fix: address feedback on large-wallet changes

[HashEngineering]

Issue being fixed or feature implemented

Related PR's and Dependencies

Screenshots / Videos

How Has This Been Tested?

• QA (Mobile Team)

Checklist:

• I have performed a self-review of my own code and added comments where necessary
• I have added or updated relevant unit/integration/functional/e2e tests

Summary by CodeRabbit

• Refactor
  • Improved thread safety and readability in background services.
  • Updated naming for identity checks to be more specific and consistent across the app.
  • Enhanced error handling with explicit exceptions for missing or uninitialized data.
  • Introduced debounced updates for coin amount entry to reduce unnecessary operations.
  • Improved null safety and replaced deprecated flows with modern equivalents.
  • Modified dialog interactions to delay actions until after user confirmation.
• Bug Fixes
  • Prevented potential crashes by adding null checks and safer property access.
• Chores
  • Cleaned up unused imports and renamed test variables for clarity.
• New Features
  • Added confirmation callback support to the MixDashFirstDialogFragment for improved user interaction flow.

[coderabbitai]

Walkthrough

This update refactors thread safety and error handling in several wallet components. It marks authenticationGroupExtension as volatile, replaces forced non-null assertions with explicit exceptions and null checks, and updates identity checks from hasIdentity to hasBlockchainIdentity. Mutex usage is modernized, and debounced state flows are introduced for coin amount updates. Additionally, dialog interaction flow is enhanced with callback support.

Changes

File(s)	Change Summary
wallet/src/de/schildbach/wallet/WalletApplication.java	Marked authenticationGroupExtension as volatile for thread safety.
wallet/src/de/schildbach/wallet/service/CoinJoinService.kt	Replaced manual mutex lock/unlock with withLock for structured concurrency.
wallet/src/de/schildbach/wallet/service/platform/PlatformSyncService.kt wallet/src/de/schildbach/wallet/ui/TransactionResultViewModel.kt wallet/src/de/schildbach/wallet/ui/dashpay/FrequentContactsLiveData.kt	Changed identity check from hasIdentity to hasBlockchainIdentity.
wallet/src/de/schildbach/wallet/ui/dashpay/PlatformRepo.kt	Renamed property to hasBlockchainIdentity; improved error handling with explicit exceptions and null checks; removed unused imports.
wallet/src/de/schildbach/wallet/ui/payments/PaymentsViewModel.kt	Added null safety for wallet access; replaced flowOf() with emptyFlow() for certain flows; updated imports accordingly.
wallet/src/de/schildbach/wallet/ui/send/SendCoinsFragment.kt	Updated amount propagation to use setAmount() method instead of direct property assignment.
wallet/src/de/schildbach/wallet/ui/send/SendCoinsViewModel.kt	Refactored currentAmount to use a debounced StateFlow and added setAmount() method; removed direct coroutine launch in setter.
wallet/src/de/schildbach/wallet/service/BlockchainServiceImpl.kt	Replaced forced non-null assertion with safe call for wallet?.reset().
wallet/src/de/schildbach/wallet/ui/main/MainActivity.kt	Changed dialog show call to include a callback that starts CreateUsernameActivity after dialog completion.
wallet/src/de/schildbach/wallet/ui/more/MixDashFirstDialogFragment.kt	Added nullable onConfirm lambda property and overloaded show method to accept a callback.
wallet/src/de/schildbach/wallet/ui/more/MoreFragment.kt	Modified dialog show call to include a callback that starts CreateUsernameActivity after dialog display.
wallet/test/de/schildbach/wallet/util/viewModels/MainViewModelTest.kt	Renamed mocked dependency to deviceInfoProvider and cleaned up unused imports.

Sequence Diagram(s)

sequenceDiagram
    participant UI as SendCoinsFragment
    participant VM as SendCoinsViewModel

    UI->>VM: setAmount(amount)
    VM->>VM: Update _currentAmount StateFlow
    Note over VM: Debounce 150ms
    VM->>VM: Execute dry run (after debounce)

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sequenceDiagram
    participant Activity as MainActivity
    participant Dialog as MixDashFirstDialogFragment
    participant CreateUsername as CreateUsernameActivity

    Activity->>Dialog: show(activity, onConfirm)
    Dialog-->>Activity: onConfirm callback invoked
    Activity->>CreateUsername: startActivity()

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Possibly related PRs

• fix: improve home screen loading for large coinjoin wallets #1386: Introduced and managed the authenticationGroupExtension field in WalletApplication.java, which is further refined for concurrency in this PR.
• fix: fix username creation bugs and remove some ANR's  #1350: Modified PlatformRepo to replace mutable authenticationGroupExtension with a read-only getter, related to handling of authenticationGroupExtension.

Suggested reviewers

• Syn-McJ

Poem

In the warren of code, threads hop and race,
Volatile fields keep them in place.
Identity checks, now blockchain-bound,
Safer mutexes quietly surround.
With debounced flows and nulls in check,
This code hops forward—oh, what the heck!
🐇✨

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between b943642 and 0f7b2b7.

📒 Files selected for processing (3)

• wallet/src/de/schildbach/wallet/service/BlockchainServiceImpl.kt (2 hunks)
• wallet/src/de/schildbach/wallet/ui/more/MixDashFirstDialogFragment.kt (3 hunks)
• wallet/src/de/schildbach/wallet/ui/more/MoreFragment.kt (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (2)

• wallet/src/de/schildbach/wallet/ui/more/MixDashFirstDialogFragment.kt
• wallet/src/de/schildbach/wallet/service/BlockchainServiceImpl.kt

⏰ Context from checks skipped due to timeout of 90000ms (1)

• GitHub Check: build

🔇 Additional comments (1)

wallet/src/de/schildbach/wallet/ui/more/MoreFragment.kt (1)

177-179: Improved dialog callback implementation.

The code now uses a lambda callback when showing MixDashFirstDialogFragment instead of relying on the dialog to directly handle navigation. This centralizes navigation logic in the parent fragment and improves maintainability by making the flow more explicit.

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[coderabbitai]

Actionable comments posted: 2

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 881b726 and b943642.

📒 Files selected for processing (3)

• wallet/src/de/schildbach/wallet/service/BlockchainServiceImpl.kt (1 hunks)
• wallet/src/de/schildbach/wallet/ui/main/MainActivity.kt (1 hunks)
• wallet/src/de/schildbach/wallet/ui/more/MixDashFirstDialogFragment.kt (3 hunks)

⏰ Context from checks skipped due to timeout of 90000ms (1)

• GitHub Check: build

🔇 Additional comments (2)

wallet/src/de/schildbach/wallet/service/BlockchainServiceImpl.kt (1)

1053-1053: Improved null safety handling.

The change from wallet!!.reset() to wallet?.reset() prevents potential null pointer exceptions by only calling the reset method if the wallet instance is not null. This is aligned with Kotlin best practices and makes the code more robust.

wallet/src/de/schildbach/wallet/ui/main/MainActivity.kt (1)

260-262: Flow improvement with callback-based dialog interaction

The code now correctly uses a callback approach for dialog interaction, deferring the CreateUsernameActivity start until after dialog confirmation. This is a good improvement in control flow.