"""ApacheParser is a member object of the ApacheConfigurator class."""
import copy
import fnmatch
import logging
import re
import sys

import six

from acme.magic_typing import Dict
from acme.magic_typing import List
from certbot import errors
from certbot.compat import os
from certbot_apache._internal import apache_util
from certbot_apache._internal import constants

logger = logging.getLogger(__name__)


class ApacheParser(object):
    """Class handles the fine details of parsing the Apache Configuration.

    .. todo:: Make parsing general... remove sites-available etc...

    :ivar str root: Normalized absolute path to the server root
        directory. Without trailing slash.
    :ivar set modules: All module names that are currently enabled.
    :ivar dict loc: Location to place directives, root - configuration origin,
        default - user config file, name - NameVirtualHost,

    """
    arg_var_interpreter = re.compile(r"\$\{[^ \}]*}")
    fnmatch_chars = {"*", "?", "\\", "[", "]"}

    def __init__(self, root, vhostroot=None, version=(2, 4),
                 configurator=None):
        # Note: Order is important here.

        # Needed for calling save() with reverter functionality that resides in
        # AugeasConfigurator superclass of ApacheConfigurator. This resolves
        # issues with aug.load() after adding new files / defines to parse tree
        self.configurator = configurator

        # Initialize augeas
        self.aug = None
        self.init_augeas()

        if not self.check_aug_version():
            raise errors.NotSupportedError(
                "Apache plugin support requires libaugeas0 and augeas-lenses "
                "version 1.2.0 or higher, please make sure you have you have "
                "those installed.")

        self.modules = {}  # type: Dict[str, str]
        self.parser_paths = {}  # type: Dict[str, List[str]]
        self.variables = {}  # type: Dict[str, str]

        # Find configuration root and make sure augeas can parse it.
        self.root = os.path.abspath(root)
        self.loc = {"root": self._find_config_root()}
        self.parse_file(self.loc["root"])

        if version >= (2, 4):
            # Look up variables from httpd and add to DOM if not already parsed
            self.update_runtime_variables()

        # This problem has been fixed in Augeas 1.0
        self.standardize_excl()

        # Parse LoadModule directives from configuration files
        self.parse_modules()

        # Set up rest of locations
        self.loc.update(self._set_locations())

        # list of the active include paths, before modifications
        self.existing_paths = copy.deepcopy(self.parser_paths)

        # Must also attempt to parse additional virtual host root
        if vhostroot:
            self.parse_file(os.path.abspath(vhostroot) + "/" +
                            self.configurator.option("vhost_files"))

        # check to see if there were unparsed define statements
        if version < (2, 4):
            if self.find_dir("Define", exclude=False):
                raise errors.PluginError("Error parsing runtime variables")

    def init_augeas(self):
        """ Initialize the actual Augeas instance """

        try:
            import augeas
        except ImportError:  # pragma: no cover
            raise errors.NoInstallationError("Problem in Augeas installation")

        self.aug = augeas.Augeas(
            # specify a directory to load our preferred lens from
            loadpath=constants.AUGEAS_LENS_DIR,
            # Do not save backup (we do it ourselves), do not load
            # anything by default
            flags=(augeas.Augeas.NONE |
                   augeas.Augeas.NO_MODL_AUTOLOAD |
                   augeas.Augeas.ENABLE_SPAN))

    def check_parsing_errors(self, lens):
        """Verify Augeas can parse all of the lens files.

        :param str lens: lens to check for errors

        :raises .errors.PluginError: If there has been an error in parsing with
            the specified lens.

