"""Configuration file parser.

A configuration file consists of sections, lead by a "[section]" header,
and followed by "name: value" entries, with continuations and such in
the style of RFC 822.

Intrinsic defaults can be specified by passing them into the
ConfigParser constructor as a dictionary.

class:

ConfigParser -- responsible for parsing a list of
                    configuration files, and managing the parsed database.

    methods:

    __init__(defaults=None, dict_type=_default_dict, allow_no_value=False,
             delimiters=('=', ':'), comment_prefixes=('#', ';'),
             inline_comment_prefixes=None, strict=True,
             empty_lines_in_values=True):
        Create the parser. When `defaults' is given, it is initialized into the
        dictionary or intrinsic defaults. The keys must be strings, the values
        must be appropriate for %()s string interpolation.

        When `dict_type' is given, it will be used to create the dictionary
        objects for the list of sections, for the options within a section, and
        for the default values.

        When `delimiters' is given, it will be used as the set of substrings
        that divide keys from values.

        When `comment_prefixes' is given, it will be used as the set of
        substrings that prefix comments in empty lines. Comments can be
        indented.

        When `inline_comment_prefixes' is given, it will be used as the set of
        substrings that prefix comments in non-empty lines.

        When `strict` is True, the parser won't allow for any section or option
        duplicates while reading from a single source (file, string or
        dictionary). Default is True.

        When `empty_lines_in_values' is False (default: True), each empty line
        marks the end of an option. Otherwise, internal empty lines of
        a multiline option are kept as part of the value.

        When `allow_no_value' is True (default: False), options without
        values are accepted; the value presented for these is None.

    sections()
        Return all the configuration section names, sans DEFAULT.

    has_section(section)
        Return whether the given section exists.

    has_option(section, option)
        Return whether the given option exists in the given section.

    options(section)
        Return list of configuration options for the named section.

    read(filenames, encoding=None)
        Read and parse the list of named configuration files, given by
        name.  A single filename is also allowed.  Non-existing files
        are ignored.  Return list of successfully read files.

    read_file(f, filename=None)
        Read and parse one configuration file, given as a file object.
        The filename defaults to f.name; it is only used in error
        messages (if f has no `name' attribute, the string `<???>' is used).

    read_string(string)
        Read configuration from a given string.

    read_dict(dictionary)
        Read configuration from a dictionary. Keys are section names,
        values are dictionaries with keys and values that should be present
        in the section. If the used dictionary type preserves order, sections
        and their keys will be added in order. Values are automatically
        converted to strings.

    get(section, option, raw=False, vars=None, fallback=_UNSET)
        Return a string value for the named option.  All % interpolations are
        expanded in the return values, based on the defaults passed into the
        constructor and the DEFAULT section.  Additional substitutions may be
        provided using the `vars' argument, which must be a dictionary whose
        contents override any pre-existing defaults. If `option' is a key in
        `vars', the value from `vars' is used.

    getint(section, options, raw=False, vars=None, fallback=_UNSET)
        Like get(), but convert value to an integer.

    getfloat(section, options, raw=False, vars=None, fallback=_UNSET)
        Like get(), but convert value to a float.

    getboolean(section, options, raw=False, vars=None, fallback=_UNSET)
        Like get(), but convert value to a boolean (currently case
        insensitively defined as 0, false, no, off for False, and 1, true,
        yes, on for True).  Returns False or True.

    items(section=_UNSET, raw=False, vars=None)
        If section is given, return a list of tuples with (section_name,
        section_proxy) for each section, including DEFAULTSECT. Otherwise,
        return a list of tuples with (name, value) for each option
        in the section.

    remove_section(section)
        Remove the given file section and all its options.

    remove_option(section, option)
        Remove the given option from the given section.

    set(section, option, value)
        Set the given option.

    write(fp, space_around_delimiters=True)
        Write the configuration state in .ini format. If
        `space_around_delimiters' is True (the default), delimiters
        between keys and values are surrounded by spaces.
"""

from collections import MutableMapping, OrderedDict as _default_dict, _ChainMap
import functools
import io
import itertools
import re
import sys
import warnings

