diff --git a/Bitkit/ViewModels/AmountInputViewModel.swift b/Bitkit/ViewModels/AmountInputViewModel.swift index c8b80eb05..3b268248d 100644 --- a/Bitkit/ViewModels/AmountInputViewModel.swift +++ b/Bitkit/ViewModels/AmountInputViewModel.swift @@ -7,6 +7,10 @@ class AmountInputViewModel: ObservableObject { @Published var displayText: String = "" @Published var errorKey: String? + /// Optional per-screen cap (e.g. the max sendable balance in the send flow). + /// When set, input is additionally blocked above this value, on top of `maxAmount`. + var maxAmountOverride: UInt64? + // MARK: - Constants private let maxAmount: UInt64 = 999_999_999 @@ -15,6 +19,12 @@ class AmountInputViewModel: ObservableObject { private let classicBitcoinDecimals = 8 private let fiatDecimals = 2 + /// The active upper bound for input: the global `maxAmount`, further restricted by `maxAmountOverride` when set. + private var effectiveMaxAmount: UInt64 { + guard let maxAmountOverride else { return maxAmount } + return Swift.min(maxAmount, maxAmountOverride) + } + // MARK: - Private Properties private var rawInputText: String = "" @@ -38,12 +48,19 @@ class AmountInputViewModel: ObservableObject { maxDecimals: maxDecimals ) + // Deletions must always apply, even when the amount is above the cap (e.g. a + // prefilled invoice amount over the available balance, or a cap that dropped + // after input). The cap only blocks growing the amount; without this, each + // delete still leaves the amount over the cap and gets rejected, trapping the + // user with an invalid amount they can't reduce. + let isDeletion = key == "delete" + // For decimal input (classic Bitcoin and fiat), preserve the text as-is // For integer input (modern Bitcoin), format the final amount if currency.primaryDisplay == .bitcoin && currency.displayUnit == .modern { let newAmount = convertToSats(newText, currency: currency) - if newAmount <= maxAmount { + if isDeletion || newAmount <= effectiveMaxAmount { rawInputText = newText displayText = formatDisplayTextFromAmount(newAmount, currency: currency) amountSats = newAmount @@ -59,7 +76,7 @@ class AmountInputViewModel: ObservableObject { // For decimal input, check limits before updating state if !newText.isEmpty { let newAmount = convertToSats(newText, currency: currency) - if newAmount <= maxAmount { + if isDeletion || newAmount <= effectiveMaxAmount { // Update both raw input and display text rawInputText = newText // Format with grouping separators but not decimal formatting diff --git a/Bitkit/Views/Wallets/Send/SendAmountView.swift b/Bitkit/Views/Wallets/Send/SendAmountView.swift index d81fe176e..a71afba76 100644 --- a/Bitkit/Views/Wallets/Send/SendAmountView.swift +++ b/Bitkit/Views/Wallets/Send/SendAmountView.swift @@ -163,6 +163,8 @@ struct SendAmountView: View { await calculateRoutingFee() } } + + updateInputCap() } .onChange(of: app.selectedWalletToPayFrom) { _, newValue in // Recalculate max sendable amount when switching wallet types @@ -186,6 +188,9 @@ struct SendAmountView: View { } } } + .onChange(of: availableAmount) { _, _ in + updateInputCap() + } } private func onContinue() async { @@ -252,6 +257,11 @@ struct SendAmountView: View { } } + private func updateInputCap() { + // Don't cap when nothing is sendable, so the pad stays usable (Continue stays disabled instead). + amountViewModel.maxAmountOverride = availableAmount > 0 ? availableAmount : nil + } + private func calculateMaxSendableAmount() async { // Make sure we have everything we need to calculate the max sendable amount guard