        """
        error_files = self.aug.match("/augeas//error")

        for path in error_files:
            # Check to see if it was an error resulting from the use of
            # the httpd lens
            lens_path = self.aug.get(path + "/lens")
            # As aug.get may return null
            if lens_path and lens in lens_path:
                msg = (
                    "There has been an error in parsing the file {0} on line {1}: "
                    "{2}".format(
                    # Strip off /augeas/files and /error
                    path[13:len(path) - 6],
                    self.aug.get(path + "/line"),
                    self.aug.get(path + "/message")))
                raise errors.PluginError(msg)

    def check_aug_version(self):
        """ Checks that we have recent enough version of libaugeas.
        If augeas version is recent enough, it will support case insensitive
        regexp matching"""

        self.aug.set("/test/path/testing/arg", "aRgUMeNT")
        try:
            matches = self.aug.match(
                "/test//*[self::arg=~regexp('argument', 'i')]")
        except RuntimeError:
            self.aug.remove("/test/path")
            return False
        self.aug.remove("/test/path")
        return matches

    def unsaved_files(self):
        """Lists files that have modified Augeas DOM but the changes have not
        been written to the filesystem yet, used by `self.save()` and
        ApacheConfigurator to check the file state.

        :raises .errors.PluginError: If there was an error in Augeas, in
            an attempt to save the configuration, or an error creating a
            checkpoint

        :returns: `set` of unsaved files
        """
        save_state = self.aug.get("/augeas/save")
        self.aug.set("/augeas/save", "noop")
        # Existing Errors
        ex_errs = self.aug.match("/augeas//error")
        try:
            # This is a noop save
            self.aug.save()
        except (RuntimeError, IOError):
            self._log_save_errors(ex_errs)
            # Erase Save Notes
            self.configurator.save_notes = ""
            raise errors.PluginError(
                "Error saving files, check logs for more info.")

        # Return the original save method
        self.aug.set("/augeas/save", save_state)

        # Retrieve list of modified files
        # Note: Noop saves can cause the file to be listed twice, I used a
        # set to remove this possibility. This is a known augeas 0.10 error.
        save_paths = self.aug.match("/augeas/events/saved")

        save_files = set()
        if save_paths:
            for path in save_paths:
                save_files.add(self.aug.get(path)[6:])
        return save_files

    def ensure_augeas_state(self):
        """Makes sure that all Augeas dom changes are written to files to avoid
        loss of configuration directives when doing additional augeas parsing,
        causing a possible augeas.load() resulting dom reset
        """

        if self.unsaved_files():
            self.configurator.save_notes += "(autosave)"
            self.configurator.save()

    def save(self, save_files):
        """Saves all changes to the configuration files.

        save() is called from ApacheConfigurator to handle the parser specific
        tasks of saving.

        :param list save_files: list of strings of file paths that we need to save.

        """
        self.configurator.save_notes = ""
        self.aug.save()

        # Force reload if files were modified
        # This is needed to recalculate augeas directive span
        if save_files:
            for sf in save_files:
                self.aug.remove("/files/"+sf)
            self.aug.load()

    def _log_save_errors(self, ex_errs):
        """Log errors due to bad Augeas save.

        :param list ex_errs: Existing errors before save

        """
        # Check for the root of save problems
        new_errs = self.aug.match("/augeas//error")
        # logger.error("During Save - %s", mod_conf)
        logger.error("Unable to save files: %s. Attempted Save Notes: %s",
                     ", ".join(err[13:len(err) - 6] for err in new_errs
                               # Only new errors caused by recent save
                               if err not in ex_errs), self.configurator.save_notes)

    def add_include(self, main_config, inc_path):
        """Add Include for a new configuration file if one does not exist

        :param str main_config: file path to main Apache config file
        :param str inc_path: path of file to include

        """
        if not self.find_dir(case_i("Include"), inc_path):
            logger.debug("Adding Include %s to %s",
                         inc_path, get_aug_path(main_config))
            self.add_dir(
                get_aug_path(main_config),
                "Include", inc_path)

            # Add new path to parser paths
            new_dir = os.path.dirname(inc_path)
            new_file = os.path.basename(inc_path)
            self.existing_paths.setdefault(new_dir, []).append(new_file)

    def add_mod(self, mod_name):
        """Shortcut for updating parser modules."""
        if mod_name + "_module" not in self.modules:
            self.modules[mod_name + "_module"] = None
        if "mod_" + mod_name + ".c" not in self.modules:
            self.modules["mod_" + mod_name + ".c"] = None

    def reset_modules(self):
        """Reset the loaded modules list. This is called from cleanup to clear
        temporarily loaded modules."""
        self.modules = {}
        self.update_modules()
        self.parse_modules()

    def parse_modules(self):
        """Iterates on the configuration until no new modules are loaded.

