feat: add ai hint that content contains ai generated text

[GretaD]

fixes #12689

[coderabbitai]

📝 Walkthrough

Walkthrough

This change introduces an AI-generated content flag across the mail stack. The IMAP fetcher reads an x-ai-generated header and passes it into IMAPMessage, which propagates it into the Message DB entity via a new flagAiGenerated field, exposed via accessors and included in JSON serialization. A migration adjusts the corresponding database schema. LocalMessage also registers a type for its existing requestMdn field. In the frontend, ThreadEnvelope.vue displays an "Contains AI content" label with an icon when the envelope's aiGenerated flag is true, with supporting layout and styling updates.

Changes

Cohort / File(s)	Summary
DB schema & migration — lib/Db/Message.php, lib/Db/LocalMessage.php, lib/Migration/Version5201Date20260604000000.php	Adds flagAiGenerated property, accessors, type registration, JSON serialization for Message; registers requestMdn type in LocalMessage; migration drops ai_generated from mail_local_messages and adds flag_ai_generated to mail_messages.
IMAP fetch & propagation — lib/IMAP/ImapMessageFetcher.php, lib/Model/IMAPMessage.php	Reads x-ai-generated header, stores flag, passes it to IMAPMessage constructor, and sets flagAiGenerated on the DB message during conversion.
UI label — src/components/ThreadEnvelope.vue	Adds AiIcon, hasAiGeneratedContent computed property, conditional label rendering, and layout/styling updates.

Sequence Diagram(s)

sequenceDiagram
  participant ImapMessageFetcher
  participant IMAPMessage
  participant Message
  participant ThreadEnvelope

  ImapMessageFetcher->>ImapMessageFetcher: parseHeaders reads x-ai-generated
  ImapMessageFetcher->>IMAPMessage: construct with isAiGenerated
  IMAPMessage->>Message: toDbMessage sets flagAiGenerated
  Message-->>ThreadEnvelope: jsonSerialize exposes flags.aiGenerated
  ThreadEnvelope->>ThreadEnvelope: hasAiGeneratedContent computed
  ThreadEnvelope->>ThreadEnvelope: render AI content label

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Related issues: #12990, #12689

Suggested labels: enhancement, feature

Suggested reviewers: GretaD, st3iny

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🐰 A whisper of AI now tags each mail,
A flag in the schema, a header in the trail,
From IMAP it travels, through message and view,
A small icon glowing, "AI wrote this too!"

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title matches the main change: adding an AI-generated content hint in the UI.
Linked Issues check	✅ Passed	[#12990] The PR implements the requested AI-generated message hint by persisting the flag and surfacing it in the thread UI.
Out of Scope Changes check	✅ Passed	All changes support detecting, storing, and displaying the AI-generated content hint; no unrelated additions are evident.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/ai-hint-for-ai-content

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[coderabbitai]

Actionable comments posted: 1

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: eed45071-7465-42a0-93d9-22edd4613038

📥 Commits

Reviewing files that changed from the base of the PR and between 7fb0a1c and b8d17c6.

📒 Files selected for processing (6)

• lib/Db/LocalMessage.php
• lib/Db/Message.php
• lib/IMAP/ImapMessageFetcher.php
• lib/Migration/Version5201Date20260604000000.php
• lib/Model/IMAPMessage.php
• src/components/ThreadEnvelope.vue

💤 Files with no reviewable changes (1)

• lib/Db/LocalMessage.php

[coderabbitai]

📐 Maintainability & Code Quality | 🟠 Major | ⚡ Quick win

Replace hardcoded pixel gaps with Nextcloud CSS variables.

gap: 6px and gap: 4px are magic numbers. Per coding guidelines, spacing should use Nextcloud CSS variables (with calc() for finer control) rather than literal pixel values.

As per coding guidelines: "Use Nextcloud CSS variables for all CSS colors, spacing, and dimensions; do not use magic numbers. Use calc(x*var) when needing more specific control over dimensions with CSS variables."

♻️ Proposed fix

 	.sender {
 		margin-inline-start: calc(var(--default-grid-baseline) * 3);
 		display: flex;
 		align-items: center;
-		gap: 6px;
+		gap: calc(var(--default-grid-baseline) * 1.5);
 		min-width: 0;

 	.ai-generated-label {
 		display: flex;
 		align-items: center;
-		gap: 4px;
+		gap: var(--default-grid-baseline);
 		opacity: 0.8;
 	}

Also applies to: 1502-1508

Source: Coding guidelines

[Copilot]

Pull request overview

This PR adds end-to-end support for flagging messages as AI-generated: the composer can mark outgoing messages, the backend transmits/detects the flag via an email header and persists it on messages, and the UI surfaces a “Contains AI content” hint in the thread view.

Changes:

• Add a composer toggle (and auto-mark on smart reply) to mark outgoing mail as AI-generated and send it via X-AI-Generated.
• Detect X-AI-Generated on IMAP fetch and persist/expose the flag via message JSON flags.aiGenerated.
• Show an AI label in the thread envelope when flags.aiGenerated is set.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/components/ThreadEnvelope.vue	Displays an AI-content label in the sender line based on envelope.flags.aiGenerated.
src/components/Composer.vue	Adds “Mark as AI generated” toggle and includes isAiGenerated in send payload; auto-sets it for smart replies.
lib/Service/MailTransmission.php	Adds X-AI-Generated: 1 header when sending AI-generated local messages.
lib/Model/IMAPMessage.php	Carries IMAP-detected AI flag into DB Message entity flags.
lib/Migration/Version5201Date20260604000000.php	Schema change related to AI-generated flag storage.
lib/IMAP/ImapMessageFetcher.php	Detects X-AI-Generated header during IMAP fetch.
lib/Db/Message.php	Persists/serializes flagAiGenerated into JSON flags.aiGenerated.
lib/Db/LocalMessage.php	Adds non-persisted aiGenerated flag on local messages (used for sending header).
lib/Controller/OutboxController.php	Accepts isAiGenerated in outbox create/update requests and sets it on the LocalMessage.

[kesselb]

Claude: Please also reset isAiGeneratedVal in reset method

[kesselb]

Claude flagged this block, because a onEditorReady event (e.g the user is changing the alias) would insert the smart reply again, reset isAiGeneratedVal to true, and overwrite the user's choice. I think it's okay for now to ignore it, but we should look into a better way as follow up.