noo/.claude/context/server.md

# Server integration

## Auth: Login Flow v2

The app **never** collects a Nextcloud password directly. It implements
[Login Flow v2](https://docs.nextcloud.com/server/latest/developer_manual/client_apis/LoginFlow/index.html#login-flow-v2)
via [`LoginFlowService`](../../lib/services/login_flow_service.dart):

1. `LoginFlowService.initiate(serverUrl)` POSTs to
   `{server}/index.php/login/v2`, gets back a browser login URL + a poll
   endpoint/token.
2. The app opens the login URL for the user to authenticate/authorize in
   [`LoginWebViewView`](../../lib/views/login_webview_view.dart), a normal
   screen this app owns (`package:webview_flutter`) - pushed by `LoginView`
   the moment `loginFlowStatus` flips to `awaitingBrowser`, for every login
   (first account or an additional one), not just add-account. This used
   to be split: first login went through a Chrome Custom Tab
   (`url_launcher`, `LaunchMode.inAppBrowserView`) for Chrome's own
   autofill, and only add-account used the embedded WebView, specifically
   to avoid a Custom Tab silently reusing Chrome's existing session for a
   different account. But a Custom Tab has real costs even for the first
   login - no way to close it automatically on success (the user has to
   switch back manually), and it's a separate task outside this app's own
   navigation entirely - so both paths now use the same owned screen.
   `url_launcher` is no longer a dependency. The cost is no
   Chrome-autofill (Android's own system Autofill framework, e.g. a
   password manager, may still work in the WebView; Chrome's own
   saved-password autofill specifically cannot, since that's Chrome-only).
   `LoginWebViewView` also clears cookies (`WebViewCookieManager().
   clearCookies()`) before every load, not just once - Android's WebView
   `CookieManager` is a single store shared/persisted across every WebView
   instance in the app process, not scoped per-controller, so without this
   a second/"Add Account" login silently reuses whichever account's
   Nextcloud session cookie is already there instead of prompting for
   credentials (the same class of bug the Custom-Tab-reuse issue above
   was, just recurring one layer down once everything moved to the owned
   WebView).
3. `ServerProvider` polls `LoginFlowService.poll(pollEndpoint, token)` every
   2 seconds (`Timer.periodic`, see `_pollTimer`/`_pollTimeoutTimer` in
   `server_provider.dart`) until it gets a 200 with `server`/`loginName`/
   `appPassword`, a non-404 error, or a 10-minute timeout. A single dropped
   connection mid-poll (`http.ClientException`) is swallowed and retried on
   the next tick rather than aborting the whole flow.
4. The returned **app password** (scoped, revocable) is what gets stored and
   used for every subsequent request — real user passwords are never in
   memory or on disk.

`LoginFlowStatus` (`idle` → `initiating` → `awaitingBrowser` → `error`)
drives `LoginView`'s UI; see `LoginFlowService`'s doc comment for the full
flow rationale before changing it.

`startLoginFlow(serverUrl, {addAccount = false})` is reused verbatim for
both the first/only login and "add another account" (pushed from Settings
while already logged into a different account, `LoginView(isAddingAccount:
true)`) — `addAccount` only flags `isAddAccountFlow` for the UI (so the
pushed screen knows to auto-pop on success and cancel the flow on
back-swipe); the persistence path on success is identical either way, see
below.

## Talking to the server

[`NextcloudService`](../../lib/services/nextcloud_service.dart) is the
client for an authenticated session — constructed with `serverUrl` +
`username` + the app password, one instance per login (held as
`ServerProvider.service`, recreated on every login/switch/logout). It's
effectively stateless per-instance (three final fields, headers rebuilt per
request), which is what makes it trivial to have one saved per account
rather than needing a rewrite for multi-account support.

