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PaymentCronTransactionHandler

import FlowTransactionScheduler from 0xe467b9dd11fa00df import FlowTransactionSchedulerUtils from 0xe467b9dd11fa00df import FlowToken from 0x1654653399040a61 import FungibleToken from 0xf233dcee88fe0abe /// CRON Payment Handler for recurring FLOW token transfers /// Schedules automatic payments at specified intervals to a recipient address access(all) contract PaymentCronTransactionHandler { /// Event emitted when a payment is successfully executed access(all) event PaymentExecuted( transactionId: UInt64, executionNumber: UInt64, recipient: Address, amount: UFix64, nextExecutionTime: UFix64? ) /// Event emitted when a payment cron job completes all executions access(all) event PaymentCronCompleted(executionCount: UInt64) /// Struct to hold payment cron configuration data access(all) struct PaymentCronConfig { access(all) let intervalSeconds: UFix64 access(all) let baseTimestamp: UFix64 access(all) let maxExecutions: UInt64? access(all) let executionCount: UInt64 access(all) let recipientAddress: Address access(all) let paymentAmount: UFix64 access(all) let schedulerManagerCap: Capability<auth(FlowTransactionSchedulerUtils.Owner) &{FlowTransactionSchedulerUtils.Manager}> access(all) let feeProviderCap: Capability<auth(FungibleToken.Withdraw) &FlowToken.Vault> access(all) let priority: FlowTransactionScheduler.Priority access(all) let executionEffort: UInt64 init( intervalSeconds: UFix64, baseTimestamp: UFix64, maxExecutions: UInt64?, executionCount: UInt64, recipientAddress: Address, paymentAmount: UFix64, schedulerManagerCap: Capability<auth(FlowTransactionSchedulerUtils.Owner) &{FlowTransactionSchedulerUtils.Manager}>, feeProviderCap: Capability<auth(FungibleToken.Withdraw) &FlowToken.Vault>, priority: FlowTransactionScheduler.Priority, executionEffort: UInt64 ) { pre { paymentAmount > 0.0: "Payment amount must be greater than zero" intervalSeconds > 0.0: "Interval must be greater than zero" executionEffort >= 10: "Execution effort must be at least 10" } self.intervalSeconds = intervalSeconds self.baseTimestamp = baseTimestamp self.maxExecutions = maxExecutions self.executionCount = executionCount self.recipientAddress = recipientAddress self.paymentAmount = paymentAmount self.schedulerManagerCap = schedulerManagerCap self.feeProviderCap = feeProviderCap self.priority = priority self.executionEffort = executionEffort } access(all) fun withIncrementedCount(): PaymentCronConfig { return PaymentCronConfig( intervalSeconds: self.intervalSeconds, baseTimestamp: self.baseTimestamp, maxExecutions: self.maxExecutions, executionCount: self.executionCount + 1, recipientAddress: self.recipientAddress, paymentAmount: self.paymentAmount, schedulerManagerCap: self.schedulerManagerCap, feeProviderCap: self.feeProviderCap, priority: self.priority, executionEffort: self.executionEffort ) } access(all) fun shouldContinue(): Bool { if let max = self.maxExecutions { return self.executionCount < max } return true } access(all) fun getNextExecutionTime(): UFix64 { let currentTime = getCurrentBlock().timestamp // If baseTimestamp is in the future, use it as the first execution time if self.baseTimestamp > currentTime { return self.baseTimestamp } // Calculate next execution time based on elapsed intervals let elapsed = currentTime - self.baseTimestamp let intervals = UFix64(UInt64(elapsed / self.intervalSeconds)) + 1.0 return self.baseTimestamp + (intervals * self.intervalSeconds) } } /// Handler resource that implements the Scheduled Transaction interface access(all) resource Handler: FlowTransactionScheduler.TransactionHandler { access(FlowTransactionScheduler.Execute) fun executeTransaction(id: UInt64, data: AnyStruct?) { // Extract payment configuration from transaction data let paymentConfig = data as! PaymentCronConfig? ?? panic("PaymentCronConfig data is required") // Perform the payment self.executePayment(transactionId: id, paymentConfig: paymentConfig) let updatedConfig = paymentConfig.withIncrementedCount() // Check if we should continue scheduling if !updatedConfig.shouldContinue() { emit PaymentCronCompleted(executionCount: updatedConfig.executionCount) log("Payment cron job completed after ".concat(updatedConfig.executionCount.toString()).concat(" executions")) return } // Calculate the next precise execution time let nextExecutionTime = paymentConfig.getNextExecutionTime() let estimate = FlowTransactionScheduler.estimate( data: updatedConfig, timestamp: nextExecutionTime, priority: paymentConfig.priority, executionEffort: paymentConfig.executionEffort ) assert( estimate.timestamp != nil || paymentConfig.priority == FlowTransactionScheduler.Priority.Low, message: estimate.error ?? "estimation failed" ) // Borrow fee provider and withdraw fees let feeVault = paymentConfig.feeProviderCap.borrow() ?? panic("Cannot borrow fee provider capability") let fees <- feeVault.withdraw(amount: estimate.flowFee ?? 