Refactor and unify the send & multisig-propose flow by n13 · Pull Request #541 · Quantus-Network/quantus-apps

n13 · 2026-06-26T03:10:01Z

Summary

This branch started as a one-line fix for the scan→continue button bug, but the scope grew into a full refactor of the send experience. The regular send and multisig propose flows were near 1:1 duplicated screens; they are now unified behind a single set of screens driven by a SendStrategy, and several related fixes/features came along with it.

Net ~−800 lines (four duplicated multisig screens deleted), no new localization keys, and the regular send flow is visually unchanged from the original Figma design.

1. Unified send & multisig-propose flows (Strategy pattern)

The two flows (recipient → amount → review → done) were copy-pasted. They now share one implementation, with a SendStrategy encapsulating everything that differs between them:

send_strategy.dart — SendStrategy + value types: SendStrings (per-flow labels), SendFee (RegularFee / ProposeFee), SendOutcome (Submitted / NeedsHardwareSignature / Failed), SendTerminalContent.
regular_send_strategy.dart — single-signer transfer from the active account (local signing, or Keystone hand-off).
multisig_propose_strategy.dart — multisig proposal (member affordability gating, propose-fee breakdown, proposal submission + provider invalidation).
Shared screens now take a strategy: select_recipient_screen.dart, input_amount_screen.dart, review_send_screen.dart, and a unified send_terminal_screen.dart (renamed from tx_submitted_screen.dart).
Deleted the duplicated multisig screens: propose_recipient_screen.dart, propose_amount_screen.dart, propose_review_screen.dart, propose_done_screen.dart.
Entry points updated: home_screen.dart, shared_address_action_sheet.dart.

Keystone signing seam: hardware signing is modeled as an orthogonal step via SendOutcome.NeedsHardwareSignature, threaded through keystone_sign_screen.dart / keystone_scan_signature_screen.dart. This leaves room for multisig + Keystone later without adding another branch.

2. "View in Explorer" on the terminal screen

The success screen now shows a "View in Explorer ↗" link built from the extrinsic hash returned by submission.
transaction_submission_service.dart now returns the extrinsic hash (it was already computed, just discarded); added an explorerImmediateTransactionUrl() helper.
Extracted a shared ExplorerLink widget and reused it across the terminal, the POS receipt (pos_qr_screen.dart), and the transaction/proposal detail sheets — removing three near-duplicate copies.

3. Self-send handling on the recipient screen

Entering or scanning your own address previously left the button silently disabled on "Enter address". Now it:

labels the (still-disabled) button "Can't Self Transfer", and
shows a warning toaster once on entry.

Works for both flows (strategy.sourceAccountId resolves to the active account for sends, the multisig address for proposals).

4. Debug QR scanner button

Added a kDebugMode-only button to the shared QrScannerPage that returns a test address, so the send / swap / add-account flows can be exercised in the simulator where the camera is unavailable.
Shared AppConstants.debugTestAddress, reused by the existing hardware-account debug fill.

5. Original fix (scan → continue button)

Scan and paste took different code paths; scan assigned the controller text inside setState, so the validation listener never enabled the button. Unified scan/paste/recent through a single _setRecipient helper (the path paste already used). This screen was subsequently folded into the refactor above.

Test plan

Regular send — recipient (scan / paste / recent / type) → amount → review → submit → terminal shows "sent" with a working explorer link
Regular send via Keystone — review hands off to the QR sign flow → broadcasts → terminal + explorer link
Multisig propose — recipient → amount → review → propose → terminal; proposal shows as pending
Self-send — entering/scanning own address shows "Can't Self Transfer" + toaster, button stays disabled (both flows)
Explorer link — terminal, POS receipt, and tx/proposal detail sheets all open the correct explorer URL
Pay mode (payment-URL QR) — recipient + amount prefilled
Regular send flow visually matches the original Figma design

Scanning an address left the send and multisig-propose recipient buttons stuck on "Enter address". Scan assigned the controller text inside setState, firing the change listener's nested setState mid-update, so validation never enabled the button. Route scan, paste, and recent through a shared _setRecipient helper that assigns the controller text outside setState (the same path paste already used), letting the listener drive validation. Also removes the duplicated assignment across the three input methods in both screens.

align with design, delete duplicated screens from msig

Revert an accidental debug edit that changed componentQrScannerTitle to "X QR Code" across the arb and generated localization files.

n13

Review

Solid, well-motivated refactor. Collapsing the duplicated send / multisig-propose screens behind a SendStrategy is the right call: the sealed SendOutcome / SendFee types are clean, and modeling the Keystone hand-off as SendNeedsHardwareSignature keeps the shared screens free of flow branching. Net −800 lines with three explorer-link copies and four screens removed is a real DRY win. CI (Analyze) passes.

