import asyncio
import struct
from binascii import hexlify, unhexlify
from decimal import Decimal
from operator import itemgetter
from typing import Optional, List, Iterable

from elasticsearch import AsyncElasticsearch, NotFoundError, ConnectionError
from elasticsearch.helpers import async_streaming_bulk

from lbry.crypto.base58 import Base58
from lbry.error import ResolveCensoredError, claim_id as parse_claim_id
from lbry.schema.result import Outputs, Censor
from lbry.schema.tags import clean_tags
from lbry.schema.url import URL, normalize_name
from lbry.utils import LRUCache
from lbry.wallet.server.db.common import CLAIM_TYPES, STREAM_TYPES
from lbry.wallet.server.util import class_logger


class ChannelResolution(str):
    pass


class StreamResolution(str):
    pass


class SearchIndex:
    def __init__(self, index_prefix: str, search_timeout=3.0):
        self.search_timeout = search_timeout
        self.sync_timeout = 600  # wont hit that 99% of the time, but can hit on a fresh import
        self.search_client: Optional[AsyncElasticsearch] = None
        self.client: Optional[AsyncElasticsearch] = None
        self.index = index_prefix + 'claims'
        self.logger = class_logger(__name__, self.__class__.__name__)
        self.claim_cache = LRUCache(2 ** 15)  # invalidated on touched
        self.short_id_cache = LRUCache(2 ** 17)  # never invalidated, since short ids are forever
        self.search_cache = LRUCache(2 ** 17)  # fixme: dont let session manager replace it
        self.resolution_cache = LRUCache(2 ** 17)

    async def start(self):
        if self.client:
            return
        self.client = AsyncElasticsearch(timeout=self.sync_timeout)
        self.search_client = AsyncElasticsearch(timeout=self.search_timeout)
        while True:
            try:
                await self.client.cluster.health(wait_for_status='yellow')
                break
            except ConnectionError:
                self.logger.warning("Failed to connect to Elasticsearch. Waiting for it!")
                await asyncio.sleep(1)
        res = await self.client.indices.create(
            self.index,
            {
                "settings":
                    {"analysis":
                        {"analyzer": {
                            "default": {"tokenizer": "whitespace", "filter": ["lowercase", "porter_stem"]}}},
                        "index":
                            {"refresh_interval": -1,
                             "number_of_shards": 1,
                             "number_of_replicas": 0}
                    },
                "mappings": {
                    "properties": {
                        "claim_id": {
                            "fields": {
                                "keyword": {
                                    "ignore_above": 256,
                                    "type": "keyword"
                                }
                            },
                            "type": "text",
                            "index_prefixes": {
                                "min_chars": 1,
                                "max_chars": 10
                            }
                        },
                        "height": {"type": "integer"},
                        "claim_type": {"type": "byte"},
                        "censor_type": {"type": "byte"},
                        "trending_mixed": {"type": "float"},
                    }
                }
            }, ignore=400
        )
        return res.get('acknowledged', False)

    def stop(self):
        clients = [self.client, self.search_client]
        self.client, self.search_client = None, None
        return asyncio.ensure_future(asyncio.gather(*(client.close() for client in clients)))

    def delete_index(self):
        return self.client.indices.delete(self.index, ignore_unavailable=True)

    async def _consume_claim_producer(self, claim_producer):
        count = 0
        for op, doc in claim_producer:
            if op == 'delete':
                yield {'_index': self.index, '_op_type': 'delete', '_id': doc}
            else:
                yield extract_doc(doc, self.index)
            count += 1
            if count % 100 == 0:
                self.logger.info("Indexing in progress, %d claims.", count)
        self.logger.info("Indexing done for %d claims.", count)

    async def claim_consumer(self, claim_producer):
        await self.client.indices.refresh(self.index)
        touched = set()
        async for ok, item in async_streaming_bulk(self.client, self._consume_claim_producer(claim_producer),
                                                   raise_on_error=False):
            if not ok:
                self.logger.warning("indexing failed for an item: %s", item)
            else:
                item = item.popitem()[1]
                touched.add(item['_id'])
        await self.client.indices.refresh(self.index)
        await self.client.indices.flush(self.index)
        self.logger.info("Indexing done.")

