docs/ui-theme-bezel-migration.md

@@ -0,0 +1,391 @@
+# UI theme migration to bezel tokens
+
+Migrate `crates/theme` and `crates/ui` from the current `ThemeColors` /
+12-step-scale system to bezel's token set and theme architecture, keeping every
+existing UI element (button, dialog, dock, menu, ...) and its public API.
+
+Upstream: <https://github.com/crabtalk/bezel> — docs at
+<https://bezel.gallery> (append `.md` to any docs URL; `llms-full.txt` has the
+whole corpus). The source of truth for exact constants is bezel's repo:
+`crates/theme/src/theme/{mod,palettes,layout,typography,syntax}.rs`.
+
+## Goal
+
+- One semantic token set (bezel's) with two designed palettes (dark, light).
+  Light is designed, not inverted — bezel's doc comment on
+  `crates/theme/src/lib.rs` is the reference for why.
+- Theming by `Brand` (tint hue, accent hue, base radius) plus a palette-builder
+  hook that survives light/dark switches.
+- Components read the theme global at paint time and take no color, font, or
+  size parameters. Radii derive from one base radius by ratio; spacing from
+  named constants.
+
+## Non-goals
+
+- No new components from bezel's catalog. The current element set stays.
+- No glass/material/vibrancy port in the first pass. The tokens exist in bezel's
+  `Theme`, but coop has no backdrop-blur surfaces today; port the fields as
+  inert defaults or omit them (see decision D6).
+- No `bezel` dependency. See D1.
+
+## Decisions
+
+- **D1 — Adapt, do not depend.** bezel is built against `bezel-gpui` (its own
+  gpui fork); coop is on `gpui-pre` 0.3.8. Adding `bezel` as a crate dependency
+  puts two gpui forks in the graph — two type universes, the failure mode
+  bezel's own docs warn about first. So we port the theme *architecture* (token
+  names, palettes, brand rotation, layout constants, paint helpers, tests) into
+  `crates/theme` and keep gpui paths as they are.
+- **D2 — Keep component APIs.** `Button`, `Dialog`, `dock`, `menu`, `Sizable`,
+  `Size`, `ButtonVariant`, ... keep their names and signatures. Variants are
+  *re-derived* from the new tokens inside `crates/ui`. Callers only break where
+  they read theme tokens directly (there are ~370 such sites; Phase 3).
+- **D3 — Semantic tokens replace scales as the public API.** The Radix-style
+  12-step `ColorScale`/`ColorScaleSet` (`crates/theme/src/scale.rs`) stop being
+  public API. The oklch-derived palette generator replaces them internally.
+  `ActiveTheme` (`cx.theme()`) stays — it is coop's `Theme::of(cx)`.
+- **D4 — JSON themes become overrides.** `assets/themes/*.json` (aurora, 4x
+  catppuccin, flexoki, forest, ocean) and `ThemeRegistry` survive, but the
+  schema changes from "full `ThemeColors` dump" to "per-appearance override
+  deltas + optional `Brand`", applied over the built-in palette by the palette
+  builder. 8 small files, migrated by hand.
+- **D5 — `gpui-base` projection is re-derived, not dropped.** `sync_base`
+  (`crates/theme/src/lib.rs`) keeps feeding the base global (focus ring,
+  selection wash, scrollbars, overlay backdrops paint from it). The mapping is
+  rewritten against the new token names.
+- **D6 — Glass/material fields: port stubs, not the renderer.** Carry
+  `vibrancy_alpha`, `vibrancy`, `glass` as settings-shaped fields with bezel's
+  defaults so a later port is additive; skip `SurfaceSpec`/`MaterialSpec`
+  machinery until a surface needs it.
+- **D7 — App chrome heights stay.** bezel's `TITLEBAR_HEIGHT = 38`,
+  `HEADER_HEIGHT = 44` are bezel-app values. coop keeps `TITLEBAR_HEIGHT = 36`,
+  `TABBAR_HEIGHT = 36`, `SIDEBAR_WIDTH = 240` (`crates/theme/src/lib.rs`) —
+  they are app layout, not tokens. `BASE_RADIUS` and the spacing constants are
+  adopted.
