Telegram-iOS/CLAUDE.md
isaac 3d9fbdec3c InstantPage V2 table: rounded corners and corner-cell fill rounding
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-05-30 18:47:04 +02:00

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# CLAUDE.md
This file provides guidance to AI assistants when working with code in this repository.
## Build
The app is built using Bazel via the `Make.py` wrapper. There is no selective per-module build — the only supported invocation builds the full `Telegram/Telegram` target.
**Command:**
```sh
python3 build-system/Make/Make.py --overrideXcodeVersion \
--cacheDir ~/telegram-bazel-cache \
build \
--configurationPath build-system/appstore-configuration.json \
--gitCodesigningRepository git@gitlab.com:peter-iakovlev/fastlanematch.git \
--gitCodesigningType development --gitCodesigningUseCurrent --buildNumber=1 --configuration=debug_sim_arm64
```
Add `--continueOnError` after `build` (forwards to bazel's `--keep_going`) when verifying changes that may surface errors in many files at once — it lets the full set of errors land in one pass instead of stopping at the first failing target.
The build needs `TELEGRAM_CODESIGNING_GIT_PASSWORD` in the environment. It is set in `~/.zshrc` but Claude Code's bash tool does NOT source shell config by default. Prefix build commands with `source ~/.zshrc 2>/dev/null;` to pick it up.
## Code Style Guidelines
- **Naming**: PascalCase for types, camelCase for variables/methods
- **Imports**: Group and sort imports at the top of files
- **Error Handling**: Properly handle errors with appropriate redaction of sensitive data
- **Formatting**: Use standard Swift/Objective-C formatting and spacing
- **Types**: Prefer strong typing and explicit type annotations where needed
- **Documentation**: Document public APIs with comments
## Project Structure
- Core launch and application extensions code is in `Telegram/` directory
- Most code is organized into libraries in `submodules/`
- External code is located in `third-party/`
- No tests are used at the moment
## Embedded watch app (`Telegram/WatchApp`)
A standalone watchOS Telegram client (developed in the separate `~/build/tgwatch` repo) is vendored into this repo at `Telegram/WatchApp/` and can be embedded into the **device** IPA under `Telegram.app/Watch/`. It is built by `xcodebuild` (not Bazel) and codesigned by the Bazel build.
**Build it:** add `--embedWatchApp` to a Make.py **device** build (`--configuration=debug_arm64` or `release_arm64`) together with `--watchApiId`, `--watchApiHash`, `--watchSigningIdentity`, `--watchProvisioningProfile`. Off by default (it adds a ~4-min xcodebuild step); simulator builds never embed, and the default `debug_sim_arm64` build is unaffected.
**`Telegram/WatchApp/` is a synced snapshot — do not hand-edit it.** The source of truth and dev tooling live in the `tgwatch` repo. To change the watch app, edit it there, then re-sync with `tgwatch/tools/export-sources.sh /abs/path/to/telegram-ios/Telegram/WatchApp` and commit the result. The committed `tgwatch.xcodeproj` is generated (kept via a `!tgwatch.xcodeproj` negation in `Telegram/WatchApp/.gitignore`, since the root `.gitignore` ignores `*.xcodeproj`); `.build`/`.swiftpm`/`xcuserdata` are excluded.
**How it's wired:** `//Telegram:TelegramWatchApp` (rule in `Telegram/prebuilt_watchos.bzl`) runs in **two actions**: `PrebuiltWatchosCompile` (`Telegram/prebuilt_watchos_compile.sh`) runs xcodebuild on the snapshot in a writable temp copy with PLACEHOLDER version/api values (the bundle ids are baked from the snapshot's pbxproj/Info.plist — `ph.telegra.Telegraph.watchkitapp` / `ph.telegra.Telegraph`), emitting an unsigned `.app`; `PrebuiltWatchosPatchSign` (`Telegram/prebuilt_watchos_patch.sh`) then rewrites **six** per-build Info.plist keys (`CFBundleShortVersionString`, `CFBundleVersion`, `TG_API_ID`, `TG_API_HASH`, `CFBundleIdentifier`, `WKCompanionAppBundleIdentifier`) and codesigns the `.app` + nested `TDLibFramework.framework` (identity + the watchkitapp profile from `--define`s). The result feeds the `Telegram` `ios_application`'s `watch_application` slot (gated by the `//Telegram:embedWatchApp` flag). The rule takes `bundle_id` (set to `"{telegram_bundle_id}.watchkitapp"` in `Telegram/BUILD`) and derives the host bundle id by stripping the `.watchkitapp` suffix; both are passed to the patch worker as args (not action inputs), so the patch action re-runs when the host bundle id changes but the (expensive) compile stays cached. **The compile action's only inputs are the snapshot (+ its worker)** — so changing the version, build number, api id/hash, host bundle id, or signing identity re-runs only the cheap patch+sign action, not xcodebuild; xcodebuild re-runs only when the snapshot changes. This is correct because none of those values reach the compiled binary: each lands only in the Info.plist (via `$(...)` substitution and a runtime `Bundle.main.object(forInfoDictionaryKey:)` lookup in `Secrets.swift`, except for the bundle-id keys which only Info.plist consumers read).
**Non-obvious invariants** (also in the `.bzl` comments): `AppleBundleInfo`'s public init is banned — use the internal `new_applebundleinfo`; `watch_application` requires BOTH `AppleBundleInfo` (with a non-None `infoplist` File) AND `WatchosApplicationBundleInfo`; the embedded watch app's `CFBundleShortVersionString`/`CFBundleVersion` must exactly equal the host's (sourced from `versions.json['app']` + `--define=buildNumber`); the host does NOT re-sign the embedded watch app, so the worker must sign it; the watch bundle id `ph.telegra.Telegraph.watchkitapp` must track the host `telegram_bundle_id`.
**Status:** verified with **development** signing on `debug_arm64` only. Open follow-ups before App Store shipping: secure timestamp (drop `codesign --timestamp=none`), distribution profile (`get-task-allow=false`), `release_arm64` + `altool --validate-app`, and committing a `Package.resolved` for hermetic remote-SwiftPM resolution.
## View frame ownership
A view does not control its own `frame`. The parent (or a layout system) sets the frame; the view positions its own subviews against `self.bounds` in response.
This matters in two places specifically:
- **Reusable components (`UIView`/`ASDisplayNode` subclasses).** Public methods like `update(...)` / `apply(...)` rebuild internal state, mutate child frames, and read `self.bounds` to lay them out — but they do not write `self.frame`. The caller has already chosen the frame; mutating it from inside the component overrides that choice and fights the parent's next layout pass.
- **`asyncLayout`-style content nodes.** The measure pass runs off-main and returns a size; the apply step runs on main and the chat layout system positions the node. A child view that writes `self.frame` from `update()` corrupts the size the parent just measured.
Rare exceptions: top-level view-controller views integrating with the system's first-responder/inset model. If you find yourself wanting `self.frame = …` from inside a child view, refactor so the parent positions it instead.
## AI streaming animation (rich-text bubbles)
`ChatMessageRichDataBubbleContentNode` progressively reveals InstantPage V2 content while `TypingDraftMessageAttribute` is on the message. Mirrors the older animation in `ChatMessageTextBubbleContentNode`, adapted to the heterogeneous V2 layout. The "Thinking…" indicator is now server-sent as `InstantPageBlock.thinking` rendered inside the pageView (see "InstantPage thinking blocks" section).
### Where things live
| File | Responsibility |
|---|---|
| `submodules/TelegramUI/Components/StreamingTextReveal/Sources/TextRevealController.swift` | Pacing controller, shared by both bubbles. EWMA inter-arrival → velocity-smoothed cursor. |
| `submodules/InstantPageUI/Sources/InstantPageRenderer.swift` (`InstantPageV2TextView`) | Drawing split: private `TextRenderView` does `draw(_)` inside a `renderContainer` whose layer carries a `revealMaskLayer`; new chars spawn cropped `SnippetLayer` siblings of the render container that animate in (blur + alpha + scale + position) and are absorbed into the mask on completion. Ported from `InteractiveTextComponent`. |
| `submodules/InstantPageUI/Sources/InstantPageV2RevealCost.swift` | `InstantPageV2RevealCostMap` + `InstantPageV2View.applyReveal(revealedCount:costMap:animated:)`. Bridges the global width-based cursor to per-text-view char counts (via `charCountForWidthBudget`) and per-item visibility / table-row pop-in. |
| `submodules/InstantPageUI/Sources/InstantPageV2Layout.swift` | `InstantPageTextLine.characterRects` (line-local CT coords, baseline-relative positive-up) populated when `computeRevealCharacterRects: true` is passed to `layoutInstantPageV2(...)`. Uses `CTFontGetBoundingRectsForGlyphs` for actual glyph ink, not advance widths. |
| `submodules/TelegramUI/Components/Chat/ChatMessageRichDataBubbleContentNode/...` | Streaming detection (`TypingDraftMessageAttribute`), display-link wiring, container sizing. The hardcoded "Thinking…" header was removed; thinking is now rendered by the pageView via `InstantPageBlock.thinking`. |
### Non-obvious invariants
- **Cost unit is points of width, not characters.** Each item's cost = its width in points along the reading direction. Text contributes sum of glyph ink widths; non-text items contribute `frame.width`. Table cells are floored at `cell.frame.width` so narrow- or empty-cell tables don't race through the cursor. Reveal pace becomes "points per second" — uniform across content types.