    async def apply_filters(self, blocked_streams, blocked_channels, filtered_streams, filtered_channels):
        def make_query(censor_type, blockdict, channels=False):
            blockdict = dict(
                (hexlify(key[::-1]).decode(), hexlify(value[::-1]).decode()) for key, value in blockdict.items())
            if channels:
                update = expand_query(channel_id__in=list(blockdict.keys()), censor_type=f"<{censor_type}")
            else:
                update = expand_query(claim_id__in=list(blockdict.keys()), censor_type=f"<{censor_type}")
            key = 'channel_id' if channels else 'claim_id'
            update['script'] = {
                "source": f"ctx._source.censor_type={censor_type}; ctx._source.censoring_channel_hash=params[ctx._source.{key}]",
                "lang": "painless",
                "params": blockdict
            }
            return update
        if filtered_streams:
            await self.client.update_by_query(self.index, body=make_query(1, filtered_streams), slices=4)
            await self.client.indices.refresh(self.index)
        if filtered_channels:
            await self.client.update_by_query(self.index, body=make_query(1, filtered_channels), slices=4)
            await self.client.indices.refresh(self.index)
            await self.client.update_by_query(self.index, body=make_query(1, filtered_channels, True), slices=4)
            await self.client.indices.refresh(self.index)
        if blocked_streams:
            await self.client.update_by_query(self.index, body=make_query(2, blocked_streams), slices=4)
            await self.client.indices.refresh(self.index)
        if blocked_channels:
            await self.client.update_by_query(self.index, body=make_query(2, blocked_channels), slices=4)
            await self.client.indices.refresh(self.index)
            await self.client.update_by_query(self.index, body=make_query(2, blocked_channels, True), slices=4)
            await self.client.indices.refresh(self.index)
        self.search_cache.clear()
        self.claim_cache.clear()
        self.resolution_cache.clear()

    async def delete_above_height(self, height):
        await self.client.delete_by_query(self.index, expand_query(height='>'+str(height)))
        await self.client.indices.refresh(self.index)

    async def session_query(self, query_name, kwargs):
        offset, total = kwargs.get('offset', 0) if isinstance(kwargs, dict) else 0, 0
        total_referenced = []
        if query_name == 'resolve':
            total_referenced, response, censor = await self.resolve(*kwargs)
        else:
            cache_item = ResultCacheItem.from_cache(str(kwargs), self.search_cache)
            if cache_item.result is not None:
                return cache_item.result
            async with cache_item.lock:
                if cache_item.result:
                    return cache_item.result
                censor = Censor(Censor.SEARCH)
                response, offset, total = await self.search(**kwargs)
                censor.apply(response)
                total_referenced.extend(response)
                if censor.censored:
                    response, _, _ = await self.search(**kwargs, censor_type=0)
                    total_referenced.extend(response)
                result = Outputs.to_base64(
                    response, await self._get_referenced_rows(total_referenced), offset, total, censor
                )
                cache_item.result = result
                return result
        return Outputs.to_base64(response, await self._get_referenced_rows(total_referenced), offset, total, censor)

    async def resolve(self, *urls):
        censor = Censor(Censor.RESOLVE)
        results = [await self.resolve_url(url) for url in urls]
        missing = await self.get_many(*filter(lambda x: isinstance(x, str), results))
        for index in range(len(results)):
            result = results[index]
            url = urls[index]
            if missing.get(result):
                results[index] = missing[result]
            elif isinstance(result, StreamResolution):
                results[index] = LookupError(f'Could not find claim at "{url}".')
            elif isinstance(result, ChannelResolution):
                results[index] = LookupError(f'Could not find channel in "{url}".')

