from samtranslator.public.sdk.template import SamTemplate
from samtranslator.public.plugins import BasePlugin
from samtranslator.public.exceptions import InvalidDocumentException

from samtranslator.plugins.globals.globals import Globals, InvalidGlobalsSectionException


class GlobalsPlugin(BasePlugin):
    """
    Plugin to process Globals section of a SAM template before the template is translated to CloudFormation.
    """

    def __init__(self):
        """
        Initialize the plugin
        """
        super(GlobalsPlugin, self).__init__(GlobalsPlugin.__name__)

    def on_before_transform_template(self, template_dict):
        """
        Hook method that runs before a template gets transformed. In this method, we parse and process Globals section
        from the template (if present).

        :param dict template_dict: SAM template as a dictionary
        """

        try:
            global_section = Globals(template_dict)
        except InvalidGlobalsSectionException as ex:
            raise InvalidDocumentException([ex])

        # For each resource in template, try and merge with Globals if necessary
        template = SamTemplate(template_dict)
        for logicalId, resource in template.iterate():
            resource.properties = global_section.merge(resource.type, resource.properties)
            template.set(logicalId, resource)

        # Remove the Globals section from template if necessary
        Globals.del_section(template_dict)