refactor(channel): share attachment infra (DM-files PR 1/2)

[2witstudios]

Summary

Pure-refactor groundwork for DM file attachments — Tasks 1–3 of the DM File Attachments epic. Channels adopt three shared modules so the second caller (DM upload route in PR 2) drops in as a thin wrapper.

• One canonical AttachmentMeta type (was 3 copies — db schema, attachment-utils, channel messages route). Lives in packages/db/src/schema/storage.ts next to files; re-exported from @pagespace/lib/types for non-db consumers.
• One MessageAttachment component (was 2 copies of a 50-line block — ChannelView.tsx + inbox/channel/[pageId]/page.tsx). Pixel-identical output by construction.
• One useAttachmentUpload hook with useEditingStore registration so SWR cannot clobber an in-flight upload — closes a latent gap that affected channels too. ChannelInput.tsx is ~75 lines lighter.
• 5 colocated unit tests for the new hook covering happy path, null-URL no-op, 413 toast, thrown-error session release, and clearAttachment. The original inline upload logic was untested; this is the right moment to lock the contract once for both channels and DMs.

Zero behavior change: channel rendering, channel upload, and channel send all work identically.

Out of scope (deliberate, lands in PR 2)

• AttachmentTarget discriminated union — the abstraction is only meaningful with a second caller, which only appears in PR 2 (DM upload route). Keeping it out of this PR avoids forcing reviewers to imagine a future branch.
• fileConversations schema migration, files.driveId nullability, DM upload endpoint, DM POST acceptance of fileId, DM composer wiring. All planned in tasks/dm-file-attachments.md.

Test plan

• pnpm turbo typecheck lint — 4/4 tasks pass, no new warnings
• vitest run src/hooks/__tests__/useAttachmentUpload.test.ts — 5/5 pass (new)
• vitest run src/lib/ai/tools/__tests__/channel-tools.test.ts — 11/11 pass
• Manual: open a channel, pick a file via the attachment button → image preview renders inline; non-image renders as download card
• Manual: open /dashboard/inbox/channel/[id], scroll history with mixed image/file attachments → identical to today
• Manual: start a slow upload, confirm SWR refresh doesn't clear the pending preview mid-upload (new behavior — uses useEditingStore)

🤖 Generated with Claude Code

Summary by CodeRabbit

Release Notes

• Refactor
  • Consolidated attachment handling infrastructure by centralizing attachment metadata type definitions across the application.
  • Extracted shared attachment upload logic into a reusable hook with improved error handling and user feedback for file upload operations.
  • Created a unified attachment rendering component to ensure consistent behavior for file preview and download functionality across the platform.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 1d049ec7-ab22-43a2-826e-40c08a84762f

📥 Commits

Reviewing files that changed from the base of the PR and between fb922ad and 1f42a3f.

📒 Files selected for processing (4)

• apps/web/src/components/layout/middle-content/page-views/channel/ChannelInput.tsx
• apps/web/src/hooks/__tests__/useAttachmentUpload.test.ts
• apps/web/src/hooks/useAttachmentUpload.ts
• tasks/dm-file-attachments.md

📝 Walkthrough

Walkthrough

The PR refactors attachment handling by extracting the shared AttachmentMeta type to a central location, creating reusable MessageAttachment component and useAttachmentUpload hook, and consolidating attachment logic from multiple components into these shared modules.

