fast-messenger/TECH_DEBT_AUDIT.md

Fast Messenger Tech Debt Audit

Critical

core/network/src/main/kotlin/dev/meloda/fast/network/interceptor/Error14HandlingInterceptor.kt

• captcha flow is built around wait/notify, a raw executor, and shared mutable state.
• risk: deadlocks, leaked jobs, hard-to-reproduce auth hangs.
• fix: rewrite as suspend-based flow with timeout and explicit cancellation.

core/domain/src/main/kotlin/dev/meloda/fast/domain/LongPollEventParser.kt

• file mixes parsing, dispatching, IO loading, and concurrency orchestration.
• risk: regressions when VK event format changes.
• fix: split by event family and add parser tests.

feature/messageshistory/src/main/kotlin/dev/meloda/fast/messageshistory/MessagesHistoryViewModelImpl.kt

• view model is doing too much: loaders, navigation, selection, long poll hooks, read peers, dialog flow.
• risk: brittle state transitions and untestable branching.
• fix: extract coordinators/handlers per concern.

app/src/main/kotlin/dev/meloda/fast/MainViewModel.kt

• root bootstrap handles auth, locale, long poll, permissions, profile, and start destination in one class.
• risk: startup bugs and hidden coupling between flows.
• fix: move startup/permission orchestration into dedicated controllers.

app/src/main/kotlin/dev/meloda/fast/presentation/RootScreen.kt

• root composable owns too many top-level flows and dialogs.
• risk: UI orchestration drift and hard-to-read navigation logic.
• fix: split dialogs, bootstrap, and navigation concern into smaller composables.

High

core/domain/src/main/kotlin/dev/meloda/fast/domain/LongPollEventParser.kt

• uses many Log.d calls and large when branches.
• fix: reduce logging noise and add structured tracing only where needed.

core/network/src/main/kotlin/dev/meloda/fast/network/ResponseConverterFactory.kt

• double-parsing response bodies and only logging malformed payloads.
• risk: opaque failures and harder debugging.
• fix: normalize error conversion and surface typed failures.

feature/profile/src/main/kotlin/dev/meloda/fast/profile/ProfileViewModel.kt

• loadAccountInfo() has an empty error branch.
• risk: profile can fail silently.
• fix: set baseError and show fallback UI.

feature/messageshistory/src/main/kotlin/dev/meloda/fast/messageshistory/presentation/attachments/Attachments.kt

• attachment preview logic still sits in UI layer and mixes fallback behavior.
• risk: silent drops of unsupported attachments.
• fix: move preview mapping to domain/ui-model layer.

feature/messageshistory/src/main/kotlin/dev/meloda/fast/messageshistory/presentation/Link.kt

• title handling is nullable and duplicated with preview logic.
• fix: create a small UI model for link rendering.

feature/messageshistory/src/main/kotlin/dev/meloda/fast/messageshistory/presentation/File.kt

• preview extraction is inline and branches on raw model internals.
• fix: extract to mapper/UI model.

feature/messageshistory/src/main/kotlin/dev/meloda/fast/messageshistory/presentation/MessagesList.kt

• message-item interaction is dense and repeated.
• fix: normalize scroll/reply handlers and reduce nested callbacks.

Medium

core/data/src/main/kotlin/dev/meloda/fast/data/VkUsersMap.kt

• lookup helpers were using unsafe assumptions on external data.
• status: already improved, but should stay covered by tests.

core/data/src/main/kotlin/dev/meloda/fast/data/VkGroupsMap.kt

• same risk profile as users map.
• status: already improved, still needs tests.

core/domain/src/main/kotlin/dev/meloda/fast/domain/OAuthUseCaseImpl.kt

• auth success mapping used forced unwraps on server data.
• status: already improved, but auth contract should be validated.

app/src/main/kotlin/dev/meloda/fast/presentation/MainActivity.kt

• service lifecycle now respects config changes, but app exit semantics should be documented.
• fix: keep explicit separation of app-close vs config-change behavior.

build-logic/convention/src/main/kotlin/dev/meloda/fast/KotlinAndroid.kt

• build-tools are pinned to the local environment.
• risk: portable builds may drift between machines.
• fix: prefer SDK-managed consistency or document required SDK version.

app/src/main/kotlin/dev/meloda/fast/presentation/RootErrorDialog.kt

• currently hardcodes English strings for some errors.
• fix: localize all texts through resources.

app/src/main/kotlin/dev/meloda/fast/presentation/RootScreen.kt

• root-level error dialog is better, but some orchestration still remains in the root composable.
• fix: split into smaller root flows over time.

Low

core/ui/src/main/kotlin/dev/meloda/fast/ui/components/AnimatedDots.kt

• marked TODO rewrite.
• fix when touching related loading UI.

core/ui/src/main/kotlin/dev/meloda/fast/ui/theme/AppTheme.kt

• color picker TODO suggests unfinished theme customization.

core/model/src/main/kotlin/dev/meloda/fast/model/api/data/LongPollUpdates.kt

• List<List<Any>> is a weakly typed API boundary.
• fix: introduce explicit event DTOs.

core/model/src/main/kotlin/dev/meloda/fast/model/api/domain/VkMessage.kt

• attachment persistence is still a TODO area.

core/model/src/main/kotlin/dev/meloda/fast/model/database/VkMessageEntity.kt

• attachment storage/restoration is unresolved.

core/common/src/main/kotlin/dev/meloda/fast/common/model/LongPollState.kt

• Android 15 support TODO.

feature/messageshistory/src/main/kotlin/dev/meloda/fast/messageshistory/MessagesHistoryViewModelImpl.kt

• large commented-out legacy block should be removed once upload flow is reimplemented.

feature/auth/src/main/kotlin/dev/meloda/fast/auth/login/LoginViewModel.kt

• debug/auth token acquisition TODO indicates unfinished auth path.

What To Do First

1. Rewrite captcha interceptor.
2. Split LongPollEventParser.
3. Extract MessagesHistoryViewModelImpl orchestration.
4. Localize RootErrorDialog strings.
5. Add tests for auth, long poll parsing, and attachment mapping.

Note

• Current code is already better on crash-prone nullable handling and service lifecycle.
• Remaining work is mostly structural and testability-focused.