"""
Cisco IOS configuration manipulation helpers

.. versionadded:: 2019.2.0

This module provides a collection of helper functions for Cisco IOS style
configuration manipulation. This module does not have external dependencies
and can be used from any Proxy or regular Minion.
"""

import difflib

import salt.utils.dictdiffer
import salt.utils.dictupdate
from salt.exceptions import SaltException

# Import Salt modules
from salt.utils.odict import OrderedDict

# ------------------------------------------------------------------------------
# module properties
# ------------------------------------------------------------------------------

__virtualname__ = "iosconfig"
__proxyenabled__ = ["*"]

# ------------------------------------------------------------------------------
# helper functions -- will not be exported
# ------------------------------------------------------------------------------


def _attach_data_to_path(obj, ele, data):
    if ele not in obj:
        obj[ele] = OrderedDict()
        obj[ele] = data
    else:
        obj[ele].update(data)


def _attach_data_to_path_tags(obj, path, data, list_=False):
    if "#list" not in obj:
        obj["#list"] = []
    path = [path]
    obj_tmp = obj
    first = True
    while True:
        obj_tmp["#text"] = " ".join(path)
        path_item = path.pop(0)
        if not path:
            break
        else:
            if path_item not in obj_tmp:
                obj_tmp[path_item] = OrderedDict()
            obj_tmp = obj_tmp[path_item]

            if first and list_:
                obj["#list"].append({path_item: obj_tmp})
                first = False
    if path_item in obj_tmp:
        obj_tmp[path_item].update(data)
    else:
        obj_tmp[path_item] = data
    obj_tmp[path_item]["#standalone"] = True


def _parse_text_config(config_lines, with_tags=False, current_indent=0, nested=False):
    struct_cfg = OrderedDict()
    while config_lines:
        line = config_lines.pop(0)
        if not line.strip() or line.lstrip().startswith("!"):
            # empty or comment
            continue
        current_line = line.lstrip()
        leading_spaces = len(line) - len(current_line)
        if leading_spaces > current_indent:
            current_block = _parse_text_config(
                config_lines,
                current_indent=leading_spaces,
                with_tags=with_tags,
                nested=True,
            )
            if with_tags:
                _attach_data_to_path_tags(
                    struct_cfg, current_line, current_block, nested
                )
            else:
                _attach_data_to_path(struct_cfg, current_line, current_block)
        elif leading_spaces < current_indent:
            config_lines.insert(0, line)
            break
        else:
            if not nested:
                current_block = _parse_text_config(
                    config_lines,
                    current_indent=leading_spaces,
                    with_tags=with_tags,
                    nested=True,
                )
                if with_tags:
                    _attach_data_to_path_tags(
                        struct_cfg, current_line, current_block, nested
                    )
                else:
                    _attach_data_to_path(struct_cfg, current_line, current_block)
            else:
                config_lines.insert(0, line)
                break
    return struct_cfg


def _get_diff_text(old, new):
    """
    Returns the diff of two text blobs.
    """
    diff = difflib.unified_diff(old.splitlines(1), new.splitlines(1))
    return "".join([x.replace("\r", "") for x in diff])


def _print_config_text(tree, indentation=0):
    """
    Return the config as text from a config tree.
    """
    config = ""
    for key, value in tree.items():
        config += "{indent}{line}\n".format(indent=" " * indentation, line=key)
        if value:
            config += _print_config_text(value, indentation=indentation + 1)
    return config


# ------------------------------------------------------------------------------
# callable functions
# ------------------------------------------------------------------------------


def tree(config=None, path=None, with_tags=False, saltenv="base"):
    """
    Transform Cisco IOS style configuration to structured Python dictionary.
    Depending on the value of the ``with_tags`` argument, this function may
    provide different views, valuable in different situations.

    config
        The configuration sent as text. This argument is ignored when ``path``
        is configured.

    path
        Absolute or remote path from where to load the configuration text. This
        argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    with_tags: ``False``
        Whether this function should return a detailed view, with tags.

    saltenv: ``base``
        Salt fileserver environment from which to retrieve the file.
        Ignored if ``path`` is not a ``salt://`` URL.

