package evm

import (
	"fmt"
	"strings"
	"sync"

	"github.com/ethereum/go-ethereum/common"
	"github.com/pkg/errors"
)

type TokenMapper interface {
	AddToken(symbol string, address common.Address)
	AddAlias(alias string, symbol string)
	GetTokenAddress(symbol string) (common.Address, error)
}

type tokenMapper struct {
	aliases map[string]string
	tokens  map[string]common.Address
	lock    *sync.Mutex
}

func NewTokenMapper() TokenMapper {
	return &tokenMapper{
		aliases: make(map[string]string),
		tokens:  make(map[string]common.Address),
		lock:    &sync.Mutex{},
	}
}

func (t *tokenMapper) AddToken(symbol string, address common.Address) {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.tokens[strings.ToUpper(symbol)] = address
}
func (t *tokenMapper) AddAlias(alias string, symbol string) {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.aliases[strings.ToUpper(alias)] = strings.ToUpper(symbol)
}

func (t *tokenMapper) GetTokenAddress(symbol string) (common.Address, error) {
	t.lock.Lock()
	defer t.lock.Unlock()
	symbol = strings.ToUpper(symbol)
	lsymbol := symbol
	if alias, ok := t.aliases[symbol]; ok {
		lsymbol = alias
	}
	address, ok := t.tokens[lsymbol]
	if !ok {
		aliasmsg := ""
		if lsymbol != symbol {
			aliasmsg = fmt.Sprintf(" (alias of %s", symbol)
		}
		return common.Address{}, errors.Errorf("no address registered for symbol %s%s", lsymbol, aliasmsg)
	}
	return address, nil
}