from pybtc import int_to_c_int, c_int_to_int, c_int_len
import asyncio
from collections import OrderedDict, deque
from pybtc import LRU

class UTXO():
    def __init__(self, db_pool, loop, log, cache_size):
        self.cached = LRU()
        self.missed = set()
        self.deleted = LRU()
        self.checkpoints = deque()
        self.log = log
        self.loaded = OrderedDict()
        self.pending_saved = OrderedDict()
        self.maturity = 100
        self.size_limit = cache_size
        self._db_pool = db_pool
        self.loop = loop
        self.clear_tail = False
        self.last_saved_block = 0
        self.last_cached_block = 0
        self.save_process = False
        self.load_utxo_future = asyncio.Future()
        self.load_utxo_future.set_result(True)
        self._requests = 0
        self._failed_requests = 0
        self._hit = 0
        self.saved_utxo = 0
        self.deleted_utxo = 0
        self.deleted_utxo_saved = 0
        self.loaded_utxo = 0
        self.destroyed_utxo = 0
        self.destroyed_utxo_block = 0
        self.outs_total = 0

    def set(self, outpoint, pointer, amount, address):
        # self.cached.put({outpoint: (pointer, amount, address)})
        self.cached[outpoint] = (pointer, amount, address)

    def remove(self, outpoint):
        del self.cached[outpoint]


    async def save_utxo(self):
        # save to db tail from cache
        if  self.save_process or not self.cached: return
        if  not self.checkpoints: return

        self.save_process = True
        try:
            self.log.critical("cached " + str(len(self.cached)) )
            checkpoint = self.checkpoints.popleft()
            lb = 0
            block_changed = False
            checkpoint_found = False
            utxo = set()
            while self.cached:
                i = self.cached.popleft()
                if lb != i[1][0] >> 42:
                    block_changed = True
                    lb = i[1][0] >> 42
                if lb - 1 == checkpoint:
                    if len(self.cached) > self.size_limit:
                        if self.checkpoints:
                            checkpoint = self.checkpoints.pop()
                    else:
                        checkpoint_found = True


                if len(self.cached) <= self.size_limit:
                    if block_changed and checkpoint_found:
                        break
                utxo.add((i[0],b"".join((int_to_c_int(i[1][0]),
                                         int_to_c_int(i[1][1]),
                                         i[1][2]))))
                self.pending_saved[i[0]] = i[1]
            if block_changed:
                self.cached.append({i[0]: i[1]})
            if not checkpoint_found:
                for i in reversed(self.pending_saved):
                    self.cached.append({i: self.pending_saved[i]})
                self.log.critical("checkpoint not found " + str(self.checkpoints))
                return
            self.log.critical("checkpoints " + str(self.checkpoints) + " > " + str(checkpoint))
            self.log.critical("found checkpoint " + str(lb) + "  len " + str(len(utxo)) + " cached " + str(len(self.cached)) )

            # self.log.critical(">" + str(len(self.cached)))
            #
            #     block_height
            # for key in iter(self.cached):
            #     i = self.cached[key]
            #     if c>0 and (i[0] >> 42) <= block_height:
            #         c -= 1
            #         lb = i[0] >> 42
            #         continue
            #     break
            #
            # if lb:
            #     d = set()
            #     for key in range(self.last_saved_block + 1, lb + 1):
            #         try:
            #             [d.add(i) for i in self.deleted[key]]
            #         except:
            #             pass
            #
            #     a = set()
            #     for key in iter(self.cached):
            #         i = self.cached[key]
            #         if (i[0] >> 42) > lb: break
            #         a.add((key,b"".join((int_to_c_int(i[0]),
            #                               int_to_c_int(i[1]),
            #                               i[2]))))

            # insert to db
            self.log.critical("start  " + str(len(utxo)))
            d = set()
            async with self._db_pool.acquire() as conn:
                async with conn.transaction():
                    if d:
                        await conn.execute("DELETE FROM connector_utxo WHERE "
                                           "outpoint = ANY($1);", d)
                    if utxo:
                        await conn.copy_records_to_table('connector_utxo',
                                                         columns=["outpoint", "data"], records=utxo)
                    await conn.execute("UPDATE connector_utxo_state SET value = $1 "
                                       "WHERE name = 'last_block';", lb)
            self.saved_utxo += len(utxo)
            self.deleted_utxo += len(d)
            self.log.critical("saved  " + str(len(utxo)))
            # # remove from cache
            # for key in a:
            #     try:
            #         self.cached.pop(key[0])
            #     except:
            #         pass
            #
            # for key in range(self.last_saved_block + 1, lb + 1):
            #     try:
            #         self.deleted.pop(key)
            #     except:
            #         pass
            self.last_saved_block = lb
        except:
            self.log.critical("implement rollback  ")
        finally:
            self.save_process = False

    def get(self, key):
        self._requests += 1
        try:
            i = self.cached.delete(key)
            self._hit += 1
            return i
        except:
            try:
                i = self.pending_saved[key]
                self._hit += 1
                return i
            except:
                self._failed_requests += 1
                self.missed.add(key)
                return None

    def get_loaded(self, key, block_height):
        try:
            i = self.loaded[key]
            try:
                self.destroyed[block_height].add(key)
            except:
                self.destroyed[block_height] = {key}
            return i
        except:
            return None

    async def load_utxo(self):
        while True:
            if not self.load_utxo_future.done():
                await self.load_utxo_future
                continue
            break
        try:

            self.load_utxo_future = asyncio.Future()
            l = set(self.missed)
            async with self._db_pool.acquire() as conn:
                rows = await conn.fetch("SELECT outpoint, connector_utxo.data "
                                        "FROM connector_utxo "
                                        "WHERE outpoint = ANY($1);", l)
            self.log.critical("-"+str(len(self.missed)))
            for i in l:
                try:
                    self.missed.remove(i)
                except:
                    pass
            for row in rows:
                d = row["data"]
                pointer = c_int_to_int(d)
                f = c_int_len(pointer)
                amount = c_int_to_int(d[f:])
                f += c_int_len(amount)
                address = d[f:]
                self.loaded[row["outpoint"]] = (pointer, amount, address)
                self.loaded_utxo += 1
        finally:
            self.load_utxo_future.set_result(True)


    def len(self):
        return len(self.cached)

    def hit_rate(self):
        if self._requests:
            return self._hit / self._requests
        else:
            return 0