        censored = [
            result if not isinstance(result, dict) or not censor.censor(result)
            else ResolveCensoredError(url, result['censoring_channel_hash'])
            for url, result in zip(urls, results)
        ]
        return results, censored, censor

    async def get_many(self, *claim_ids):
        missing = [claim_id for claim_id in claim_ids if claim_id not in self.claim_cache]
        if missing:
            results = await self.search_client.mget(
                index=self.index, body={"ids": missing}, _source_excludes=['description', 'title']
            )
            results = expand_result(filter(lambda doc: doc['found'], results["docs"]))
            for result in results:
                self.claim_cache.set(result['claim_id'], result)
        return {claim_id: self.claim_cache[claim_id] for claim_id in claim_ids if claim_id in self.claim_cache}

    async def full_id_from_short_id(self, name, short_id, channel_id=None):
        key = (channel_id or '') + name + short_id
        if key not in self.short_id_cache:
            query = {'name': name, 'claim_id': short_id}
            if channel_id:
                query['channel_id'] = channel_id
                query['order_by'] = ['^channel_join']
                query['channel_id'] = channel_id
                query['signature_valid'] = True
            else:
                query['order_by'] = '^creation_height'
            result, _, _ = await self.search(**query, limit=1)
            if len(result) == 1:
                result = result[0]['claim_id']
                self.short_id_cache[key] = result
        return self.short_id_cache.get(key, None)

    async def search(self, **kwargs):
        if 'channel' in kwargs:
            channel_id = await self.resolve_url(kwargs.pop('channel'))
            if not channel_id or not isinstance(channel_id, str):
                return [], 0, 0
            kwargs['channel_id'] = channel_id
        try:
            result = await self.search_client.search(
                expand_query(**kwargs), index=self.index, track_total_hits=200
            )
        except NotFoundError:
            # index has no docs, fixme: log something
            return [], 0, 0
        return expand_result(result['hits']['hits']), 0, result['hits']['total']['value']

    async def resolve_url(self, raw_url):
        if raw_url not in self.resolution_cache:
            self.resolution_cache[raw_url] = await self._resolve_url(raw_url)
        return self.resolution_cache[raw_url]

    async def _resolve_url(self, raw_url):
        try:
            url = URL.parse(raw_url)
        except ValueError as e:
            return e

        stream = LookupError(f'Could not find claim at "{raw_url}".')

        channel_id = await self.resolve_channel_id(url)
        if isinstance(channel_id, LookupError):
            return channel_id
        stream = (await self.resolve_stream(url, channel_id if isinstance(channel_id, str) else None)) or stream
        if url.has_stream:
            return StreamResolution(stream)
        else:
            return ChannelResolution(channel_id)

    async def resolve_channel_id(self, url: URL):
        if not url.has_channel:
            return
        if url.channel.is_fullid:
            return url.channel.claim_id
        if url.channel.is_shortid:
            channel_id = await self.full_id_from_short_id(url.channel.name, url.channel.claim_id)
            if not channel_id:
                return LookupError(f'Could not find channel in "{url}".')
            return channel_id

        query = url.channel.to_dict()
        if set(query) == {'name'}:
            query['is_controlling'] = True
        else:
            query['order_by'] = ['^creation_height']
        matches, _, _ = await self.search(**query, limit=1)
        if matches:
            channel_id = matches[0]['claim_id']
        else:
            return LookupError(f'Could not find channel in "{url}".')
        return channel_id

    async def resolve_stream(self, url: URL, channel_id: str = None):
        if not url.has_stream:
            return None
        if url.has_channel and channel_id is None:
            return None
        query = url.stream.to_dict()
        if url.stream.claim_id is not None:
            if url.stream.is_fullid:
                claim_id = url.stream.claim_id
            else:
                claim_id = await self.full_id_from_short_id(query['name'], query['claim_id'], channel_id)
            return claim_id

        if channel_id is not None:
            if set(query) == {'name'}:
                # temporarily emulate is_controlling for claims in channel
                query['order_by'] = ['effective_amount', '^height']
            else:
                query['order_by'] = ['^channel_join']
            query['channel_id'] = channel_id
            query['signature_valid'] = True
        elif set(query) == {'name'}:
            query['is_controlling'] = True
        matches, _, _ = await self.search(**query, limit=1)
        if matches:
            return matches[0]['claim_id']

