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

from __future__ import absolute_import, division, print_function

__author__ = "Sebastian Kroczek"
__copyright__ = "Copyright 2018"
__credits__ = ["Sebastian Kroczek"]
__license__ = "MIT"
__email__ = "me@xbug.de"
__status__ = "Prototype"


import io
import os

from configobj import ConfigObj
from ansible.module_utils.basic import AnsibleModule


def cmp(d1, d2):
    if d1 == d2:
        return True
    if not isinstance(d1, dict) and not isinstance(d2, dict):
        return False
    for k in d1.keys():
        if k not in d2.keys():
            return False
        elif isinstance(d1[k], dict):
            if not cmp(d1[k], d2[k]):
                return False
        elif d1[k] != d2[k]:
            return False
    return True


def find(key, cfg):
    parts = key.split(".", 1)
    if len(parts) > 1:
        if isinstance(cfg[parts[0]], dict):
            return find(parts[1], cfg[parts[0]])
        else:
            return None
    return cfg[parts[0]]


def delete(key, cfg):
    parts = key.split(".", 1)
    if len(parts) > 1:
        delete(parts[1], cfg[parts[0]])
        return
    del (cfg[parts[0]])


def set_value(key, value, cfg):
    parts = key.split(".", 1)
    if len(parts) > 1:
        try:
            ncfg = cfg[parts[0]]
        except KeyError:
            ncfg = cfg[parts[0]] = {}
        set_value(parts[1], value, ncfg)
        return
    cfg[parts[0]] = value


def main():
    arg_spec = dict(
        path=dict(required=True, type='path'),
        state=dict(default='present', choices=['present', 'absent', 'read']),
        key=dict(required=True),
        section=dict(type='dict'),
        value=dict(),
    )

    module = AnsibleModule(argument_spec=arg_spec, supports_check_mode=True)

    path = str(os.path.expanduser(module.params['path']))
    key = module.params['key']
    state = module.params['state']
    section = module.params['section']
    value = module.params['value']

    if 'present' == state and not section and not value:
        module.fail_json(msg="On state 'present' either section or value is required.")

    if 'present' == state and section and value:
        module.fail_json(msg="On state 'present' either section or value must be set, not both.")

    value = value or section

    # create = module.params['create']
    check_mode = module.check_mode

    diff = {'before': '',
            'after': '',
            'before_header': '%s (content)' % path,
            'after_header': '%s (content)' % path}

    cfg = ConfigObj(path)

    before = io.BytesIO()
    cfg.write(before)
    diff['before'] = before.getvalue()
    before.close()

    try:
        cvalue = find(key, cfg=cfg)
    except KeyError:
        if 'read' == state:
            module.fail_json(msg="Key %s do not exist." % key)
        elif "absent" == state:
            module.exit_json(changed=False)
        else:
            cvalue = float('nan')

    if 'read' == state:
        module.exit_json(value=cvalue, changed=False)

    if "absent" == state:
        delete(key, cfg)
        if not check_mode:
            cfg.write()

        after = io.BytesIO()
        cfg.write(after)
        diff['after'] = after.getvalue()
        after.close()
        module.exit_json(changed=True, diff=diff)

    if 'present' == state:
        if cmp(cvalue, value):
            module.exit_json(changed=False)
        set_value(key, value, cfg)
        if not check_mode:
            cfg.write()

        after = io.BytesIO()
        cfg.write(after)
        diff['after'] = after.getvalue()
        after.close()

        module.exit_json(changed=True, diff=diff)

    module.fail_json(msg="Unknown state %s. Known states are: read, present and absent." % state, changed=False)


if __name__ == '__main__':
    main()