        ..todo:: This should be attempted to be done with a binary to avoid
            the iteration issue.  Else... parse and enable mods at same time.

        """
        mods = {}  # type: Dict[str, str]
        matches = self.find_dir("LoadModule")
        iterator = iter(matches)
        # Make sure prev_size != cur_size for do: while: iteration
        prev_size = -1

        while len(mods) != prev_size:
            prev_size = len(mods)

            for match_name, match_filename in six.moves.zip(
                    iterator, iterator):
                mod_name = self.get_arg(match_name)
                mod_filename = self.get_arg(match_filename)
                if mod_name and mod_filename:
                    mods[mod_name] = mod_filename
                    mods[os.path.basename(mod_filename)[:-2] + "c"] = mod_filename
                else:
                    logger.debug("Could not read LoadModule directive from Augeas path: %s",
                                 match_name[6:])
        self.modules.update(mods)

    def update_runtime_variables(self):
        """Update Includes, Defines and Includes from httpd config dump data"""

        self.update_defines()
        self.update_includes()
        self.update_modules()

    def update_defines(self):
        """Updates the dictionary of known variables in the configuration"""

        self.variables = apache_util.parse_defines(self.configurator.option("ctl"))

    def update_includes(self):
        """Get includes from httpd process, and add them to DOM if needed"""

        # Find_dir iterates over configuration for Include and IncludeOptional
        # directives to make sure we see the full include tree present in the
        # configuration files
        _ = self.find_dir("Include")

        matches = apache_util.parse_includes(self.configurator.option("ctl"))
        if matches:
            for i in matches:
                if not self.parsed_in_current(i):
                    self.parse_file(i)

    def update_modules(self):
        """Get loaded modules from httpd process, and add them to DOM"""

        matches = apache_util.parse_modules(self.configurator.option("ctl"))
        for mod in matches:
            self.add_mod(mod.strip())

    def filter_args_num(self, matches, args):
        """Filter out directives with specific number of arguments.

        This function makes the assumption that all related arguments are given
        in order.  Thus /files/apache/directive[5]/arg[2] must come immediately
        after /files/apache/directive[5]/arg[1]. Runs in 1 linear pass.

        :param string matches: Matches of all directives with arg nodes
        :param int args: Number of args you would like to filter

        :returns: List of directives that contain # of arguments.
            (arg is stripped off)

        """
        filtered = []
        if args == 1:
            for i, match in enumerate(matches):
                if match.endswith("/arg"):
                    filtered.append(matches[i][:-4])
        else:
            for i, match in enumerate(matches):
                if match.endswith("/arg[%d]" % args):
                    # Make sure we don't cause an IndexError (end of list)
                    # Check to make sure arg + 1 doesn't exist
                    if (i == (len(matches) - 1) or
                            not matches[i + 1].endswith("/arg[%d]" %
                                                        (args + 1))):
                        filtered.append(matches[i][:-len("/arg[%d]" % args)])

        return filtered

    def add_dir_to_ifmodssl(self, aug_conf_path, directive, args):
        """Adds directive and value to IfMod ssl block.

        Adds given directive and value along configuration path within
        an IfMod mod_ssl.c block.  If the IfMod block does not exist in
        the file, it is created.