+
+## Token mapping
+
+Old → new. The census command to re-run at any time:
+
+```
+grep -rhoE "theme\(\)\.[a-z_0-9]+" --include="*.rs" crates desktop web | sort | uniq -c | sort -rn
+```
+
+Current usage counts (2026-10-09) are in the right column; zero means the token
+is only consumed via `sync_base` or not at all.
+
+### Surfaces
+
+| Old (`ThemeColors`) | New (`Theme`) | Notes | Uses |
+| --- | --- | --- | --- |
+| `background` | `bg` | main content plane | 6 |
+| `surface_background` | `surface` | shell / sidebar plane | 16 |
+| `elevated_surface_background` | `surface_raised` | review each site; inline cards → `surface_card` | 14 |
+| `panel_background` | `surface` | | 3 |
+| `overlay` | `scrim()` helper | surfaces mount on `surface_overlay` | 1 |
+| `title_bar` | `surface` | currently transparent | 0 |
+| `title_bar_inactive` | `surface` | | 0 |
+| `window_border` | `border` | | 0 |
+
+### Borders
+
+| Old | New | Notes | Uses |
+| --- | --- | --- | --- |
+| `border` | `border` | | 21 |
+| `border_variant` | `border_faint` | dividers, nested frames | 11 |
+| `border_focused` | `border_strong` | focus *rings* use `ring` | 1 |
+| `border_selected` | `border_strong` | | 1 |
+| `border_transparent` | drop | `gpui::transparent_black()` inline | 3 |
+| `border_disabled` | `border_faint` | | 0 |
+| `ring` | `ring` | | 0 |
+
+### Text and icons
+
+| Old | New | Notes | Uses |
+| --- | --- | --- | --- |
+| `text` | `text` | | 16 |
+| `text_muted` | `text_muted` | | 53 |
+| `text_placeholder` | `text_faint` | | 25 |
+| `text_accent` | `accent` | | 1 |
+| `text_danger` | `danger` | soft/inline error copy → `danger_muted` | 10 |
+| `text_warning` | `warning` | soft copy → `warning_muted` | 2 |
+| `icon` | `text_muted` | bezel has no icon tokens; tone is a text token | 2 |
+| `icon_muted` | `text_faint` | | 10 |
+| `icon_accent` | `accent` | | 6 |
+
+### Plates and states
+
+| Old | New | Notes | Uses |
+| --- | --- | --- | --- |
+| `element_foreground` | `on_solid` | label on the primary plate | 2 |
+| `element_background` | `solid` | bezel's primary button plate is the max-contrast solid; use `accent_strong` + `on_accent` only where a brand plate is wanted | 4 |
+| `element_hover` | `element_hover` | | 2 |
+| `element_active` | `element_active` | | 5 |
+| `element_selected` | `element_active` | | 1 |
+| `element_disabled` | `wash()` at disabled alpha | helper, not token | 2 |
+| `secondary_foreground` | `text` | tinted secondary buttons use `accent` | 8 |
+| `secondary_background` | `surface_raised` | | 5 |
+| `secondary_hover` | `element_hover` | | 1 |
+| `secondary_active` | `element_active` | | 2 |
+| `secondary_selected` | `element_active` | | 1 |
+| `secondary_disabled` | `wash()` at disabled alpha | | 1 |
+| `danger_foreground` | `on_accent` | over the `danger_strong` plate | 5 |
+| `danger_background` | `danger_strong` | destructive plate; tinted chips → `danger_muted` | 4 |
+| `danger_hover` / `danger_active` / `danger_selected` | plate-hover helper | one helper that brightens (dark) / darkens (light) a plate | 1/1/1 |
+| `danger_disabled` | `wash()` at disabled alpha | | 1 |
+| `warning_foreground` | `text` | icons/rules may use `warning` | 5 |
+| `warning_background` | `warning_muted` | | 5 |
+| `warning_hover` / `warning_active` / `warning_selected` | `element_hover` / `element_active` | on the chip | 1/1/1 |