- **Files**: WebDAV (`PROPFIND`/`MKCOL`/`DELETE`/`MOVE`/`PUT` etc. against
  `/remote.php/dav/files/{username}/...`) via raw `http`/`dio` calls with a
  hand-rolled XML request body and `package:xml` for parsing responses —
  there is no WebDAV client dependency. `_parseDavDate`/`_davPath` in this
  file exist because WebDAV responses use RFC 1123 dates and either bare
  paths or full URLs for `href`; reuse them rather than re-deriving.
- **Everything else** (shares, activity, trash, favorites, quota, user info,
  file versions) goes through Nextcloud's OCS APIs (`/ocs/v2.php/...`), JSON
  in, with the `OCS-APIRequest: true` header required on every OCS call.
- Auth header is HTTP Basic (`username:appPassword`, base64), built in
  `_headers`/exposed as `authHeaders` for widgets that need to hit URLs
  directly (e.g. `Image.network(url, headers: service.authHeaders)` for
  thumbnails/previews).
- Downloads stream through `Dio` (`downloadToFile`) for progress callbacks;
  small in-app previews (text/PDF) use `fetchBytes` via `package:http`.
- **Uploads** (`uploadFileFromPath(folderPath, fileName, localFilePath,
  {onProgress})`) stream the local file via `Dio().put()` with an explicit
  `Content-Length` and `onSendProgress`, mirroring the download path. The
  `ServerProvider` wrapper always uploads into `_currentFolderPath` — the
  share-to-upload flow (`ShareUploadView`) gets a caller-chosen destination
  by navigating there first (`navigateToAbsoluteFolder`), then uploading.
- **Receiving a shared file from another app**: hand-rolled in
  `MainActivity.kt` (Android `ACTION_SEND`/`ACTION_SEND_MULTIPLE`,
  `android:launchMode` `singleTask` in the manifest so a second share while
  running hits `onNewIntent` instead of spawning a new instance) plus
  [`ShareIntentService`](../../lib/services/share_intent_service.dart) on
  the Dart side - not the `receive_sharing_intent` plugin, which this used
  to be. That plugin resolves a shared `content://` Uri by synchronously
  copying the *entire* file into the cache dir on the main thread during
  activity startup; for a large file that blocks long enough that Android
  kills the newly-launched activity for failing to draw a first frame,
  dropping the user straight back to the home screen with no error and no
  Dart code ever running. `MainActivity.kt`'s doc comment has the full
  story. The fix: `getInitialShare`/`onNewShare` only ever query cheap Uri
  metadata (name/size/mime, not content) so `ShareUploadView`'s destination
  picker - which mirrors the Files tab's own controls/filters/listing,
  reusing the same `ServerProvider` fields and `widgets/item_icon.dart` -
  always appears instantly regardless of file size.
- **Uploading a shared file**: once the user picks a destination in
  `ShareUploadView`, [`UploadService`](../../lib/services/upload_service.dart)
  hands the whole batch off to `ShareUploadService.kt`, an Android
  foreground service, rather than uploading from Dart in that screen. This
  is deliberate, not just an implementation detail: the point is that
  closing the app right after confirming a destination doesn't interrupt
  the upload, the same guarantee a real file-manager app's upload
  notification gives you - a plain Dart `Future` (even one kept alive by a
  singleton service class) stops running once the Flutter engine/Activity
  are gone, only an actual Android `Service` survives that. The service
  re-implements the WebDAV PUT itself in Kotlin (`HttpURLConnection`, no
  new HTTP dependency) since it can't reach the Dart-side `NextcloudService`/
  Dio from a separate process lifecycle - `UploadService.startUpload` passes
  everything the Kotlin side needs (the pre-built `Authorization` header
  from `NextcloudService.authHeaders`, not the raw password) as Intent
  extras, a one-way handoff with no channel back to Dart afterward. Keep
  the two upload implementations in sync manually if upload semantics
  change. Progress/cancellation is entirely notification-driven (one
  ongoing, updatable notification for the whole batch; its Cancel action
  re-delivers an Intent to the same running service instance, which an
  `AtomicBoolean` the copy/upload loops poll) - there's no plumbing back to
  the Dart UI, by design, since the app may not even be running.

## Being picked by other apps (photo/file picker)

Noo can also be launched *by* another app as a `GET_CONTENT` picker (e.g.
Google Drive/Instagram's "choose a file" flow), the reverse direction of
"Share to Noo" above - hand-rolled the same way, not a plugin.