__all__ = ["NoSectionError", "DuplicateOptionError", "DuplicateSectionError",
           "NoOptionError", "InterpolationError", "InterpolationDepthError",
           "InterpolationSyntaxError", "ParsingError",
           "MissingSectionHeaderError",
           "ConfigParser", "SafeConfigParser", "RawConfigParser",
           "DEFAULTSECT", "MAX_INTERPOLATION_DEPTH"]

DEFAULTSECT = "DEFAULT"

MAX_INTERPOLATION_DEPTH = 10



# exception classes
class Error(Exception):
    """Base class for ConfigParser exceptions."""

    def _get_message(self):
        """Getter for 'message'; needed only to override deprecation in
        BaseException.
        """
        return self.__message

    def _set_message(self, value):
        """Setter for 'message'; needed only to override deprecation in
        BaseException.
        """
        self.__message = value

    # BaseException.message has been deprecated since Python 2.6.  To prevent
    # DeprecationWarning from popping up over this pre-existing attribute, use
    # a new property that takes lookup precedence.
    message = property(_get_message, _set_message)

    def __init__(self, msg=''):
        self.message = msg
        Exception.__init__(self, msg)

    def __repr__(self):
        return self.message

    __str__ = __repr__


class NoSectionError(Error):
    """Raised when no section matches a requested option."""

    def __init__(self, section):
        Error.__init__(self, 'No section: %r' % (section,))
        self.section = section
        self.args = (section, )


class DuplicateSectionError(Error):
    """Raised when a section is repeated in an input source.

    Possible repetitions that raise this exception are: multiple creation
    using the API or in strict parsers when a section is found more than once
    in a single input file, string or dictionary.
    """

    def __init__(self, section, source=None, lineno=None):
        msg = [repr(section), " already exists"]
        if source is not None:
            message = ["While reading from ", source]
            if lineno is not None:
                message.append(" [line {0:2d}]".format(lineno))
            message.append(": section ")
            message.extend(msg)
            msg = message
        else:
            msg.insert(0, "Section ")
        Error.__init__(self, "".join(msg))
        self.section = section
        self.source = source
        self.lineno = lineno
        self.args = (section, source, lineno)


class DuplicateOptionError(Error):
    """Raised by strict parsers when an option is repeated in an input source.

    Current implementation raises this exception only when an option is found
    more than once in a single file, string or dictionary.
    """

    def __init__(self, section, option, source=None, lineno=None):
        msg = [repr(option), " in section ", repr(section),
               " already exists"]
        if source is not None:
            message = ["While reading from ", source]
            if lineno is not None:
                message.append(" [line {0:2d}]".format(lineno))
            message.append(": option ")
            message.extend(msg)
            msg = message
        else:
            msg.insert(0, "Option ")
        Error.__init__(self, "".join(msg))
        self.section = section
        self.option = option
        self.source = source
        self.lineno = lineno
        self.args = (section, option, source, lineno)


class NoOptionError(Error):
    """A requested option was not found."""

    def __init__(self, option, section):
        Error.__init__(self, "No option %r in section: %r" %
                       (option, section))
        self.option = option
        self.section = section
        self.args = (option, section)


class InterpolationError(Error):
    """Base class for interpolation-related exceptions."""

    def __init__(self, option, section, msg):
        Error.__init__(self, msg)
        self.option = option
        self.section = section
        self.args = (option, section, msg)


class InterpolationMissingOptionError(InterpolationError):
    """A string substitution required a setting which was not available."""

    def __init__(self, option, section, rawval, reference):
        msg = ("Bad value substitution:\n"
               "\tsection: [%s]\n"
               "\toption : %s\n"
               "\tkey    : %s\n"
               "\trawval : %s\n"
               % (section, option, reference, rawval))
        InterpolationError.__init__(self, option, section, msg)
        self.reference = reference
        self.args = (option, section, rawval, reference)


class InterpolationSyntaxError(InterpolationError):
    """Raised when the source text contains invalid syntax.

