#!/usr/bin/python
#
# 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/>.
#

DOCUMENTATION = """
---
module: iosxr_config
version_added: "2.1"
author: "Peter Sprygada (@privateip)"
short_description: Manage Cisco IOS XR configuration sections
description:
  - Cisco IOS XR configurations use a simple block indent file syntax
    for segmenting configuration into sections.  This module provides
    an implementation for working with IOS XR configuration sections in
    a deterministic way.
extends_documentation_fragment: iosxr
options:
  lines:
    description:
      - The ordered set of commands that should be configured in the
        section.  The commands must be the exact same commands as found
        in the device running-config.  Be sure to note the configuration
        command syntax as some commands are automatically modified by the
        device config parser.
    required: false
    default: null
    aliases: ['commands']
  parents:
    description:
      - The ordered set of parents that uniquely identify the section
        the commands should be checked against.  If the parents argument
        is omitted, the commands are checked against the set of top
        level or global commands.
    required: false
    default: null
  src:
    description:
      - Specifies the source path to the file that contains the configuration
        or configuration template to load.  The path to the source file can
        either be the full path on the Ansible control host or a relative
        path from the playbook or role root directory.  This argument is mutually
        exclusive with I(lines).
    required: false
    default: null
    version_added: "2.2"
  before:
    description:
      - The ordered set of commands to push on to the command stack if
        a change needs to be made.  This allows the playbook designer
        the opportunity to perform configuration commands prior to pushing
        any changes without affecting how the set of commands are matched
        against the system
    required: false
    default: null
  after:
    description:
      - The ordered set of commands to append to the end of the command
        stack if a changed needs to be made.  Just like with I(before) this
        allows the playbook designer to append a set of commands to be
        executed after the command set.
    required: false
    default: null
  match:
    description:
      - Instructs the module on the way to perform the matching of
        the set of commands against the current device config.  If
        match is set to I(line), commands are matched line by line.  If
        match is set to I(strict), command lines are matched with respect
        to position.  If match is set to I(exact), command lines
        must be an equal match.  Finally, if match is set to I(none), the
        module will not attempt to compare the source configuration with
        the running configuration on the remote device.
    required: false
    default: line
    choices: ['line', 'strict', 'exact', 'none']
  replace:
    description:
      - Instructs the module on the way to perform the configuration
        on the device.  If the replace argument is set to I(line) then
        the modified lines are pushed to the device in configuration
        mode.  If the replace argument is set to I(block) then the entire
        command block is pushed to the device in configuration mode if any
        line is not correct
    required: false
    default: line
    choices: ['line', 'block']
  force:
    description:
      - The force argument instructs the module to not consider the
        current devices running-config.  When set to true, this will
        cause the module to push the contents of I(src) into the device
        without first checking if already configured.
      - Note this argument should be considered deprecated.  To achieve
        the equivalent, set the match argument to none.  This argument
        will be removed in a future release.
    required: false
    default: false
    choices: [ "yes", "no" ]
    version_added: "2.2"
  update:
    description:
      - The I(update) argument controls how the configuration statements
        are processed on the remote device.  Valid choices for the I(update)
        argument are I(merge) and I(check).  When the argument is set to
        I(merge), the configuration changes are merged with the current
        device running configuration.  When the argument is set to I(check)
        the configuration updates are determined but not actually configured
        on the remote device.
    required: false
    default: merge
    choices: ['merge', 'replace', 'check']
    version_added: "2.2"
  config:
    description:
      - The module, by default, will connect to the remote device and
        retrieve the current running-config to use as a base for comparing
        against the contents of source.  There are times when it is not
        desirable to have the task get the current running-config for
        every task in a playbook.  The I(config) argument allows the
        implementer to pass in the configuration to use as the base
        config for comparison.
    required: false
    default: null
  backup:
    description:
      - This argument will cause the module to create a full backup of
        the current C(running-config) from the remote device before any
        changes are made.  The backup file is written to the C(backup)
        folder in the playbook root directory.  If the directory does not
        exist, it is created.
    required: false
    default: no
    choices: ['yes', 'no']
    version_added: "2.2"
  comment:
    description:
      - Allows a commit description to be specified to be included
        when the configuration is committed.  If the configuration is
        not changed or committed, this argument is ignored.
    required: false
    default: 'configured by iosxr_config'
    version_added: "2.2"
"""

EXAMPLES = """
# Note: examples below use the following provider dict to handle
#       transport and authentication to the node.
vars:
  cli:
    host: "{{ inventory_hostname }}"
    username: cisco
    password: cisco
    transport: cli

