import os
import asyncio
import binascii
import logging
import typing
from typing import Optional
from lbry.file.source import ManagedDownloadSource
if typing.TYPE_CHECKING:
    from lbry.conf import Config
    from lbry.extras.daemon.analytics import AnalyticsManager
    from lbry.extras.daemon.storage import SQLiteStorage

log = logging.getLogger(__name__)

comparison_operators = {
    'eq': lambda a, b: a == b,
    'ne': lambda a, b: a != b,
    'g': lambda a, b: a > b,
    'l': lambda a, b: a < b,
    'ge': lambda a, b: a >= b,
    'le': lambda a, b: a <= b,
}


def path_or_none(p) -> Optional[str]:
    if not p:
        return
    return binascii.unhexlify(p).decode()


class SourceManager:
    filter_fields = {
        'rowid',
        'status',
        'file_name',
        'added_on',
        'claim_name',
        'claim_height',
        'claim_id',
        'outpoint',
        'txid',
        'nout',
        'channel_claim_id',
        'channel_name'
    }

    source_class = ManagedDownloadSource

    def __init__(self, loop: asyncio.AbstractEventLoop, config: 'Config', storage: 'SQLiteStorage',
                 analytics_manager: Optional['AnalyticsManager'] = None):
        self.loop = loop
        self.config = config
        self.storage = storage
        self.analytics_manager = analytics_manager
        self._sources: typing.Dict[str, ManagedDownloadSource] = {}
        self.started = asyncio.Event(loop=self.loop)

    def add(self, source: ManagedDownloadSource):
        self._sources[source.identifier] = source

    def remove(self, source: ManagedDownloadSource):
        if source.identifier not in self._sources:
            return
        self._sources.pop(source.identifier)
        source.stop_tasks()

    async def initialize_from_database(self):
        raise NotImplementedError()

    async def start(self):
        await self.initialize_from_database()
        self.started.set()

    def stop(self):
        while self._sources:
            _, source = self._sources.popitem()
            source.stop_tasks()
        self.started.clear()

    async def create(self, file_path: str, key: Optional[bytes] = None, **kw) -> ManagedDownloadSource:
        raise NotImplementedError()

    async def _delete(self, source: ManagedDownloadSource):
        raise NotImplementedError()

    async def delete(self, source: ManagedDownloadSource, delete_file: Optional[bool] = False):
        await self._delete(source)
        self.remove(source)
        if delete_file and source.output_file_exists:
            os.remove(source.full_path)

    def get_filtered(self, sort_by: Optional[str] = None, reverse: Optional[bool] = False,
                     comparison: Optional[str] = None, **search_by) -> typing.List[ManagedDownloadSource]:
        """
        Get a list of filtered and sorted ManagedStream objects

        :param sort_by: field to sort by
        :param reverse: reverse sorting
        :param comparison: comparison operator used for filtering
        :param search_by: fields and values to filter by
        """
        if sort_by and sort_by not in self.filter_fields:
            raise ValueError(f"'{sort_by}' is not a valid field to sort by")
        if comparison and comparison not in comparison_operators:
            raise ValueError(f"'{comparison}' is not a valid comparison")
        if 'full_status' in search_by:
            del search_by['full_status']
        for search in search_by.keys():
            if search not in self.filter_fields:
                raise ValueError(f"'{search}' is not a valid search operation")
        if search_by:
            comparison = comparison or 'eq'
            sources = []
            for stream in self._sources.values():
                for search, val in search_by.items():
                    if comparison_operators[comparison](getattr(stream, search), val):
                        sources.append(stream)
                        break
        else:
            sources = list(self._sources.values())
        if sort_by:
            sources.sort(key=lambda s: getattr(s, sort_by))
            if reverse:
                sources.reverse()
        return sources