        :param str aug_conf_path: Desired Augeas config path to add directive
        :param str directive: Directive you would like to add, e.g. Listen
        :param args: Values of the directive; str "443" or list of str
        :type args: list

        """
        # TODO: Add error checking code... does the path given even exist?
        #       Does it throw exceptions?
        if_mod_path = self.get_ifmod(aug_conf_path, "mod_ssl.c")
        # IfModule can have only one valid argument, so append after
        self.aug.insert(if_mod_path + "arg", "directive", False)
        nvh_path = if_mod_path + "directive[1]"
        self.aug.set(nvh_path, directive)
        if len(args) == 1:
            self.aug.set(nvh_path + "/arg", args[0])
        else:
            for i, arg in enumerate(args):
                self.aug.set("%s/arg[%d]" % (nvh_path, i + 1), arg)

    def get_ifmod(self, aug_conf_path, mod, beginning=False):
        """Returns the path to <IfMod mod> and creates one if it doesn't exist.

        :param str aug_conf_path: Augeas configuration path
        :param str mod: module ie. mod_ssl.c
        :param bool beginning: If the IfModule should be created to the beginning
            of augeas path DOM tree.

        :returns: Augeas path of the requested IfModule directive that pre-existed
            or was created during the process. The path may be dynamic,
            i.e. .../IfModule[last()]
        :rtype: str

        """
        if_mods = self.aug.match(("%s/IfModule/*[self::arg='%s']" %
                                  (aug_conf_path, mod)))
        if not if_mods:
            return self.create_ifmod(aug_conf_path, mod, beginning)

        # Strip off "arg" at end of first ifmod path
        return if_mods[0].rpartition("arg")[0]

    def create_ifmod(self, aug_conf_path, mod, beginning=False):
        """Creates a new <IfMod mod> and returns its path.

        :param str aug_conf_path: Augeas configuration path
        :param str mod: module ie. mod_ssl.c
        :param bool beginning: If the IfModule should be created to the beginning
            of augeas path DOM tree.

        :returns: Augeas path of the newly created IfModule directive.
            The path may be dynamic, i.e. .../IfModule[last()]
        :rtype: str

        """
        if beginning:
            c_path_arg = "{}/IfModule[1]/arg".format(aug_conf_path)
            # Insert IfModule before the first directive
            self.aug.insert("{}/directive[1]".format(aug_conf_path),
                            "IfModule", True)
            retpath = "{}/IfModule[1]/".format(aug_conf_path)
        else:
            c_path = "{}/IfModule[last() + 1]".format(aug_conf_path)
            c_path_arg = "{}/IfModule[last()]/arg".format(aug_conf_path)
            self.aug.set(c_path, "")
            retpath = "{}/IfModule[last()]/".format(aug_conf_path)
        self.aug.set(c_path_arg, mod)
        return retpath

    def add_dir(self, aug_conf_path, directive, args):
        """Appends directive to the end fo the file given by aug_conf_path.

        .. note:: Not added to AugeasConfigurator because it may depend
            on the lens

        :param str aug_conf_path: Augeas configuration path to add directive
        :param str directive: Directive to add
        :param args: Value of the directive. ie. Listen 443, 443 is arg
        :type args: list or str

        """
        self.aug.set(aug_conf_path + "/directive[last() + 1]", directive)
        if isinstance(args, list):
            for i, value in enumerate(args, 1):
                self.aug.set(
                    "%s/directive[last()]/arg[%d]" % (aug_conf_path, i), value)
        else:
            self.aug.set(aug_conf_path + "/directive[last()]/arg", args)

    def add_dir_beginning(self, aug_conf_path, dirname, args):
        """Adds the directive to the beginning of defined aug_conf_path.