- **Mask uses per-glyph ink bounds, unioned per line.** Each revealed glyph's mask rect comes from `CTFontGetBoundingRectsForGlyphs` (not advance widths) so italics, accents, descenders are covered exactly. Per line, glyphs are unioned into one mask rect; consecutive fully-revealed lines union further — fully-revealed prefix is always one `CALayer`.
- **`containerNode` does ALL the clipping.** During streaming, containerNode is sized to `revealedItemsMaxY` (no header offset, no closing pad; `streamingHeaderOffset` is `0.0`). The bubble itself is taller (`revealedContentSize.height + 2`) — the strip below containerNode is empty bubble background. pageView keeps its full `pageLayout.contentSize`; anything past containerNode's bottom is clipped at containerNode (`clipsToBounds = true` set in init). Do NOT shorten the pageView or set `pageView.clipsToBounds`.
- **The pageView is REUSED across `stableVersion` bumps for the same message id.** `ensurePageView` calls `existing.renderContext?.updateContent(webpage:)` (where `webpage` is now a `public private(set) var` with an `updateContent` mutator) and returns the existing view; `update(layout:)` then diffs item views by stable id, tearing down only views whose block was removed. The pageView is rebuilt only when the bubble is recycled with a different message or webpage. The reveal cursor on `TextRevealController` persists across chunks; the seed re-apply (`applyReveal(revealedCount: previousAnimateGlyphCount, …, animated: false)`) is now a continuation from the reused views' state, eliminating the per-chunk flash-of-full-text-then-mask that required the earlier from-scratch re-seed.
- **Layout cache key includes `message.stableVersion`.** Each AI chunk bumps stableVersion; without this the cached layout would shadow newly-arrived content.
- **`TypingDraftMessageAttribute` is the streaming gate.** Same trigger TextBubble uses. The InstantPage's `isComplete` flag is informational only.
- **Width-based cost → char count bridge.** Mask APIs (`updateRevealCharacterCount`) still take character counts. `applyRevealEntry` calls `charCountForWidthBudget(textItem:widthBudget:)` to translate the width-based local cursor into the per-text-view character count.
- **The hardcoded "Thinking…" header was removed.** `streamingStatusTextNode`, `streamingStatusShimmerView`, and the header-layout machinery no longer exist. `streamingHeaderOffset` is now a constant `0.0` — the pageView starts at the top of the bubble. The "Thinking…" indicator is now server-sent as `InstantPageBlock.thinking` and rendered inside the pageView (see "InstantPage thinking blocks" section below).
- **Display-link tick re-layouts on extent change.** Tick reads `revealedContentSize` at the new cursor; if the height differs from the previous cursor, calls `requestFullUpdate`. So the bubble grows in flight when the cursor crosses a line/item boundary, not just between chunks. Tick passes `animated: true` to `applyReveal` to fire the snippet pop-in.
### Status node (date/time/checks) positioning
The `ChatMessageDateAndStatusNode` mirrors TextBubble's placement, adapted to the heterogeneous V2 layout. The node is a child of `self` (the content node), **not** of the clipping `containerNode`, so it is never clipped — the bubble height must be grown to contain it.
- **X is a fixed left edge, not the last line's `minX`.** Anchor x = `pageHorizontalInset` (10pt, the page layout's text inset; pageView sits at self-x 0). The status layout is measured with `boundingWidth - 2·pageHorizontalInset` (mirrors TextBubble's `boundingWidth - sideInsets`) so the right-aligned date lands at the right inset instead of off the bubble. Using `lastTextLineFrame.minX` (which is large for nested/indented last lines) shoved the date off to the right.
- **Trail the last line only when the bottom-most item is text.** `lastTextLineFrameIfLastItemIsText(in:)` (in `InstantPageV2Layout.swift`) returns the last line frame *only* when the bottom-most top-level item (max `maxY`) is a `.text`; otherwise nil, so the date wraps below all content (anchored at `contentSize.height`). For tables/images/etc. the date must not trail text buried above the final item.
- **InstantPage draws the baseline at the line frame's `maxY`** (`InstantPageRenderer` draws each line at `lineOrigin.y + lineFrame.height`), so the visible text of a plain line sits ~5pt below `maxY`. A date that **trails** on the line (`statusHeight == 0`) adds `trailingBottomPadding` (5pt) to align with the text; a date that **wraps** onto its own line below (`statusHeight > 0`) sits at the bare `maxY`. The pad is 0 for lines taller than their font line height (an inline animated emoji, ~`pointSize·24/17`, already pushes `maxY` down). `lastTextLineFrameIfLastItemIsText` returns `(frame, trailingBottomPadding)`; the bubble applies the pad only in the trailing case.
- **Bubble height leaves ~6pt below the date.** One unified formula for all cases: `boundingSize.height = max(boundingSize.height, statusBottomEdge + 6.0)`, where `statusBottomEdge = statusAnchorY + max(1, statusHeight)`. The `statusAnchorY` in the measure (`continue`) closure must mirror the `statusFrameY` in the apply closure exactly, or the date will be clipped/misplaced. (`streamingHeaderOffset` is `0.0` — there is no header offset to add.) 6pt matches TextBubble's bottom bubble inset.
- **`hasDraft` adds the same 6pt at the streaming site.** The status max() above is gated by `!hasDraft`, so during streaming (status hidden, alpha=0) it can't supply the bubble's bottom inset. A separate `boundingSize.height += 6.0` inside `if hasDraft` in the SizeBlock closure does it instead — same 6pt, so the streaming bubble's bottom breathing room matches its post-stream height and there's no 6pt grow-pop when the status node fades in at finalize. The `hadDraft && !hasDraft` finalize pass doesn't need it because `!hasDraft` re-enables the status max(). If you ever refactor the `+6.0` constant out of the status max() into a `bottomInset` (TextBubble's pattern), kill this separate term at the same time — they're two ends of the same invariant.
## InstantPage V2 table — flush frame, inset borders, rounded corners
A V2 `.table` block's item frame is **full-width / flush** with the bubble interior (so a horizontally-scrollable wide table's scroll container bleeds edge-to-edge), but the actual grid **borders start at the body-text side inset** — matching the V1 renderer. The grid card also has a **10pt rounded outer border**. Specs: [`…-table-inset-design.md`](docs/superpowers/specs/2026-05-30-instantpage-v2-table-inset-design.md), [`…-table-corner-radius-design.md`](docs/superpowers/specs/2026-05-30-instantpage-v2-table-corner-radius-design.md).
### Non-obvious invariants
- **`InstantPageV2TableItem.contentInset` (= page `horizontalInset`) is the linchpin.** `layoutTable` (`InstantPageV2Layout.swift`) sizes columns against `contentBoundingWidth = boundingWidth horizontalInset·2` (so a fitting table aligns with body text on both sides) and stores `contentInset` on the item; the item `frame.width` is the flush `boundingWidth`, and `contentSize.width` stays the **bare grid width** (`totalWidth`, no inset).
- **The renderer (`InstantPageV2TableView`) realizes the inset as a view shift, not baked coordinates.** In `init` AND `update` it shifts the grid `contentView` to `x: contentInset`, sets `scrollView.contentSize.width = contentSize.width + contentInset` (**left margin only**), and `scrollView.clipsToBounds = true`. Cells, inner border lines, and the title stay x=0-relative inside `contentView`, so the single shift carries them all; the rounded outer border is `contentView.layer`'s own border (see below), which wraps the shifted layer automatically.
- **Scrollable tables clip to the full width with no inset on the clip.** The inset lives inside the scroll content as a left margin only: a fitting table (`grid + inset ≤ boundingWidth`) doesn't scroll and shows both-side inset; an overflowing table rests with its left border at the inset and scrolls its right border flush to the full-width edge (no trailing gap).
- **Manual cell-coordinate helpers MUST add `contentInset`.** Because the shift is a real `contentView` frame change, UIKit `hitTest` and `self.convert(_:to:)` paths (`propagateVisibilityRect`, the row-reveal mask) handle it automatically — but the *manual* coordinate helpers `findTextItem` / `collectSelectableTextItems` (the live tap / URL / text-selection path) compute cell/title positions arithmetically and must add `table.contentInset` to the x-offset, or in-cell hit-testing is off by the inset. (These helpers still do **not** account for the table's live horizontal `scrollView.contentOffset` — a pre-existing limitation, so in-cell hit-testing is only correct at scroll offset 0.) The dead-but-symmetric `lastTextLineFrame(in:)` table branch has the same omission but has no callers.