Changes

Cohort / File(s)	Summary
Type Centralization packages/db/src/schema/storage.ts, packages/lib/src/types.ts, packages/db/src/schema/chat.ts, apps/web/src/app/api/channels/.../route.ts, apps/web/src/lib/attachment-utils.ts	New AttachmentMeta interface defined in schema/storage and re-exported through lib/types; all local definitions replaced with imports from shared type source. MessageWithAttachment now exported from attachment-utils.
Shared Component & Hook apps/web/src/components/shared/MessageAttachment.tsx, apps/web/src/hooks/useAttachmentUpload.ts	New MessageAttachment component for rendering image previews and file downloads with icon/size metadata. New useAttachmentUpload hook handles file upload with authenticated requests, error-specific toast messages, and session management. FileAttachment type moved to hook module.
Component Integration apps/web/src/components/layout/.../ChannelInput.tsx, apps/web/src/components/layout/.../ChannelView.tsx, apps/web/src/app/dashboard/inbox/channel/.../page.tsx	Components refactored to use shared MessageAttachment component for rendering and useAttachmentUpload hook for uploads; removed local attachment logic, utilities, and icon imports.
Documentation plan.md, tasks/dm-file-attachments.md	Added active epic tracking DM file attachments feature; detailed planning document outlining polymorphic upload service, DB schema updates for fileConversations join table, permission checks, and test coverage requirements.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• Refactor inbox to unified messaging interface with channels and DMs #345 — Touches the same inbox/channel messaging UI and file-attachment components (ChannelInput, ChannelView, inbox channel page, and attachment rendering logic).
• Support file relation for message attachments #459 — Directly modifies attachment-related codepaths including attachment-utils.ts, AttachmentMeta type definitions, and channel message attachment handling in the same files.

Poem

🐰 Files unite, attachments now share,
A hop through hooks and components with care,
No more repeats in the code we create,
Just shared little types, oh how they're great!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'refactor(channel): share attachment infra (DM-files PR 1/2)' accurately describes the main objective: consolidating and sharing attachment infrastructure across the channel module as preparation for DM file attachments.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch pu/dm-files

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[2witstudios]

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Actionable comments posted: 3

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@apps/web/src/hooks/useAttachmentUpload.ts`:
- Around line 38-47: The uploadFile concurrency bug: multiple invocations race
on isUploading/setIsUploading; add a persistent ref-based in-flight counter
(e.g., uploadCountRef = useRef(0)) and in uploadFile (and the other upload
handler at lines ~90-93) increment uploadCountRef.current before starting, call
setIsUploading(true) if count becomes >0, then in finally decrement the counter
and call setIsUploading(uploadCountRef.current > 0); use the same
sessionId/startEditing/endEditing logic but rely on the ref counter to ensure
the loading flag is only cleared when all uploads complete.
- Around line 57-60: The response.json() results in useAttachmentUpload
currently assume a specific shape and directly access properties like
errorData.error and result.file.id/originalName/size/mimeType which can throw;
update the fetch error and success handling in the useAttachmentUpload hook to
perform runtime shape validation (e.g., using a small runtime guard or a schema
validator) before accessing fields: verify that errorData is an object with a
string "error" property before reading it, and verify that result is an object
with a "file" object containing string id, originalName, mimeType and numeric
size before constructing the Attachment payload; if validation fails, return or
throw a clear, handled error so callers don't encounter undefined-property
runtime exceptions (apply the checks around the response.json() usages in the
error branch and the success branch that reference result.file.*).

In `@tasks/dm-file-attachments.md`:
- Line 14: Update the doc to point to the canonical definition of AttachmentMeta
in the DB schema module (storage.ts) rather than the lib re-export; change the
line that currently references packages/lib/src/types.ts to reference the
schema's AttachmentMeta and note that channelMessages.attachmentMeta and
directMessages.attachmentMeta JSONB columns import that canonical type (i.e.,
reference AttachmentMeta in the DB schema module and mention both
channelMessages.attachmentMeta and directMessages.attachmentMeta).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 2a87bc01-6d93-47b4-9505-396fdf7a56da

📥 Commits

Reviewing files that changed from the base of the PR and between c961de7 and fb922ad.

📒 Files selected for processing (12)

• apps/web/src/app/api/channels/[pageId]/messages/route.ts
• apps/web/src/app/dashboard/inbox/channel/[pageId]/page.tsx
• apps/web/src/components/layout/middle-content/page-views/channel/ChannelInput.tsx
• apps/web/src/components/layout/middle-content/page-views/channel/ChannelView.tsx
• apps/web/src/components/shared/MessageAttachment.tsx
• apps/web/src/hooks/useAttachmentUpload.ts
• apps/web/src/lib/attachment-utils.ts
• packages/db/src/schema/chat.ts
• packages/db/src/schema/storage.ts
• packages/lib/src/types.ts
• plan.md
• tasks/dm-file-attachments.md