    Current implementation raises this exception when the source text into
    which substitutions are made does not conform to the required syntax.
    """


class InterpolationDepthError(InterpolationError):
    """Raised when substitutions are nested too deeply."""

    def __init__(self, option, section, rawval):
        msg = ("Value interpolation too deeply recursive:\n"
               "\tsection: [%s]\n"
               "\toption : %s\n"
               "\trawval : %s\n"
               % (section, option, rawval))
        InterpolationError.__init__(self, option, section, msg)
        self.args = (option, section, rawval)


class ParsingError(Error):
    """Raised when a configuration file does not follow legal syntax."""

    def __init__(self, source=None, filename=None):
        # Exactly one of `source'/`filename' arguments has to be given.
        # `filename' kept for compatibility.
        if filename and source:
            raise ValueError("Cannot specify both `filename' and `source'. "
                             "Use `source'.")
        elif not filename and not source:
            raise ValueError("Required argument `source' not given.")
        elif filename:
            source = filename
        Error.__init__(self, 'Source contains parsing errors: %s' % source)
        self.source = source
        self.errors = []
        self.args = (source, )

    @property
    def filename(self):
        """Deprecated, use `source'."""
        warnings.warn(
            "The 'filename' attribute will be removed in future versions.  "
            "Use 'source' instead.",
            DeprecationWarning, stacklevel=2
        )
        return self.source

    @filename.setter
    def filename(self, value):
        """Deprecated, user `source'."""
        warnings.warn(
            "The 'filename' attribute will be removed in future versions.  "
            "Use 'source' instead.",
            DeprecationWarning, stacklevel=2
        )
        self.source = value

    def append(self, lineno, line):
        self.errors.append((lineno, line))
        self.message += '\n\t[line %2d]: %s' % (lineno, line)


class MissingSectionHeaderError(ParsingError):
    """Raised when a key-value pair is found before any section header."""

    def __init__(self, filename, lineno, line):
        Error.__init__(
            self,
            'File contains no section headers.\nfile: %s, line: %d\n%r' %
            (filename, lineno, line))
        self.source = filename
        self.lineno = lineno
        self.line = line
        self.args = (filename, lineno, line)


# Used in parser getters to indicate the default behaviour when a specific
# option is not found it to raise an exception. Created to enable `None' as
# a valid fallback value.
_UNSET = object()


class Interpolation:
    """Dummy interpolation that passes the value through with no changes."""

    def before_get(self, parser, section, option, value, defaults):
        return value

    def before_set(self, parser, section, option, value):
        return value

    def before_read(self, parser, section, option, value):
        return value

    def before_write(self, parser, section, option, value):
        return value


class BasicInterpolation(Interpolation):
    """Interpolation as implemented in the classic ConfigParser.

    The option values can contain format strings which refer to other values in
    the same section, or values in the special default section.

    For example:

        something: %(dir)s/whatever

    would resolve the "%(dir)s" to the value of dir.  All reference
    expansions are done late, on demand. If a user needs to use a bare % in
    a configuration file, she can escape it by writing %%. Other other % usage
    is considered a user error and raises `InterpolationSyntaxError'."""

    _KEYCRE = re.compile(r"%\(([^)]+)\)s")

    def before_get(self, parser, section, option, value, defaults):
        L = []
        self._interpolate_some(parser, option, L, value, section, defaults, 1)
        return ''.join(L)

    def before_set(self, parser, section, option, value):
        tmp_value = value.replace('%%', '') # escaped percent signs
        tmp_value = self._KEYCRE.sub('', tmp_value) # valid syntax
        if '%' in tmp_value:
            raise ValueError("invalid interpolation syntax in %r at "
                             "position %d" % (value, tmp_value.find('%')))
        return value

