break
            except Exception as e:
                self.module.fail_json(msg="failed to read hostname: %s" %
                                          to_native(e), exception=traceback.format_exc())
        finally:
            f.close()

        return name

    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 as e:
                self.module.fail_json(msg="failed to update hostname: %s" %
                                          to_native(e), exception=traceback.format_exc())
        finally:
            f.close()


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


class SLESHostname(Hostname):
    platform = 'Linux'
    distribution = 'Sles'
    try:
        distribution_version = get_distribution_version()
        # cast to float may raise ValueError on non SLES, we use float for a little more safety over int
        if distribution_version and 10 <= float(distribution_version) <= 12:
            strategy_class = SLESStrategy
        else:
            raise ValueError()
    except ValueError:
        strategy_class = UnimplementedStrategy


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


class OpenSUSELeapHostname(Hostname):
    platform = 'Linux'
    distribution = 'Opensuse-leap'
    strategy_class = SystemdStrategy


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


class ArchARMHostname(Hostname):
    platform = 'Linux'
    distribution = 'Archarm'
    strategy_class = SystemdStrategy


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


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


class ClearLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Clear-linux-os'
    strategy_class = SystemdStrategy


class CloudlinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Cloudlinux'
    strategy_class = RedHatStrategy


class CoreosHostname(Hostname):
    platform = 'Linux'
    distribution = 'Coreos'
    strategy_class = SystemdStrategy


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


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


class VirtuozzoLinuxHostname(Hostname):
    platform = 'Linux'
    distribution = 'Virtuozzo'
    strategy_class = RedHatStrategy


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


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


class CumulusHostname(Hostname):
    platform = 'Linux'
    distribution = 'Cumulus-linux'
    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 DevuanHostname(Hostname):
    platform = 'Linux'
    distribution = 'Devuan'
    strategy_class = DebianStrategy


class RaspbianHostname(Hostname):
    platform = 'Linux'
    distribution = 'Raspbian'
    strategy_class = DebianStrategy


class GentooHostname(Hostname):
    platform = 'Linux'
    distribution = 'Gentoo'
    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


class NetBSDHostname(Hostname):
    platform = 'NetBSD'
    distribution = None
    strategy_class = FreeBSDStrategy


class NeonHostname(Hostname):
    platform = 'Linux'
    distribution = 'Neon'
    strategy_class = DebianStrategy


def main():
    module = AnsibleModule(
        argument_spec=dict(
            name=dict(type='str', required=True),
            use=dict(type='str', choices=STRATS.keys())
        ),
        supports_check_mode=True,
    )

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

    current_hostname = hostname.get_current_hostname()
    permanent_hostname = hostname.get_permanent_hostname()

    changed = hostname.update_current_and_permanent_hostname()

    if name != current_hostname:
        name_before = current_hostname
    elif name != permanent_hostname:
        name_before = permanent_hostname

    kw = dict(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 changed:
        kw['diff'] = {'after': 'hostname = ' + name + '\n',
                      'before': 'hostname = ' + name_before + '\n'}

    module.exit_json(**kw)


if __name__ == '__main__':
    main()
