import time
import struct
import apsw
import logging
from operator import itemgetter
from typing import Tuple, List, Dict, Union, Type, Optional
from binascii import unhexlify
from decimal import Decimal
from contextvars import ContextVar
from functools import wraps
from itertools import chain
from dataclasses import dataclass

from lbry.wallet.database import query, interpolate
from lbry.error import ResolveCensoredError
from lbry.schema.url import URL, normalize_name
from lbry.schema.tags import clean_tags
from lbry.schema.result import Outputs, Censor
from lbry.wallet import Ledger, RegTestLedger

from .common import CLAIM_TYPES, STREAM_TYPES, COMMON_TAGS
from .full_text_search import FTS_ORDER_BY


class SQLiteOperationalError(apsw.Error):
    def __init__(self, metrics):
        super().__init__('sqlite query errored')
        self.metrics = metrics


class SQLiteInterruptedError(apsw.InterruptError):
    def __init__(self, metrics):
        super().__init__('sqlite query interrupted')
        self.metrics = metrics


ATTRIBUTE_ARRAY_MAX_LENGTH = 100

INTEGER_PARAMS = {
    'height', 'creation_height', 'activation_height', 'expiration_height',
    'timestamp', 'creation_timestamp', 'duration', 'release_time', 'fee_amount',
    'tx_position', 'channel_join', 'reposted',
    'amount', 'effective_amount', 'support_amount',
    'trending_group', 'trending_mixed',
    'trending_local', 'trending_global',
}

SEARCH_PARAMS = {
    'name', 'text', 'claim_id', 'claim_ids', 'txid', 'nout', 'channel', 'channel_ids', 'not_channel_ids',
    'public_key_id', 'claim_type', 'stream_types', 'media_types', 'fee_currency',
    'has_channel_signature', 'signature_valid',
    'any_tags', 'all_tags', 'not_tags', 'reposted_claim_id',
    'any_locations', 'all_locations', 'not_locations',
    'any_languages', 'all_languages', 'not_languages',
    'is_controlling', 'limit', 'offset', 'order_by',
    'no_totals',
} | INTEGER_PARAMS


ORDER_FIELDS = {
   'name', 'claim_hash'
} | INTEGER_PARAMS


@dataclass
class ReaderState:
    db: apsw.Connection
    stack: List[List]
    metrics: Dict
    is_tracking_metrics: bool
    ledger: Type[Ledger]
    query_timeout: float
    log: logging.Logger
    blocked_streams: Dict
    blocked_channels: Dict
    filtered_streams: Dict
    filtered_channels: Dict

    def close(self):
        self.db.close()

    def reset_metrics(self):
        self.stack = []
        self.metrics = {}

    def set_query_timeout(self):
        stop_at = time.perf_counter() + self.query_timeout

        def interruptor():
            if time.perf_counter() >= stop_at:
                self.db.interrupt()
            return

        self.db.setprogresshandler(interruptor, 100)

    def get_resolve_censor(self) -> Censor:
        return Censor(self.blocked_streams, self.blocked_channels)

    def get_search_censor(self) -> Censor:
        return Censor(self.filtered_streams, self.filtered_channels)


ctx: ContextVar[Optional[ReaderState]] = ContextVar('ctx')


def row_factory(cursor, row):
    return {
        k[0]: (set(row[i].split(',')) if k[0] == 'tags' else row[i])
        for i, k in enumerate(cursor.getdescription())
    }


def initializer(log, _path, _ledger_name, query_timeout, _measure=False, block_and_filter=None):
    db = apsw.Connection(_path, flags=apsw.SQLITE_OPEN_READONLY | apsw.SQLITE_OPEN_URI)
    db.setrowtrace(row_factory)
    if block_and_filter:
        blocked_streams, blocked_channels, filtered_streams, filtered_channels = block_and_filter
    else:
        blocked_streams = blocked_channels = filtered_streams = filtered_channels = {}
    ctx.set(
        ReaderState(
            db=db, stack=[], metrics={}, is_tracking_metrics=_measure,
            ledger=Ledger if _ledger_name == 'mainnet' else RegTestLedger,
            query_timeout=query_timeout, log=log,
            blocked_streams=blocked_streams, blocked_channels=blocked_channels,
            filtered_streams=filtered_streams, filtered_channels=filtered_channels,
        )
    )


