10 — Interaction Specification (Files Module)

• 1. Opening the upload sheet
• 2. Picking a file
• 3. Upload progress
• 4. Upload failure
• 5. Download interaction
• 6. Delete confirmation
• 7. Long-press & swipe (proposed)
• 8. Drag & drop (desktop) (forward-looking)
• 9. Offline behavior
• 10. Pull-to-refresh
• 11. Motion budget summary

Micro-interactions and motion for file flows. Motion tokens (m-fast, m-base), haptics, and platform patterns are authoritative in 00-shared/08_Interaction_&_Motion — this file applies them to the files domain.

1. Opening the upload sheet

• Trigger: "Attach" CTA → AppBottomSheet slides up (m-base, 280 ms, ease-out); scrim dims list.
• Tablet/desktop: centered dialog ≤ 480 dp, scale+fade (m-fast).
• Haptic: light (HapticFeedback.lightImpact) on open (mobile).

2. Picking a file

• System picker is a platform-owned transition (no app animation).
• On selection return: preview card animates in (m-fast fade+slide 8 dp); Upload CTA becomes enabled (color shift per tokens — no bounce).
• Re-pick replaces the preview (old card out m-fast, new in).

3. Upload progress

• Progress card: AppProgress fills 0→100% with per-frame value from transport onSendProgress; percent label; bytes counter 1.2 MB / 3.2 MB.
• Indeterminate until first progress event (server buffering) — AppProgress indeterminate variant, not a frozen 0%.
• Cancel: press state ripple; card collapses out (m-fast); snackbar "Upload cancelled".
• Success: card → green check 200 ms → auto-dismiss; tile inserts into list with m-base slide + highlight pulse (2 × m-fast).

4. Upload failure

• Card flips to error color; inline "Retry" button (re-POST). Error shake on the card (8 dp, m-fast) per 00-shared/08.
• Snackbar alternative only when the card is dismissed.

5. Download interaction

• Tap download → progress row appears under the tile (inline, no full-screen dialog for single files).
• Percent from onReceiveProgress; indeterminate until first bytes.
• Done (web): browser download UI takes over — show snackbar "Downloaded name".
• Done (mobile): system notification; tap → share/open sheet (forward-looking).
• Failure: row shows error + Retry (restarts from 0 — no resume).

6. Delete confirmation

• Menu → AppDialog destructive variant: title + file name + red Delete (danger color token), Cancel ghost.
• Confirm: button spinner (no double-tap), row removal animates out (m-base collapse), snackbar "File deleted". No undo action (proposed: restore later).
• Dismiss: scrim tap / back / ESC cancels without animation of the row.

7. Long-press & swipe (proposed)

• Long-press row → multi-select mode (proposed); swipe-left → delete shortcut on admin rows (proposed) — requires server multi-delete (planned) before shipping.

8. Drag & drop (desktop) (forward-looking)

• Drag a local file onto the list/section → drop zone highlight → auto-open UploadSheet prefilled. Browser-only; no server change.

9. Offline behavior

• Offline banner pins to top of list; upload/download actions disabled with explanation (no server reachability). Reconnect → retry queue drains (forward-looking).

10. Pull-to-refresh

• List re-fetch (GET /files) with standard RefreshIndicator; no haptic unless completion > 500 ms (platform default).

11. Motion budget summary