Meta Registry

@view
@external
def find_pools_for_coins(_from: address, _to: address) -> DynArray[address, 1000]:
    """
    @notice Find all pools that contain the input pair
    @param _from Address of coin to be sent
    @param _to Address of coin to be received
    @return Pool addresses
    """
    pools_found: DynArray[address, 1000]= empty(DynArray[address, 1000])
    pool: address = empty(address)
    registry: address = empty(address)

    for registry_index in range(MAX_REGISTRIES):

        registry = self.get_registry[registry_index]
        if registry == empty(address):
            break

        for j in range(0, 65536):

            pool = RegistryHandler(registry).find_pool_for_coins(_from, _to, j)
            if pool == empty(address):
                break
            pools_found.append(pool)

    return pools_found

@view
@external
def find_pool_for_coins(
    _from: address, _to: address, i: uint256 = 0
) -> address:
    """
    @notice Find the ith available pool containing the input pair
    @param _from Address of coin to be sent
    @param _to Address of coin to be received
    @param i Index of the pool to return
    @return Pool address
    """
    pools_found: uint256 = 0
    pool: address = empty(address)
    registry: address = empty(address)

    for registry_index in range(MAX_REGISTRIES):

        registry = self.get_registry[registry_index]
        if registry == empty(address):
            break

        for j in range(0, 65536):

            pool = RegistryHandler(registry).find_pool_for_coins(_from, _to, j)
            if pool == empty(address):
                break
            pools_found += 1
            if pools_found > i:
                return pool

    return pool

@view
@external
def find_pool_for_coins(_from: address, _to: address, i: uint256 = 0) -> address:
    """
    @notice Find the ith available pool containing the input pair
    @param _from Address of coin to be sent
    @param _to Address of coin to be received
    @param i Index of the pool to return
    @return Pool address
    """
    pools_found: uint256 = 0
    pool: address = empty(address)
    registry: address = empty(address)

    for registry_index in range(MAX_REGISTRIES):

        registry = self.get_registry[registry_index]
        if registry == empty(address):
            break

        for j in range(0, 65536):

            pool = RegistryHandler(registry).find_pool_for_coins(_from, _to, j)
            if pool == empty(address):
                break
            pools_found += 1
            if pools_found > i:
                return pool

    return pool

# get registry/registry_handler by index, index starts at 0:
get_registry: public(HashMap[uint256, address])
registry_length: public(uint256)

@external
@view
def pool_count() -> uint256:
    """
    @notice Return the total number of pools tracked by the metaregistry
    @return uint256 The number of pools in the metaregistry
    """
    total_pools: uint256 = 0
    for i in range(MAX_REGISTRIES):
        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]
        total_pools += RegistryHandler(handler).pool_count()
    return total_pools            

# get registry/registry_handler by index, index starts at 0:
get_registry: public(HashMap[uint256, address])
registry_length: public(uint256)

@external
@view
def pool_list(_index: uint256) -> address:
    """
    @notice Return the pool at a given index in the metaregistry
    @param _index The index of the pool in the metaregistry
    @return The address of the pool at the given index
    """
    pools_skip: uint256 = 0
    for i in range(MAX_REGISTRIES):
        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]
        count: uint256 = RegistryHandler(handler).pool_count()
        if _index - pools_skip < count:
            return RegistryHandler(handler).pool_list(_index - pools_skip)
        pools_skip += count
    return empty(address)

@external
@view
def get_pool_name(_pool: address, _handler_id: uint256 = 0) -> String[64]:
    """
    @notice Get the given name for a pool
    @param _pool Pool address
    @return The name of a pool
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_pool_name(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def is_meta(_pool: address) -> bool: view

@external
@view
def is_meta(_pool: address, _handler_id: uint256 = 0) -> bool:
    """
    @notice Verify `_pool` is a metapool
    @param _pool Pool address
    @param _handler_id id of registry handler
    @return True if `_pool` is a metapool
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).is_meta(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_base_pool(_pool: address) -> address: view