        :param str aug_conf_path: Augeas configuration path to add directive
        :param str dirname: Directive to add
        :param args: Value of the directive. ie. Listen 443, 443 is arg
        :type args: list or str
        """
        first_dir = aug_conf_path + "/directive[1]"
        self.aug.insert(first_dir, "directive", True)
        self.aug.set(first_dir, dirname)
        if isinstance(args, list):
            for i, value in enumerate(args, 1):
                self.aug.set(first_dir + "/arg[%d]" % (i), value)
        else:
            self.aug.set(first_dir + "/arg", args)

    def add_comment(self, aug_conf_path, comment):
        """Adds the comment to the augeas path

        :param str aug_conf_path: Augeas configuration path to add directive
        :param str comment: Comment content

        """
        self.aug.set(aug_conf_path + "/#comment[last() + 1]", comment)

    def find_comments(self, arg, start=None):
        """Finds a comment with specified content from the provided DOM path

        :param str arg: Comment content to search
        :param str start: Beginning Augeas path to begin looking

        :returns: List of augeas paths containing the comment content
        :rtype: list

        """
        if not start:
            start = get_aug_path(self.root)

        comments = self.aug.match("%s//*[label() = '#comment']" % start)

        results = []
        for comment in comments:
            c_content = self.aug.get(comment)
            if c_content and arg in c_content:
                results.append(comment)
        return results

    def find_dir(self, directive, arg=None, start=None, exclude=True):
        """Finds directive in the configuration.

        Recursively searches through config files to find directives
        Directives should be in the form of a case insensitive regex currently

        .. todo:: arg should probably be a list
        .. todo:: arg search currently only supports direct matching. It does
            not handle the case of variables or quoted arguments. This should
            be adapted to use a generic search for the directive and then do a
            case-insensitive self.get_arg filter

        Note: Augeas is inherently case sensitive while Apache is case
        insensitive.  Augeas 1.0 allows case insensitive regexes like
        regexp(/Listen/, "i"), however the version currently supported
        by Ubuntu 0.10 does not.  Thus I have included my own case insensitive
        transformation by calling case_i() on everything to maintain
        compatibility.

        :param str directive: Directive to look for
        :param arg: Specific value directive must have, None if all should
                    be considered
        :type arg: str or None

        :param str start: Beginning Augeas path to begin looking
        :param bool exclude: Whether or not to exclude directives based on
            variables and enabled modules

        """
        # Cannot place member variable in the definition of the function so...
        if not start:
            start = get_aug_path(self.loc["root"])

        # No regexp code
        # if arg is None:
        #     matches = self.aug.match(start +
        # "//*[self::directive='" + directive + "']/arg")
        # else:
        #     matches = self.aug.match(start +
        # "//*[self::directive='" + directive +
        #   "']/* [self::arg='" + arg + "']")

        # includes = self.aug.match(start +
        # "//* [self::directive='Include']/* [label()='arg']")

        regex = "(%s)|(%s)|(%s)" % (case_i(directive),
                                    case_i("Include"),
                                    case_i("IncludeOptional"))
        matches = self.aug.match(
            "%s//*[self::directive=~regexp('%s')]" % (start, regex))

        if exclude:
            matches = self.exclude_dirs(matches)

        if arg is None:
            arg_suffix = "/arg"
        else:
            arg_suffix = "/*[self::arg=~regexp('%s')]" % case_i(arg)

        ordered_matches = []  # type: List[str]

        # TODO: Wildcards should be included in alphabetical order
        # https://httpd.apache.org/docs/2.4/mod/core.html#include
        for match in matches:
            dir_ = self.aug.get(match).lower()
            if dir_ in ("include", "includeoptional"):
                ordered_matches.extend(self.find_dir(
                    directive, arg,
                    self._get_include_path(self.get_arg(match + "/arg")),
                    exclude))
            # This additionally allows Include
            if dir_ == directive.lower():
                ordered_matches.extend(self.aug.match(match + arg_suffix))

        return ordered_matches

    def get_all_args(self, match):
        """
        Tries to fetch all arguments for a directive. See get_arg.

        Note that if match is an ancestor node, it returns all names of
        child directives as well as the list of arguments.