    def _interpolate_some(self, parser, option, accum, rest, section, map,
                          depth):
        if depth > MAX_INTERPOLATION_DEPTH:
            raise InterpolationDepthError(option, section, rest)
        while rest:
            p = rest.find("%")
            if p < 0:
                accum.append(rest)
                return
            if p > 0:
                accum.append(rest[:p])
                rest = rest[p:]
            # p is no longer used
            c = rest[1:2]
            if c == "%":
                accum.append("%")
                rest = rest[2:]
            elif c == "(":
                m = self._KEYCRE.match(rest)
                if m is None:
                    raise InterpolationSyntaxError(option, section,
                        "bad interpolation variable reference %r" % rest)
                var = parser.optionxform(m.group(1))
                rest = rest[m.end():]
                try:
                    v = map[var]
                except KeyError:
                    raise InterpolationMissingOptionError(
                        option, section, rest, var)
                if "%" in v:
                    self._interpolate_some(parser, option, accum, v,
                                           section, map, depth + 1)
                else:
                    accum.append(v)
            else:
                raise InterpolationSyntaxError(
                    option, section,
                    "'%%' must be followed by '%%' or '(', "
                    "found: %r" % (rest,))


class ExtendedInterpolation(Interpolation):
    """Advanced variant of interpolation, supports the syntax used by
    `zc.buildout'. Enables interpolation between sections."""

    _KEYCRE = re.compile(r"\$\{([^}]+)\}")

    def before_get(self, parser, section, option, value, defaults):
        L = []
        self._interpolate_some(parser, option, L, value, section, defaults, 1)
        return ''.join(L)

    def before_set(self, parser, section, option, value):
        tmp_value = value.replace('$$', '') # escaped dollar signs
        tmp_value = self._KEYCRE.sub('', tmp_value) # valid syntax
        if '$' in tmp_value:
            raise ValueError("invalid interpolation syntax in %r at "
                             "position %d" % (value, tmp_value.find('%')))
        return value

    def _interpolate_some(self, parser, option, accum, rest, section, map,
                          depth):
        if depth > MAX_INTERPOLATION_DEPTH:
            raise InterpolationDepthError(option, section, rest)
        while rest:
            p = rest.find("$")
            if p < 0:
                accum.append(rest)
                return
            if p > 0:
                accum.append(rest[:p])
                rest = rest[p:]
            # p is no longer used
            c = rest[1:2]
            if c == "$":
                accum.append("$")
                rest = rest[2:]
            elif c == "{":
                m = self._KEYCRE.match(rest)
                if m is None:
                    raise InterpolationSyntaxError(option, section,
                        "bad interpolation variable reference %r" % rest)
                path = m.group(1).split(':')
                rest = rest[m.end():]
                sect = section
                opt = option
                try:
                    if len(path) == 1:
                        opt = parser.optionxform(path[0])
                        v = map[opt]
                    elif len(path) == 2:
                        sect = path[0]
                        opt = parser.optionxform(path[1])
                        v = parser.get(sect, opt, raw=True)
                    else:
                        raise InterpolationSyntaxError(
                            option, section,
                            "More than one ':' found: %r" % (rest,))
                except (KeyError, NoSectionError, NoOptionError):
                    raise InterpolationMissingOptionError(
                        option, section, rest, ":".join(path))
                if "$" in v:
                    self._interpolate_some(parser, opt, accum, v, sect,
                                           dict(parser.items(sect, raw=True)),
                                           depth + 1)
                else:
                    accum.append(v)
            else:
                raise InterpolationSyntaxError(
                    option, section,
                    "'$' must be followed by '$' or '{', "
                    "found: %r" % (rest,))


class LegacyInterpolation(Interpolation):
    """Deprecated interpolation used in old versions of ConfigParser.
    Use BasicInterpolation or ExtendedInterpolation instead."""

