# Copyright: (c) 2021, Red Hat | Ansible
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

import os
from typing import Dict, Iterable, List, Optional, Union, cast

from ansible.module_utils.urls import Request

try:
    import yaml
except ImportError:
    # Handled in module setup
    pass


class ResourceDefinition(dict):
    """Representation of a resource definition.

    This is a thin wrapper around a dictionary representation of a resource
    definition, with a few properties defined for conveniently accessing the
    commonly used fields.
    """

    @property
    def kind(self) -> Optional[str]:
        return self.get("kind")

    @property
    def api_version(self) -> Optional[str]:
        return self.get("apiVersion")

    @property
    def namespace(self) -> Optional[str]:
        metadata = self.get("metadata", {})
        return metadata.get("namespace")

    @property
    def name(self) -> Optional[str]:
        metadata = self.get("metadata", {})
        return metadata.get("name")


def create_definitions(params: Dict) -> List[ResourceDefinition]:
    """Create a list of ResourceDefinitions from module inputs.

    This will take the module's inputs and return a list of ResourceDefintion
    objects. The resource definitions returned by this function should be as
    complete a definition as we can create based on the input. Any *List kinds
    will be removed and replaced by the resources contained in it.
    """
    if params.get("resource_definition"):
        d = cast(Union[str, List, Dict], params.get("resource_definition"))
        definitions = from_yaml(d)
    elif params.get("src"):
        d = cast(str, params.get("src"))
        if hasattr(d, "startswith") and d.startswith(("https://", "http://", "ftp://")):
            data = Request().open("GET", d).read().decode("utf8")
            definitions = from_yaml(data)
        else:
            definitions = from_file(d)
    else:
        # We'll create an empty definition and let merge_params set values
        # from the module parameters.
        definitions = [{}]

    resource_definitions: List[Dict] = []
    for definition in definitions:
        merge_params(definition, params)
        kind = cast(Optional[str], definition.get("kind"))
        if kind and kind.endswith("List"):
            resource_definitions += flatten_list_kind(definition, params)
        else:
            resource_definitions.append(definition)
    return list(map(ResourceDefinition, resource_definitions))


def from_yaml(definition: Union[str, List, Dict]) -> Iterable[Dict]:
    """Load resource definitions from a yaml definition."""
    definitions: List[Dict] = []
    if isinstance(definition, str):
        definitions += yaml.safe_load_all(definition)
    elif isinstance(definition, list):
        for item in definition:
            if isinstance(item, str):
                definitions += yaml.safe_load_all(item)
            else:
                definitions.append(item)
    else:
        definition = cast(Dict, definition)
        definitions.append(definition)
    return filter(None, definitions)


def from_file(filepath: str) -> Iterable[Dict]:
    """Load resource definitions from a path to a yaml file."""
    path = os.path.normpath(filepath)
    with open(path, "rb") as f:
        definitions = list(yaml.safe_load_all(f))
    return filter(None, definitions)


def merge_params(definition: Dict, params: Dict) -> Dict:
    """Merge module parameters with the resource definition.

    Fields in the resource definition take precedence over module parameters.
    """
    definition.setdefault("kind", params.get("kind"))
    definition.setdefault("apiVersion", params.get("api_version"))
    metadata = definition.setdefault("metadata", {})
    # The following should only be set if we have values for them
    if params.get("namespace"):
        metadata.setdefault("namespace", params.get("namespace"))
    if params.get("name"):
        metadata.setdefault("name", params.get("name"))
    if params.get("generate_name"):
        metadata.setdefault("generateName", params.get("generate_name"))
    return definition


def flatten_list_kind(definition: Dict, params: Dict) -> List[Dict]:
    """Replace *List kind with the items it contains.

    This will take a definition for a *List resource and return a list of
    definitions for the items contained within the List.
    """
    items = []
    kind = cast(str, definition.get("kind"))[:-4]
    api_version = definition.get("apiVersion")
    for item in definition.get("items", []):
        item.setdefault("kind", kind)
        item.setdefault("apiVersion", api_version)
        items.append(merge_params(item, params))
    return items