# Copyright (C) 2010  Leonard Thomas
#
# This file is part of Dodai.
#
# Dodai is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Dodai is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Dodai.  If not, see <http://www.gnu.org/licenses/>.

import os
import ConfigParser
from dodai.config.sections import ConfigSections
from dodai.exception import InvalidConfigParser
from dodai.exception import FileDoesNotExist
from dodai.exception import FileIsDirectory

class ConfigFiles(object):

    REQUIRED_METHODS = ['read', 'sections', 'options', 'get']

    def __init__(self, ordered_dict_object, section_object, string_object):

        self._ordered_dict_object = ordered_dict_object
        self._section_object = section_object
        self._string_object = string_object
        self.parser_objects = []
        self.files = self._ordered_dict_object()
        self.files_read = []

    def register_parser_object(self, parser_object):
        """Registers a config file parser with this object.  Raises
        InvalidConfigParser error if the parser does not have the 'read',
        'sections', 'options' and 'get' methods.

        """
        if self.check_parser_object(parser_object):
            self.parser_objects.append(parser_object)

    def check_parser_object(self, parser_object):
        """Checks the given parser object to insure it has all of the required
        methods needed to parse files.

        """
        for name in self.REQUIRED_METHODS:
            if not hasattr(parser_object, name):
                raise InvalidConfigParser(self.REQUIRED_METHODS,
                                          parser_object.__name__)
        return True

    def add(self, filename, encoding=None):
        """Adds the given filename to this object to be parsed.

        """
        if os.path.exists(filename):
            if os.path.isdir(filename):
                raise FileIsDirectory(filename)
            else:
                filename = os.path.realpath(filename)
                self.files[filename] = encoding
        else:
            raise FileDoesNotExist(filename)

    def _read(self):
        self.files_read = []
        out = self._ordered_dict_object()
        for filename, encoding in self.files.items():
            error = False
            for parser_obj in self.parser_objects:
                try:
                    parser = parser_obj()
                    parser.read(filename)
                except Exception, e:
                    error = True
                else:
                    out[filename] = self._ordered_dict_object()
                    out[filename]['encoding'] = encoding
                    out[filename]['parser'] = parser
                    self.files_read.append(filename)
                    error = False
                    break
            if error:
                raise e
        return out


    def load(self):
        """Returns a ConfigSections object, which acts like a dictionary,
        that contains all parsed data.

        """
        files = self._read()
        sections = ConfigSections(self._ordered_dict_object,
                                  self._section_object, self._string_object)
        for filename, data in files.items():
            encoding = data['encoding']
            parser = data['parser']
            sections(parser, encoding)
        return sections