exchanges/engine: Add multichain deposit/withdrawal support (#794)

* Add exchange multichain support

* Start tidying up

* Add multichain transfer support for Bitfinex and fix poloniex bug

* Add Coinbene multichain support

* Start adjusting the deposit address manager

* Fix deposit tests and further enhancements

* Cleanup

* Add bypass flag, expand tests plus error coverage for Huobi

Adjust helpers

* Address nitterinos

* BFX wd changes

* Address nitterinos

* Minor fixes rebasing on master

* Fix BFX acceptableMethods test

* Add some TO-DOs for 2 tests WRT races

* Fix acceptableMethods test round 2

* Address nitterinos

engine/depositaddress.go

@@ -7,55 +7,86 @@ import (
 	"sync"
 
 	"github.com/thrasher-corp/gocryptotrader/currency"
+	"github.com/thrasher-corp/gocryptotrader/exchanges/deposit"
 )
 
 // vars related to the deposit address helpers
 var (
-	ErrDepositAddressStoreIsNil = errors.New("deposit address store is nil")
-	ErrDepositAddressNotFound   = errors.New("deposit address does not exist")
+	ErrDepositAddressStoreIsNil    = errors.New("deposit address store is nil")
+	ErrDepositAddressNotFound      = errors.New("deposit address does not exist")
+	errDepositAddressChainNotFound = errors.New("deposit address for specified chain not found")
+	errNoDepositAddressesRetrieved = errors.New("no deposit addresses retrieved")
 )
 
 // DepositAddressManager manages the exchange deposit address store
 type DepositAddressManager struct {
-	m     sync.Mutex
-	store map[string]map[string]string
+	m     sync.RWMutex
+	store map[string]map[string][]deposit.Address
+}
+
+// IsSynced returns whether or not the deposit address store has synced its data
+func (m *DepositAddressManager) IsSynced() bool {
+	if m.store == nil {
+		return false
+	}
+	m.m.RLock()
+	defer m.m.RUnlock()
+	return len(m.store) > 0
 }
 
 // SetupDepositAddressManager returns a DepositAddressManager
 func SetupDepositAddressManager() *DepositAddressManager {
 	return &DepositAddressManager{
-		store: make(map[string]map[string]string),
+		store: make(map[string]map[string][]deposit.Address),
 	}
 }
 
 // GetDepositAddressByExchangeAndCurrency returns a deposit address for the specified exchange and cryptocurrency
 // if it exists
-func (m *DepositAddressManager) GetDepositAddressByExchangeAndCurrency(exchName string, currencyItem currency.Code) (string, error) {
-	m.m.Lock()
-	defer m.m.Unlock()
+func (m *DepositAddressManager) GetDepositAddressByExchangeAndCurrency(exchName, chain string, currencyItem currency.Code) (deposit.Address, error) {
+	m.m.RLock()
+	defer m.m.RUnlock()
 
 	if len(m.store) == 0 {
-		return "", ErrDepositAddressStoreIsNil
+		return deposit.Address{}, ErrDepositAddressStoreIsNil
 	}
 
 	r, ok := m.store[strings.ToUpper(exchName)]
 	if !ok {
-		return "", ErrExchangeNotFound
+		return deposit.Address{}, ErrExchangeNotFound
 	}
 
 	addr, ok := r[strings.ToUpper(currencyItem.String())]
 	if !ok {
-		return "", ErrDepositAddressNotFound
+		return deposit.Address{}, ErrDepositAddressNotFound
 	}
 
-	return addr, nil
+	if len(addr) == 0 {
+		return deposit.Address{}, errNoDepositAddressesRetrieved
+	}
+
+	if chain != "" {
+		for x := range addr {
+			if strings.EqualFold(addr[x].Chain, chain) {
+				return addr[x], nil
+			}
+		}
+		return deposit.Address{}, errDepositAddressChainNotFound
+	}
+
+	for x := range addr {
+		if strings.EqualFold(addr[x].Chain, currencyItem.String()) {
+			return addr[x], nil
+		}
+	}
+	return addr[0], nil
 }
 
 // GetDepositAddressesByExchange returns a list of cryptocurrency addresses for the specified
 // exchange if they exist
-func (m *DepositAddressManager) GetDepositAddressesByExchange(exchName string) (map[string]string, error) {
-	m.m.Lock()
-	defer m.m.Unlock()
+func (m *DepositAddressManager) GetDepositAddressesByExchange(exchName string) (map[string][]deposit.Address, error) {
+	m.m.RLock()
+	defer m.m.RUnlock()
 
 	if len(m.store) == 0 {
 		return nil, ErrDepositAddressStoreIsNil
@@ -66,11 +97,15 @@ func (m *DepositAddressManager) GetDepositAddressesByExchange(exchName string) (
 		return nil, ErrDepositAddressNotFound
 	}
 
-	return r, nil
+	cpy := make(map[string][]deposit.Address, len(r))
+	for k, v := range r {
+		cpy[k] = v
+	}
+	return cpy, nil
 }
 
 // Sync synchronises all deposit addresses
-func (m *DepositAddressManager) Sync(addresses map[string]map[string]string) error {
+func (m *DepositAddressManager) Sync(addresses map[string]map[string][]deposit.Address) error {
 	if m == nil {
 		return fmt.Errorf("deposit address manager %w", ErrNilSubsystem)
 	}
@@ -81,7 +116,7 @@ func (m *DepositAddressManager) Sync(addresses map[string]map[string]string) err
 	}
 
 	for k, v := range addresses {
-		r := make(map[string]string)
+		r := make(map[string][]deposit.Address)
 		for w, x := range v {
 			r[strings.ToUpper(w)] = x
 		}