+| `warning_disabled` | `wash()` at disabled alpha | | 1 |
+| `ghost_element_background` | transparent | drop | 6 |
+| `ghost_element_background_alt` | `surface_raised` | or `band` for strips | 3 |
+| `ghost_element_hover` | `element_hover` | | 7 |
+| `ghost_element_active` / `ghost_element_selected` | `element_active` | | 7/1 |
+| `ghost_element_disabled` | `wash()` at disabled alpha | | 1 |
+
+### Tabs, input, misc
+
+| Old | New | Notes | Uses |
+| --- | --- | --- | --- |
+| `tab_background` | `surface` | | 2 |
+| `tab_foreground` | `text_muted` | | 1 |
+| `tab_hover_background` | `element_hover` | | 2 |
+| `tab_active_background` | `bg` | active tab merges with the content plane, hairline separates | 1 |
+| `tab_active_foreground` | `text` | | 2 |
+| `scrollbar_*` (5 tokens) | gpui-base scrollbar tokens | via `sync_base` only | 0 |
+| `drop_target_background` | `drop_target` | | 1 |
+| `cursor` | `cursor` | | 1 |
+| `selection` | `selection` | | 0 |
+| `radius` | `Theme::button_radius()` | 1x; controls inside controls → `control_radius()` (0.75x). Review each of the 43 sites | 43 |
+| `radius_lg` | `panel_radius()` (1.25x) or `surface_radius()` (1.5x) | cards → panel, dialogs/popovers → surface | 8 |
+| `shadow` | `surface_shadows()` helper | keep the on/off setting | 10 |
+| `font_size` | `base_text_size()` | stays 15px | 1 |
+| `font_family` | `font_sans` | | 1 |
+| `notification` | stays | `NotificationSettings` remains a coop extension field | 2 |
+
+### Tokens coop gains
+
+`text_dim` (one notch below muted), `success` / `success_muted` / `busy`
+(message delivery and presence states), `accent` / `accent_strong` /
+`on_accent`, `input_bg`, `caret`, `band`, `surface_card` / `surface_dialog` /
+`surface_overlay` (elevation ladder), `surface_raised_hover`, `drop_line`,
+`code_text` / `code_wash` / `syntax: SyntaxPalette` / `diff_add` / `diff_del` /
+`diff_hunk_bg` (for `markdown.rs`), and the paint helpers `ink(alpha)` /
+`hairline(alpha)` / `wash(alpha)` / `scrim()`.
+
+### Tokens coop drops
+
+The `ColorScale`/`ColorScaleSet` public API, `ThemeColors` as a public struct,
+`element_*`/`secondary_*`/`ghost_element_*`/`tab_*`/`warning_*`/`danger_*`
+families, `icon*` tokens, `title_bar*`, `window_border`, `scrollbar_*` on the
+coop theme.
+
+## Phases
+
+Each phase is one PR (or a small series), compiles, and ships with the
+validation listed. Follow the PR hygiene in `AGENTS.md`.
+
+### Phase 0 — Baseline
+
+- [ ] Capture light/dark screenshots of the main surfaces: chat panel,
+      message hover/actions, relays & trace dialogs, settings dialog, group
+      (nip29) views, workspace tabs/dock, notifications.
+- [ ] Record the token census (command above) as the migration checklist.
+- [ ] Branch. No code changes.
+
+### Phase 1 — Port the theme core into `crates/theme`
+
+Port in this order; after each step `cargo check --workspace` must pass because
+old token names still resolve (they become computed aliases over the new
+palette until Phase 3 removes them).
+
+- [ ] **Palette generator.** New `palette.rs`: port bezel's oklch-derived
+      neutral scale and the two designed palettes. Copy the constants from
+      bezel's `crates/theme/src/theme/palettes.rs` — do not re-derive. Keep the
+      "light is designed, not inverted" structure: surface order, elevation
+      ladder, and accent contrast are per-appearance, not mirrored.