    async def _get_referenced_rows(self, txo_rows: List[dict]):
        txo_rows = [row for row in txo_rows if isinstance(row, dict)]
        repost_hashes = set(filter(None, map(itemgetter('reposted_claim_id'), txo_rows)))
        channel_hashes = set(filter(None, (row['channel_id'] for row in txo_rows)))
        channel_hashes |= set(map(parse_claim_id, filter(None, (row['censoring_channel_hash'] for row in txo_rows))))

        reposted_txos = []
        if repost_hashes:
            reposted_txos = list((await self.get_many(*repost_hashes)).values())
            channel_hashes |= set(filter(None, (row['channel_id'] for row in reposted_txos)))

        channel_txos = []
        if channel_hashes:
            channel_txos = list((await self.get_many(*channel_hashes)).values())

        # channels must come first for client side inflation to work properly
        return channel_txos + reposted_txos


def extract_doc(doc, index):
    doc['claim_id'] = hexlify(doc.pop('claim_hash')[::-1]).decode()
    if doc['reposted_claim_hash'] is not None:
        doc['reposted_claim_id'] = hexlify(doc.pop('reposted_claim_hash')[::-1]).decode()
    else:
        doc['reposted_claim_id'] = None
    channel_hash = doc.pop('channel_hash')
    doc['channel_id'] = hexlify(channel_hash[::-1]).decode() if channel_hash else channel_hash
    channel_hash = doc.pop('censoring_channel_hash')
    doc['censoring_channel_hash'] = hexlify(channel_hash[::-1]).decode() if channel_hash else channel_hash
    txo_hash = doc.pop('txo_hash')
    doc['tx_id'] = hexlify(txo_hash[:32][::-1]).decode()
    doc['tx_nout'] = struct.unpack('<I', txo_hash[32:])[0]
    doc['is_controlling'] = bool(doc['is_controlling'])
    doc['signature'] = hexlify(doc.pop('signature') or b'').decode() or None
    doc['signature_digest'] = hexlify(doc.pop('signature_digest') or b'').decode() or None
    doc['public_key_bytes'] = hexlify(doc.pop('public_key_bytes') or b'').decode() or None
    doc['public_key_hash'] = hexlify(doc.pop('public_key_hash') or b'').decode() or None
    doc['signature_valid'] = bool(doc['signature_valid'])
    doc['claim_type'] = doc.get('claim_type', 0) or 0
    doc['stream_type'] = int(doc.get('stream_type', 0) or 0)
    return {'doc': doc, '_id': doc['claim_id'], '_index': index, '_op_type': 'update',
           'doc_as_upsert': True}


FIELDS = {'is_controlling', 'last_take_over_height', 'claim_id', 'claim_name', 'normalized', 'tx_position', 'amount',
          'timestamp', 'creation_timestamp', 'height', 'creation_height', 'activation_height', 'expiration_height',
          'release_time', 'short_url', 'canonical_url', 'title', 'author', 'description', 'claim_type', 'reposted',
          'stream_type', 'media_type', 'fee_amount', 'fee_currency', 'duration', 'reposted_claim_hash', 'censor_type',
          'claims_in_channel', 'channel_join', 'signature_valid', 'effective_amount', 'support_amount',
          'trending_group', 'trending_mixed', 'trending_local', 'trending_global', 'channel_id', 'tx_id', 'tx_nout',
          'signature', 'signature_digest', 'public_key_bytes', 'public_key_hash', 'public_key_id', '_id', 'tags',
          'reposted_claim_id'}
TEXT_FIELDS = {'author', 'canonical_url', 'channel_id', 'claim_name', 'description', 'claim_id',
               'media_type', 'normalized', 'public_key_bytes', 'public_key_hash', 'short_url', 'signature',
               'signature_digest', 'stream_type', 'title', 'tx_id', 'fee_currency', 'reposted_claim_id', 'tags'}
RANGE_FIELDS = {
    'height', 'creation_height', 'activation_height', 'expiration_height',
    'timestamp', 'creation_timestamp', 'duration', 'release_time', 'fee_amount',
    'tx_position', 'channel_join', 'reposted', 'limit_claims_per_channel',
    'amount', 'effective_amount', 'support_amount',
    'trending_group', 'trending_mixed', 'censor_type',
    'trending_local', 'trending_global',
}
REPLACEMENTS = {
    'name': 'normalized',
    'txid': 'tx_id',
    'claim_hash': '_id'
}