0.0) // Schedule next transaction through the manager let schedulerManager = paymentConfig.schedulerManagerCap.borrow() ?? panic("Cannot borrow scheduler manager capability") // Use scheduleByHandler since this handler has already been used let transactionId = schedulerManager.scheduleByHandler( handlerTypeIdentifier: self.getType().identifier, handlerUUID: self.uuid, data: updatedConfig, timestamp: nextExecutionTime, priority: paymentConfig.priority, executionEffort: paymentConfig.executionEffort, fees: <-fees as! @FlowToken.Vault ) emit PaymentExecuted( transactionId: id, executionNumber: updatedConfig.executionCount, recipient: paymentConfig.recipientAddress, amount: paymentConfig.paymentAmount, nextExecutionTime: nextExecutionTime ) log("Next payment cron transaction scheduled (id: ".concat(transactionId.toString()).concat(") at ").concat(nextExecutionTime.toString()).concat(" (execution #").concat(updatedConfig.executionCount.toString()).concat(")")) } /// Execute the actual payment access(all) fun executePayment(transactionId: UInt64, paymentConfig: PaymentCronConfig) { // Borrow the fee provider vault which has withdraw capability let feeVault = paymentConfig.feeProviderCap.borrow() ?? panic("Cannot borrow fee provider capability") // Withdraw the payment amount let tokens <- feeVault.withdraw(amount: paymentConfig.paymentAmount) // Get the recipient account let recipient = getAccount(paymentConfig.recipientAddress) // Get the recipient's receiver capability let recipientReceiverCap = recipient.capabilities.get<&{FungibleToken.Receiver}>(/public/flowTokenReceiver) if recipientReceiverCap.check() { let recipientReceiver = recipientReceiverCap.borrow() ?? panic("Cannot borrow recipient receiver") recipientReceiver.deposit(from: <-tokens) log("Payment executed: ".concat(paymentConfig.paymentAmount.toString()).concat(" FLOW sent to ").concat(paymentConfig.recipientAddress.toString()).concat(" (execution #").concat((paymentConfig.executionCount + 1).toString()).concat(")")) } else { // If recipient doesn't have a receiver capability, panic and return tokens destroy tokens panic("Recipient account ".concat(paymentConfig.recipientAddress.toString()).concat(" does not have a valid FlowToken receiver capability. Recipient must set up their account to receive tokens.")) } } /// Returns the list of metadata views this handler supports access(all) view fun getViews(): [Type] { return [Type<StoragePath>(), Type<PublicPath>()] } /// Resolves a specific metadata view access(all) fun resolveView(_ view: Type): AnyStruct? { switch view { case Type<StoragePath>(): return /storage/PaymentCronTransactionHandler case Type<PublicPath>(): return /public/PaymentCronTransactionHandler default: return nil } } } /// Factory for the handler resource access(all) fun createHandler(): @Handler { return <- create Handler() } /// Helper function to create a payment cron configuration access(all) fun createPaymentCronConfig( intervalSeconds: UFix64, baseTimestamp: UFix64?, maxExecutions: UInt64?, recipientAddress: Address, paymentAmount: UFix64, schedulerManagerCap: Capability<auth(FlowTransactionSchedulerUtils.Owner) &{FlowTransactionSchedulerUtils.Manager}>, feeProviderCap: Capability<auth(FungibleToken.Withdraw) &FlowToken.Vault>, priority: FlowTransactionScheduler.Priority, executionEffort: UInt64 ): PaymentCronConfig { let base = baseTimestamp ?? getCurrentBlock().timestamp return PaymentCronConfig( intervalSeconds: intervalSeconds, baseTimestamp: base, maxExecutions: maxExecutions, executionCount: 0, recipientAddress: recipientAddress, paymentAmount: paymentAmount, schedulerManagerCap: schedulerManagerCap, feeProviderCap: feeProviderCap, priority: priority, executionEffort: executionEffort ) } }