+- [ ] **New `Theme` struct.** Rewrite `colors.rs` into the semantic token set
+      from the mapping above (flat fields on `Theme`, bezel-style; drop the
+      `Theme` → `ThemeColors` Deref). `Appearance` (Dark/Light) replaces
+      `ThemeMode` as the internal enum; keep `From<WindowAppearance>`.
+      Ship both palettes as `Theme::for_appearance(appearance)`.
+- [ ] **Appearance plumbing.** New `appearance.rs`: `init(mode, cx)` with
+      `AppearanceMode::{System, Light, Dark}` (serde), `observe_window(window, cx)
+      -> Subscription`, `set_mode`. Wire it so `Theme::change` /
+      `sync_system_appearance` delegate to it. Boot order rule: init before the
+      first window opens; observe every opened window (workspace already
+      syncs on window activation — keep that hook).
+- [ ] **Brand.** New `brand.rs`: `Tint { hue, chroma }` (oklch), `Brand {
+      tint, accent, radius, vibrancy_alpha, vibrancy, glass }`, hue rotation
+      over the palette (semantic tokens keep their hue; translucent ink is
+      untouched; chroma 0 reproduces the shipped palette). `set_brand` /
+      `set_palette(builder)` on an `AppExt` trait; the builder runs first on
+      every appearance switch, then overrides from the registry, then brand
+      rotation. All of it before `appearance::init` resolves.
+- [ ] **Layout constants.** New `layout.rs`: `SPACE = 8.0`,
+      `CONTENT_MARGIN = 20.0`, `BASE_RADIUS = 8.0`, and the ratio functions
+      `control_radius()` 0.75x, `button_radius()` 1x, `panel_radius()` 1.25x,
+      `surface_radius()` 1.5x, `bubble_radius()` 2x, plus
+      `inset_radius(outer, inset)`. Keep coop's chrome heights (D7).
+- [ ] **Typography.** `font_sans` (platform default, as today), add
+      `font_body` (defaults to `font_sans`) and `font_mono`. Keep
+      `base_text_size()` at 15px. Keep the existing Tailwind-style text-size
+      helpers in `crates/ui/src/styled.rs`; sizes are named per call site, not
+      themed.
+- [ ] **Paint helpers.** `ink(alpha)`, `hairline(alpha)`, `wash(alpha)`,
+      `scrim()`, plate-hover helper, `INK_FILL_SCALE` / `INK_HAIRLINE_SCALE`.
+- [ ] **Old names as aliases.** Temporarily keep `ThemeColors` and the old
+      `Theme` fields as computed accessors over the new tokens (mapping table
+      above) so the workspace still compiles. Mark `#[deprecated]` to make
+      Phase 3 greppable.
+- [ ] **`sync_base` rewrite.** Project the new tokens onto
+      `gpui_base::Theme`: `bg→background`, `text→foreground`,
+      `surface→surface`, `solid→primary`, `on_solid→primary_foreground`,
+      `surface_raised→secondary`, `text→secondary_foreground`,
+      `surface_card→muted`, `text_muted→muted_foreground`,
+      `element_hover→accent`, `text→accent_foreground`,
+      `danger_strong→destructive`, `on_accent→destructive_foreground`,
+      `border→border`, `border→input`, `ring→ring`, `selection→selection`.
+      Verify against `gpui-base`'s actual token names when writing the code.
+- [ ] **Contrast tests.** Port bezel's `tests/theme.rs` idea: assert each
+      light token lands within ~0.5 of its dark counterpart's contrast ratio
+      against its background, and `text` on `bg` ≥ 16:1. This is the safety
+      net for every palette override that follows.
+- [ ] Delete nothing yet. Validation: `cargo test -p theme`, workspace check,
+      screenshots must be pixel-equivalent (aliases map to equivalent values
+      or the mapping table records an intentional change).