def expand_query(**kwargs):
    if "amount_order" in kwargs:
        kwargs["limit"] = 1
        kwargs["order_by"] = "effective_amount"
        kwargs["offset"] = int(kwargs["amount_order"]) - 1
    if 'name' in kwargs:
        kwargs['name'] = normalize_name(kwargs.pop('name'))
    if kwargs.get('is_controlling') is False:
        kwargs.pop('is_controlling')
    query = {'must': [], 'must_not': []}
    collapse = None
    for key, value in kwargs.items():
        key = key.replace('claim.', '')
        many = key.endswith('__in') or isinstance(value, list)
        if many:
            key = key.replace('__in', '')
            value = list(filter(None, value))
        if value is None or isinstance(value, list) and len(value) == 0:
            continue
        key = REPLACEMENTS.get(key, key)
        if key in FIELDS:
            partial_id = False
            if key == 'claim_type':
                if isinstance(value, str):
                    value = CLAIM_TYPES[value]
                else:
                    value = [CLAIM_TYPES[claim_type] for claim_type in value]
            if key == '_id':
                if isinstance(value, Iterable):
                    value = [hexlify(item[::-1]).decode() for item in value]
                else:
                    value = hexlify(value[::-1]).decode()
            if not many and key in ('_id', 'claim_id') and len(value) < 20:
                partial_id = True
            if key == 'public_key_id':
                key = 'public_key_hash'
                value = hexlify(Base58.decode(value)[1:21]).decode()
            if key == 'signature_valid':
                continue  # handled later
            if key in TEXT_FIELDS:
                key += '.keyword'
            ops = {'<=': 'lte', '>=': 'gte', '<': 'lt', '>': 'gt'}
            if partial_id:
                query['must'].append({"prefix": {"claim_id": value}})
            elif key in RANGE_FIELDS and isinstance(value, str) and value[0] in ops:
                operator_length = 2 if value[:2] in ops else 1
                operator, value = value[:operator_length], value[operator_length:]
                if key == 'fee_amount':
                    value = str(Decimal(value)*1000)
                query['must'].append({"range": {key: {ops[operator]: value}}})
            elif many:
                query['must'].append({"terms": {key: value}})
            else:
                if key == 'fee_amount':
                    value = str(Decimal(value)*1000)
                query['must'].append({"term": {key: {"value": value}}})
        elif key == 'not_channel_ids':
            for channel_id in value:
                query['must_not'].append({"term": {'channel_id.keyword': channel_id}})
                query['must_not'].append({"term": {'_id': channel_id}})
        elif key == 'channel_ids':
            query['must'].append({"terms": {'channel_id.keyword': value}})
        elif key == 'claim_ids':
            query['must'].append({"terms": {'claim_id.keyword': value}})
        elif key == 'media_types':
            query['must'].append({"terms": {'media_type.keyword': value}})
        elif key == 'stream_types':
            query['must'].append({"terms": {'stream_type': [STREAM_TYPES[stype] for stype in value]}})
        elif key == 'any_languages':
            query['must'].append({"terms": {'languages': clean_tags(value)}})
        elif key == 'any_languages':
            query['must'].append({"terms": {'languages': value}})
        elif key == 'all_languages':
            query['must'].extend([{"term": {'languages': tag}} for tag in value])
        elif key == 'any_tags':
            query['must'].append({"terms": {'tags.keyword': clean_tags(value)}})
        elif key == 'all_tags':
            query['must'].extend([{"term": {'tags.keyword': tag}} for tag in clean_tags(value)])
        elif key == 'not_tags':
            query['must_not'].extend([{"term": {'tags.keyword': tag}} for tag in clean_tags(value)])
        elif key == 'not_claim_id':
            query['must_not'].extend([{"term": {'claim_id.keyword': cid}} for cid in value])
        elif key == 'limit_claims_per_channel':
            collapse = ('channel_id.keyword', value)
    if kwargs.get('has_channel_signature'):
        query['must'].append({"exists": {"field": "signature_digest"}})
        if 'signature_valid' in kwargs:
            query['must'].append({"term": {"signature_valid": bool(kwargs["signature_valid"])}})
    elif 'signature_valid' in kwargs:
        query.setdefault('should', [])
        query["minimum_should_match"] = 1
        query['should'].append({"bool": {"must_not": {"exists": {"field": "signature_digest"}}}})
        query['should'].append({"term": {"signature_valid": bool(kwargs["signature_valid"])}})
    if kwargs.get('text'):
        query['must'].append(
                    {"simple_query_string":
                         {"query": kwargs["text"], "fields": [
                             "claim_name^4", "channel_name^8", "title^1", "description^.5", "author^1", "tags^.5"
                         ]}})
    query = {
        "_source": {"excludes": ["description", "title"]},
        'query': {'bool': query},
        "sort": [],
    }
    if "limit" in kwargs:
        query["size"] = kwargs["limit"]
    if 'offset' in kwargs:
        query["from"] = kwargs["offset"]
    if 'order_by' in kwargs:
        if isinstance(kwargs["order_by"], str):
            kwargs["order_by"] = [kwargs["order_by"]]
        for value in kwargs['order_by']:
            if 'trending_group' in value:
                # fixme: trending_mixed is 0 for all records on variable decay, making sort slow.
                continue
            is_asc = value.startswith('^')
            value = value[1:] if is_asc else value
            value = REPLACEMENTS.get(value, value)
            if value in TEXT_FIELDS:
                value += '.keyword'
            query['sort'].append({value: "asc" if is_asc else "desc"})
    if collapse:
        query["collapse"] = {
            "field": collapse[0],
            "inner_hits": {
                "name": collapse[0],
                "size": collapse[1],
                "sort": query["sort"]
            }
        }
    return query