        """

        if match[-1] != "/":
            match = match+"/"
        allargs = self.aug.match(match + '*')
        return [self.get_arg(arg) for arg in allargs]

    def get_arg(self, match):
        """Uses augeas.get to get argument value and interprets result.

        This also converts all variables and parameters appropriately.

        """
        value = self.aug.get(match)

        # No need to strip quotes for variables, as apache2ctl already does
        # this, but we do need to strip quotes for all normal arguments.

        # Note: normal argument may be a quoted variable
        # e.g. strip now, not later
        if not value:
            return None
        value = value.strip("'\"")

        variables = ApacheParser.arg_var_interpreter.findall(value)

        for var in variables:
            # Strip off ${ and }
            try:
                value = value.replace(var, self.variables[var[2:-1]])
            except KeyError:
                raise errors.PluginError("Error Parsing variable: %s" % var)

        return value

    def get_root_augpath(self):
        """
        Returns the Augeas path of root configuration.
        """
        return get_aug_path(self.loc["root"])

    def exclude_dirs(self, matches):
        """Exclude directives that are not loaded into the configuration."""
        filters = [("ifmodule", self.modules.keys()), ("ifdefine", self.variables)]

        valid_matches = []

        for match in matches:
            for filter_ in filters:
                if not self._pass_filter(match, filter_):
                    break
            else:
                valid_matches.append(match)
        return valid_matches

    def _pass_filter(self, match, filter_):
        """Determine if directive passes a filter.

        :param str match: Augeas path
        :param list filter: list of tuples of form
            [("lowercase if directive", set of relevant parameters)]

        """
        match_l = match.lower()
        last_match_idx = match_l.find(filter_[0])

        while last_match_idx != -1:
            # Check args
            end_of_if = match_l.find("/", last_match_idx)
            # This should be aug.get (vars are not used e.g. parser.aug_get)
            expression = self.aug.get(match[:end_of_if] + "/arg")

            if expression.startswith("!"):
                # Strip off "!"
                if expression[1:] in filter_[1]:
                    return False
            else:
                if expression not in filter_[1]:
                    return False

            last_match_idx = match_l.find(filter_[0], end_of_if)

        return True

    def standard_path_from_server_root(self, arg):
        """Ensure paths are consistent and absolute

        :param str arg: Argument of directive

        :returns: Standardized argument path
        :rtype: str
        """
        # Remove beginning and ending quotes
        arg = arg.strip("'\"")

        # Standardize the include argument based on server root
        if not arg.startswith("/"):
            # Normpath will condense ../
            arg = os.path.normpath(os.path.join(self.root, arg))
        else:
            arg = os.path.normpath(arg)
        return arg

    def _get_include_path(self, arg):
        """Converts an Apache Include directive into Augeas path.

        Converts an Apache Include directive argument into an Augeas
        searchable path

        .. todo:: convert to use os.path.join()

        :param str arg: Argument of Include directive

        :returns: Augeas path string
        :rtype: str

        """
        # Check to make sure only expected characters are used <- maybe remove
        # validChars = re.compile("[a-zA-Z0-9.*?_-/]*")
        # matchObj = validChars.match(arg)
        # if matchObj.group() != arg:
        #     logger.error("Error: Invalid regexp characters in %s", arg)
        #     return []
        arg = self.standard_path_from_server_root(arg)

        # Attempts to add a transform to the file if one does not already exist
        if os.path.isdir(arg):
            self.parse_file(os.path.join(arg, "*"))
        else:
            self.parse_file(arg)

        # Argument represents an fnmatch regular expression, convert it
        # Split up the path and convert each into an Augeas accepted regex
        # then reassemble
        split_arg = arg.split("/")
        for idx, split in enumerate(split_arg):
            if any(char in ApacheParser.fnmatch_chars for char in split):
                # Turn it into an augeas regex
                # TODO: Can this instead be an augeas glob instead of regex
                split_arg[idx] = ("* [label()=~regexp('%s')]" %
                                  self.fnmatch_to_re(split))
        # Reassemble the argument
        # Note: This also normalizes the argument /serverroot/ -> /serverroot
        arg = "/".join(split_arg)

        return get_aug_path(arg)

    def fnmatch_to_re(self, clean_fn_match):
        """Method converts Apache's basic fnmatch to regular expression.