def cleanup():
    ctx.get().close()
    ctx.set(None)


def measure(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        state = ctx.get()
        if not state.is_tracking_metrics:
            return func(*args, **kwargs)
        metric = {}
        state.metrics.setdefault(func.__name__, []).append(metric)
        state.stack.append([])
        start = time.perf_counter()
        try:
            return func(*args, **kwargs)
        finally:
            elapsed = int((time.perf_counter()-start)*1000)
            metric['total'] = elapsed
            metric['isolated'] = (elapsed-sum(state.stack.pop()))
            if state.stack:
                state.stack[-1].append(elapsed)
    return wrapper


def reports_metrics(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        state = ctx.get()
        if not state.is_tracking_metrics:
            return func(*args, **kwargs)
        state.reset_metrics()
        r = func(*args, **kwargs)
        return r, state.metrics
    return wrapper


@reports_metrics
def search_to_bytes(constraints) -> Union[bytes, Tuple[bytes, Dict]]:
    return encode_result(search(constraints))


@reports_metrics
def resolve_to_bytes(urls) -> Union[bytes, Tuple[bytes, Dict]]:
    return encode_result(resolve(urls))


def encode_result(result):
    return Outputs.to_bytes(*result)


@measure
def execute_query(sql, values, row_offset: int, row_limit: int, censor: Censor) -> List:
    context = ctx.get()
    context.set_query_timeout()
    try:
        c = context.db.cursor()
        def row_filter(cursor, row):
            nonlocal row_offset
            row = row_factory(cursor, row)
            if len(row) > 1 and censor.censor(row):
                return
            if row_offset:
                row_offset -= 1
                return
            return row
        c.setrowtrace(row_filter)
        i, rows = 0, []
        for row in c.execute(sql, values):
            i += 1
            rows.append(row)
            if i >= row_limit:
                break
        return rows
    except apsw.Error as err:
        plain_sql = interpolate(sql, values)
        if context.is_tracking_metrics:
            context.metrics['execute_query'][-1]['sql'] = plain_sql
        if isinstance(err, apsw.InterruptError):
            context.log.warning("interrupted slow sqlite query:\n%s", plain_sql)
            raise SQLiteInterruptedError(context.metrics)
        context.log.exception('failed running query', exc_info=err)
        raise SQLiteOperationalError(context.metrics)


def claims_query(cols, for_count=False, **constraints) -> Tuple[str, Dict]:
    if 'order_by' in constraints:
        order_by_parts = constraints['order_by']
        if isinstance(order_by_parts, str):
            order_by_parts = [order_by_parts]
        sql_order_by = []
        for order_by in order_by_parts:
            is_asc = order_by.startswith('^')
            column = order_by[1:] if is_asc else order_by
            if column not in ORDER_FIELDS:
                raise NameError(f'{column} is not a valid order_by field')
            if column == 'name':
                column = 'normalized'
            sql_order_by.append(
                f"claim.{column} ASC" if is_asc else f"claim.{column} DESC"
            )
        constraints['order_by'] = sql_order_by

    ops = {'<=': '__lte', '>=': '__gte', '<': '__lt', '>': '__gt'}
    for constraint in INTEGER_PARAMS:
        if constraint in constraints:
            value = constraints.pop(constraint)
            postfix = ''
            if isinstance(value, str):
                if len(value) >= 2 and value[:2] in ops:
                    postfix, value = ops[value[:2]], value[2:]
                elif len(value) >= 1 and value[0] in ops:
                    postfix, value = ops[value[0]], value[1:]
            if constraint == 'fee_amount':
                value = Decimal(value)*1000
            constraints[f'claim.{constraint}{postfix}'] = int(value)

    if constraints.pop('is_controlling', False):
        if {'sequence', 'amount_order'}.isdisjoint(constraints):
            for_count = False
            constraints['claimtrie.claim_hash__is_not_null'] = ''
    if 'sequence' in constraints:
        constraints['order_by'] = 'claim.activation_height ASC'
        constraints['offset'] = int(constraints.pop('sequence')) - 1
        constraints['limit'] = 1
    if 'amount_order' in constraints:
        constraints['order_by'] = 'claim.effective_amount DESC'
        constraints['offset'] = int(constraints.pop('amount_order')) - 1
        constraints['limit'] = 1