- **The 10pt rounded outer border is `contentView.layer`'s own border, NOT sublayers.** `v2TableCornerRadius = 10.0` (`InstantPageV2Layout.swift`). The renderer sets `contentView.layer.cornerRadius`/`borderColor`/`borderWidth = bordered ? v2TableBorderWidth : 0.0` in BOTH `init` and `update` (the four straight outer-edge rect layers were removed; `lineLayers` now holds only inner grid lines). **Border-only — deliberately no `masksToBounds`:** `cornerRadius` rounds the layer's border without clipping contents (filled corner cells round their own fills separately — see next bullet), and there is **zero interaction with the streaming reveal mask** (`contentView.layer.mask`, set only during AI streaming) — the border reveals row-by-row with the rows and is part of the masked layer. The rounded card belongs to the grid (scrolls with it). For a non-empty-title table (never produced by markdown/AI), the border wraps title+grid since `contentView` includes the title region — an accepted, approved nuance.
- **Filled corner cells round their own fills to match the border.** A header/striped cell's background is a stripe `CALayer`; `tableStripeCornerMask(cellFrame:gridWidth:gridHeight:effectiveBorderWidth:)` detects which grid corners the cell's (grid-local) frame touches — `firstCol/firstRow` via `frame.min{X,Y} <= effectiveBorderWidth/2 + 0.5`, `lastCol/lastRow` via `frame.max{X,Y} >= grid{Width,Height} - …` (gridWidth = `item.contentSize.width`, gridHeight = `item.contentSize.height - gridOffsetY`) — and rounds only those corners: `stripe.cornerRadius = max(0, v2TableCornerRadius - effectiveBorderWidth)` (the `-borderWidth` leaves an even border ring; borderless → full radius) + `stripe.maskedCorners`, in BOTH `init` and `update`. A `CALayer`'s `backgroundColor` honors `cornerRadius`+`maskedCorners` with no `masksToBounds`. A full-width (colspan) header rounds both top corners; a one-row filled table rounds all four; bottom corners round only when the last row is filled. The empty-mask branch resets `cornerRadius = 0` **and** `maskedCorners = []` so reused stripes (persist across streaming chunks) don't keep stale rounding. Detection is grid-local, so it's independent of the `contentInset` shift / horizontal scroll.
## Inline custom emoji (RichText.textCustomEmoji)
`RichText.textCustomEmoji(fileId:alt:)` renders an inline **animated** custom emoji inside rich-data bubbles. Covers API parsing, Postbox + FlatBuffers serialization, and display in the InstantPage V2 renderer; the emoji participates in the streaming reveal above.
### Where things live
| File | Responsibility |
|---|---|
| `submodules/TelegramCore/Sources/SyncCore/SyncCore_RichText.swift` | Enum case `textCustomEmoji(fileId: Int64, alt: String)` + Postbox coding (discriminator 17, keys `ce.f`/`ce.a`), `==`, `plainText` (returns `alt`), and FlatBuffers codec. |
| `submodules/TelegramCore/FlatSerialization/Models/RichText.fbs` | FlatBuffers schema — `RichText_CustomEmoji` union member + table. **Source of truth**; the Bazel `flatc` genrule regenerates `*_generated.swift` at build time (the checked-in `Sources/*_generated.swift` is stale). |
| `submodules/TelegramCore/Sources/ApiUtils/RichText.swift` | `Api.RichText.textCustomEmoji` ⇄ Swift, lossless both ways. |
| `submodules/InstantPageUI/Sources/InstantPageTextItem.swift` (`attributedStringForRichText`) | Emits a single placeholder char carrying `ChatTextInputAttributes.customEmoji` (a `ChatTextInputTextCustomEmojiAttribute`) + a `CTRunDelegate` sized `font.pointSize · 24/17`. |
| `submodules/InstantPageUI/Sources/InstantPageV2Layout.swift` (line-breaker) | Collects per-line `InstantPageTextLine.emojiItems`; overwrites each placeholder char's `characterRect` with a full cell (`width = itemSize`) so it feeds the reveal cost map. |
| `submodules/InstantPageUI/Sources/InstantPageRenderer.swift` (`InstantPageV2View`) | Owns the `InlineStickerItemLayer`s: `updateInlineEmoji` (create/reuse/remove/position), `updateEmojiReveal` (reveal-driven pop-in), `updateEmojiVisibility` + `propagateVisibilityRect`. Layers attach to each text view's `emojiContainerView`. |
### Non-obvious invariants
- **flatc casing/`required` gotchas.** Edit `RichText.fbs`, not the generated Swift. Scalars (`long`) cannot be `(required)` — only strings/tables can. A union member `RichText_CustomEmoji` generates the Swift enum case `.richtextCustomemoji` (everything after the suffix's first letter is lowercased); the table type stays `TelegramCore_RichText_CustomEmoji` and field accessors keep `.fbs` casing (`value.fileId`). See the `flatbuffers-codegen` memory.
- **`ChatTextInputTextCustomEmojiAttribute` is reused end-to-end** (display layer ⇄ layout model). The attribute is written to the placeholder in `attributedStringForRichText` and read back by the V2 line-breaker under the SAME key (`ChatTextInputAttributes.customEmoji`); `InlineStickerItemLayer.init` consumes it directly and resolves the file lazily from `fileId`.
- **Emoji participates in the streaming reveal.** Its placeholder char's `characterRect` is overwritten to a full cell (width = `itemSize`, baseline-relative bottom at `y=0`), so the width-based cost map charges it like other content. `updateEmojiReveal` pops the layer in (alpha 0→1 + scale) when `charIndexInItem < currentRevealCharacterCount`; unrevealed → opacity 0.
- **Layers sit ABOVE the reveal mask.** They attach to `InstantPageV2TextView.emojiContainerView` (a sibling above `renderContainer`), NOT inside it — so the reveal mask wipes glyphs while emoji pop in independently. Adding a CTRunDelegate-glyph to the mask would clip-wipe them instead.
- **Layers are owned by `InstantPageV2View`, not the text view.** Keyed by `InlineStickerItemLayer.Key(id: fileId, index: occurrence)`. The pageView is now REUSED across `stableVersion` bumps (see streaming section), so the inline-emoji dict PERSISTS across chunks; `updateInlineEmoji` prunes stale keys (emoji whose blocks have been removed) and creates/repositions layers for new or unchanged emoji each update pass.
- **`visibilityRect` gates looping; `nil` means "not visible".** The bubble's `visibility` override pushes a full-width sub-rect to the root `pageView.visibilityRect`, re-pushed in the apply closure after `pageView.frame` is set. `propagateVisibilityRect` converts the rect into each nested V2View's coordinate space (`self.convert(_:to:)`) for details bodies / table cells+title, fanning out via each child's `didSet`.
- **CTRunDelegate extent buffers must be freed.** Every inline-attachment arm (`.image`/`.formula`/`.textCustomEmoji`) in `attributedStringForRichText` allocates an `extentBuffer`; the `dealloc` callback must `deallocate()` it (it re-runs per layout pass).
## RichText entity cases (mention / hashtag / bot command / bank card / auto link)
`RichText.textMention`, `.textMentionName(text:peerId:)`, `.textHashtag`, `.textCashtag`, `.textBotCommand`, `.textBankCard`, `.textAutoUrl`, `.textAutoEmail`, `.textAutoPhone` render the message-entity flavors of rich text inside rich-data bubbles with full tap interaction mirroring `ChatMessageTextBubbleContentNode`. Covers API parsing, Postbox + FlatBuffers serialization, display, and tap routing. (`textDate`/`textSpoiler` remain unimplemented — `.plain("")`.)
### Where things live
| File | Responsibility |
|---|---|
| `submodules/TelegramCore/Sources/SyncCore/SyncCore_RichText.swift` | The 9 enum cases (each wraps `text: RichText`; `textMentionName` adds raw `peerId: Int64`) + Postbox coding (discriminators 1826, wrapped text under key `"t"`, mention-name peerId under `"mn.p"`), `==`, `plainText`, FlatBuffers codec. |
| `submodules/TelegramCore/FlatSerialization/Models/RichText.fbs` | Union members + tables (`RichText_MentionName` adds `peerId:long`). Source of truth — same flatc gotchas as the custom-emoji section above. |
| `submodules/TelegramCore/Sources/ApiUtils/RichText.swift` | `Api.RichText` ⇄ Swift, lossless. `textMentionName` carries `userId``peerId`. |
| `submodules/InstantPageUI/Sources/InstantPageTextItem.swift` (`attributedStringForRichText`) | Display: auto url/email/phone reuse the `InstantPageUrlItem` (`url:`) path; the six entity cases push `.link(false)`, recurse, then attach the matching `TelegramTextAttributes.*` key over the produced range. |
| `submodules/TelegramUI/Components/Chat/ChatMessageRichDataBubbleContentNode/...` | Tap routing: `entityForTapLocation` reads the attribute dict at the tapped point; `entityTapContent` maps keys → `ChatMessageBubbleContentTapAction.Content`. |
### Non-obvious invariants
- **Display attaches the same `TelegramTextAttributes.*` keys the chat text bubble uses; the bubble reads them back.** Contract: `textMention``PeerTextMention` (String); `textMentionName``PeerMention` (`TelegramPeerMention`, peerId built as `EnginePeer.Id(namespace: Namespaces.Peer.CloudUser, …)``InstantPageTextItem` imports TelegramCore but NOT Postbox, so bare `PeerId` is out of scope); `textHashtag` AND `textCashtag``Hashtag` (`TelegramHashtag`; no dedicated cashtag key/tap-action — the leading `$` distinguishes them); `textBotCommand``BotCommand`; `textBankCard``BankCard`. Auto url/email/phone go through the URL path (`mailto:`/`tel:`/raw), NOT an entity key.