        Assumption - Configs are assumed to be well-formed and only writable by
        privileged users.

        https://apr.apache.org/docs/apr/2.0/apr__fnmatch_8h_source.html

        :param str clean_fn_match: Apache style filename match, like globs

        :returns: regex suitable for augeas
        :rtype: str

        """
        if sys.version_info < (3, 6):
            # This strips off final /Z(?ms)
            return fnmatch.translate(clean_fn_match)[:-7]  # pragma: no cover
        # Since Python 3.6, it returns a different pattern like (?s:.*\.load)\Z
        return fnmatch.translate(clean_fn_match)[4:-3]  # pragma: no cover

    def parse_file(self, filepath):
        """Parse file with Augeas

        Checks to see if file_path is parsed by Augeas
        If filepath isn't parsed, the file is added and Augeas is reloaded

        :param str filepath: Apache config file path

        """
        use_new, remove_old = self._check_path_actions(filepath)
        # Ensure that we have the latest Augeas DOM state on disk before
        # calling aug.load() which reloads the state from disk
        self.ensure_augeas_state()
        # Test if augeas included file for Httpd.lens
        # Note: This works for augeas globs, ie. *.conf
        if use_new:
            inc_test = self.aug.match(
                "/augeas/load/Httpd['%s' =~ glob(incl)]" % filepath)
            if not inc_test:
                # Load up files
                # This doesn't seem to work on TravisCI
                # self.aug.add_transform("Httpd.lns", [filepath])
                if remove_old:
                    self._remove_httpd_transform(filepath)
                self._add_httpd_transform(filepath)
                self.aug.load()

    def parsed_in_current(self, filep):
        """Checks if the file path is parsed by current Augeas parser config
        ie. returns True if the file is found on a path that's found in live
        Augeas configuration.

        :param str filep: Path to match

        :returns: True if file is parsed in existing configuration tree
        :rtype: bool
        """
        return self._parsed_by_parser_paths(filep, self.parser_paths)

    def parsed_in_original(self, filep):
        """Checks if the file path is parsed by existing Apache config.
        ie. returns True if the file is found on a path that matches Include or
        IncludeOptional statement in the Apache configuration.

        :param str filep: Path to match

        :returns: True if file is parsed in existing configuration tree
        :rtype: bool
        """
        return self._parsed_by_parser_paths(filep, self.existing_paths)

    def _parsed_by_parser_paths(self, filep, paths):
        """Helper function that searches through provided paths and returns
        True if file path is found in the set"""
        for directory in paths:
            for filename in paths[directory]:
                if fnmatch.fnmatch(filep, os.path.join(directory, filename)):
                    return True
        return False

    def _check_path_actions(self, filepath):
        """Determine actions to take with a new augeas path

        This helper function will return a tuple that defines
        if we should try to append the new filepath to augeas
        parser paths, and / or remove the old one with more
        narrow matching.

        :param str filepath: filepath to check the actions for

        """

        try:
            new_file_match = os.path.basename(filepath)
            existing_matches = self.parser_paths[os.path.dirname(filepath)]
            if "*" in existing_matches:
                use_new = False
            else:
                use_new = True
            remove_old = new_file_match == "*"
        except KeyError:
            use_new = True
            remove_old = False
        return use_new, remove_old

    def _remove_httpd_transform(self, filepath):
        """Remove path from Augeas transform

        :param str filepath: filepath to remove
        """

        remove_basenames = self.parser_paths[os.path.dirname(filepath)]
        remove_dirname = os.path.dirname(filepath)
        for name in remove_basenames:
            remove_path = remove_dirname + "/" + name
            remove_inc = self.aug.match(
                "/augeas/load/Httpd/incl [. ='%s']" % remove_path)
            self.aug.remove(remove_inc[0])
        self.parser_paths.pop(remove_dirname)

    def _add_httpd_transform(self, incl):
        """Add a transform to Augeas.