- `MainActivity.kt` matches `ACTION_GET_CONTENT` (`OPENABLE`, any
  mimeType - a single `*/*` filter, since Android matches it against
  whatever the caller actually requested) alongside its existing
  `ACTION_SEND`/`SEND_MULTIPLE` filters, and exposes the caller's requested
  mimeType/multi-select flag/app label via the
  `dev.ayushya.noo/pick_intent` method+event channel pair
  ([`PickIntentService`](../../lib/services/pick_intent_service.dart)/
  [`PickRequest`](../../lib/models/pick_request.dart)) - same
  cold-start-vs-already-running split as the share-intent channels.
- `ServerProvider.pickRequest`/`isPicking` drive picking mode app-wide once
  `MainShellView` learns about a request at startup or via
  `onNewPickRequest`. While picking, `MainShellView` restricts the visible
  bottom-nav tabs to just Files and Photos (see `architecture.md`) -
  `FilesView`/`PhotosView` route taps through
  `itemMatchesPickFilter`/`confirmPick` instead of their normal
  open/select behavior (folders still navigate; a mime-mismatched file is
  rejected with a snackbar; matching files toggle-select or immediately
  confirm depending on `PickRequest.allowMultiple`).
- `ServerProvider.confirmPick` downloads the selected item(s) to a
  `picker/` scratch subfolder in the app's cache dir (`downloadToFile`,
  same as any other download) - each item into its own `picker/<item.id>/`
  subfolder, keeping the on-disk filename as plain `item.name` rather than
  prefixing it with the id to dodge collisions between same-named items;
  the caller reads that on-disk name back as the display name, so
  prefixing it there was a real bug (Drive showing e.g. `163332_photo.jpg`
  instead of `photo.jpg`) - then hands the local paths to
  `PickIntentService.finishPick`, which calls back into
  `MainActivity.kt.finishPick`: it wraps each file in a `content://` Uri
  via this app's own `FileProvider` (`${applicationId}.picker.fileprovider`,
  scoped to just that cache subfolder - see `android/app/src/main/res/xml/
  file_paths.xml`) and returns it to the caller via `setResult`. Single
  file uses `setDataAndType` (never `.data =`/`.type =` as two separate
  calls - each one silently nulls out the other field on a plain
  `Intent`); multiple files use `ClipData`. `cancelPick` mirrors this for
  backing out (system back while picking, or a picked-item mismatch) with
  `RESULT_CANCELED` instead.

## Multi-account storage & session persistence

[`AccountStore`](../../lib/services/account_store.dart) owns everything
account-identity-related; `ServerProvider` owns everything about which
account is *currently* live (see `architecture.md`).