@external
@view
def get_base_pool(_pool: address, _handler_id: uint256 = 0) -> address:
    """
    @notice Get the base pool for a given factory metapool
    @dev Will return empty(address) if pool is not a metapool
    @param _pool Metapool address
    @param _handler_id id of registry handler
    @return Address of base pool
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_base_pool(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_fees(_pool: address) -> uint256[10]: view

@external
@view
def get_fees(_pool: address, _handler_id: uint256 = 0) -> uint256[10]:
    """
    @notice Get pool fees
    @dev Fees are expressed as integers
    @param _pool Pool address
    @param _handler_id id of registry handler
    @return Pool fee as uint256 with 1e10 precision
            Admin fee as 1e10 percentage of pool fee
            Mid fee
            Out fee
            6 blank spots for future use cases
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_fees(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_pool_params(_pool: address) -> uint256[20]: view

@external
@view
def get_pool_params(_pool: address, _handler_id: uint256 = 0) -> uint256[MAX_POOL_PARAMS]:
    """
    @notice Get the parameters of a pool
    @param _pool Pool address
    @param _handler_id id of registry handler
    @return Pool parameters
    """
    registry_handler: address = self._get_registry_handlers_from_pool(_pool)[_handler_id]
    return RegistryHandler(registry_handler).get_pool_params(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_lp_token(_pool: address) -> address: view

@external
@view
def get_lp_token(_pool: address, _handler_id: uint256 = 0) -> address:
    """
    @notice Get the address of the LP token of a pool
    @param _pool Pool address
    @param _handler_id id of registry handler
    @return Address of the LP token
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_lp_token(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_pool_asset_type(_pool: address) -> uint256: view

@external
@view
def get_pool_asset_type(_pool: address, _handler_id: uint256 = 0) -> uint256:
    """
    @notice Query the asset type of `_pool`
    @param _pool Pool Address
    @return The asset type as an unstripped string
    @dev 0 : USD, 1: ETH, 2: BTC, 3: Other, 4: CryptoSwap
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_pool_asset_type(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

@external
@view
def get_pool_from_lp_token(_token: address, _handler_id: uint256 = 0) -> address:
    """
    @notice Get the pool associated with an LP token
    @param _token LP token address
    @return Pool address
    """
    return self._get_pool_from_lp_token(_token)

@internal
@view
def _get_pool_from_lp_token(_token: address) -> address:
    for i in range(MAX_REGISTRIES):
        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]
        pool: address = RegistryHandler(handler).get_pool_from_lp_token(_token)
        if pool != empty(address):
            return pool
    return empty(address)

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_virtual_price_from_lp_token(_addr: address) -> uint256: view

@external
@view
def get_virtual_price_from_lp_token(_token: address, _handler_id: uint256 = 0) -> uint256:
    """
    @notice Get the virtual price of a pool LP token
    @param _token LP token address
    @param _handler_id id of registry handler
    @return uint256 Virtual price
    """
    pool: address = self._get_pool_from_lp_token(_token)
    registry_handler: address = self._get_registry_handlers_from_pool(pool)[_handler_id]
    return RegistryHandler(registry_handler).get_virtual_price_from_lp_token(_token)

@internal
@view
def _get_pool_from_lp_token(_token: address) -> address:
    for i in range(MAX_REGISTRIES):
        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]
        pool: address = RegistryHandler(handler).get_pool_from_lp_token(_token)
        if pool != empty(address):
            return pool
    return empty(address)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

@external
@view
def is_registered(_pool: address, _handler_id: uint256 = 0) -> bool:
    """
    @notice Check if a pool is in the metaregistry using get_n_coins
    @param _pool The address of the pool
    @param _handler_id id of registry handler
    @return A bool corresponding to whether the pool belongs or not
    """
    return self._get_registry_handlers_from_pool(_pool)[_handler_id] != empty(address)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_gauges(_pool: address) -> (address[10], int128[10]): view

