# Copyright (c) 2014-2015, Intel Corporation
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import json
import logging


class Scenario:

    """
        Class which can handle several TestVectors and script
        to play a complete scenario.
    """

    def __init__(self,
                 consoleLogger,
                 scenarioFileName,
                 actionGathererFileName,
                 testFactory,
                 testLauncher):
        """
            Init function

            :param consoleLogger: console log handler
            :type consoleLogger: Handler
            :param scenarioFileName: name of file containing scenario description
            :type scenarioFileName: string
            :param actionGathererFileName: conf file which allows to reduce action repetition
            :type actionGathererFileName: string
            :param testFactory: the factory used to generate tests from setCriterion actions
            :type testFactory: TestVectorFactory
            :param testLauncher: object used to execute actions from scenarios
            :type testLauncher: TestLauncher
        """
        self.__logger = logging.getLogger(__name__)
        self.__logger.addHandler(consoleLogger)

        self.__testFactory = testFactory
        self.__testLauncher = testLauncher

        # Simplify the way to get an action behaviour
        # Python way to replace switch statement but keeping the possibility
        # to get keys (usefull in __parseScenarioActions)
        self.__actionTypeBehaviour = {
            "setCriterion":
                lambda rawCriterions:
                    self.__testLauncher.executeTestVector(
                        self.__testFactory.generateTestVector(rawCriterions)),
            "script":
                self.__testLauncher.executeScript
        }

        self.__scenarioActions = self.__parseScenarioActions(
            scenarioFileName,
            actionGathererFileName)

    def __parseScenarioActions(self, scenarioFileName, actionGathererFileName):
        """
            Parse actions from a scenario.
            Convert user-defined actions in system-known actions.

            :param scenarioFileName: name of file containing scenario description
            :type scenarioFileName: string
            :param actionGathererFileName: conf file which allows to reduce action repetition
            :type actionGathererFileName: string

            :return: parsed scenario's actions with system-known types
            :rtype: dict
        """

        # Parsing of Json test file
        with open(scenarioFileName, "r") as scenarioFile:
            scenarioActions = json.load(scenarioFile)

        # Parsing the action Gatherer file which allows defining new
        # actions types
        scenarioGatheredActions = {}
        if actionGathererFileName:
            with open(actionGathererFileName, "r") as actionGathererFile:
                scenarioGatheredActions = json.load(actionGathererFile)

        for action in scenarioActions:
            actionDefinedType = self.__getActionType(action)
            if actionDefinedType in self.__actionTypeBehaviour.keys():
                continue

            try:
                actionValue = action.pop(actionDefinedType)
                actionGatherer = scenarioGatheredActions[actionDefinedType]
            except KeyError as e:
                self.__logger.error(
                    "Actions {} from {} file is not valid".format(
                        actionDefinedType,
                        scenarioFileName))
                raise e

            if self.__getActionType(actionGatherer) == "script":
                raise UngatherableTypeException(
                    "Unable to redefine {} type, please edit your {} file".format(
                        self.__getActionType(actionGatherer),
                        actionGathererFileName))

            # Fusion of gathered Actions and other desired actions which
            # are directly writed in the scenario's file
            actionValue.update(self.__getActionValue(actionGatherer))

            # Change the user defined key which was previously popped
            # by the known one
            action[self.__getActionType(actionGatherer)] = actionValue

        return scenarioActions

    def __getActionType(self, action):
        """
            Return the type of an action (the key)
            An action is a dictionary with only one element

            :param action: the action you want to get the type
            :type action: dict

            :return: the type of the desired action
            :rtype: string
        """
        return list(action.keys())[0]

    def __getActionValue(self, action):
        """
            Return the Value of an action
            An action is a dictionary with only one element

            :param action: the action you want to get the type
            :type action: dict

            :return: the value of the desired action
            :rtype: string or dict
        """
        return list(action.values())[0]

    def play(self):
        """
            Execute a Scenario
        """

        for action in self.__scenarioActions:
            # Launch the adequate behaviour depending on the key of the action dict
            # No need to try KeyError as it would have been raised during init
            # process
            self.__actionTypeBehaviour[self.__getActionType(action)](
                self.__getActionValue(action))


class UngatherableTypeException(Exception):

    """
        Exception raised in case of problem with a type that the
        user try to personalize
    """

    def __init__(self, msg):
        self.__msg = msg

    def __str__(self):
        return "Ungatherable type Error : " + self.__msg