- **Per-account secrets**: one `flutter_secure_storage` key per account,
  `nc_app_password_<accountId>` — never `shared_preferences`. `accountId` is
  deterministic (`SavedAccount.makeId(serverUrl, username)`, a slug of both),
  so re-adding the same account refreshes its password instead of creating a
  duplicate.
- **Account identity list** (non-secret: id/serverUrl/username) and
  **which one is active** live in `shared_preferences` as `accounts_list`
  (JSON array) and `active_account_id`.
- **Global UI prefs** (theme, dynamic color, AMOLED, bottom-bar
  opacity/blur, tap-to-scroll-top, seek bar style, tab order/hidden/default,
  swipe actions) stay flat, un-namespaced `shared_preferences` keys — same
  as before multi-account, untouched by switching.
- **Per-account browsing prefs** (grid/list view, favorites-only ×2,
  storage scope, show-hidden ×2, Photos sort field/ascending, Files'
  per-folder sort map, cache policy/interval — the full list is
  `AccountStore.perAccountPrefKeys`) are namespaced `acct_<accountId>_<key>`
  and reloaded on every switch via `ServerProvider._applyAccountPrefs`.
- **Legacy migration**: `AccountStore.migrateLegacyIfNeeded` runs once ever
  (guarded by the `account_migration_v1_done` flag), turning a pre-multi-
  account install's 3 flat secure-storage keys + flat browsing prefs into
  the first saved (and active) account, so upgrading users are never logged
  out. Never assume the legacy keys are gone — always check the migration
  flag rather than the keys' absence.
- On startup, `ServerProvider._init()` awaits the migration, loads the
  account list + active id, then `_restoreSession()` looks up the active
  account's password and calls `_applyCredentialsForAccount` (the renamed,
  generation-guarded, account-aware version of what used to be
  `_applyCredentials`) to rebuild the session without re-hitting the login
  flow.
- **Switching accounts** (`switchAccount`/`cycleToNextAccount`/
  `cycleToPreviousAccount`/`removeAccount`'s fallback, plus landing on a
  freshly-added account) all funnel through the single `_activateAccount`
  engine: bump `_sessionGeneration`, cancel any pending login flow, clear
  every content field *without* ever setting `isLoggedIn` false (that's the
  detail that keeps `main.dart`'s root routing from bouncing through
  `LoginView` mid-switch), reload the target account's prefs, then verify
  its credentials and refetch everything. This is a full teardown-and-reload
  every time — there is deliberately no simultaneous multi-account state or
  background sync; only one account's content is ever live.
- **`logout()` vs `removeAccount()`** are deliberately different actions,
  both funneling into a shared `_deactivateSession()` helper for the
  teardown/pointer-clearing part:
  - `logout()` ends the active session but keeps the account itself fully
    intact (password, prefs, its entry in `accounts` all untouched) —
    always lands on `LoginView` even if other accounts are saved (it does
    *not* fall back to one of them the way `removeAccount` does). This
    exists so `LoginView` can offer a "Continue as ..." one-tap resume list
    (`_SavedAccountsSection` in `login_view.dart`) with no Login Flow v2
    needed - logging out must never be mistaken for forgetting an account.
  - `removeAccount(id)` deletes everything for that account (secure-storage
    password, namespaced prefs, its `accounts` entry) and, only if it was
    the active one, falls back to another saved account or - if none
    remain - calls the same `_deactivateSession()`. This is the only path
    (besides `logout()`) that can set `isLoggedIn` false, and the only one
    that's actually destructive/irreversible - UI call sites (`AccountView`)
    gate it behind a confirmation dialog; `logout()` doesn't need one.
  - Any UI code that calls either and might have ended the session should
    check `!provider.isLoggedIn` afterward and `Navigator.popUntil((r) =>
    r.isFirst)` if so — otherwise a screen pushed on top (Settings) is left
    stranded over a root route that's silently swapped to `LoginView`
    underneath it. Don't pop unconditionally — removing a *non-active*
    account, or one that fell back to another, keeps the user logged in and
    Settings should just stay open.

## App lock (login lock)

An orthogonal, app-wide security layer on top of the Nextcloud
login/session above — not account credentials, just a gate on *using* the
app. [`AppLockService`](../../lib/services/app_lock_service.dart) wraps
`local_auth`; this app never implements its own PIN entry/storage/hashing —
`authenticate()` always delegates to whatever the OS already has configured
(biometric, or device PIN/pattern/password as fallback, via
`biometricOnly: false`). Never build a custom in-app PIN screen for this —
extend `AppLockService`/the `ServerProvider` gates described in
`architecture.md` instead.

**Android native requirements** (both already done, keep them if you touch
these files): `MainActivity.kt` must extend `FlutterFragmentActivity`, not
the default `FlutterActivity` — `local_auth`'s Android implementation hosts
its prompt via a Fragment and silently fails to build/crashes without it.
`AndroidManifest.xml` needs `<uses-permission
android:name="android.permission.USE_BIOMETRIC"/>` (also declared by the
plugin's own manifest via merge, but kept explicit here too).
`android/app/build.gradle.kts` floors `minSdk` at 24 (`local_auth_android`'s
own requirement) via `maxOf(24, flutter.minSdkVersion)` rather than trusting
Flutter's own default to already be high enough.

`isRestoringSession` still gates the splash screen until the above resolves
— see `standards.md` for why widget tests must mock both storage channels
rather than relying on this async path throwing naturally.