from samtranslator.model.exceptions import InvalidDocumentException, InvalidTemplateException, InvalidResourceException
from samtranslator.validator.validator import SamTemplateValidator
from samtranslator.plugins import LifeCycleEvents
from samtranslator.public.sdk.template import SamTemplate


class Parser:
    def __init__(self):
        pass

    def parse(self, sam_template, parameter_values, sam_plugins):
        self._validate(sam_template, parameter_values)
        sam_plugins.act(LifeCycleEvents.before_transform_template, sam_template)

    # private methods
    def _validate(self, sam_template, parameter_values):
        """ Validates the template and parameter values and raises exceptions if there's an issue

        :param dict sam_template: SAM template
        :param dict parameter_values: Dictionary of parameter values provided by the user
        """
        if parameter_values is None:
            raise ValueError("`parameter_values` argument is required")

        if ("Resources" not in sam_template or not isinstance(sam_template["Resources"], dict) or not
                sam_template["Resources"]):
            raise InvalidDocumentException(
                [InvalidTemplateException("'Resources' section is required")])

        if (not all(isinstance(sam_resource, dict) for sam_resource in sam_template["Resources"].values())):
            raise InvalidDocumentException(
                [InvalidTemplateException(
                    "All 'Resources' must be Objects. If you're using YAML, this may be an "
                    "indentation issue."
                )])

        sam_template_instance = SamTemplate(sam_template)

        for resource_logical_id, sam_resource in sam_template_instance.iterate():
            # NOTE: Properties isn't required for SimpleTable, so we can't check
            # `not isinstance(sam_resources.get("Properties"), dict)` as this would be a breaking change.
            # sam_resource.properties defaults to {} in SamTemplate init
            if (not isinstance(sam_resource.properties, dict)):
                raise InvalidDocumentException(
                    [InvalidResourceException(resource_logical_id,
                                              "All 'Resources' must be Objects and have a 'Properties' Object. If "
                                              "you're using YAML, this may be an indentation issue."
                                              )])

        SamTemplateValidator.validate(sam_template)