#

# 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: 

#

'''

A plugin implementation for rule generation.

'''

import os

import sys

import logging

import shutil

import __init__

import re

from ruleplugin import relations

from cone.public import exceptions,plugin,utils,api,rules

class RuleImpl(plugin.ImplBase):

    """

    MakeImpl plugin finds feature references that are configured in a .ruleml file

    and generate a rule from them

    """

    IMPL_TYPE_ID = 'ruleml'

    DEFAULT_INVOCATION_PHASE = 'pre'

    def __init__(self, ref, configuration, relation_container):

        """

        Overloading the default constructor

        """

        plugin.ImplBase.__init__(self,ref,configuration)

        self.logger = logging.getLogger('cone.ruleml(%s)' % self.ref)

        self.relation_container = relation_container

    def list_output_files(self):

        """

        Return a list of output files as an array. 

        """

        return []

    def generate(self, context=None):

        self.logger.info("Generating rules from %s" % self.ref)

        relation_container = self.get_relation_container()

        relation_container.context = context

        return relation_container.execute()

    def has_tag(self, tags, policy=None):

        # RuleML should always be executed, regardless of the tags

        return True

    def get_relation_container(self):

        return self.relation_container

class RulemlRelationContainer(plugin.RelationContainer):

    """

    Relation container for RuleML rules.

    Basically this is a wrapper for rules.RelationContainer that adapts

    it to the interface of plugin.RelationContainer.

    """

    def __init__(self, configuration, source, rule_list, eval_globals):

        plugin.RelationContainer.__init__(self, configuration, source=source)

        self.logger = logging.getLogger('cone.ruleml_relation_container(%s)' % self.source)

        self.configuration = configuration

        self.relation_container = rules.RelationContainerImpl()

        self.eval_globals = eval_globals

        self.context = None

        for rule in rule_list:

            self.relation_container.add_relation(rule)

    def execute(self):

        results = []

        # Create the autoconfig if not done already

        plugin.get_autoconfig(self.configuration)

        # Register relations etc. to the rule engine.

        # Due to unit test issues the relations are not registered

        # in the relations module, but only for the duration of

        # rule parsing and execution

        relations.register()

        try:

            # Using the configuration to pass the eval globals dict to the

            # eval expression. The configuration only contains the globals

            # dict for the duration of the rule execution, so hopefully this

            # shouldn't mess anything up

            self._set_builtin_eval_globals()

            self.configuration._eval_expression_globals_dict = self.eval_globals

            for i, rel in enumerate(self.relation_container):

                index = i + 1

                # Execute

                self._execute_relation_and_log_error(rel, self.source, index)

                # Collect execution result if supported

                if hasattr(rel, 'get_execution_result'):

                    result = rel.get_execution_result()

                    if isinstance(result, plugin.RelationExecutionResult):

                        result.source = self.source

                        result.index = index

                        results.append(result)

            del self.configuration._eval_expression_globals_dict

            if self.relation_container.has_errors():

                for error in self.relation_container.get_errors():

                    self.logger.error(error)

            if self.context:

                self.context.results += results

            return results

        finally:

            relations.unregister()

    def get_relation_count(self):

        return len(self.relation_container)

    def _set_builtin_eval_globals(self):

        """

        Add built-in attributes into the eval globals dictionary.

        """

        class RuleBuiltinsModule(object):

            pass

        builtins = RuleBuiltinsModule()

        builtins.configuration = self.configuration

        self.eval_globals['ruleml'] = builtins

class RuleImplReaderBase(plugin.ReaderBase):

    NAMESPACE = None # Used as a base class, so should have no namespace

    FILE_EXTENSIONS = ['ruleml']

    def __init__(self, resource_ref, configuration):

        self.resource_ref = resource_ref

        self.configuration = configuration

        self.logger = logging.getLogger('cone.ruleml(%s)' % self.resource_ref)

    @classmethod

    def read_impl(cls, resource_ref, configuration, etree):

        reader = cls(resource_ref, configuration)

        # Register relations etc. to the rule engine.

        # Due to unit test issues the relations are not registered

        # in the relations module, but only for the duration of

        # rule parsing and execution

        relations.register()

        try:

            rules = reader.parse_rules(etree)

            eval_globals = reader.parse_eval_globals(etree)

            relation_container = RulemlRelationContainer(

                configuration   = configuration,

                source          = resource_ref,

                rule_list       = rules,

                eval_globals    = eval_globals)

            impl = RuleImpl(resource_ref, configuration, relation_container)

        finally:

            relations.unregister()

        return impl

class RuleImplReader1(RuleImplReaderBase):

    NAMESPACE = 'http://www.s60.com/xml/ruleml/1'

    def __init__(self, resource_ref, configuration):

        RuleImplReaderBase.__init__(self, resource_ref, configuration)

    def parse_rules(self, etree):

        rules = []

        for elem in etree.getiterator("{%s}rule" % self.NAMESPACE):

            rules.extend(relations.RelationFactory.get_relations(self.configuration, elem.text))

        return rules

    def parse_eval_globals(self, etree):

        return {}

class RuleImplReader2(RuleImplReaderBase):

    NAMESPACE = 'http://www.s60.com/xml/ruleml/2'

    def __init__(self, resource_ref, configuration):

        RuleImplReaderBase.__init__(self, resource_ref, configuration)

    def parse_rules(self, etree):

        rules = []

        for elem in etree.getiterator("{%s}rule" % self.NAMESPACE):

            rules.extend(relations.RelationFactory.get_relations(self.configuration, self._replace_eval_blocks(elem.text)))

        return rules

    def parse_eval_globals(self, etree):

        eval_globals = {}

        for elem in etree.getiterator("{%s}eval_globals" % self.NAMESPACE):

            text = ""

            if elem.get('file') != None:

                self._read_eval_globals_from_file(elem.get('file'), eval_globals)

            else:

                try: 

                    # Strip surrounding whitespace, otherwise there might be Python

                    # indentation errors

                    text = elem.text.strip()

                    exec(text, eval_globals)

                except Exception, e:

                    self.logger.warning('Failed to evaluate eval_globals block, exception: %s' % (e))

        return eval_globals

    def _read_eval_globals_from_file(self, relative_path, eval_globals):

        # Get the actual path (relative to the current implementation file)

        base_path = os.path.dirname(self.resource_ref)

        pyfile_path = os.path.normpath(os.path.join(base_path, relative_path)).replace('\\', '/')

        # Read the data and execute

        try:

            resource = None

            resource = self.configuration.get_resource(pyfile_path)

            text = resource.read()

            exec(text.replace('\r', ''), eval_globals)

        except Exception, e:

            self.logger.warning('Cannot import eval file: %s. Exception: %s' % (pyfile_path, e))

        finally:

            if resource is not None: resource.close()

    @classmethod

    def _replace_eval_blocks(cls, code):

        return utils.expand_delimited_tokens(

            string          = code,

            expander_func   = lambda ref, index: '__eval__ %r' % ref,

            delimiters      =('{%', '%}'))