Blocking (now fixed)

Accidental localization corruption — componentQrScannerTitle → "X QR Code". This looked like a stray debug edit that landed in app_en.arb, app_localizations.dart, and app_localizations_en.dart, shipping a broken QR-scanner title to users. I've pushed a fix restoring "Scan QR Code" (commit 22a4d369).

Non-blocking suggestions

DRY: _estimateFeeAmount duplicated. The identical BigInt.from(1000) * NumberFormattingService.scaleFactorBigInt now lives in both regular_send_strategy.dart and multisig_propose_strategy.dart. Lift it to a shared location (a static on SendStrategy, or a fee constant).
Regular send reuses a multisig-named l10n key. RegularSendStrategy.strings sets feeFetchFailedMessage: l10n.multisigProposeFeeFetchFailed. It renders fine, but a regular transfer surfacing a multisigPropose... string is a semantic mismatch and fragile if that copy changes. Consider a neutral sendFeeFetchFailed key.
MultisigProposeStrategy finds the signer two ways. estimateFee uses a manual for loop; submit uses .firstWhere(... orElse: throw). Same lookup — collapse into one helper.
Fail-early inconsistency. submit throws when the member account is missing, but estimateFee silently falls back to a zero-networkFee static breakdown when signer == null. If that's only meant to cover "accounts still loading", at least debugPrint to distinguish loading from genuinely-missing so a wrong/cheap estimate isn't shown silently.

Nits

review_send_screen.dart: mainAxisAlignment: MainAxisAlignment.spaceBetween is a no-op inside a SingleChildScrollView (carried over from the old _summarySection).
input_amount_screen._openReview: bails with sendInputAmountChecksumRequired even when the real cause is fee == null (button is disabled in that state, so not reachable, but the message would be wrong if it were).
Self-send guard only runs on SelectRecipientScreen; the shared_address_action_sheet → InputAmountScreen deep-link path skips it. Likely out of scope, just flagging.

Nicely done

Generation-counter (_feeFetchGeneration) fix for stale/dropped fee responses is a real improvement over the old if (_isFetchingFee) return;.
Returning the already-computed extrinsic hash from transaction_submission_service (instead of discarding it) to drive the explorer link.
ExplorerLink + explorerImmediateTransactionUrl removing three near-identical copies.
kDebugMode-gating the scanner debug button and sharing AppConstants.debugTestAddress (de-duping the hardcoded address).

dewabisma · 2026-06-29T10:15:41Z

    },

-    "componentQrScannerTitle": "Scan QR Code",
+    "componentQrScannerTitle": "X QR Code",


its already fixed ;) was just a test

dewabisma · 2026-06-29T10:24:04Z

-      final feeData = await balancesService.getBalanceTransferFee(displayAccount.account, toAddress, amount);
-      if (!mounted) return;
+      final fee = await widget.strategy.estimateFee(ref, recipient: widget.recipientAddress.trim(), amount: _amount);
+      if (!mounted || generation != _feeFetchGeneration) return;


I don't really understand why we need this generation != _feeFetchGeneration.

dewabisma · 2026-06-29T10:37:38Z

+  Widget _successMark(AppColorsV2 colors) {
    return Container(
-      width: containerSize,
-      height: containerSize,


Not sure why delete this var for repeated value?

dewabisma · 2026-06-29T10:37:51Z

      ),
      alignment: Alignment.center,
-      child: Icon(Icons.check, size: iconSize, color: colors.success),
+      child: Icon(Icons.check, size: 32, color: colors.success),


Yeah single value fine to hard code I guess

dewabisma

Added some comments. Minor clarifications.

Is there any UI change for the send in multisig? Or it just merged into one flow now which mean the view shared the same. Because previously multisig has it's own distinct proposal details and success submit screen.

n13 added 5 commits June 25, 2026 16:52

refactor send flow

260b309

align with design, delete duplicated screens from msig

debug scanner code in test mode

296849e

formatting

0c4ac98

handle self send error

34f1847

n13 mentioned this pull request Jun 26, 2026

Refactor and unify the send & multisig-propose flow #540

Closed

7 tasks

Restore Scan QR Code scanner title

22a4d36

Revert an accidental debug edit that changed componentQrScannerTitle to "X QR Code" across the arb and generated localization files.

n13 commented Jun 29, 2026

View reviewed changes

dewabisma reviewed Jun 29, 2026

View reviewed changes

n13 added 3 commits June 30, 2026 12:35

rename fetch fee counter and add comment

05ab89c

debug address change

764b4f9

format

4e6de56

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Refactor and unify the send & multisig-propose flow#541

Refactor and unify the send & multisig-propose flow#541
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n13 commented Jun 26, 2026

Summary

1. Unified send & multisig-propose flows (Strategy pattern)

2. "View in Explorer" on the terminal screen

3. Self-send handling on the recipient screen

4. Debug QR scanner button

5. Original fix (scan → continue button)

Test plan

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Blocking (now fixed)

Non-blocking suggestions

Nits

Nicely done

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