    if 'claim_id' in constraints:
        claim_id = constraints.pop('claim_id')
        if len(claim_id) == 40:
            constraints['claim.claim_id'] = claim_id
        else:
            constraints['claim.claim_id__like'] = f'{claim_id[:40]}%'
    elif 'claim_ids' in constraints:
        constraints['claim.claim_id__in'] = set(constraints.pop('claim_ids'))

    if 'reposted_claim_id' in constraints:
        constraints['claim.reposted_claim_hash'] = unhexlify(constraints.pop('reposted_claim_id'))[::-1]

    if 'name' in constraints:
        constraints['claim.normalized'] = normalize_name(constraints.pop('name'))

    if 'public_key_id' in constraints:
        constraints['claim.public_key_hash'] = (
            ctx.get().ledger.address_to_hash160(constraints.pop('public_key_id')))
    if 'channel_hash' in constraints:
        constraints['claim.channel_hash'] = constraints.pop('channel_hash')
    if 'channel_ids' in constraints:
        channel_ids = constraints.pop('channel_ids')
        if channel_ids:
            constraints['claim.channel_hash__in'] = {
                unhexlify(cid)[::-1] for cid in channel_ids
            }
    if 'not_channel_ids' in constraints:
        not_channel_ids = constraints.pop('not_channel_ids')
        if not_channel_ids:
            not_channel_ids_binary = {
                unhexlify(ncid)[::-1] for ncid in not_channel_ids
            }
            if constraints.get('has_channel_signature', False):
                constraints['claim.channel_hash__not_in'] = not_channel_ids_binary
            else:
                constraints['null_or_not_channel__or'] = {
                    'claim.signature_valid__is_null': True,
                    'claim.channel_hash__not_in': not_channel_ids_binary
                }
    if 'signature_valid' in constraints:
        has_channel_signature = constraints.pop('has_channel_signature', False)
        if has_channel_signature:
            constraints['claim.signature_valid'] = constraints.pop('signature_valid')
        else:
            constraints['null_or_signature__or'] = {
                'claim.signature_valid__is_null': True,
                'claim.signature_valid': constraints.pop('signature_valid')
            }
    elif constraints.pop('has_channel_signature', False):
        constraints['claim.signature_valid__is_not_null'] = True

    if 'txid' in constraints:
        tx_hash = unhexlify(constraints.pop('txid'))[::-1]
        nout = constraints.pop('nout', 0)
        constraints['claim.txo_hash'] = tx_hash + struct.pack('<I', nout)

    if 'claim_type' in constraints:
        constraints['claim.claim_type'] = CLAIM_TYPES[constraints.pop('claim_type')]
    if 'stream_types' in constraints:
        stream_types = constraints.pop('stream_types')
        if stream_types:
            constraints['claim.stream_type__in'] = {
                STREAM_TYPES[stream_type] for stream_type in stream_types
            }
    if 'media_types' in constraints:
        media_types = constraints.pop('media_types')
        if media_types:
            constraints['claim.media_type__in'] = set(media_types)

    if 'fee_currency' in constraints:
        constraints['claim.fee_currency'] = constraints.pop('fee_currency').lower()

    _apply_constraints_for_array_attributes(constraints, 'tag', clean_tags, for_count)
    _apply_constraints_for_array_attributes(constraints, 'language', lambda _: _, for_count)
    _apply_constraints_for_array_attributes(constraints, 'location', lambda _: _, for_count)

    if 'text' in constraints:
        constraints["search"] = constraints.pop("text")
        constraints["order_by"] = FTS_ORDER_BY
        select = f"SELECT {cols} FROM search JOIN claim ON (search.rowid=claim.rowid)"
    else:
        select = f"SELECT {cols} FROM claim"
    if not for_count:
        select += " LEFT JOIN claimtrie USING (claim_hash)"
    return query(select, **constraints)


def select_claims(censor: Censor, cols: str, for_count=False, **constraints) -> List:
    if 'channel' in constraints:
        channel_url = constraints.pop('channel')
        match = resolve_url(channel_url)
        if isinstance(match, dict):
            constraints['channel_hash'] = match['claim_hash']
        else:
            return [{'row_count': 0}] if cols == 'count(*) as row_count' else []
    row_offset = constraints.pop('offset', 0)
    row_limit = constraints.pop('limit', 20)
    sql, values = claims_query(cols, for_count, **constraints)
    return execute_query(sql, values, row_offset, row_limit, censor)