def expand_result(results):
    inner_hits = []
    expanded = []
    for result in results:
        if result.get("inner_hits"):
            for _, inner_hit in result["inner_hits"].items():
                inner_hits.extend(inner_hit["hits"]["hits"])
            continue
        result = result['_source']
        result['claim_hash'] = unhexlify(result['claim_id'])[::-1]
        if result['reposted_claim_id']:
            result['reposted_claim_hash'] = unhexlify(result['reposted_claim_id'])[::-1]
        else:
            result['reposted_claim_hash'] = None
        result['channel_hash'] = unhexlify(result['channel_id'])[::-1] if result['channel_id'] else None
        result['txo_hash'] = unhexlify(result['tx_id'])[::-1] + struct.pack('<I', result['tx_nout'])
        result['tx_hash'] = unhexlify(result['tx_id'])[::-1]
        if result['censoring_channel_hash']:
            result['censoring_channel_hash'] = unhexlify(result['censoring_channel_hash'])[::-1]
        expanded.append(result)
    if inner_hits:
        return expand_result(inner_hits)
    return expanded


class ResultCacheItem:
    __slots__ = '_result', 'lock', 'has_result'

    def __init__(self):
        self.has_result = asyncio.Event()
        self.lock = asyncio.Lock()
        self._result = None

    @property
    def result(self) -> str:
        return self._result

    @result.setter
    def result(self, result: str):
        self._result = result
        if result is not None:
            self.has_result.set()

    @classmethod
    def from_cache(cls, cache_key, cache):
        cache_item = cache.get(cache_key)
        if cache_item is None:
            cache_item = cache[cache_key] = ResultCacheItem()
        return cache_item