- **`linkSelectionRects` and the bubble tap path check all six interactive keys** (URL + the five entity keys), not just URL, so press-highlight and the link-loading shimmer cover entities too.
- **Rich-data text selection must reach a line's trailing edge.** This is general to rich-data selection, not just entities: `InstantPageTextItem.attributesAtPoint(_:orNearest:)`'s `orNearest: true` (selection-drag) path returns `line.range.upperBound` (via `CTLineGetStringRange`) when the point is at/past `lineFrame.maxX`. `TextSelectionNode` uses that index as the **exclusive** upper bound, so clamping to the last character's index — as the `orNearest: false` hit-testing path correctly does — would leave the last character/item of every line unselectable. Mirrors `Display.TextNode`. Do not collapse the two `orNearest` paths back together.
## Markdown send: entity vs. rich detection
On message send, the app auto-decides: if the typed markdown maps onto the regular message-entity set (bold/italic/code/strikethrough/spoiler/links/blockquote/fenced-code) it sends a **normal message** via the existing entity path; if it contains structure the entity set can't represent it sends a **rich message** (`RichTextMessageAttribute` carrying an `InstantPage`, rendered by `ChatMessageRichDataBubbleContentNode`). Always-on (no flag). **Effective rich triggers are headings, lists, and tables only.**
### Where things live
| File | Responsibility |
|---|---|
| `submodules/BrowserUI/Sources/BrowserMarkdown.swift` | The classifier `richMarkdownAttributeIfNeeded(context:text:)` (pre-filter `markdownMightNeedRichLayout` → parse via existing `inputRichTextAttributeFromText` → block inspection `instantPageNeedsRichLayout`/`blockIsEntityExpressible`/`richTextIsEntityExpressible`), plus the markdown→InstantPage conversion (`markdownWebpage`, `markdownBlocks(from:)`, `markdownBlocksWithGeneratedAnchors`). |
| `submodules/TelegramUI/Sources/ChatControllerNode.swift` (`sendCurrentMessage`, ~line 4860) | The gate: `if !isSpecialChatContents, let attribute = richMarkdownAttributeIfNeeded(context:, text: effectiveInputText.string)` routes to the rich branch; the unchanged `else` is the entity path. |
### Non-obvious invariants
- **Boundary rule:** send rich iff the parse yields an `InstantPageBlock` with no entity equivalent. Entity-expressible whitelist (→ normal): `.paragraph`, `.preformatted`, `.blockQuote` (empty caption), `.anchor`, `.unsupported`, **and `.divider`** (`---` is too common in casual text to trigger rich). **`.formula` (block and inline) DOES trigger rich**, gated by strict math detection (see "Formulas trigger rich messages" below) so casual `$` usage (`$5-$10`, `$FOO=$BAR`) stays plain. So effective triggers = headings, lists, tables, formulas.
- **Approach A (parse-then-inspect):** the classifier reuses the real parser, so "what triggers rich" can't drift from "what the rich renderer shows." `markdownMightNeedRichLayout` is a cheap necessary-condition over-approximation — it may over-trigger a parse but must **never** false-negative. It detects `#`, list markers, dash-lines (`-{1,}`, which also catches setext-H2 underlines → heading blocks), `\n=` (setext H1), `|`, `![`, and math delimiters `$`/`\(`/`\[` (formulas now trigger rich; the strict detection step decides whether a `$` run is actually math).
- **Chat vs. document path = `file == nil` / `context.documentURL == nil`.** `inputRichTextAttributeFromText` passes `file: nil`; the document-attachment path passes a real file. Two chat-only behaviors key off this: (a) generated heading anchors are **skipped** (`markdownBlocksWithGeneratedAnchors` runs only for documents — anchors exist for intra-document `#slug` links and otherwise prepend a spurious invisible `.anchor` block per heading); (b) a level-1 `#` heading maps to `.heading(text:, level: 1)`, not `.title` (the document/article-title treatment). H2H6 → `.heading(level: 2…6)` for both paths. This converter only ever emits `.title` (H1-doc) or `.heading` — never `.header`/`.subheader`.
- **The classifier is fed the RAW `effectiveInputText.string`**, not the post-`convertMarkdownToAttributes` `inputText`, so inline `**bold**` survives into the rich render. The entity branch still uses the converted `inputText`.
- **Bypassed for `.customChatContents`** (business links / quick replies) via `isSpecialChatContents`. The compose/send gate lives here; **editing has its own symmetric re-classification** — see "Editing rich messages" below.
- **Transmission:** `RichTextMessageAttribute``Api.InputRichMessage` via `messages.sendMessage(richMessage:)` (flag bit 23, `StandaloneSendMessage.swift`); recipients reconstruct it from the incoming `richMessage` field (`StoreMessage_Telegram.swift`). The rich branch sends `text: ""` + the attribute, nils `mediaReference` (no separate webpage preview), and bypasses 4096-char chunking. iOS < 15 / oversize markdown `inputRichTextAttributeFromText` returns nil entity path (which chunks).
- **`debugRichText` experimental flag is now orphaned** it previously gated this path and is no longer read anywhere, though `DebugController`/`ExperimentalUISettings` still define/persist it. Optional cleanup.
## Editing rich messages (InstantPage → markdown)
Rich messages (`RichTextMessageAttribute`, `text == ""`) are made editable by reconstructing markdown source from the stored `InstantPage`, populating the editor with it, and re-classifying on save the inverse of the send path above. Always-on (no flag). Images/videos are out of scope (skipped by the converter).
### Where things live
| File | Responsibility |
|---|---|
| `submodules/BrowserUI/Sources/InstantPageToMarkdown.swift` | `markdownStringFromInstantPage(_:)` the inverse converter (block + inline + list + table + escaping). Pure, best-effort, never fails. |
| `submodules/TelegramUI/Sources/Chat/ChatControllerLoadDisplayNode.swift` | `setupEditMessage`: rich message reconstruct markdown into the edit field. `editMessage` (save): re-classify the raw input, route rich-or-plain. |
| `submodules/TelegramStringFormatting/Sources/InstantPagePreviewText.swift` | `previewText()` extensions (`RichText`/`InstantPage*`) one-line plaintext previews. |
| `submodules/TelegramStringFormatting/Sources/MessageContentKind.swift` | `messageContentKind` returns `.text(instantPage.previewText())` for rich, cascading to all preview surfaces. |
### Non-obvious invariants
- **The converter emits CommonMark inline, NOT the entity-regex dialect.** `**bold**`, `*italic*`, `` `code` ``, `~~strike~~`, `[text](url)` — because re-send re-parses the text through the *rich* path (`richMarkdownAttributeIfNeeded` → `NSAttributedString(markdown:)`, Apple CommonMark), not `convertMarkdownToAttributes` (whose dialect is `__italic__`/`||spoiler||`). The two parsers disagree on `__`/`*`; the rich round-trip is the contract.
- **Re-classify every edit (edit send).** `editMessage` runs the same `richMarkdownAttributeIfNeeded` on the RAW input string. Rich `pendingUpdateMessageManager.add(text: "", entities: nil, richText: attr, …)`; else the unchanged plain path. So normalrich (add a table) and richplain (drop all triggers) both work. Bypassed for `.customChatContents`.
- **Change-detection compares the rich attribute.** The save guard adds `currentRichText != richTextAttribute` (rich branch skips no-op rich edits) and `currentRichText != nil` (plain branch so richplain still saves even when `text.string` looks unchanged). `RichTextMessageAttribute` is `Equatable` on `instantPage`.
- **The `text.length == 0` early-return guard is safe for rich.** `convertMarkdownToAttributes` only rewrites inline tokens, never strips `#`/`-`/`|`, so a rich message's markdown source stays non-empty and passes; the rich branch then sends `text: ""`.
- **Known limitation:** a richplain edit that leaves only inline-formatted text loses `*italic*` (the entity path recognizes only `__…__`). Rare edge; the rich round-trip contract holds.
- **`previewText()` lives in TelegramStringFormatting, not TextFormat/TelegramCore.** It will gain a `strings: PresentationStrings` param (to localize the `"Photo"`/`"Video"`/`"Table"` placeholders), so it must sit in a UI-string module `messageContentKind`/`descriptionStringForMessage` (same module) already take `strings:`. Teaching `messageContentKind` about rich cascades the preview to the edit accessory panel, reply/pinned panels, and forward preview in one place (those surfaces need no individual change).
