"""
All the structures needed for Kubernetes patching.

Currently, it is implemented via a JSON merge-patch (RFC 7386),
i.e. a simple dictionary with field overrides, and ``None`` for field deletions.

In the future, it can be extended to a standalone object, which exposes
a dict-like behaviour, and remembers the changes in order of their execution,
and then generates the JSON patch (RFC 6902).
"""
from typing import Dict, MutableMapping, Optional, Any

from kopf.structs import dicts


class MetaPatch(dicts.MutableMappingView[str, Any]):
    _labels: dicts.MutableMappingView[str, Optional[str]]
    _annotations: dicts.MutableMappingView[str, Optional[str]]

    def __init__(self, __src: "Patch") -> None:
        super().__init__(__src, 'metadata')
        self._labels = dicts.MutableMappingView(self, 'labels')
        self._annotations = dicts.MutableMappingView(self, 'annotations')

    @property
    def labels(self) -> dicts.MutableMappingView[str, Optional[str]]:
        return self._labels

    @property
    def annotations(self) -> dicts.MutableMappingView[str, Optional[str]]:
        return self._annotations


class SpecPatch(dicts.MutableMappingView[str, Any]):
    def __init__(self, __src: "Patch") -> None:
        super().__init__(__src, 'spec')


class StatusPatch(dicts.MutableMappingView[str, Any]):
    def __init__(self, __src: "Patch") -> None:
        super().__init__(__src, 'status')


# Event-handling structures, used internally in the framework and handlers only.
class Patch(Dict[str, Any]):

    def __init__(self, __src: Optional[MutableMapping[str, Any]] = None) -> None:
        super().__init__(__src or {})
        self._meta = MetaPatch(self)
        self._spec = SpecPatch(self)
        self._status = StatusPatch(self)

    @property
    def meta(self) -> MetaPatch:
        return self._meta

    @property
    def spec(self) -> SpecPatch:
        return self._spec

    @property
    def status(self) -> StatusPatch:
        return self._status