- name: configure top level configuration
  iosxr_config:
    lines: hostname {{ inventory_hostname }}
    provider: "{{ cli }}"

- name: configure interface settings
  iosxr_config:
    lines:
      - description test interface
      - ip address 172.31.1.1 255.255.255.0
    parents: interface GigabitEthernet0/0/0/0
    provider: "{{ cli }}"

- name: load a config from disk and replace the current config
  iosxr_config:
    src: config.cfg
    update: replace
    backup: yes
    provider: "{{ cli }}"
"""

RETURN = """
updates:
  description: The set of commands that will be pushed to the remote device
  returned: always
  type: list
  sample: ['...', '...']
backup_path:
  description: The full path to the backup file
  returned: when backup is yes
  type: path
  sample: /playbooks/ansible/backup/iosxr01.2016-07-16@22:28:34
"""
from ansible.module_utils.basic import get_exception
from ansible.module_utils.netcfg import NetworkConfig, dumps
from ansible.module_utils.iosxr import NetworkModule, NetworkError

DEFAULT_COMMIT_COMMENT = 'configured by iosxr_config'


def invoke(name, *args, **kwargs):
    func = globals().get(name)
    if func:
        return func(*args, **kwargs)

def check_args(module, warnings):
    if module.params['parents']:
        if not module.params['lines'] or module.params['src']:
            warnings.append('ignoring unnecessary argument parents')
    if module.params['match'] == 'none' and module.params['replace']:
        warnings.append('ignoring unnecessary argument replace')
    if module.params['update'] == 'replace' and not module.params['src']:
        module.fail_json(msg='Must specify src when update is `replace`')
    if module.params['force']:
        warnings.append('The force argument is deprecated, please use '
                        'match=none instead.  This argument will be '
                        'removed in the future')


def get_config(module, result):
    contents = module.params['config'] or result.get('__config__')
    if not contents:
        contents = module.config.get_config()
    return NetworkConfig(indent=1, contents=contents)

def get_candidate(module):
    candidate = NetworkConfig(indent=1)
    if module.params['src']:
        candidate.load(module.params['src'])
    elif module.params['lines']:
        parents = module.params['parents'] or list()
        candidate.add(module.params['lines'], parents=parents)
    return candidate

def load_config(module, commands, result):
    replace = module.params['update'] == 'replace'
    comment = module.params['comment']
    commit = not module.check_mode
    diff = module.config.load_config(commands, replace=replace, commit=commit,
                                     comment=comment)
    result['diff'] = dict(prepared=diff)
    result['changed'] = True

def run(module, result):
    match = module.params['match']
    replace = module.params['replace']
    update = module.params['update']

    candidate = get_candidate(module)

    if match != 'none' and update != 'replace':
        config = get_config(module, result)
        configobjs = candidate.difference(config, match=match, replace=replace)
    else:
        config = None
        configobjs = candidate.items

    if configobjs:
        commands = dumps(configobjs, 'commands')

        if module.params['before']:
            commands[:0] = module.params['before']

        if module.params['after']:
            commands.extend(module.params['after'])

        result['updates'] = commands.split('\n')

        if update != 'check':
            load_config(module, commands, result)

def main():
    """main entry point for module execution
    """
    argument_spec = dict(
        lines=dict(aliases=['commands'], type='list'),
        parents=dict(type='list'),

        src=dict(type='path'),

        before=dict(type='list'),
        after=dict(type='list'),

        match=dict(default='line', choices=['line', 'strict', 'exact', 'none']),
        replace=dict(default='line', choices=['line', 'block']),

        update=dict(choices=['merge', 'replace', 'check'], default='merge'),
        backup=dict(type='bool', default=False),
        comment=dict(default=DEFAULT_COMMIT_COMMENT),

        # this argument is deprecated in favor of setting match: none
        # it will be removed in a future version
        force=dict(default=False, type='bool'),

        config=dict(),
    )

    mutually_exclusive = [('lines', 'src')]

    module = NetworkModule(argument_spec=argument_spec,
                           connect_on_load=False,
                           mutually_exclusive=mutually_exclusive,
                           supports_check_mode=True)

    if module.params['force'] is True:
        module.params['match'] = 'none'

    warnings = list()
    check_args(module, warnings)

    result = dict(changed=False, warnings=warnings)

    if module.params['backup']:
        config = module.config.get_config()
        result['__config__'] = config
        result['__backup__'] = config

    try:
        run(module, result)
    except NetworkError:
        exc = get_exception()
        module.fail_json(msg=str(exc), **exc.kwargs)

    module.exit_json(**result)


if __name__ == '__main__':
    main()