## Copying rich messages as markdown (whole message + partial selection)
Rich messages (`RichTextMessageAttribute`, `text == ""`) are copyable as markdown two ways: the context-menu **Copy** action copies the whole message; a **text selection** inside the rich-data bubble copies just the selected range. Both reconstruct markdown that mirrors the edit round-trip (`markdownStringFromInstantPage`). Always-on.
### Where things live
| File | Responsibility |
|---|---|
| `submodules/TelegramUI/Sources/ChatInterfaceStateContextMenus.swift` | Whole-message Copy. Computes `richMessageMarkdown` from the message's `RichTextMessageAttribute.instantPage` (after `let message = messages[0]`), opens the Copy gate with `richMessageMarkdown != nil`, and short-circuits `copyTextWithEntities` to `storeMessageTextInPasteboard(markdown, entities: nil)`. |
| `submodules/BrowserUI/Sources/InstantPageToMarkdown.swift` | `markdownStringFromInstantPage` the block-tree markdown converter (also used by the edit round-trip). Blocks joined by `\n\n`; nested blockquotes via recursive `> ` wrapping. |
| `submodules/InstantPageUI/Sources/InstantPageTextItem.swift` | `InstantPageMarkdownBlockContext` (`kind` + `quoteDepth`) and the `markdownContext: InstantPageMarkdownBlockContext?` field on `InstantPageTextItem`. |
| `submodules/InstantPageUI/Sources/InstantPageV2Layout.swift` | `stampMarkdownContext`/`bumpQuoteDepth`; stamps `markdownContext` during layout (heading/title/code/list/blockQuote/`layoutQuoteText`/table-cell). |
| `submodules/InstantPageUI/Sources/InstantPageMultiTextAdapter.swift` | `markdownForRange(_ range: NSRange)` + the private attributed-substringinline-markdown converter `inlineMarkdown(from:)`. |
| `submodules/TelegramUI/Components/Chat/ChatMessageRichDataBubbleContentNode/.../ChatMessageRichDataBubbleContentNode.swift` | Intercepts `.copy` in the `TextSelectionNode` `performAction` closure: `textSelectionNode.getSelection()` `adapter.markdownForRange(range)` stores as plain `NSAttributedString(string:)`. |
### Non-obvious invariants
- **The V2 layout discards block role.** A `.text` layout item from an `H2` heading is byte-identical to a body paragraph heading level and the title category are dropped with no back-reference to the source `InstantPageBlock`. Precise structural markdown for a *selection* therefore requires stamping `markdownContext` at layout time (lists/code/tables/details are structurally recoverable; **heading level and `.title` are not**, so they MUST be stamped). Plain paragraphs stay `nil` (≡ plain).
- **`quoteDepth` is orthogonal to `kind`** so a heading/list/code line inside a blockquote round-trips (e.g. `> ## Title`). `bumpQuoteDepth` lifts a quote's children by 1; nested quotes accumulate. `layoutQuoteText` (single-paragraph blockquote fast path AND `.pullQuote`) bumps once it is never reached by the multi-block recursion, so no double-count.
- **A blockquote is exploded into one text item per line.** `markdownForRange` must re-coalesce a run of consecutive `quoteDepth > 0` segments into ONE `\n`-joined block (each line prefixed at its own depth); otherwise every quote line becomes its own block separated by a blank line. Code/table/list runs are likewise coalesced (one fence; one pipe table; one tight list).
- **Both converters emit compact nested-quote markers (`>>`, not `> >`).** Selection: `String(repeating: ">", count: depth) + " "`. Whole-message: when wrapping a line that already starts with `>`, prepend a bare `>`. Keep the two in sync.
- **Inline markdown is read from display attributes, not the RichText tree.** `inlineMarkdown` inspects the slice's `UIFont` (bold/italic/mono font-based, no symbolic-trait flag for named fonts), `.strikethroughStyle`, and `TelegramTextAttributes.URL` (→ `InstantPageUrlItem.url`, angle-bracketed if it contains `(`/`)`/space). Custom-emoji placeholders are dropped (no `alt` on the display attribute).
- **`.copy` stores plain text.** Passing `NSAttributedString(string: markdown)` through the existing `performTextSelectionAction(.copy)` path (`storeAttributedTextInPasteboard`) generates no entities, so the literal `**`/`#`/`>`/`|` survive. The whole-message Copy uses `storeMessageTextInPasteboard(_, entities: nil)` directly.
- **Fidelity caveats (intentional):** custom emoji omitted; ordered list + checkbox loses the ordinal (`-` wins); a partial table selection emits touched cells as rows (no forced header `---` separator); block prefixes apply to the whole touched line on a mid-line selection (correct markdown).
## Formulas trigger rich messages (strict math detection)
`$…$`/`$$…$$` (and `\(…\)`/`\[…\]`) math triggers a rich message, gated by a
strict boundary rule so casual `$` stays plain. Inverse companion of the
markdown-send gate above.
### Non-obvious invariants
- **Inline `$…$`/`$$…$$` detection requires a 4-way boundary** (in `markdownReplacingInlineFormulas`, `BrowserMarkdown.swift`): outer side of each delimiter = line edge OR non-alphanumeric; inner side = non-whitespace; opener/closer `$`-counts must match (1 or 2). This is what rejects `$5-$10`/`$FOO=$BAR`/`cost$5$total` (alphanumeric outer) while keeping `$x$`, `($x$)`, `the answer is $x$.`. The outer check is the addition over a plain "no-space-inside" rule.
- **Block `$$` detection** (`markdownBlockFormulaReplacement`): single-line `$$…$$` requires an exact `$$` opener (not `$$$`) and trailing whitespace only; multi-line requires a **bare** `$$` opener line. `$$x$$ trailing text` falls through to the inline rule. The `\[…\]` opener path is unchanged and exempt from these `$$`-only guards.
- **Detection is shared with the document path; the gate is chat-only.** `markdownPreparedSource` (detection) runs for both chat and document attachments. The triggers (`richTextIsEntityExpressible`/`blockIsEntityExpressible` `.formula` is non-expressible; `$`/`\(`/`\[` in `markdownMightNeedRichLayout`) are read only by the chat classifier `richMarkdownAttributeIfNeeded`.
## InstantPageListItem task-list checkboxes (`- [ ]` / `- [x]`)
`InstantPageListItem` carries a first-class `checked: Bool?` the **third** associated value of `.text(RichText, String?, Bool?)` / `.blocks([InstantPageBlock], String?, Bool?)`, orthogonal to the ordered-list `num` representing a GitHub-style task-list checkbox. `nil` = not a checkbox item, `false` = unchecked, `true` = checked. Covers markdown parse, Postbox + FlatBuffers serialization, Telegram API transmission, display (V1 + V2), the edit round-trip, and previews.
Spec: [`docs/superpowers/specs/2026-05-27-instantpage-list-checkbox-design.md`](docs/superpowers/specs/2026-05-27-instantpage-list-checkbox-design.md). Plan: [`docs/superpowers/plans/2026-05-27-instantpage-list-checkbox.md`](docs/superpowers/plans/2026-05-27-instantpage-list-checkbox.md).
### Where things live
| File | Responsibility |
|---|---|
| `submodules/TelegramCore/Sources/SyncCore/SyncCore_InstantPage.swift` | The `checked: Bool?` enum payload; Postbox coding (key `"ck"`, tri-state Int32); `==`; FlatBuffers codec. Internal tri-state helpers `checkedFromTriState`/`triState(fromChecked:)`. |
| `submodules/TelegramCore/FlatSerialization/Models/InstantPageBlock.fbs` | `checkState:int32 (id: 2)` on `InstantPageListItem_Text` + `_Blocks`. **Source of truth**; the Bazel `flatc` genrule regenerates the Swift (checked-in `*_generated.swift` is stale). |
| `submodules/TelegramCore/Sources/ApiUtils/InstantPage.swift` | `checked` / `num` accessors; reads & writes the API `checkbox`=flags.0 / `checked`=flags.1 bits via `checkedFromApiFlags` / `apiFlags(fromChecked:)` across all four list-item types. |
| `submodules/BrowserUI/Sources/BrowserMarkdown.swift` | Forward parse: `markdownTaskListMarker` detects `[ ]`/`[x]`/`[X]`; the result routes into `checked` (NOT `num`). |
| `submodules/BrowserUI/Sources/InstantPageToMarkdown.swift` | Reverse: emits `- [ ] ` / `- [x] ` from `item.checked` for the edit round-trip. |
| `submodules/InstantPageUI/Sources/InstantPageV2Layout.swift` | V2 detection via `item.checked`; `.checklist(checked:colors:)` marker carrying `InstantPageV2CheckboxColors`. |
| `submodules/InstantPageUI/Sources/InstantPageRenderer.swift` | V2 marker view (`InstantPageV2ListMarkerView`) hosts a real `CheckNode`. |
| `submodules/InstantPageUI/Sources/InstantPageLayout.swift` | V1 detection via `item.checked` (renders the existing `InstantPageChecklistMarkerItem`). |
| `submodules/TelegramStringFormatting/Sources/InstantPagePreviewText.swift` | `previewText()` renders a `☐`/`☑︎` glyph + body for checkbox items. |
### Non-obvious invariants
- **`checked` is orthogonal to `num`.** The API keeps `checkbox`/`checked` as flags **separate from the list number**, so an ordered item can be both numbered AND a checkbox. This is exactly why the first-class field replaced an earlier sentinel-string-in-`num` prototype (which could not represent both). No `\u{001f}tg-md-task:*` sentinel remains anywhere.