    CLI Example:

    .. code-block:: bash

        salt '*' iosconfig.tree path=salt://path/to/my/config.txt
        salt '*' iosconfig.tree path=https://bit.ly/2mAdq7z
    """
    if path:
        config = __salt__["cp.get_file_str"](path, saltenv=saltenv)
        if config is False:
            raise SaltException("{} is not available".format(path))
    config_lines = config.splitlines()
    return _parse_text_config(config_lines, with_tags=with_tags)


def clean(config=None, path=None, saltenv="base"):
    """
    Return a clean version of the config, without any special signs (such as
    ``!`` as an individual line) or empty lines, but just lines with significant
    value in the configuration of the network device.

    config
        The configuration sent as text. This argument is ignored when ``path``
        is configured.

    path
        Absolute or remote path from where to load the configuration text. This
        argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    saltenv: ``base``
        Salt fileserver environment from which to retrieve the file.
        Ignored if ``path`` is not a ``salt://`` URL.

    CLI Example:

    .. code-block:: bash

        salt '*' iosconfig.clean path=salt://path/to/my/config.txt
        salt '*' iosconfig.clean path=https://bit.ly/2mAdq7z
    """
    config_tree = tree(config=config, path=path, saltenv=saltenv)
    return _print_config_text(config_tree)


def merge_tree(
    initial_config=None,
    initial_path=None,
    merge_config=None,
    merge_path=None,
    saltenv="base",
):
    """
    Return the merge tree of the ``initial_config`` with the ``merge_config``,
    as a Python dictionary.

    initial_config
        The initial configuration sent as text. This argument is ignored when
        ``initial_path`` is set.

    initial_path
        Absolute or remote path from where to load the initial configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    merge_config
        The config to be merged into the initial config, sent as text. This
        argument is ignored when ``merge_path`` is set.

    merge_path
        Absolute or remote path from where to load the merge configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    saltenv: ``base``
        Salt fileserver environment from which to retrieve the file.
        Ignored if ``initial_path`` or ``merge_path`` is not a ``salt://`` URL.

    CLI Example:

    .. code-block:: bash

        salt '*' iosconfig.merge_tree initial_path=salt://path/to/running.cfg merge_path=salt://path/to/merge.cfg
    """
    merge_tree = tree(config=merge_config, path=merge_path, saltenv=saltenv)
    initial_tree = tree(config=initial_config, path=initial_path, saltenv=saltenv)
    return salt.utils.dictupdate.merge(initial_tree, merge_tree)


def merge_text(
    initial_config=None,
    initial_path=None,
    merge_config=None,
    merge_path=None,
    saltenv="base",
):
    """
    Return the merge result of the ``initial_config`` with the ``merge_config``,
    as plain text.

    initial_config
        The initial configuration sent as text. This argument is ignored when
        ``initial_path`` is set.

    initial_path
        Absolute or remote path from where to load the initial configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    merge_config
        The config to be merged into the initial config, sent as text. This
        argument is ignored when ``merge_path`` is set.

    merge_path
        Absolute or remote path from where to load the merge configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    saltenv: ``base``
        Salt fileserver environment from which to retrieve the file.
        Ignored if ``initial_path`` or ``merge_path`` is not a ``salt://`` URL.