@measure
def count_claims(**constraints) -> int:
    constraints.pop('offset', None)
    constraints.pop('limit', None)
    constraints.pop('order_by', None)
    count = select_claims(Censor(), 'count(*) as row_count', for_count=True, **constraints)
    return count[0]['row_count']


def search_claims(censor: Censor, **constraints) -> List:
    return select_claims(
        censor,
        """
        claimtrie.claim_hash as is_controlling,
        claimtrie.last_take_over_height,
        claim.claim_hash, claim.txo_hash,
        claim.claims_in_channel, claim.reposted,
        claim.height, claim.creation_height,
        claim.activation_height, claim.expiration_height,
        claim.effective_amount, claim.support_amount,
        claim.trending_group, claim.trending_mixed,
        claim.trending_local, claim.trending_global,
        claim.short_url, claim.canonical_url,
        claim.channel_hash, claim.reposted_claim_hash,
        claim.signature_valid
        """, **constraints
    )


def _get_referenced_rows(txo_rows: List[dict], censor_channels: List[bytes]):
    censor = ctx.get().get_resolve_censor()
    repost_hashes = set(filter(None, map(itemgetter('reposted_claim_hash'), txo_rows)))
    channel_hashes = set(chain(
        filter(None, map(itemgetter('channel_hash'), txo_rows)),
        censor_channels
    ))

    reposted_txos = []
    if repost_hashes:
        reposted_txos = search_claims(censor, **{'claim.claim_hash__in': repost_hashes})
        channel_hashes |= set(filter(None, map(itemgetter('channel_hash'), reposted_txos)))

    channel_txos = []
    if channel_hashes:
        channel_txos = search_claims(censor, **{'claim.claim_hash__in': channel_hashes})

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

@measure
def search(constraints) -> Tuple[List, List, int, int, Censor]:
    assert set(constraints).issubset(SEARCH_PARAMS), \
        f"Search query contains invalid arguments: {set(constraints).difference(SEARCH_PARAMS)}"
    total = None
    if not constraints.pop('no_totals', False):
        total = count_claims(**constraints)
    constraints['offset'] = abs(constraints.get('offset', 0))
    constraints['limit'] = min(abs(constraints.get('limit', 10)), 50)
    context = ctx.get()
    search_censor = context.get_search_censor()
    txo_rows = search_claims(search_censor, **constraints)
    extra_txo_rows = _get_referenced_rows(txo_rows, search_censor.censored.keys())
    return txo_rows, extra_txo_rows, constraints['offset'], total, search_censor


@measure
def resolve(urls) -> Tuple[List, List]:
    txo_rows = [resolve_url(raw_url) for raw_url in urls]
    extra_txo_rows = _get_referenced_rows(
        [txo for txo in txo_rows if isinstance(txo, dict)],
        [txo.censor_hash for txo in txo_rows if isinstance(txo, ResolveCensoredError)]
    )
    return txo_rows, extra_txo_rows


@measure
def resolve_url(raw_url):
    censor = ctx.get().get_resolve_censor()

    try:
        url = URL.parse(raw_url)
    except ValueError as e:
        return e

    channel = None

    if url.has_channel:
        query = url.channel.to_dict()
        if set(query) == {'name'}:
            query['is_controlling'] = True
        else:
            query['order_by'] = ['^creation_height']
        matches = search_claims(censor, **query, limit=1)
        if matches:
            channel = matches[0]
        elif censor.censored:
            return ResolveCensoredError(raw_url, next(iter(censor.censored)))
        else:
            return LookupError(f'Could not find channel in "{raw_url}".')

    if url.has_stream:
        query = url.stream.to_dict()
        if channel 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_hash'] = channel['claim_hash']
            query['signature_valid'] = 1
        elif set(query) == {'name'}:
            query['is_controlling'] = 1
        matches = search_claims(censor, **query, limit=1)
        if matches:
            return matches[0]
        elif censor.censored:
            return ResolveCensoredError(raw_url, next(iter(censor.censored)))
        else:
            return LookupError(f'Could not find claim at "{raw_url}".')

