"""
Class that provides layers from a given SAM template
"""
import logging
from typing import Dict, List, Optional

from samcli.lib.utils.resources import AWS_LAMBDA_LAYERVERSION, AWS_SERVERLESS_LAYERVERSION

from .provider import LayerVersion, Stack
from .sam_base_provider import SamBaseProvider
from .sam_stack_provider import SamLocalStackProvider

LOG = logging.getLogger(__name__)


class SamLayerProvider(SamBaseProvider):
    """
    Fetches and returns Layers from a SAM Template. The SAM template passed to this provider is assumed to be valid,
    normalized and a dictionary.

    It may or may not contain a layer.
    """

    def __init__(self, stacks: List[Stack], use_raw_codeuri: bool = False) -> None:
        """
        Initialize the class with SAM template data. The SAM template passed to this provider is assumed
        to be valid, normalized and a dictionary. It should be normalized by running all pre-processing
        before passing to this class. The process of normalization will remove structures like ``Globals``, resolve
        intrinsic functions etc.
        This class does not perform any syntactic validation of the template.

        After the class is initialized, any changes to the ``template_dict`` will not be reflected in here.
        You need to explicitly update the class with new template, if necessary.

        Parameters
        ----------
        :param dict stacks: List of stacks layers are extracted from
        :param bool use_raw_codeuri: Do not resolve adjust core_uri based on the template path, use the raw uri.
            Note(xinhol): use_raw_codeuri is temporary to fix a bug, and will be removed for a permanent solution.
        """
        self._stacks = stacks
        self._use_raw_codeuri = use_raw_codeuri

        self._layers = self._extract_layers()

    def get(self, name: str) -> Optional[LayerVersion]:
        """
        Returns the layer with given name or logical id.
        If it is in a nested stack, name can be prefixed with stack path to avoid ambiguity

        Parameters
        ----------
        name: name or logical id of the layer.

        Returns
        -------
        LayerVersion object of one layer.

        """
        if not name:
            raise ValueError("Layer name is required")

        for layer in self._layers:
            if name in (layer.full_path, layer.layer_id, layer.name):
                return layer
        return None

    def get_all(self) -> List[LayerVersion]:
        """
        Returns all Layers in template
        Returns
        -------
        [LayerVersion] list of layer version objects.
        """
        return self._layers

    def _extract_layers(self) -> List[LayerVersion]:
        """
        Extracts all resources with Type AWS::Lambda::LayerVersion and AWS::Serverless::LayerVersion and return a list
        of those resources.
        """
        layers = []
        for stack in self._stacks:
            for name, resource in stack.resources.items():
                # In the list of layers that is defined within a template, you can reference a LayerVersion resource.
                # When running locally, we need to follow that Ref so we can extract the local path to the layer code.
                resource_type = resource.get("Type")
                resource_properties = resource.get("Properties", {})

                if resource_type in [AWS_LAMBDA_LAYERVERSION, AWS_SERVERLESS_LAYERVERSION]:
                    code_property_key = SamBaseProvider.CODE_PROPERTY_KEYS[resource_type]
                    if SamBaseProvider._is_s3_location(resource_properties.get(code_property_key)):
                        # Content can be a dictionary of S3 Bucket/Key or a S3 URI, neither of which are supported
                        SamBaseProvider._warn_code_extraction(resource_type, name, code_property_key)
                        continue
                    codeuri = SamBaseProvider._extract_codeuri(resource_properties, code_property_key)

                    compatible_runtimes = resource_properties.get("CompatibleRuntimes")
                    compatible_architectures = resource_properties.get("CompatibleArchitectures", None)

                    metadata = resource.get("Metadata", None)
                    layers.append(
                        self._convert_lambda_layer_resource(
                            stack, name, codeuri, compatible_runtimes, metadata, compatible_architectures
                        )
                    )
        return layers

    def _convert_lambda_layer_resource(
        self,
        stack: Stack,
        layer_logical_id: str,
        codeuri: str,
        compatible_runtimes: Optional[List[str]],
        metadata: Optional[Dict],
        compatible_architectures: Optional[List[str]],
    ) -> LayerVersion:
        """
        Convert layer resource into {LayerVersion} object.
        Parameters
        ----------
        stack
        layer_logical_id
            LogicalID of resource.
        codeuri
            codeuri of the layer
        compatible_runtimes
            list of compatible runtimes
        metadata
            dictionary of layer metadata
        compatible_architectures
            list of compatible architecture
        Returns
        -------
        LayerVersion
            The layer object
        """
        if codeuri and not self._use_raw_codeuri:
            LOG.debug("--base-dir is not presented, adjusting uri %s relative to %s", codeuri, stack.location)
            codeuri = SamLocalStackProvider.normalize_resource_path(stack.location, codeuri)

        return LayerVersion(
            layer_logical_id,
            codeuri,
            compatible_runtimes,
            metadata,
            compatible_architectures=compatible_architectures,
            stack_path=stack.stack_path,
        )