    CLI Example:

    .. code-block:: bash

        salt '*' iosconfig.merge_text initial_path=salt://path/to/running.cfg merge_path=salt://path/to/merge.cfg
    """
    candidate_tree = merge_tree(
        initial_config=initial_config,
        initial_path=initial_path,
        merge_config=merge_config,
        merge_path=merge_path,
        saltenv=saltenv,
    )
    return _print_config_text(candidate_tree)


def merge_diff(
    initial_config=None,
    initial_path=None,
    merge_config=None,
    merge_path=None,
    saltenv="base",
):
    """
    Return the merge diff, as text, after merging the merge config into the
    initial config.

    initial_config
        The initial configuration sent as text. This argument is ignored when
        ``initial_path`` is set.

    initial_path
        Absolute or remote path from where to load the initial configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    merge_config
        The config to be merged into the initial config, sent as text. This
        argument is ignored when ``merge_path`` is set.

    merge_path
        Absolute or remote path from where to load the merge configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    saltenv: ``base``
        Salt fileserver environment from which to retrieve the file.
        Ignored if ``initial_path`` or ``merge_path`` is not a ``salt://`` URL.

    CLI Example:

    .. code-block:: bash

        salt '*' iosconfig.merge_diff initial_path=salt://path/to/running.cfg merge_path=salt://path/to/merge.cfg
    """
    if initial_path:
        initial_config = __salt__["cp.get_file_str"](initial_path, saltenv=saltenv)
    candidate_config = merge_text(
        initial_config=initial_config,
        merge_config=merge_config,
        merge_path=merge_path,
        saltenv=saltenv,
    )
    clean_running_dict = tree(config=initial_config)
    clean_running = _print_config_text(clean_running_dict)
    return _get_diff_text(clean_running, candidate_config)


def diff_tree(
    candidate_config=None,
    candidate_path=None,
    running_config=None,
    running_path=None,
    saltenv="base",
):
    """
    Return the diff, as Python dictionary, between the candidate and the running
    configuration.

    candidate_config
        The candidate configuration sent as text. This argument is ignored when
        ``candidate_path`` is set.

    candidate_path
        Absolute or remote path from where to load the candidate configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    running_config
        The running configuration sent as text. This argument is ignored when
        ``running_path`` is set.

    running_path
        Absolute or remote path from where to load the running configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    saltenv: ``base``
        Salt fileserver environment from which to retrieve the file.
        Ignored if ``candidate_path`` or ``running_path`` is not a
        ``salt://`` URL.

    CLI Example:

    .. code-block:: bash

        salt '*' iosconfig.diff_tree candidate_path=salt://path/to/candidate.cfg running_path=salt://path/to/running.cfg
    """
    candidate_tree = tree(config=candidate_config, path=candidate_path, saltenv=saltenv)
    running_tree = tree(config=running_config, path=running_path, saltenv=saltenv)
    return salt.utils.dictdiffer.deep_diff(running_tree, candidate_tree)


def diff_text(
    candidate_config=None,
    candidate_path=None,
    running_config=None,
    running_path=None,
    saltenv="base",
):
    """
    Return the diff, as text, between the candidate and the running config.

    candidate_config
        The candidate configuration sent as text. This argument is ignored when
        ``candidate_path`` is set.

    candidate_path
        Absolute or remote path from where to load the candidate configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    running_config
        The running configuration sent as text. This argument is ignored when
        ``running_path`` is set.

    running_path
        Absolute or remote path from where to load the running configuration
        text. This argument allows any URI supported by
        :py:func:`cp.get_url <salt.modules.cp.get_url>`), e.g., ``salt://``,
        ``https://``, ``s3://``, ``ftp:/``, etc.

    saltenv: ``base``
        Salt fileserver environment from which to retrieve the file.
        Ignored if ``candidate_path`` or ``running_path`` is not a
        ``salt://`` URL.

    CLI Example:

    .. code-block:: bash

        salt '*' iosconfig.diff_text candidate_path=salt://path/to/candidate.cfg running_path=salt://path/to/running.cfg
    """
    candidate_text = clean(
        config=candidate_config, path=candidate_path, saltenv=saltenv
    )
    running_text = clean(config=running_config, path=running_path, saltenv=saltenv)
    return _get_diff_text(running_text, candidate_text)
