import base64
import struct
from typing import List
from binascii import hexlify
from itertools import chain

from lbry.schema.types.v2.result_pb2 import Outputs as OutputsMessage


class Censor:

    __slots__ = 'streams', 'channels', 'censored', 'total'

    def __init__(self, streams: dict = None, channels: dict = None):
        self.streams = streams or {}
        self.channels = channels or {}
        self.censored = {}
        self.total = 0

    def censor(self, row) -> bool:
        was_censored = False
        for claim_hash, lookup in (
                (row['claim_hash'], self.streams),
                (row['claim_hash'], self.channels),
                (row['channel_hash'], self.channels)):
            censoring_channel_hash = lookup.get(claim_hash)
            if censoring_channel_hash:
                was_censored = True
                self.censored.setdefault(censoring_channel_hash, 0)
                self.censored[censoring_channel_hash] += 1
                break
        if was_censored:
            self.total += 1
        return was_censored

    def to_message(self, outputs: OutputsMessage):
        outputs.blocked_total = self.total
        for censoring_channel_hash, count in self.censored.items():
            block = outputs.blocked.add()
            block.count = count
            block.channel_hash = censoring_channel_hash


class Outputs:

    __slots__ = 'txos', 'extra_txos', 'txs', 'offset', 'total', 'blocked', 'blocked_total'

    def __init__(self, txos: List, extra_txos: List, txs: set,
                 offset: int, total: int, blocked: List, blocked_total: int):
        self.txos = txos
        self.txs = txs
        self.extra_txos = extra_txos
        self.offset = offset
        self.total = total
        self.blocked = blocked
        self.blocked_total = blocked_total

    def inflate(self, txs):
        tx_map = {tx.hash: tx for tx in txs}
        for txo_message in self.extra_txos:
            self.message_to_txo(txo_message, tx_map)
        txos = [self.message_to_txo(txo_message, tx_map) for txo_message in self.txos]
        return txos, self.inflate_blocked()

    def inflate_blocked(self):
        return {
            "total": self.blocked_total,
            "channels": {
                hexlify(message.channel_hash[::-1]).decode(): message.count
                for message in self.blocked
            }
        }

    def message_to_txo(self, txo_message, tx_map):
        if txo_message.WhichOneof('meta') == 'error':
            return None
        txo = tx_map[txo_message.tx_hash].outputs[txo_message.nout]
        if txo_message.WhichOneof('meta') == 'claim':
            claim = txo_message.claim
            txo.meta = {
                'short_url': f'lbry://{claim.short_url}',
                'canonical_url': f'lbry://{claim.canonical_url or claim.short_url}',
                'reposted': claim.reposted,
                'is_controlling': claim.is_controlling,
                'take_over_height': claim.take_over_height,
                'creation_height': claim.creation_height,
                'activation_height': claim.activation_height,
                'expiration_height': claim.expiration_height,
                'effective_amount': claim.effective_amount,
                'support_amount': claim.support_amount,
                'trending_group': claim.trending_group,
                'trending_mixed': claim.trending_mixed,
                'trending_local': claim.trending_local,
                'trending_global': claim.trending_global,
            }
            if claim.HasField('channel'):
                txo.channel = tx_map[claim.channel.tx_hash].outputs[claim.channel.nout]
            if claim.HasField('repost'):
                txo.reposted_claim = tx_map[claim.repost.tx_hash].outputs[claim.repost.nout]
            try:
                if txo.claim.is_channel:
                    txo.meta['claims_in_channel'] = claim.claims_in_channel
            except:
                pass
        return txo

    @classmethod
    def from_base64(cls, data: str) -> 'Outputs':
        return cls.from_bytes(base64.b64decode(data))

    @classmethod
    def from_bytes(cls, data: bytes) -> 'Outputs':
        outputs = OutputsMessage()
        outputs.ParseFromString(data)
        txs = set()
        for txo_message in chain(outputs.txos, outputs.extra_txos):
            if txo_message.WhichOneof('meta') == 'error':
                continue
            txs.add((hexlify(txo_message.tx_hash[::-1]).decode(), txo_message.height))
        return cls(
            outputs.txos, outputs.extra_txos, txs,
            outputs.offset, outputs.total,
            outputs.blocked, outputs.blocked_total
        )

    @classmethod
    def to_base64(cls, txo_rows, extra_txo_rows, offset=0, total=None, blocked=None) -> str:
        return base64.b64encode(cls.to_bytes(txo_rows, extra_txo_rows, offset, total, blocked)).decode()

    @classmethod
    def to_bytes(cls, txo_rows, extra_txo_rows, offset=0, total=None, blocked: Censor = None) -> bytes:
        page = OutputsMessage()
        page.offset = offset
        if total is not None:
            page.total = total
        if blocked is not None:
            blocked.to_message(page)
        for row in txo_rows:
            cls.row_to_message(row, page.txos.add(), extra_txo_rows)
        for row in extra_txo_rows:
            cls.row_to_message(row, page.extra_txos.add(), extra_txo_rows)
        return page.SerializeToString()

    @classmethod
    def row_to_message(cls, txo, txo_message, extra_txo_rows):
        if isinstance(txo, Exception):
            txo_message.error.text = txo.args[0]
            if isinstance(txo, ValueError):
                txo_message.error.code = txo_message.error.INVALID
            elif isinstance(txo, LookupError):
                txo_message.error.code = txo_message.error.NOT_FOUND
            return
        txo_message.tx_hash = txo['txo_hash'][:32]
        txo_message.nout, = struct.unpack('<I', txo['txo_hash'][32:])
        txo_message.height = txo['height']
        txo_message.claim.short_url = txo['short_url']
        txo_message.claim.reposted = txo['reposted']
        if txo['canonical_url'] is not None:
            txo_message.claim.canonical_url = txo['canonical_url']
        txo_message.claim.is_controlling = bool(txo['is_controlling'])
        if txo['last_take_over_height'] is not None:
            txo_message.claim.take_over_height = txo['last_take_over_height']
        txo_message.claim.creation_height = txo['creation_height']
        txo_message.claim.activation_height = txo['activation_height']
        txo_message.claim.expiration_height = txo['expiration_height']
        if txo['claims_in_channel'] is not None:
            txo_message.claim.claims_in_channel = txo['claims_in_channel']
        txo_message.claim.effective_amount = txo['effective_amount']
        txo_message.claim.support_amount = txo['support_amount']
        txo_message.claim.trending_group = txo['trending_group']
        txo_message.claim.trending_mixed = txo['trending_mixed']
        txo_message.claim.trending_local = txo['trending_local']
        txo_message.claim.trending_global = txo['trending_global']
        cls.set_reference(txo_message, 'channel', txo['channel_hash'], extra_txo_rows)
        cls.set_reference(txo_message, 'repost', txo['reposted_claim_hash'], extra_txo_rows)

    @staticmethod
    def set_blocked(message, blocked):
        message.blocked_total = blocked.total

    @staticmethod
    def set_reference(message, attr, claim_hash, rows):
        if claim_hash:
            for txo in rows:
                if claim_hash == txo['claim_hash']:
                    reference = getattr(message.claim, attr)
                    reference.tx_hash = txo['txo_hash'][:32]
                    reference.nout = struct.unpack('<I', txo['txo_hash'][32:])[0]
                    reference.height = txo['height']
                    break