+
+### Phase 2 — Reskin `crates/ui`
+
+Keep public APIs (D2). Per file, replace old token reads with new tokens,
+radii with ratio functions, ad-hoc spacing with `SPACE` steps where it is a
+real deviation, and state washes with the paint helpers.
+
+- [ ] `button.rs` — variant table: Primary → `solid`/`on_solid` +
+      `surface_raised_hover`-style plate hover; Secondary →
+      `surface_raised` + `border` + `text`; Danger → `danger_strong` +
+      `on_accent`; Warning → `warning_muted` chip treatment; Ghost →
+      transparent + `element_hover`/`element_active`; Custom stays (sources
+      defaults from new tokens). Size → bezel `ControlSize` ladder values via
+      the existing `Size` enum. Radius: `button_radius()`, `bubble_radius()`
+      when `rounded`.
+- [ ] `input/` — `input_bg`, `border_faint` resting / `border_strong` focus,
+      `ring`, `caret`, `selection`, `text_faint` placeholder.
+- [ ] `dialog.rs` — `surface_dialog` over `scrim()`, `surface_radius()`,
+      frame shadows.
+- [ ] `popover.rs`, `menu/` — `surface_overlay`, hairline border,
+      `popover_surface` stub (D6: plain wash for now).
+- [ ] `tab.rs` — mapping table row: `bg` active plane, `element_hover`
+      hover, `text_muted`/`text` labels, `border_faint` separators.
+- [ ] `nav.rs`, `nav_item.rs` — `element_hover`/`element_active` states,
+      `accent` selection markers.
+- [ ] `title_bar.rs` — `surface`; drag handlers unchanged; height stays 36.
+- [ ] `tooltip.rs` — `surface_overlay` plate, `text` label.
+- [ ] `switch.rs` — on: `accent_strong` track + `on_solid` knob; off:
+      `input_bg` track + `border`.
+- [ ] `indicator.rs`, `kbd.rs` — indicator gets `success`/`busy`/`danger`
+      dots; kbd: `surface_raised` + `border_faint` + `text_muted`.
+- [ ] `avatar.rs` — `border_faint` ring; keep blob behavior.
+- [ ] `message.rs` — `bubble_radius()` on bubbles, `text_dim` for file-path /
+      secondary labels, `success`/`busy`/`danger` delivery states, `band` for
+      composer strips.
+- [ ] `markdown.rs` — `code_text`/`code_wash`, `SyntaxPalette`,
+      `text_muted` headings hierarchy.
+- [ ] `notification.rs` — `surface_overlay` plate + semantic accents.
+- [ ] `group_box.rs` — `panel_radius()`, `border_faint`, `band` header.
+- [ ] `dock/`, `resizable/` — `drop_target`, `drop_line`, `border_faint`.
+- [ ] `scroll/` — scrollbar paints from gpui-base tokens; verify
+      `ScrollbarMode` setting still lands via `sync_base`.
+- [ ] `root.rs` — `bg` + `border` window frame, frame shadows.
+- [ ] `icon.rs` — tones from text tokens; keep the `IconName` set as-is.
+- [ ] `styled.rs` — `divider()` → `border_faint` / `hairline()`;
+      `popover_style()` → `surface_overlay` + `surface_radius()`. Keep
+      `h_flex`/`v_flex` names (bezel's `stack::row`/`column` equivalents).
+- [ ] `animation.rs` — leave as-is this pass; note bezel's named-motion
+      catalog as follow-up.
+
+Validation: `cargo check -p ui`, run desktop, walk every component in
+light/dark against Phase 0 screenshots.
+
+### Phase 3 — Migrate consumers
+
+Mechanical per the mapping table; ~370 sites across 8 crates. Use the
+deprecated accessors as the worklist — the goal is zero deprecated hits.
+
+- [ ] `crates/chat_ui` (largest: ~200 sites) — chips and rows on
+      `elevated_surface_background` review to `surface_raised` vs
+      `surface_card`; reactions/toggles to `element_*`; report banners to
+      `warning_muted`/`danger_muted`.
+- [ ] `crates/workspace` — tabs, dock, settings dialog, theme picker.