- **API bits are `checkbox`=flags.0, `checked`=flags.1 on ALL FOUR list-item constructors** (`pageListItemText`/`Blocks` and `pageListOrderedItemText`/`Blocks`, in and out `pageListItemText#2f58683c`, `pageListOrderedItemText#cd3ea036`, etc.). The iOS `Api.*` layer exposes only `flags: Int32`; mask the bits (`apiFlags(fromChecked:)` / `checkedFromApiFlags`). Because state rides the flags (not the text), it survives the server round-trip for sender + recipients **including the sender's own send-confirmation echo** (`applyUpdateMessage` replaces local attributes with the server's reconstruction, `ApplyUpdateMessage.swift`).
- **Tri-state persistence `0=nil, 1=unchecked, 2=checked`** in BOTH Postbox (key `"ck"`, decoded with `decodeInt32ForKey(orElse: 0)`) and FlatBuffers (`checkState:int32`, default 0). Absent/0 `nil`, so pre-existing stored pages decode unchanged.
- **Detection reads `item.checked != nil`** in both layout engines (was `instantPageTaskListMarkerState(item.num)`); the V2 marker kind is `.checklist(checked: item.checked == true, colors:)`. The empty-blocks `.blocks → .text(.plain(" "), num, checked)` promotion must carry `checked` through, not drop it.
- **V2 `CheckNode` is hosted directly in a plain `UIView`**, not an ASDisplayNode tree, so `checkNode.displaysAsynchronously = false` is set to avoid a first-draw blank flash. (The V2 pageView is now REUSED across streaming chunks via stable-id diffing see the AI streaming section; `CheckNode` views survive across chunks as long as their list item is present.) `InstantPageV2CheckboxColors` (background`panelAccentColor`, stroke`pageBackgroundColor`, border`controlColor`) is carried on the `.checklist` payload and mirrors the V1 `instantPageChecklistMarkerTheme`.
- **Forward parser keeps `[ ]` detection but routes to `checked`.** `markdownApplyTaskListMarker`/`markdownStrippingTaskListMarker`/`markdownTaskListMarker` still strip the marker from the item text; the state flows into `checked` while ordered items keep their real `"\(ordinal)"` number. The reverse converter emits lowercase `[x]` / `[ ]`, which the forward `hasPrefix` guards re-parse that is the round-trip contract.
- **The enum-arity change is compile-enforced.** Adding the third associated value broke every `.text`/`.blocks` construction/destructure; the full build is the completeness gate. Read-only consumers outside the core set exist (`BrowserInstantPageContent.swift`, `CachedFaqInstantPage.swift`) grep `\.(text|blocks)\(` repo-wide when touching the enum again.
## InstantPageBlock.blockQuote nested blocks
`InstantPageBlock.blockQuote` carries `(blocks: [InstantPageBlock], caption: RichText)` a sequence of nested page blocks (paragraphs, headings, lists, code, even nested quotes), not the legacy text-only payload. `.pullQuote` is unchanged (still `(text: RichText, caption: RichText)`; the TL API has no `pullQuoteBlocks` constructor).
Spec: [`docs/superpowers/specs/2026-05-29-instantpage-blockquote-blocks-design.md`](docs/superpowers/specs/2026-05-29-instantpage-blockquote-blocks-design.md).
### Where things live
| File | Responsibility |
|---|---|
| `submodules/TelegramCore/Sources/SyncCore/SyncCore_InstantPage.swift` | Enum case shape; Postbox coding (legacy `"t"` lift new `"b"` object array); equality (array-aware, mirrors `.collage`); FlatBuffers codec. |
| `submodules/TelegramCore/FlatSerialization/Models/InstantPageBlock.fbs` | `InstantPageBlock_BlockQuote`: `text` (now optional, legacy fallback) + `caption (required)` + new `blocks:[InstantPageBlock] (id: 2)`. **Source of truth**; Bazel regenerates the `*_generated.swift`. |
| `submodules/TelegramCore/Sources/ApiUtils/InstantPage.swift` | Parse both `pageBlockBlockquote` (lift text`[.paragraph]`) and `pageBlockBlockquoteBlocks`; encode legacy-when-possible. |
| `submodules/InstantPageUI/Sources/InstantPageV2Layout.swift` | `layoutBlockQuote(blocks:…)` recurses into children; legacy single-paragraph fast path delegates to `layoutQuoteText` (the renamed shared text core, also used by `.pullQuote`). |
| `submodules/InstantPageUI/Sources/InstantPageLayout.swift` | V1 `.blockQuote` arm recurses via `layoutInstantPageBlock(...)`; same single-paragraph fast path. |
| `submodules/BrowserUI/Sources/BrowserMarkdown.swift` | Forward: one quote carrying all child blocks. Entity-expressibility gate (below). |
| `submodules/BrowserUI/Sources/InstantPageToMarkdown.swift` | Reverse: `markdownBlockQuoteBlocks(_:)` recurses per child and prefixes `> ` per line. |
| `submodules/TelegramStringFormatting/Sources/InstantPagePreviewText.swift` | Concatenates child `previewText()`s + caption. |
### Non-obvious invariants
- **Legacy shapes lift to `[.paragraph(text)]` at every decode boundary.** API `pageBlockBlockquote`, the Postbox `"t"` key (old cached pages), and the FlatBuffers `text` field (now optional) each lift into a single-paragraph blocks array. New writes emit only `blocks` (`"b"` / the FB vector). So pre-existing stored pages and older senders decode unchanged.
- **Outbound stays on the legacy wire constructor when the shape allows.** `apiInputBlock()` emits `pageBlockBlockquote` for empty or single-`.paragraph` quotes (so older recipients understand the common chat case) and `pageBlockBlockquoteBlocks` only for genuinely nested quotes.
- **Both renderers share one text core for the single-paragraph fast path.** `layoutQuoteText` (V2; the function formerly named `layoutBlockQuote`, `isPull:` distinguishes pull vs block) and the V1 fast-path branch keep the legacy italicized-body styling; nested children render with their own normal category styling.
- **Nested children use a FIXED 10pt inter-child gap, not `spacingBetweenBlocks`.** The full page-flow spacing (~27pt around quotes) is too airy when nested, and 0 is too tight. `childSpacing = 10.0` lives in both layout files; the first child hugs the container's `verticalInset` (no leading gap). Combined with a nested quote's own 4pt top inset this gives ~14pt effective separation.
- **Entity-expressibility:** a quote is entity-expressible (→ regular message path) only if its caption is empty AND every child is an entity-expressible `.paragraph`. A nested-structure or multi-paragraph quote is not, so it sends via the rich path. **Behavior change:** markdown `> p1\n>\n> p2` is now ONE quote with two paragraphs (rich) rather than two consecutive entity quotes correct semantics.
- **The enum-arity change is compile-enforced** across all modules; the full Bazel build is the completeness gate (no per-module build). `CachedFaqInstantPage.swift` matches `case .blockQuote:` payload-less and needs no edit. `BrowserReadability.swift` constructs `.blockQuote(blocks: [.paragraph(.italic(...))], …)` and is easy to miss in the spec's file list grep `\.blockQuote(` repo-wide when touching the case again.
## InstantPage thinking blocks (InstantPageBlock.thinking)
`InstantPageBlock.thinking(RichText)` renders server-sent reasoning as dimmed, continuously-shimmering text inside rich-data bubbles. V2 renderer only; V1 ignores the block (returns `[]`). The shimmer and fade-in mechanics are deliberately separate from the char-reveal cursor so thinking blocks do not affect the reveal pacing of the answer content that follows them.
### Where things live
| File | Responsibility |
|---|---|
| `submodules/InstantPageUI/Sources/InstantPageV2Layout.swift` | `InstantPageV2ThinkingItem` layout item + `layoutThinking(...)` (paragraph color × 0.55 alpha for the dimmed style) + `layoutBlock` `.thinking` arm. |
| `submodules/InstantPageUI/Sources/InstantPageRenderer.swift` | `InstantPageV2ThinkingView` a `ShimmeringMaskView` wrapping a private inner `InstantPageV2TextView`; `InstantPageV2StableItemId.thinking(Int)` stable-id namespace; `makeItemView`/`reuse`/`stableId` arms for the `.thinking` item kind; the two-counter (content + thinking) stable-id loop in `InstantPageV2View.update`. |
| `submodules/InstantPageUI/Sources/InstantPageV2RevealCost.swift` | `.thinking(start:)` cost entry: contributes **zero** cursor cost; triggers whole-block alpha fade-in when `revealedCount >= start`. |
| `submodules/InstantPageUI/Sources/InstantPageLayout.swift` | V1 has no explicit `.thinking` case it falls through `layoutInstantPageBlock`'s `default:` to an empty layout (no-op). |
### Non-obvious invariants
- **Zero reveal cost is the linchpin.** Thinking blocks do not advance the width-based cursor, so the answer's reveal position is identical whether or not thinking blocks are present and is unaffected as they appear and disappear across streaming chunks. The answer text always reveals at the same rate regardless of how much thinking precedes it.
