#

# Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

# All rights reserved.

# This component and the accompanying materials are made available

# under the terms of "Eclipse Public License v1.0"

# which accompanies this distribution, and is available

# at the URL "http://www.eclipse.org/legal/epl-v10.html".

#

# Initial Contributors:

# Nokia Corporation - initial contribution.

#

# Contributors:

#

# Description: 

#

import os

import re

import logging

import xml.parsers.expat

try:

    from cElementTree import ElementTree

except ImportError:

    try:    

        from elementtree import ElementTree

    except ImportError:

        try:

            from xml.etree import cElementTree as ElementTree

        except ImpotError:

            from xml.etree import ElementTree

from cone.public import exceptions  

from cone.public import api, utils

#from cone.storage.configurationpersistence import ConfigurationReader, ConfigurationWriter

from cone.storage import metadata, common

from cone.confml import persistentconfml

debug = 0

class FileStorage(common.StorageBase):

    """

    A file system based implementation for Storage.

    @param path : path to the storage folder

    @param mode: the mode for the folder. Default is a=append that expects the folder to exist.

    """

    def __init__(self,path,mode="r", **kwargs):

        super(FileStorage, self).__init__(path)

        self.logger = logging.getLogger('cone')

        self.logger.debug("FileStorage path %s" % self.get_path())

        self.persistentmodule = persistentconfml

        self.mode = mode

        if mode.find("a")!=-1 or mode.find("r")!=-1:

            # check that the given folder exists and is a folder    

            if not os.path.isdir(self.get_path()):

                raise exceptions.StorageException("The given data folder for storage does not exist! %s" % self.get_path())

        elif mode.find("w")!=-1:

            # check if the given folder exists and create it if it does not

            if not os.path.exists(os.path.abspath(self.get_path())):

                os.makedirs(self.get_path())

        else:

            raise exceptions.StorageException("Unsupported creation mode given! %s" % mode)

    @classmethod

    def supported_storage(cls,path):

        """

        Class method for determing if the given clas supports a storage by given path. 

        E.g. foo.zip, foo.cpd, foo/bar, http://foo.com/

        @param path:

        @return: Boolean value. True if the storage of the path is supported. False if not.  

        """

        if path.startswith('http://'):

            return False

        path = os.path.abspath(path)

        (name,ext) = os.path.splitext(path)

        if path != "" and ext == "":

            return True

        elif os.path.isdir(path):

            return True

        else:

            return False

    def open_resource(self,path,mode="r"):

        # make sure that path exists if we are creating a file

        path = utils.resourceref.remove_end_slash(path)

        path = utils.resourceref.remove_begin_slash(path)

        path = utils.resourceref.join_refs([self.get_current_path(), path])

        fullpath = utils.resourceref.join_refs([self.get_path(),path])

        if mode.find("w") != -1:

            dirpath = os.path.dirname(fullpath)

            if not os.path.exists(dirpath):

                os.makedirs(dirpath)

        try:

            res = FileResource(self,path,mode,open(fullpath,mode)) 

            self.__opened__(res)

            return res

        except IOError,e:

            raise exceptions.NotResource("%s, %s" % (path,e) )

    def delete_resource(self,path):

        if self.is_resource(path):

            try:

                path = utils.resourceref.remove_begin_slash(path)

                path = utils.resourceref.join_refs([self.get_path(),self.get_current_path(),path])

                for res in self.__get_open__(path):

                    res.close()

                    self.__closed__(res)

                os.unlink(path)

            except IOError:

                raise exceptions.NotResource(path)

        else:

            raise exceptions.NotResource(path)

    def close_resource(self, res):

        """

        Close the given resource instance. Normally this is called by the Resource object 

        in its own close.

        @param res: the resource object to close. 

        """

        try:

            self.__closed__(res)

            #if not res.get_mode() == api.Storage.MODE_READ:

            #    self._get(utils.resourceref.to_dref(res.path)).data = res.getvalue()

        except KeyError,e:

            raise exceptions.StorageException("No such %s open resource! %s" % (res.path,e))

    def save_resource(self, res):

        """

        Flush the changes of a given resource instance. Normally this is called by the Resource object 

        in its own save.

        @param res: the resource to the resource to save. 

        """

        if not self.__has_resource__(res):

            raise exceptions.NotResource("No such %s open resource!" % res.path)

        else:

            res.save()

    def is_resource(self,path):

        path = utils.resourceref.remove_begin_slash(path)

        path = utils.resourceref.join_refs([self.get_current_path(), path])

        path = utils.resourceref.join_refs([self.get_path(),path])

        norm_path = os.path.normpath(path)

        return os.path.isfile(norm_path)

    def fix_entry(self,entry,current_root):

        entry = entry.replace(current_root,'')

        entry = entry.replace("\\","/")

        entry = utils.resourceref.remove_begin_slash(entry)

        return entry

    def list_resources(self,path,recurse=False,empty_folders=False):

        """

        Get an array of files in a folder

        """

        retarray = []

        path = utils.resourceref.remove_begin_slash(path)

        fullpath = utils.resourceref.join_refs([self.get_path(),self.get_current_path(),path])

        joined = os.path.join(self.get_path(), self.get_current_path())

        current_root = os.path.normpath(os.path.abspath(joined))

        # return always unix type file paths

        if recurse:    

            # Walk through all files in the layer

            for root, dirs, files in os.walk(fullpath):

                for name in files:

                    entry = os.path.join(root, name)

                    entry = os.path.normpath(os.path.abspath(entry))

                    if os.path.isfile(entry):

                        retarray.append(self.fix_entry(entry,current_root))

                if empty_folders: 

                    for name in dirs:

                        entry = os.path.join(root, name)

                        entry = os.path.normpath(os.path.abspath(entry))

                        if  os.path.isdir(entry)  and  len(os.listdir(entry)) ==0:

                            retarray.append(self.fix_entry(entry,current_root))

        else:

            filelist = os.listdir(fullpath)

            for name in filelist:

                entry = os.path.join(path, name)

                entry = os.path.normpath(entry)

                entry = entry.replace("\\","/")               

                entry = utils.resourceref.remove_begin_slash(entry)

                # ignore non file entries

                fileentry = os.path.join(current_root,entry)

                if os.path.isfile(fileentry):

                    if debug: print "list_resources adding %s" % entry

                    retarray.append(entry)

                if os.path.isdir(fileentry) and empty_folders:

                    if debug: print "list_resources adding %s" % entry

                    retarray.append(entry)

        return retarray

    def import_resources(self,paths,storage):

        for path in paths:

            if not storage.is_resource(path):

                logging.getLogger('cone').warning("The given path is not a Resource in the storage %s! Ignoring from export!" % path)

                continue

            wres = self.open_resource(path,'wb')

            res  = storage.open_resource(path,"rb")

            wres.write(res.read())

            wres.close()

            res.close()

    def export_resources(self,paths,storage,empty_folders=False):

        """

        """

        for path in paths:

            if not self.is_resource(path) and empty_folders==False:

                logging.getLogger('cone').warning("The given path is not a Resource in this storage %s! Ignoring from export!" % path)

                continue

            if self.is_resource(path):

                wres = storage.open_resource(path,'wb')

                res  = self.open_resource(path,"rb")

                wres.write(res.read())

                wres.close()

                res.close()

            if  self.is_folder(path) and  empty_folders:

                storage.create_folder(path)

    def create_folder(self,path):

        """

        Create a folder entry to a path

        @param path : path to the folder

        """

        path = utils.resourceref.join_refs([self.get_path(), self.get_current_path(), path])

        if not os.path.exists(path):

            os.makedirs(path)

    def delete_folder(self,path):

        """

        Delete a folder entry from a path. The path must be empty.

        @param path : path to the folder

        """

        path = utils.resourceref.join_refs([self.get_path(), self.get_current_path(), path])

        if os.path.isdir(path):

            os.rmdir(path)

        else:

            raise exceptions.StorageException("Not a folder %s" % path)

    def is_folder(self,path):

        """

        Check if the given path is an existing folder in the storage

        @param path : path to the folder

        """

        path = utils.resourceref.join_refs([self.get_path(), self.get_current_path(), path])

        return os.path.isdir(path)

    def unload(self, path, object):

        """

        Dump a given object to the storage (reference is fetched from the object)

        @param object: The object to dump to the storage, which is expected to be an instance 

        of Base class.

        """

        # Add the current path in front of the given path

        path = utils.resourceref.join_refs([self.get_current_path(), path])

        if not isinstance(object, api.Configuration):

            raise exceptions.StorageException("Cannot dump object type %s" % object.__class__)

        # Skip the unload storing to storage if the storage is opened in read mode

        if self.get_mode(self.mode) != api.Storage.MODE_READ:

            res = self.open_resource(path,"wb")

            data = self.persistentmodule.dumps(object)

            res.write(data)

            res.close()

        return

    def load(self, path):

        """

        Load an from a reference.

        """

        # Add the current path in front of the given path

        path = utils.resourceref.join_refs([self.get_current_path(), path])

        if not utils.resourceref.get_ext(path) == "confml":

            raise exceptions.StorageException("Cannot load reference type %s" % utils.resourceref.get_ext(path))

        if self.is_resource(path):

            res = self.open_resource(path,"r")

            # read the resource with persistentmodule

            try:

                obj = self.persistentmodule.loads(res.read())

                #obj.set_path(path)

                res.close()

                return obj

            except exceptions.ParseError,e:

                logging.getLogger('cone').error("Resource %s parsing failed with exception: %s" % (path,e))

                # returning an empty config in case of xml parsing failure.

                return api.Configuration(path)

        else:

            raise exceptions.NotResource("No such %s resource!" % path)

class FileResource(api.Resource):

    def __init__(self,storage,path,mode,handle):

        api.Resource.__init__(self,storage,path,mode)

        self.handle = handle

    def read(self,bytes=0):

        if bytes == 0:

            return self.handle.read()

        else:

            return self.handle.read(bytes)

    def write(self,string):

        if self.get_mode() == api.Storage.MODE_READ:

            raise exceptions.StorageException("Writing attempted to %s in read-only mode." % self.path)

        else:

            self.handle.write(string)

    def truncate(self, size=0):

        self.handle.truncate(0)

        self.handle.seek(size, 0)

    def save(self):

        if not self.handle.closed:

            self.handle.save()

    def close(self):

        self.storage.close_resource(self)

        self.handle.close()

    def get_size(self):

        if self.get_mode() == api.Storage.MODE_WRITE:

            raise exceptions.StorageException("Reading size attempted to %s in write-only mode." % self.path)

        orig_pos = self.handle.tell()

        self.handle.seek(0, os.SEEK_END)

        try:        return self.handle.tell()

        finally:    self.handle.seek(orig_pos, os.SEEK_SET)

    def get_content_info(self):

        orig_pos = self.handle.tell()

        self.handle.seek(0, os.SEEK_SET)

        data = self.handle.read()

        self.handle.seek(orig_pos, os.SEEK_SET)

        if self.content_info == None:

            self.content_info = utils.make_content_info(self, data)

        return self.content_info