Claude
60edd473c7
- Updates CLAUDE.md tech stack to current versions (Compose 1.10.3, Kotlin 2.3.20). - Reframes kotlin-multiplatform iOS as mature; adds secp256k1-kmp 0.23.0 references. - Updates desktop-expert Main.kt references (code grew from ~270 to 1341 lines and NavigationRail moved to ui/deck/SinglePaneLayout.kt); replaces obsolete "hardcoded ctrl = true" anti-pattern note with accurate isMacOS branching. - Removes compose-desktop.md (superseded by desktop-expert/). - Adds nostr-expert references: nip19-bech32, event-factory, crypto-and-encryption, large-cache. Adds kotlin-expert/common-utilities, compose-expert/rich-text-parsing, android-expert/image-loading. - New skills: account-state (Account + LocalCache), relay-client (subscriptions, filter assemblers, preloaders), feed-patterns (FeedFilter + FeedViewModel family), auth-signers (NostrSigner across internal / NIP-46 / NIP-55).
91 lines
3.6 KiB
Markdown
91 lines
3.6 KiB
Markdown
# ViewModel Base Classes
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Inheritance tree for the shared feed ViewModels in `commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/viewmodels/`.
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## Tree
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```
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androidx.lifecycle.ViewModel
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│
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▼
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InvalidatableContent (interface)
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│
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▼
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FeedViewModel(localFilter: FeedFilter<Note>, cacheProvider: ICacheProvider)
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│
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├── ListChangeFeedViewModel (list membership changes often)
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│ │
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│ └── (concrete bookmark / list feeds)
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│
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├── ChatroomFeedViewModel (DM thread)
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│
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└── MarmotGroupFeedViewModel (NIP-29 group chat)
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```
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Tangentially related (same folder, not in the tree):
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- `LiveStreamTopZappersViewModel.kt` — sidebar state for live streams.
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- `SearchBarState.kt` — search input + suggestions.
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- `ChatNewMessageState.kt` — composer state for a new DM.
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- `thread/*` — thread ViewModels (not technically feeds but share wiring).
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## `FeedViewModel`
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```kotlin
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abstract class FeedViewModel(
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localFilter: FeedFilter<Note>,
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val cacheProvider: ICacheProvider,
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) : ViewModel(), InvalidatableContent {
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val feedState = FeedContentState(localFilter, viewModelScope, cacheProvider)
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fun invalidateAll() // full recompute
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fun invalidateInsertData(newNotes: Set<Note>) // additive path
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fun invalidateReplace(replaced: Set<Note>) // replaceable/addressable update
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}
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```
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`FeedContentState` is the thing the UI collects:
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- `feedContent: StateFlow<FeedState>` — the actual list, loading flag, paging state.
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- Runs the `localFilter.feed()` on a background dispatcher.
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- Debounces consecutive invalidations so bursts of relay frames don't thrash the filter.
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## `ListChangeFeedViewModel`
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Extends `FeedViewModel`. Override point:
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```kotlin
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abstract class ListChangeFeedViewModel(...) : FeedViewModel(...) {
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// Automatically re-invalidates on Account list-flow changes
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abstract fun dependencyList(): List<Flow<*>>
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}
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```
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Used for bookmarks, mutes, and custom `NIP-51` lists — anything whose membership is decided by an `Account` StateFlow.
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## `ChatroomFeedViewModel`
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Wraps filter + relay subscription + typing-indicator state for a single DM thread. Use directly for chat screens; don't reimplement per-thread.
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## `MarmotGroupFeedViewModel`
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NIP-29 (marmot variant) group feed. Adds group membership / moderator state on top of the base feed.
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## When to Extend vs Reuse
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- **Just a new filter** → instantiate `FeedViewModel` with your filter; no new class needed.
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- **New invalidation signal** → subclass and override `init` to add collectors.
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- **Entirely new paging model** (infinite scroll, server-assisted paging) → subclass with a custom `FeedContentState`.
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- **Non-feed state** (search, composer) → don't use `FeedViewModel` at all; see `SearchBarState.kt` / `ChatNewMessageState.kt` for narrow-state patterns.
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## Platform Wrapping
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On Android, feed ViewModels are created via `viewModel { HashtagFeedViewModel(...) }` in the composable. On Desktop, they're instantiated directly and stored in a `WorkspaceManager` column (see `desktopApp/.../ui/deck/WorkspaceManager.kt`). The ViewModel class itself is KMP-friendly.
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## Gotchas
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- **Multiple subscribers to `feedContent`** are fine — it's a `StateFlow`.
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- **ViewModels survive configuration changes on Android** but not on Desktop `key {}` rebuilds — re-instantiate in Desktop's workspace lifecycle.
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- **`cacheProvider` is almost always `LocalCache`** but the parameter exists so tests can inject a fixture.
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- **Don't call `invalidateAll()` from UI** — it's triggered by the ViewModel's own collectors. Calling it from the composable just causes extra filter runs.
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