app.selectedWalletToPayFrom == .onchain else { return } diff --git a/BitkitTests/NumberPadTests.swift b/BitkitTests/NumberPadTests.swift index e5d8d2d16..3122e43f0 100644 --- a/BitkitTests/NumberPadTests.swift +++ b/BitkitTests/NumberPadTests.swift @@ -53,6 +53,40 @@ final class NumberPadTests: XCTestCase { XCTAssertNotNil(viewModel.errorKey) } + func testMaxAmountOverrideBlocksInputAboveBalance() { + let viewModel = AmountInputViewModel() + let currency = mockCurrency(primaryDisplay: .bitcoin, displayUnit: .modern) + viewModel.maxAmountOverride = 50000 + + // Up to the cap is allowed + for digit in "50000" { + viewModel.handleNumberPadInput(String(digit), currency: currency) + } + XCTAssertEqual(viewModel.amountSats, 50000) + + // Next keystroke would make 500_000 > 50_000 and is blocked + viewModel.handleNumberPadInput("0", currency: currency) + XCTAssertEqual(viewModel.amountSats, 50000) // Should not change + XCTAssertNotNil(viewModel.errorKey) + } + + func testClearingMaxAmountOverrideRestoresGlobalCap() { + let viewModel = AmountInputViewModel() + let currency = mockCurrency(primaryDisplay: .bitcoin, displayUnit: .modern) + + // With a low override, input is blocked above it + viewModel.maxAmountOverride = 100 + viewModel.handleNumberPadInput("9", currency: currency) + viewModel.handleNumberPadInput("9", currency: currency) + viewModel.handleNumberPadInput("9", currency: currency) // 999 > 100 -> blocked + XCTAssertEqual(viewModel.amountSats, 99) + + // Clearing the override lets input grow again, up to the global cap + viewModel.maxAmountOverride = nil + viewModel.handleNumberPadInput("9", currency: currency) + XCTAssertEqual(viewModel.amountSats, 999) + } + // MARK: - Classic Bitcoin Tests func testClassicBitcoinDecimalInput() { @@ -206,6 +240,35 @@ final class NumberPadTests: XCTestCase { XCTAssertEqual(viewModel.amountSats, 100_000) } + func testDeleteAllowedWhenAmountAboveCap() { + let viewModel = AmountInputViewModel() + let currency = mockCurrency(primaryDisplay: .bitcoin, displayUnit: .modern) + + // A prefilled amount lands above a low cap (e.g. an invoice that exceeds the + // available balance, set via updateFromSats which does not enforce the cap). + viewModel.maxAmountOverride = 1000 + viewModel.updateFromSats(123_456, currency: currency) + XCTAssertEqual(viewModel.amountSats, 123_456) + + // Adding a digit is still blocked: it would grow the amount further above the cap. + viewModel.handleNumberPadInput("7", currency: currency) + XCTAssertEqual(viewModel.amountSats, 123_456) // unchanged + XCTAssertNotNil(viewModel.errorKey) + + // Deleting is allowed even though the result is still above the cap, so the user + // can reduce an over-cap amount instead of being stuck. + viewModel.handleNumberPadInput("delete", currency: currency) + XCTAssertEqual(viewModel.displayText, "12 345") + XCTAssertEqual(viewModel.amountSats, 12345) + XCTAssertNil(viewModel.errorKey) + + // Keep deleting down below the cap. + viewModel.handleNumberPadInput("delete", currency: currency) // 1 234 + viewModel.handleNumberPadInput("delete", currency: currency) // 123 + XCTAssertEqual(viewModel.amountSats, 123) + XCTAssertNil(viewModel.errorKey) + } + // MARK: - Leading Zero Tests func testLeadingZeroBehavior() { diff --git a/changelog.d/next/346.fixed.md b/changelog.d/next/346.fixed.md new file mode 100644 index 000000000..2b713053d --- /dev/null +++ b/changelog.d/next/346.fixed.md @@ -0,0 +1 @@ +The send amount number pad now caps entry at your available balance, so you can no longer enter more than you can send.