"""
This is a heavily hacked version of ConfigParser to keep the order in
which options and sections are read, and allow multiple options with
the same key.
"""

import contextlib
import os
import re
import string

__all__ = [
    "MAX_INTERPOLATION_DEPTH",
    "ConfigParser",
    "DuplicateSectionError",
    "InterpolationDepthError",
    "InterpolationError",
    "MissingSectionHeaderError",
    "NoOptionError",
    "NoSectionError",
    "ParsingError",
]

DEFAULTSECT = "DEFAULT"

MAX_INTERPOLATION_DEPTH = 10

# exception classes
class Error(Exception):
    def __init__(self, msg=''):
        self._msg = msg
        Exception.__init__(self, msg)
    def __repr__(self):
        return self._msg
    __str__ = __repr__

class NoSectionError(Error):
    def __init__(self, section):
        Error.__init__(self, 'No section: %s' % section)
        self.section = section

class DuplicateSectionError(Error):
    def __init__(self, section):
        Error.__init__(self, "Section %s already exists" % section)
        self.section = section

class NoOptionError(Error):
    def __init__(self, option, section):
        Error.__init__(self, "No option `%s' in section: %s" %
                       (option, section))
        self.option = option
        self.section = section

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

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

class ParsingError(Error):
    def __init__(self, filename):
        Error.__init__(self, 'File contains parsing errors: %s' % filename)
        self.filename = filename
        self.errors = []

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

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

class ConfigParser:
    def __init__(self, defaults=None):
        # Options are stored in __sections_list like this:
        # [(sectname, [(optname, optval), ...]), ...]
        self.__sections_list = []
        self.__sections_dict = {}
        if defaults is None:
            self.__defaults = {}
        else:
            self.__defaults = defaults

    def defaults(self):
        return self.__defaults

    def sections(self):
        return list(self.__sections_dict.keys())

    def has_section(self, section):
        return section in self.__sections_dict

    def options(self, section):
        self.__sections_dict[section]
        try:
            opts = list(self.__sections_dict[section].keys())
        except KeyError as e:
            raise NoSectionError(section) from e
        return list(self.__defaults.keys())+opts

    def read(self, filenames):
        if isinstance(filenames , str):
            filenames = [filenames]
        for filename in filenames:
            with contextlib.suppress(OSError), open(filename) as fp:
                self.__read(fp, filename)

    def readfp(self, fp, filename=None):
        if filename is None:
            try:
                filename = fp.name
            except AttributeError:
                filename = '<???>'
        self.__read(fp, filename)

    def set(self, section, option, value):
        if section in self.__sections_dict:
            sectdict = self.__sections_dict[section]
            sectlist = []
            self.__sections_list.append((section, sectlist))
        elif section == DEFAULTSECT:
            sectdict = self.__defaults
            sectlist = None
        else:
            sectdict = {}
            self.__sections_dict[section] = sectdict
            sectlist = []
            self.__sections_list.append((section, sectlist))
        xform = self.optionxform(option)
        sectdict[xform] = value
        if sectlist is not None:
            sectlist.append([xform, value])

    def get(self, section, option, raw=0, vars=None):
        d = self.__defaults.copy()
        try:
            d.update(self.__sections_dict[section])
        except KeyError as e:
            if section != DEFAULTSECT:
                raise NoSectionError(section) from e
        if vars:
            d.update(vars)
        option = self.optionxform(option)
        try:
            rawval = d[option]
        except KeyError as e:
            raise NoOptionError(option, section) from e
        if raw:
            return rawval
        return self.__interpolate(rawval, d, option, section)

    def getall(self, section, option, raw=0, vars=None):
        option = self.optionxform(option)
        values = []
        d = self.__defaults.copy()
        if section != DEFAULTSECT:
            for sectname, options in self.__sections_list:
                if sectname == section:
                    for optname, value in options:
                        if optname == option:
                            values.append(value)
                        d[optname] = value
        if raw:
            return values
        if vars:
            d.update(vars)
        for i in range(len(values)):
            values[i] = self.__interpolate(values[i], d, option, section)
        return values

    def walk(self, section, option=None, raw=0, vars=None):
        # Build dictionary for interpolation
        try:
            d = self.__sections_dict[section].copy()
        except KeyError as e:
            if section == DEFAULTSECT:
                d = {}
            else:
                raise NoSectionError(section) from e
        d.update(self.__defaults)
        if vars:
            d.update(vars)

        # Start walking
        if option:
            option = self.optionxform(option)
        if section != DEFAULTSECT:
            for sectname, options in self.__sections_list:
                if sectname == section:
                    for optname, value in options:
                        if not option or optname == option:
                            if not raw:
                                value = self.__interpolate(value, d, option, section)
                            yield (optname, value)

    def __interpolate(self, value, vars, option, section):
        rawval = value
        depth = 0
        while depth < 10:
            depth = depth + 1
            if value.find("%(") >= 0:
                try:
                    value = value % vars
                except KeyError as key:
                    raise InterpolationError(key, option, section, rawval) from key
            else:
                break
        if value.find("%(") >= 0:
            raise InterpolationDepthError(option, section, rawval)
        return value

    def __get(self, section, conv, option):
        return conv(self.get(section, option))

    def getint(self, section, option):
        return self.__get(section, int, option)

    def getfloat(self, section, option):
        return self.__get(section, float, option)

    def getboolean(self, section, option):
        states = {'1': 1, 'yes': 1, 'true': 1, 'on': 1,
                  '0': 0, 'no': 0, 'false': 0, 'off': 0}
        v = self.get(section, option)
        if v.lower() not in states:
            raise ValueError('Not a boolean: %s' % v)
        return states[v.lower()]

    def optionxform(self, optionstr):
        #return optionstr.lower()
        return optionstr

    def has_option(self, section, option):
        """Check for the existence of a given option in a given section."""
        if not section or section == "DEFAULT":
            return option in self.__defaults
        if not self.has_section(section):
            return 0
        option = self.optionxform(option)
        return option in self.__sections_dict[section]

