# Copyright (c) "Neo4j"
# Neo4j Sweden AB [https://neo4j.com]
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


from __future__ import annotations

import typing as t

from .._async_compat.concurrency import AsyncCooperativeLock
from .._async_compat.util import AsyncUtil
from ..api import (
    AsyncBookmarkManager,
    Bookmarks,
)


TBmSupplier = t.Callable[[], t.Union[Bookmarks, t.Awaitable[Bookmarks]]]
TBmConsumer = t.Callable[[Bookmarks], t.Union[None, t.Awaitable[None]]]


def _bookmarks_to_set(
    bookmarks: t.Union[Bookmarks, t.Iterable[str]]
) -> t.Set[str]:
    if isinstance(bookmarks, Bookmarks):
        return set(bookmarks.raw_values)
    return set(map(str, bookmarks))


class AsyncNeo4jBookmarkManager(AsyncBookmarkManager):
    def __init__(
        self,
        initial_bookmarks: t.Union[None, Bookmarks, t.Iterable[str]] = None,
        bookmarks_supplier: t.Optional[TBmSupplier] = None,
        bookmarks_consumer: t.Optional[TBmConsumer] = None
    ) -> None:
        super().__init__()
        self._bookmarks_supplier = bookmarks_supplier
        self._bookmarks_consumer = bookmarks_consumer
        if not initial_bookmarks:
            self._bookmarks = set()
        else:
            self._bookmarks = set(getattr(
                initial_bookmarks, "raw_values",
                t.cast(t.Iterable[str], initial_bookmarks)
            ))
        self._lock = AsyncCooperativeLock()

    async def update_bookmarks(
        self, previous_bookmarks: t.Collection[str],
        new_bookmarks: t.Collection[str]
    ) -> None:
        if not new_bookmarks:
            return
        with self._lock:
            self._bookmarks.difference_update(previous_bookmarks)
            self._bookmarks.update(new_bookmarks)
            if self._bookmarks_consumer:
                curr_bms_snapshot = Bookmarks.from_raw_values(self._bookmarks)
        if self._bookmarks_consumer:
            await AsyncUtil.callback(self._bookmarks_consumer,
                                     curr_bms_snapshot)

    async def get_bookmarks(self) -> t.Set[str]:
        with self._lock:
            bms = set(self._bookmarks)
        if self._bookmarks_supplier:
            extra_bms = await AsyncUtil.callback(self._bookmarks_supplier)
            bms.update(extra_bms.raw_values)
        return bms