@external
@view
def get_gauge(_pool: address, gauge_idx: uint256 = 0, _handler_id: uint256 = 0) -> address:
    """
    @notice Get a single liquidity gauge contract associated with a pool
    @param _pool Pool address
    @param gauge_idx Index of gauge to return
    @param _handler_id id of registry handler
    @return Address of gauge
    """
    registry_handler: RegistryHandler = RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id])
    handler_output: address[10] = registry_handler.get_gauges(_pool)[0]
    return handler_output[gauge_idx]

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_gauges(_pool: address) -> (address[10], int128[10]): view

@external
@view
def get_gauge_type(_pool: address, gauge_idx: uint256 = 0, _handler_id: uint256 = 0) -> int128:
    """
    @notice Get gauge_type of a single liquidity gauge contract associated with a pool
    @param _pool Pool address
    @param gauge_idx Index of gauge to return
    @param _handler_id id of registry handler
    @return Address of gauge
    """
    registry_handler: RegistryHandler = RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id])
    handler_output: int128[10] = registry_handler.get_gauges(_pool)[1]
    return handler_output[gauge_idx]

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_coins(_pool: address) -> address[MAX_COINS]: view

@external
@view
def get_coins(_pool: address, _handler_id: uint256 = 0) -> address[MAX_COINS]:
    """
    @notice Get the coins within a pool
    @dev For metapools, these are the wrapped coin addresses
    @param _pool Pool address
    @param _handler_id id of registry handler
    @return List of coin addresses
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_coins(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_n_coins(_pool: address) -> uint256: view

@external
@view
def get_n_coins(_pool: address, _handler_id: uint256 = 0) -> uint256:
    """
    @notice Get the number of coins in a pool
    @dev For metapools, it is tokens + wrapping/lending token (no underlying)
    @param _pool Pool address
    @return Number of coins
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_n_coins(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_decimals(_pool: address) -> uint256[MAX_COINS]: view

@external
@view
def get_decimals(_pool: address, _handler_id: uint256 = 0) -> uint256[MAX_COINS]:
    """
    @notice Get decimal places for each coin within a pool
    @dev For metapools, these are the wrapped coin decimal places
    @param _pool Pool address
    @param _handler_id id of registry handler
    @return uint256 list of decimals
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_decimals(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler

# registry and registry handlers are considered to be the same here.
# registry handlers are just wrapper contracts that simplify/fix underlying registries
# for integrating it into the Metaregistry.
interface RegistryHandler:
    def get_balances(_pool: address) -> uint256[MAX_COINS]: view

@external
@view
def get_balances(_pool: address, _handler_id: uint256 = 0)  -> uint256[MAX_COINS]:
    """
    @notice Get balances for each coin within a pool
    @dev For metapools, these are the wrapped coin balances
    @param _pool Pool address
    @param _handler_id id of registry handler
    @return uint256 list of balances
    """
    return RegistryHandler(self._get_registry_handlers_from_pool(_pool)[_handler_id]).get_balances(_pool)

@internal
@view
def _get_registry_handlers_from_pool(_pool: address) -> address[MAX_REGISTRIES]:
    """
    @notice Get registry handler that handles the registry api for a pool
    @dev sometimes a factory pool can be registered in a manual registry
        because of this, we always take the last registry a pool is
        registered in and not the first, as manual registries are first
        and factories come later
    @param _pool address of the pool
    @return registry_handlers: address[MAX_REGISTRIES]
    """

    pool_registry_handler: address[MAX_REGISTRIES] = empty(address[MAX_REGISTRIES])
    c: uint256 = 0
    for i in range(MAX_REGISTRIES):

        if i == self.registry_length:
            break
        handler: address = self.get_registry[i]

        if RegistryHandler(handler).is_registered(_pool):
            pool_registry_handler[c] = handler
            c += 1

    if pool_registry_handler[0] == empty(address):
        raise "no registry"
    return pool_registry_handler