- **Whole-block fade, not char reveal.** The inner text is drawn fully under the shimmer mask at all times; the reveal mechanism is a simple alpha visibility keyed to the block's `start` index. A top-of-page thinking block (`start == 0`) is visible from the very first frame.
- **Shimmer runs continuously while the view is displayed** via `ShimmeringMaskView`'s `HierarchyTrackingLayer` self-animation. It does not stop when streaming ends.
- **Top-level only; separate stable-id namespace.** Thinking blocks appear only at the top level of the page. They use the `InstantPageV2StableItemId.thinking(Int)` namespace, numbered by a counter independent of content blocks. This means adding or removing a thinking block never renumbers the stable ids of content blocks which, combined with pageView reuse, ensures content views and reveal state persist as thinking blocks come and go across chunks.
- **V1 is a no-op.** `InstantPageLayout.swift` has no `.thinking` case; the block falls through `layoutInstantPageBlock`'s `default:` to an empty layout, so V1 rendering silently skips it.
## Postbox → TelegramEngine refactor (in progress)
A gradual migration is underway to eliminate direct `import Postbox` from consumer submodules in favor of `TelegramEngine`.
**Historical record:** Wave-by-wave outcomes, the running tally of Postbox-free modules, and full verbose forms of the guidance subsections below live in [`docs/superpowers/postbox-refactor-log.md`](docs/superpowers/postbox-refactor-log.md). Read that file when you need wave-specific context, a full worked example of a pattern, or the history of a particular module's migration.
Waves landed so far (as of 2026-05-04): 238 waves plus standalone cleanups. See the log file for per-wave detail; the list of still-open migration opportunities lives in the `project_postbox_refactor_next_wave.md` memory file.
### Rules that apply to every wave
1. `TelegramCore` does **not** `@_exported import Postbox`. Once a consumer drops `import Postbox`, every remaining Postbox-type reference must use an engine-typealiased equivalent.
2. **Never typealias `Postbox`, `Account`, or `MediaBox`.** These umbrella types rename without encapsulating. Narrow utility typealiases (`MemoryBuffer`, `PostboxDecoder`, `PostboxEncoder`, `AdaptedPostboxDecoder`, `MediaResource`, …) remain allowed and expected.
3. No new engine wrapper **structs** unless the wave's spec explicitly allows only typealiases and thin forwarding methods.
4. **Discovery first:** before adding any new engine wrapper/typealias, grep `submodules/TelegramCore/Sources/TelegramEngine/` for existing equivalents. Record the search result in the commit message.
5. **Abandonment protocol:** if a module can only be refactored by violating rule 2 or by editing a module outside the current wave's list, mark the task Abandoned with a recorded reason. Do NOT substitute a new module mid-wave.
6. Full project build per module. No unit tests exist in this project.
7. **TelegramCore never imports UIKit/Display.** `TelegramCore` is shared with the Telegram-Mac codebase; its Bazel `deps` and source files must not reference UIKit, Display, or any Apple-UI framework. UIKit-needing helpers (image scaling, rendering, etc.) stay in consumer-side submodules.
8. **Never substitute Postbox protocols (`Media`, `Peer`, `Message`) with `Any` / `AnyObject`** in code that previously used them. Type erasure throws away the domain semantics that the next reader expects. Use the matching engine wrapper (`EngineMedia`, `EnginePeer`, `EngineMessage`) extending it as needed (e.g. add a missing case-init or convenience). If neither typealias nor wrapper covers the use site, restore the original Postbox import + type for now and flag the case for a future facade. Existing `Any`/`AnyObject` parameters predating the refactor are not in scope for this rule.
### Engine typealias cheat sheet (existing aliases)
```
PeerId → EnginePeer.Id
MessageId → EngineMessage.Id
MessageIndex → EngineMessage.Index
MessageTags → EngineMessage.Tags
MessageAttribute → EngineMessage.Attribute
MessageFlags → EngineMessage.Flags
MessageForwardInfo → EngineMessage.ForwardInfo
MediaId → EngineMedia.Id
PreferencesEntry → EnginePreferencesEntry
TempBox → EngineTempBox
PinnedItemId → EngineChatList.PinnedItem.Id
MemoryBuffer → EngineMemoryBuffer (added 2026-04)
PostboxDecoder → EnginePostboxDecoder (added 2026-04)
PostboxEncoder → EnginePostboxEncoder (added 2026-04)
AdaptedPostboxDecoder → EngineAdaptedPostboxDecoder (added 2026-04)
ItemCollectionId → EngineItemCollectionId (added 2026-04-20)
FetchResourceSourceType → EngineFetchResourceSourceType (added 2026-04-20)
FetchResourceError → EngineFetchResourceError (added 2026-04-20)
StoryId → EngineStoryId (added 2026-05-02)
ChatListIndex → EngineChatListIndex (added 2026-05-03)
TempBoxFile → EngineTempBoxFile (added 2026-05-03)
ItemCollectionItemIndex → EngineItemCollectionItemIndex (added 2026-05-03)
ItemCollectionViewEntryIndex → EngineItemCollectionViewEntryIndex (added 2026-05-03)
ValueBoxEncryptionParameters → EngineValueBoxEncryptionParameters (added 2026-05-03)
MessageAndThreadId → EngineMessageAndThreadId (added 2026-05-03)
PeerStoryStats → EnginePeerStoryStats (added 2026-05-03)
MessageHistoryAnchorIndex → EngineMessageHistoryAnchorIndex (added 2026-05-03)
ChatListTotalUnreadStateCategory → EngineChatListTotalUnreadStateCategory (added 2026-05-03)
ChatListTotalUnreadStateStats → EngineChatListTotalUnreadStateStats (added 2026-05-03)
PeerSummaryCounterTags → EnginePeerSummaryCounterTags (added 2026-05-03)
ChatListTotalUnreadState → EngineChatListTotalUnreadState (added 2026-05-04)
ItemCacheEntryId → EngineItemCacheEntryId (added 2026-05-04)
HashFunctions → EngineHashFunctions (added 2026-05-04 wave 251)
CachedMediaResourceRepresentationResult → EngineCachedMediaResourceRepresentationResult (added 2026-05-04 wave 265)
MediaResourceDataFetchResult → EngineMediaResourceDataFetchResult (added 2026-05-04 wave 266)
MediaResourceDataFetchError → EngineMediaResourceDataFetchError (added 2026-05-04 wave 266)
MediaResourceStatus → EngineMediaResourceStatus (added 2026-05-04 wave 272)
```
**Free-function thin forwarders in TelegramCore** (rule 3 allows):
- `engineFileSize(_ path:, useTotalFileAllocatedSize: Bool = false)` forwards to Postbox's `fileSize(...)` (added 2026-05-04 wave 268)
**TelegramEngineUnauthorized.resources facade**: `UnauthorizedResources.storeResourceData(id: EngineMediaResource.Id, data:, synchronous:)` bridges to `account.postbox.mediaBox.storeResourceData` (added 2026-05-04 wave 271)
For the `MediaResource` Postbox protocol, prefer the TelegramCore subtype `TelegramMediaResource` when the consumer's usage allows (note: `EngineMediaResource` is a wrapper **class**, not a typealias, so it is not interchangeable with the protocol).
### MediaResource → EngineMediaResource consumer migration
`EngineMediaResource` is a `final class` in `TelegramCore` wrapping a `MediaResource` value. Unlike the typealiases above it is **not** interchangeable with the protocol, but it does provide wrap/unwrap helpers:
- `EngineMediaResource(rawResource)` wrap a raw `MediaResource`.
- `engineResource._asResource()` unwrap to the raw `MediaResource`.
- `EngineMediaResource.ResourceData(rawResourceData)` wrap `MediaResourceData`.
- `EngineMediaResource.Id(rawMediaResourceId)` wrap `MediaResourceId`.
**Pattern for facade functions:** when a `TelegramEngine.<Area>` method leaks raw `MediaResource` in its public signature, **change the facade signature in place** to `EngineMediaResource` (and change any closure parameter types the same way). Bridge inside the facade body by calling the existing `_internal_*` function with `engineResource._asResource()` / wrapping raw inputs from inner closures with `EngineMediaResource(rawResource)`. Update all call sites in the same commit. The `_internal_*` function stays on raw `MediaResource` it is the Postbox-facing layer.
Do **not** add opt-in `EngineMediaResource` overloads alongside raw-`MediaResource` overloads. Duplicate signatures fragment the public API and leave the leak in place forever.
For consumer modules, prefer `EngineMediaResource` as the type in properties, locals, generic arguments and function parameters when the usage is a pure type reference. Do **not** try to use `EngineMediaResource` where a class must conform to `TelegramMediaResource` (Postbox protocol) or override `isEqual(to: MediaResource)` those remain `import Postbox`.