    SECTCRE = re.compile(r'\[(?P<header>[^]]+)\]')
    OPTCRE = re.compile(r'(?P<option>\S+)\s*(?P<vi>[:=])\s*(?P<value>.*)$')

    def __read(self, fp, fpname):
        cursectdict: dict[str, str] | None = None
        cursectlist: list[list[str]] | None = None
        optname = None
        lineno = 0
        e: ParsingError | None = None
        while 1:
            line = fp.readline()
            if not line:
                break
            lineno = lineno + 1
            # comment or blank line?
            if line.strip() == '' or line[0] in '#;':
                continue
            if line.split()[0].lower() == 'rem' \
               and line[0] in "rR":      # no leading whitespace
                continue
            # continuation line?
            if line[0] in ' \t' and cursectdict is not None and optname:
                value = line.strip()
                if value:
                    k = self.optionxform(optname)
                    cursectdict[k] = "%s\n%s" % (cursectdict[k], value)
                    cursectlist[-1][1] = "%s\n%s" % (cursectlist[-1][1], value)
            # a section header or option header?
            else:
                # is it a section header?
                mo = self.SECTCRE.match(line)
                if mo:
                    sectname = mo.group('header')
                    if sectname in self.__sections_dict:
                        cursectdict = self.__sections_dict[sectname]
                        cursectlist = []
                        self.__sections_list.append((sectname, cursectlist))
                    elif sectname == DEFAULTSECT:
                        cursectdict = self.__defaults
                        cursectlist = None
                    else:
                        cursectdict = {}
                        self.__sections_dict[sectname] = cursectdict
                        cursectlist = []
                        self.__sections_list.append((sectname, cursectlist))
                    # So sections can't start with a continuation line
                    optname = None
                # no section header in the file?
                elif cursectdict is None:
                    raise MissingSectionHeaderError(fpname, lineno, repr(line))
                # an option line?
                else:
                    mo = self.OPTCRE.match(line)
                    if mo:
                        optname, vi, optval = mo.group('option', 'vi', 'value')
                        if vi in ('=', ':') and ';' in optval:
                            # ';' is a comment delimiter only if it follows
                            # a spacing character
                            pos = optval.find(';')
                            if pos and optval[pos-1] in string.whitespace:
                                optval = optval[:pos]
                        optval = optval.strip()
                        # allow empty values
                        if optval == '""':
                            optval = ''
                        xform = self.optionxform(optname)
                        cursectdict[xform] = optval
                        if cursectlist is not None:
                            cursectlist.append([xform, optval])
                    else:
                        # a non-fatal parsing error occurred.  set up the
                        # exception but keep going. the exception will be
                        # raised at the end of the file and will contain a
                        # list of all bogus lines
                        if not e:
                            e = ParsingError(fpname)
                        e.append(lineno, repr(line))
        # if any parsing errors occurred, raise an exception
        if e:
            raise e

# Here we wrap this hacked ConfigParser into something more useful
# for us.

class Config:
    def __init__(self):
        self._config = ConfigParser()
        self._wrapped = {}
        conffiles = []
        mgarepo_conf = os.environ.get("MGAREPO_CONF")
        if mgarepo_conf:
            conffiles.append(mgarepo_conf)
        else:
            conffiles.append("/etc/mgarepo.conf")
            conffiles.append(os.path.expanduser("~/.mgarepo/config"))
        for file in conffiles:
            if os.path.isfile(file):
                self._config.read(file)

    def wrap(self, section, handler, option=None):
        """Set one wrapper for a given section

        The wrapper must be a function
        f(section, option=None, default=None, walk=False).
        """
        self._wrapped[section] = handler

    def sections(self):
        try:
            return self._config.sections()
        except Error:
            return []

    def options(self, section):
        try:
            return self._config.options(section)
        except Error:
            return []

    def set(self, section, option, value):
        return self._config.set(section, option, value)

    def walk(self, section, option=None, raw=0, vars=None):
        handler = self._wrapped.get(section)
        if handler:
            return handler(section, option, walk=True)
        return self._config.walk(section, option, raw, vars)

    def get(self, section, option, default=None, raw=False, wrap=True):
        if wrap:
            handler = self._wrapped.get(section)
            if handler:
                handler = self._wrapped.get(section)
                return handler(section, option, default)
        try:
            return self._config.get(section, option, raw=raw)
        except Error:
            return default

    def getint(self, section, option, default=None):
        ret = self.get(section, option, default)
        if isinstance(ret, str):
            return int(ret)

    def getbool(self, section, option, default=None):
        ret = self.get(section, option, default)
        states = {'1': 1, 'yes': 1, 'true': 1, 'on': 1,
                  '0': 0, 'no': 0, 'false': 0, 'off': 0}
        if isinstance(ret, str) and ret.lower() in states:
            return states[ret.lower()]
        return default

def test():
    config = Config()
    def handler(section, option=None, default=None, walk=False):
        d = {"fulano": "ciclano",
             "foolano": "ceeclano"}
        if walk:
            return list(d.items())
        if option in d:
            return d[option]
        return config.get(section, option, default, wrap=False)
    config.wrap("users", handler=handler)
    print(config.get("users", "fulano")) # found in wrapper
    print(config.get("users", "andreas")) # found in repsys.conf
    print(config.walk("users"))

if __name__ == "__main__":
    test()
# vim:ts=4:sw=4:et