113 lines
3.1 KiB
Go
113 lines
3.1 KiB
Go
//
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// lurkcoin
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// Copyright © 2020 by luk3yx
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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//
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package lurkcoin
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import (
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"errors"
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"log"
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)
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// The transaction limit, currently 1e+11 so clients that parse JSON numbers as
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// 64-bit floats won't run into issues.
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// var transactionLimit Currency = CurrencyFromInt64(100000000000)
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// Temporarily changed to 10,000 due to broken exchange rate calculations
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var transactionLimit Currency = CurrencyFromInt64(10000)
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// Sends a payment.
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func (sourceServer *Server) Pay(source, target string,
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targetServer *Server, sentAmount Currency, localCurrency bool,
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revertable bool) (*Transaction, error) {
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// Ensure the source and target usernames aren't too long.
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var length int
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source, length = PasteuriseUsername(source)
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if length > 48 {
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return nil, errors.New("ERR_SOURCEUSERNAMETOOLONG")
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}
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target, length = PasteuriseUsername(target)
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if length > 48 {
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return nil, errors.New("ERR_USERNAMETOOLONG")
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}
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// Get the amount being sent in lurkcoins
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var amount Currency
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if localCurrency {
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amount, _ = sourceServer.GetExchangeRate(sentAmount, true)
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} else {
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amount = sentAmount
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}
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// No stealing
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if !sentAmount.GtZero() || !amount.GtZero() {
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if amount.IsZero() {
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return nil, errors.New("ERR_CANNOTPAYNOTHING")
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}
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return nil, errors.New("ERR_INVALIDAMOUNT")
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}
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if sentAmount.Gt(transactionLimit) || amount.Gt(transactionLimit) {
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return nil, errors.New("ERR_TRANSACTIONLIMIT")
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}
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var receivedAmount Currency
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if sourceServer == targetServer {
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receivedAmount = sentAmount
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} else {
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receivedAmount, _ = targetServer.GetExchangeRate(amount, false)
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}
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if !receivedAmount.GtZero() {
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return nil, errors.New("ERR_CANNOTPAYNOTHING")
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}
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if receivedAmount.Gt(transactionLimit) {
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return nil, errors.New("ERR_TRANSACTIONLIMIT")
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}
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// Remove the amount
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if !sourceServer.ChangeBal(amount.Neg()) {
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return nil, errors.New("ERR_CANNOTAFFORD")
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}
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if !targetServer.ChangeBal(amount) {
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// This should never happen
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// Revert the previous balance change before returning
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sourceServer.ChangeBal(amount)
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return nil, errors.New("ERR_INTERNALERROR")
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}
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transaction := MakeTransaction(source, sourceServer.Name, target,
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targetServer.Name, amount, sentAmount, receivedAmount)
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if revertable {
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transaction.Revertable = true
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}
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// Add the transaction to the history
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if sourceServer != targetServer {
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sourceServer.AddToHistory(transaction)
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}
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targetServer.AddToHistory(transaction)
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// Log the transaction
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log.Print(transaction)
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return &transaction, nil
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}
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