    return channel


def _apply_constraints_for_array_attributes(constraints, attr, cleaner, for_count=False):
    any_items = set(cleaner(constraints.pop(f'any_{attr}s', []))[:ATTRIBUTE_ARRAY_MAX_LENGTH])
    all_items = set(cleaner(constraints.pop(f'all_{attr}s', []))[:ATTRIBUTE_ARRAY_MAX_LENGTH])
    not_items = set(cleaner(constraints.pop(f'not_{attr}s', []))[:ATTRIBUTE_ARRAY_MAX_LENGTH])

    all_items = {item for item in all_items if item not in not_items}
    any_items = {item for item in any_items if item not in not_items}

    any_queries = {}

    if attr == 'tag':
        common_tags = any_items & COMMON_TAGS.keys()
        if common_tags:
            any_items -= common_tags
        if len(common_tags) < 5:
            for item in common_tags:
                index_name = COMMON_TAGS[item]
                any_queries[f'#_common_tag_{index_name}'] = f"""
                EXISTS(
                    SELECT 1 FROM tag INDEXED BY tag_{index_name}_idx WHERE claim.claim_hash=tag.claim_hash
                    AND tag = '{item}'
                )
                """
        elif len(common_tags) >= 5:
            constraints.update({
                f'$any_common_tag{i}': item for i, item in enumerate(common_tags)
            })
            values = ', '.join(
                f':$any_common_tag{i}' for i in range(len(common_tags))
            )
            any_queries[f'#_any_common_tags'] = f"""
            EXISTS(
                SELECT 1 FROM tag WHERE claim.claim_hash=tag.claim_hash
                AND tag IN ({values})
            )
            """

    if any_items:

        constraints.update({
            f'$any_{attr}{i}': item for i, item in enumerate(any_items)
        })
        values = ', '.join(
            f':$any_{attr}{i}' for i in range(len(any_items))
        )
        if for_count or attr == 'tag':
            any_queries[f'claim.claim_hash__in#_any_{attr}'] = f"""
            SELECT claim_hash FROM {attr} WHERE {attr} IN ({values})
            """
        else:
            any_queries[f'#_any_{attr}'] = f"""
            EXISTS(
                SELECT 1 FROM {attr} WHERE
                    claim.claim_hash={attr}.claim_hash
                AND {attr} IN ({values})
            )
            """

    if len(any_queries) == 1:
        constraints.update(any_queries)
    elif len(any_queries) > 1:
        constraints[f'ORed_{attr}_queries__any'] = any_queries

    if all_items:
        constraints[f'$all_{attr}_count'] = len(all_items)
        constraints.update({
            f'$all_{attr}{i}': item for i, item in enumerate(all_items)
        })
        values = ', '.join(
            f':$all_{attr}{i}' for i in range(len(all_items))
        )
        if for_count:
            constraints[f'claim.claim_hash__in#_all_{attr}'] = f"""
                SELECT claim_hash FROM {attr} WHERE {attr} IN ({values})
                GROUP BY claim_hash HAVING COUNT({attr}) = :$all_{attr}_count
            """
        else:
            constraints[f'#_all_{attr}'] = f"""
                {len(all_items)}=(
                    SELECT count(*) FROM {attr} WHERE
                        claim.claim_hash={attr}.claim_hash
                    AND {attr} IN ({values})
                )
            """

    if not_items:
        constraints.update({
            f'$not_{attr}{i}': item for i, item in enumerate(not_items)
        })
        values = ', '.join(
            f':$not_{attr}{i}' for i in range(len(not_items))
        )
        if for_count:
            constraints[f'claim.claim_hash__not_in#_not_{attr}'] = f"""
                SELECT claim_hash FROM {attr} WHERE {attr} IN ({values})
            """
        else:
            constraints[f'#_not_{attr}'] = f"""
                NOT EXISTS(
                    SELECT 1 FROM {attr} WHERE
                        claim.claim_hash={attr}.claim_hash
                    AND {attr} IN ({values})
                )
            """