        This function will correctly add a transform to augeas
        The existing augeas.add_transform in python doesn't seem to work for
        Travis CI as it loads in libaugeas.so.0.10.0

        :param str incl: filepath to include for transform

        """
        last_include = self.aug.match("/augeas/load/Httpd/incl [last()]")
        if last_include:
            # Insert a new node immediately after the last incl
            self.aug.insert(last_include[0], "incl", False)
            self.aug.set("/augeas/load/Httpd/incl[last()]", incl)
        # On first use... must load lens and add file to incl
        else:
            # Augeas uses base 1 indexing... insert at beginning...
            self.aug.set("/augeas/load/Httpd/lens", "Httpd.lns")
            self.aug.set("/augeas/load/Httpd/incl", incl)
        # Add included path to paths dictionary
        try:
            self.parser_paths[os.path.dirname(incl)].append(
                os.path.basename(incl))
        except KeyError:
            self.parser_paths[os.path.dirname(incl)] = [
                os.path.basename(incl)]

    def standardize_excl(self):
        """Standardize the excl arguments for the Httpd lens in Augeas.

        Note: Hack!
        Standardize the excl arguments for the Httpd lens in Augeas
        Servers sometimes give incorrect defaults
        Note: This problem should be fixed in Augeas 1.0.  Unfortunately,
        Augeas 0.10 appears to be the most popular version currently.

        """
        # attempt to protect against augeas error in 0.10.0 - ubuntu
        # *.augsave -> /*.augsave upon augeas.load()
        # Try to avoid bad httpd files
        # There has to be a better way... but after a day and a half of testing
        # I had no luck
        # This is a hack... work around... submit to augeas if still not fixed

        excl = ["*.augnew", "*.augsave", "*.dpkg-dist", "*.dpkg-bak",
                "*.dpkg-new", "*.dpkg-old", "*.rpmsave", "*.rpmnew",
                "*~",
                self.root + "/*.augsave",
                self.root + "/*~",
                self.root + "/*/*augsave",
                self.root + "/*/*~",
                self.root + "/*/*/*.augsave",
                self.root + "/*/*/*~"]

        for i, excluded in enumerate(excl, 1):
            self.aug.set("/augeas/load/Httpd/excl[%d]" % i, excluded)

        self.aug.load()

    def _set_locations(self):
        """Set default location for directives.

        Locations are given as file_paths
        .. todo:: Make sure that files are included

        """
        default = self.loc["root"]

        temp = os.path.join(self.root, "ports.conf")
        if os.path.isfile(temp):
            listen = temp
            name = temp
        else:
            listen = default
            name = default

        return {"default": default, "listen": listen, "name": name}

    def _find_config_root(self):
        """Find the Apache Configuration Root file."""
        location = ["apache2.conf", "httpd.conf", "conf/httpd.conf"]
        for name in location:
            if os.path.isfile(os.path.join(self.root, name)):
                return os.path.join(self.root, name)
        raise errors.NoInstallationError("Could not find configuration root")


def case_i(string):
    """Returns case insensitive regex.

    Returns a sloppy, but necessary version of a case insensitive regex.
    Any string should be able to be submitted and the string is
    escaped and then made case insensitive.
    May be replaced by a more proper /i once augeas 1.0 is widely
    supported.

    :param str string: string to make case i regex

    """
    return "".join("[" + c.upper() + c.lower() + "]"
                    if c.isalpha() else c for c in re.escape(string))


def get_aug_path(file_path):
    """Return augeas path for full filepath.

    :param str file_path: Full filepath

    """
    return "/files%s" % file_path
