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

class UTXO():
    def __init__(self, db_pool, loop, log, cache_size):
        self.cached = LRU()
        self.missed = set()
        self.destroyed = deque()
        self.deleted = LRU()
        self.log = log
        self.loaded = 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_future = asyncio.Future()
        self.save_future.set_result(True)
        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)})


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

    async def destroy_utxo(self):
        while self.destroyed:
            outpoint = self.destroyed.pop()
            try:
                del self.cached[outpoint]
                self.destroyed_utxo += 1
            except:
                try:
                    del self.loaded[outpoint]
                    self.destroyed_utxo += 1
                except:
                    self.destroyed_utxo += 1
                    pass


    async def save_utxo(self):
        # save to db tail from cache
        self.log.critical("save utxo>>>>")
        return
        if not self.save_future.done():
            await self.save_future.done()
            return
        self.save_future = asyncio.Future()
        while True:
            c = len(self.cached) - self._cache_soft_limit - self.block_txo_max
            if c <= 0: break
            self.log.critical("str>>>>")
            try:
                lb = 0
                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
                    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 a:
                                await conn.copy_records_to_table('connector_utxo',
                                                                 columns=["outpoint", "data"], records=a)
                            await conn.execute("UPDATE connector_utxo_state SET value = $1 "
                                               "WHERE name = 'last_block';", lb)
                            await conn.execute("UPDATE connector_utxo_state SET value = $1 "
                                               "WHERE name = 'last_cached_block';", block_height)
                    self.saved_utxo += len(a)
                    self.deleted_utxo += len(d)

                    # 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
            finally:
                self.save_future = False

    def get(self, key):
        self._requests += 1
        try:
            i = self.cached[key]
            self.destroyed.append(key)
            # try:
            #     self.destroyed[block_height].add(key)
            # except:
            #     self.destroyed[block_height] = {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)
            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