    _KEYCRE = re.compile(r"%\(([^)]*)\)s|.")

    def before_get(self, parser, section, option, value, vars):
        rawval = value
        depth = MAX_INTERPOLATION_DEPTH
        while depth:                    # Loop through this until it's done
            depth -= 1
            if value and "%(" in value:
                replace = functools.partial(self._interpolation_replace,
                                            parser=parser)
                value = self._KEYCRE.sub(replace, value)
                try:
                    value = value % vars
                except KeyError as e:
                    raise InterpolationMissingOptionError(
                        option, section, rawval, e.args[0])
            else:
                break
        if value and "%(" in value:
            raise InterpolationDepthError(option, section, rawval)
        return value

    def before_set(self, parser, section, option, value):
        return value

    @staticmethod
    def _interpolation_replace(match, parser):
        s = match.group(1)
        if s is None:
            return match.group()
        else:
            return "%%(%s)s" % parser.optionxform(s)


class RawConfigParser(MutableMapping):
    """ConfigParser that does not do interpolation."""

    # Regular expressions for parsing section headers and options
    _SECT_TMPL = r"""
        \[                                 # [
        (?P<header>[^]]+)                  # very permissive!
        \]                                 # ]
        """
    _OPT_TMPL = r"""
        (?P<option>.*?)                    # very permissive!
        \s*(?P<vi>{delim})\s*              # any number of space/tab,
                                           # followed by any of the
                                           # allowed delimiters,
                                           # followed by any space/tab
        (?P<value>.*)$                     # everything up to eol
        """
    _OPT_NV_TMPL = r"""
        (?P<option>.*?)                    # very permissive!
        \s*(?:                             # any number of space/tab,
        (?P<vi>{delim})\s*                 # optionally followed by
                                           # any of the allowed
                                           # delimiters, followed by any
                                           # space/tab
        (?P<value>.*))?$                   # everything up to eol
        """
    # Interpolation algorithm to be used if the user does not specify another
    _DEFAULT_INTERPOLATION = Interpolation()
    # Compiled regular expression for matching sections
    SECTCRE = re.compile(_SECT_TMPL, re.VERBOSE)
    # Compiled regular expression for matching options with typical separators
    OPTCRE = re.compile(_OPT_TMPL.format(delim="=|:"), re.VERBOSE)
    # Compiled regular expression for matching options with optional values
    # delimited using typical separators
    OPTCRE_NV = re.compile(_OPT_NV_TMPL.format(delim="=|:"), re.VERBOSE)
    # Compiled regular expression for matching leading whitespace in a line
    NONSPACECRE = re.compile(r"\S")
    # Possible boolean values in the configuration.
    BOOLEAN_STATES = {'1': True, 'yes': True, 'true': True, 'on': True,
                      '0': False, 'no': False, 'false': False, 'off': False}

    def __init__(self, defaults=None, dict_type=_default_dict,
                 allow_no_value=False, *, delimiters=('=', ':'),
                 comment_prefixes=('#', ';'), inline_comment_prefixes=None,
                 strict=True, empty_lines_in_values=True,
                 default_section=DEFAULTSECT,
                 interpolation=_UNSET):

        self._dict = dict_type
        self._sections = self._dict()
        self._defaults = self._dict()
        self._proxies = self._dict()
        self._proxies[default_section] = SectionProxy(self, default_section)
        if defaults:
            for key, value in defaults.items():
                self._defaults[self.optionxform(key)] = value
        self._delimiters = tuple(delimiters)
        if delimiters == ('=', ':'):
            self._optcre = self.OPTCRE_NV if allow_no_value else self.OPTCRE
        else:
            d = "|".join(re.escape(d) for d in delimiters)
            if allow_no_value:
                self._optcre = re.compile(self._OPT_NV_TMPL.format(delim=d),
                                          re.VERBOSE)
            else:
                self._optcre = re.compile(self._OPT_TMPL.format(delim=d),
                                          re.VERBOSE)
        self._comment_prefixes = tuple(comment_prefixes or ())
        self._inline_comment_prefixes = tuple(inline_comment_prefixes or ())
        self._strict = strict
        self._allow_no_value = allow_no_value
        self._empty_lines_in_values = empty_lines_in_values
        self.default_section=default_section
        self._interpolation = interpolation
        if self._interpolation is _UNSET:
            self._interpolation = self._DEFAULT_INTERPOLATION
        if self._interpolation is None:
            self._interpolation = Interpolation()