### Wave-selection guidance
Distilled lessons from waves 126. Each bullet below has a full-form counterpart in `postbox-refactor-log.md` (same subsection heading) with backstory, example scripts, and per-wave numbers.
**Shape selection.** The "leaf module, drop Postbox in isolation" approach (wave 1) only works when the candidate's public API doesn't leak Postbox domain types. Most candidates DO leak (`postbox: Postbox` / `account: Account` in public inits, `Media`/`Message` as public parameter types). Grep each candidate for `:\s*Postbox\b`, `:\s*Account\b`, `:\s*MediaBox\b`, and `Media`/`Message` as public parameter types before committing to a wave; abandon candidates whose public API leaks.
**Inventory at execution time, not just planning time.** Planning-time grep often undercounts. Re-inventory at Task-1 time using the full token set `\b(postbox|mediaBox|transaction|PostboxView|combinedView|MediaResource|PostboxDecoder|PostboxEncoder|MemoryBuffer)\b|^import Postbox` over the module's sources. If the count exceeds the plan, abandon before editing code rather than substituting a different module.
**Two feasible wave shapes.** Shape 1 = "per-module Postbox drop" (fragile; wave 1 lost 6 of 10 candidates). Shape 2 = "per-engine-facade-API migrate in place, update all call sites in one commit" (validated from wave 2 onward). Prefer shape 2 when the target is an API surface that multiple consumer modules depend on.
**Enum-payload migrations need full case-site grep.** When changing the payload type of a public enum, grep `case \.` / `let \.` / `\.<caseName>\(` across the enum's defining module not just call sites of the facade that returns it. Wave 4 undercounted by 6 sites (shortcut constructions and destructures inside the same file as the facade) because the inventory only grepped facade callers.
**Unused-import sweeps** (wave-shape applied in waves 6, 14). Speculatively drop `^import Postbox$` from every candidate file, build with `--continueOnError`, extract failing files and restore their imports, iterate. After a few iterations, do pattern-based preemptive restores for files naming Postbox-only symbols (`MediaBox`, `PostboxCoding`, `PostboxDecoder`, `PostboxEncoder`, `TempBoxFile`, `ValueBoxKey`, `Postbox\b`, `PeerId`, `MessageId`, `MediaId`, `MessageIndex`, `MessageAndThreadId`, `PeerNameIndex`). Scope never leaves the consumer-module candidate set halt if errors surface in TelegramCore / Postbox / TelegramApi. Run a matching BUILD-dep sweep immediately after (near-zero execution risk). Full methodology, scripts, and iteration-count history in the log.
**Public-Postbox-type inventory** (wave-11-pattern planning). Grep candidate modules against the full Postbox public-types allowlist, not just the pattern's target tokens. Waves before 16 missed types like `EngineMessageHistoryThread.Info` (Postbox-defined despite its "Engine" prefix) and `PeerStoryStats`. "Engine"-prefixed types can still be Postbox-defined grep for the defining module, don't trust naming. Build allowlist with `grep -rhE "^public\s+(class|struct|enum|protocol|typealias)\s+\w+" submodules/Postbox/Sources/ | awk '{print $3}' | sed 's/[(:<].*//' | sort -u`, then grep candidates against it. Full script in the log.
**Wave-shape G: facade addition + consumer sweep in one commit** (validated across waves 1926). Recipe:
1. Target a `MediaBox` method whose Postbox signature uses clean leaf types (`MediaResourceId`, `Data`, `String`, `Bool`) and whose return type is either non-Postbox or has an existing `Engine*` wrapper.
2. Pre-flight inventory: classify each call site as Shape A (`context.account.postbox.mediaBox.X(...)`, migratable), Shape B (different overload via `AccountContext`, migratable), Shape C (raw `account: Account` local, skip needs per-module rework), Shape D (`self.postbox` stored field, skip). Also check for `accountManager.mediaBox.X(...)` a separate migration path.
3. Design facade with `EngineMediaResource.Id` or `EngineMediaResource` parameters and engine-or-clean return types; preserve default argument values.
4. WIP-interference check: `git status --short | grep -v "^??"` if any Shape-A site is in a WIP file, either skip those sites or wait.
5. Name-collision check: if the facade signature names a Swift stdlib type with availability restrictions (`RangeSet`, iOS 18+), verify the third-party module import is present in `TelegramEngineResources.swift`.
6. Batch duplicate call expressions with `replace_all=true`.
7. Cheapness: 550 sites per wave, single atomic commit, expected first-pass-clean build. If post-migration grep for the migrated expression returns empty (excluding Shape C/D) and build is green, commit.
Full per-shape recipe and wave-specific examples in the log.
### TelegramEngine.Resources facade inventory (as of wave 32)
All mediaBox methods with clean signatures (no Postbox-protocol leaks, no complex return-type migrations) have been migrated to `TelegramEngine.Resources`. Quick reference for consumers all of these live in `submodules/TelegramCore/Sources/TelegramEngine/Resources/TelegramEngineResources.swift`:
| Facade | Wave | Wraps |
|---|---|---|
| `fetch(reference:userLocation:userContentType:)` | 3 | `fetchedMediaResource` |
| `status(resource:)` | 3 | `MediaBox.resourceStatus` (resource-based) |
| `status(id:, resourceSize:)` | 32 | `MediaBox.resourceStatus(_ id:, resourceSize:)` |
| `data(resource:, pathExtension:, waitUntilFetchStatus:)` | 3 | `MediaBox.resourceData` (resource-based) |
| `data(id:, attemptSynchronously:)` | 3 | `MediaBox.resourceData` (id-based, defaults to `.complete(waitUntilFetchStatus: false)`) |
| `custom(id:, fetch:, cacheTimeout:, attemptSynchronously:)` | pre-wave-21 | `MediaBox.customResourceData` |
| `httpData(url:, preserveExactUrl:)` | pre-wave-21 | `fetchHttpResource` |
| `shortLivedResourceCachePathPrefix(id:)` | 19 | `MediaBox.shortLivedResourceCachePathPrefix` |
| `completedResourcePath(id:, pathExtension:)` | 21 | `MediaBox.completedResourcePath(id:, pathExtension:)` |
| `storeResourceData(id:, data:, synchronous:)` | 22 | `MediaBox.storeResourceData(_ id:, data:, synchronous:)` |
| `cancelInteractiveResourceFetch(id:)` | 23 | `MediaBox.cancelInteractiveResourceFetch(resourceId:)` |
| `moveResourceData(id:, toTempPath:)` | 24 | `MediaBox.moveResourceData(_ id:, toTempPath:)` |
| `moveResourceData(from:, to:, synchronous:)` | 24 | `MediaBox.moveResourceData(from:, to:, synchronous:)` |
| `copyResourceData(id:, fromTempPath:)` | 25 | `MediaBox.copyResourceData(_ id:, fromTempPath:)` |
| `copyResourceData(from:, to:, synchronous:)` | 25 | `MediaBox.copyResourceData(from:, to:, synchronous:)` |
| `resourceRangesStatus(resource:)` | 26 | `MediaBox.resourceRangesStatus(_ resource:)` |
| `removeCachedResources(ids:, force:, notify:)` | 26 | `MediaBox.removeCachedResources(_ ids:, force:, notify:)` |
| `clearCachedMediaResources(mediaResourceIds:)` | 223 | `_internal_clearCachedMediaResources` |
**Facade-shape convention:** all of these take `EngineMediaResource.Id` or `EngineMediaResource` (never raw `MediaResourceId`/`MediaResource`). Return types either don't leak Postbox (`Void`, `String`, `String?`, `Signal<RangeSet<Int64>, NoError>`, `Signal<Float, NoError>`) or wrap via TelegramCore type (`Signal<EngineMediaResource.ResourceData, NoError>`).
**Swift-stdlib-vs-third-party-module name collisions** (learned in wave 26): `RangeSet<Int64>` collides with Swift stdlib's `RangeSet` (iOS 18+ only). Fix: `import RangeSet` at the file top of any TelegramCore file that names `RangeSet` in a signature. `TelegramCore/BUILD` already depends on `//submodules/Utils/RangeSet:RangeSet`. Future facade additions in TelegramEngineResources.swift should re-check this if new signature types are introduced.
## tgcalls Testbench
This repo includes a tgcalls testbench (CLI tool, Go/Pion SFU, Docker build) layered on top of the iOS source. All testbench code, build instructions, and architecture docs live inside the tgcalls submodule:
- `submodules/TgVoipWebrtc/tgcalls/CLAUDE.md` top-level testbench overview, build/run commands
- `submodules/TgVoipWebrtc/tgcalls/tools/cli/CLAUDE.md` CLI test tool architecture
- `submodules/TgVoipWebrtc/tgcalls/tools/go_sfu/CLAUDE.md` Go SFU internals
- `submodules/TgVoipWebrtc/CLAUDE.md` tgcalls library internals + macOS/Linux build patches
Build the test binary from this directory with:
`./build-input/bazel-8.4.2 build //submodules/TgVoipWebrtc/tgcalls/tools/cli:tgcalls_cli`