+- [ ] `crates/nip29_ui`, `crates/settings`, `crates/nip4e`, `desktop`, `web`.
+- [ ] Replace `radius`/`radius_lg` with the ratio function the element is
+      (control inside control → 0.75x, control → 1x, card → 1.25x, floating →
+      1.5x, bubble → 2x). This is the judgment-heavy step; do it per crate,
+      not with sed.
+- [ ] `cargo check --workspace` clean; `grep -rn "theme().\(element\|secondary\|ghost_element\|tab_\|icon\|warning_\|danger_\|title_bar\|window_border\|panel_background\|surface_background\|elevated\)"` returns nothing.
+
+### Phase 4 — Settings, registry, shipped themes
+
+- [ ] `crates/settings/src/lib.rs`: replace persisted `theme_mode: ThemeMode`
+      with `appearance_mode: AppearanceMode` (`System`/`Light`/`Dark`).
+      Serde-compat: custom `Deserialize` that maps the old `Light`/`Dark`
+      values and falls back to `System` (or version the field) so existing
+      configs keep loading. `apply_theme` becomes: install registry overrides
+      → `set_brand` → `appearance::set_mode`.
+- [ ] `ThemeRegistry` + `assets/themes/*.json`: new schema —
+      `{ id, name, author, brand?: { tint, accent, radius }, overrides: {
+      light?: {...}, dark?: {...} } }` where overrides are a *subset* of
+      semantic tokens. Re-derive the 8 shipped themes as override deltas over
+      the new base palette (catppuccin hues go through `Brand.tint`; only hues
+      rotation cannot reach stay as overrides — flexoki is the likely
+      candidate).
+- [ ] `workspace/src/dialogs/settings.rs`: add the `System` appearance option
+      next to Light/Dark.
+- [ ] Contrast tests from Phase 1 run against every registered theme — a
+      shipped theme that fails contrast is a bug in that JSON, fix the JSON.
+
+### Phase 5 — Removal and docs
+
+- [ ] Delete `ThemeColors`, the deprecated aliases, `ColorScale`/
+      `ColorScaleSet` public exports (`scale.rs` either goes private as the
+      palette generator's internal or is deleted), `ThemeMode`.
+- [ ] `crates/ui/src/lib.rs`: `init` becomes `appearance::init` +
+      `gpui_base::init` + `menu::init`; `theme::sync_base` is now called from
+      the appearance change path, not app boot.
+- [ ] Update `README`/docs mentions of theme customization; document
+      `Brand` + override JSON as the two supported ways to theme coop.
+- [ ] Final census run: only new token names remain.
+
+## Risks
+
+- **Fork mismatch (D1).** If `gpui-pre` and `bezel-gpui` ever unify, a direct
+  `bezel` dependency becomes possible and Phase 1's ported code could be
+  swapped for the real crate. Do not half-adopt (bezel + own gpui) — that is
+  the two-gpuis trap.
+- **Light regressions.** coop's light palettes today are scale-derived; the
+  new light palette is designed. Expect intentional differences in surface
+  order and accent tones; judge against the Phase 0 screenshots, and record
+  intentional deltas in the PR description.
+- **gpui-base drift.** Anything base paints (focus ring, text selection,
+  scrollbars, overlay backdrops) bypasses coop tokens. `sync_base` is the only
+  seam — keep it total, and keep it on the appearance-change path.
+- **Init order.** `appearance::init` must run before the first window opens or
+  the first frame paints the wrong palette; `observe_window` must be attached
+  per window for live light/dark flips.
+- **Settings serde.** Old persisted `theme_mode` values must not break load;
+  covered by Phase 4 compat shim and a round-trip test.
+- **No component gallery.** coop has no bezel-gallery equivalent; the Phase 0
+  screenshots are the review surface. If Phase 2 review gets painful, a
+  throwaway debug window that renders one of each component is cheaper than
+  regressions.
+
+## References
+
+- bezel theme docs: <https://bezel.gallery/docs/theme.md>,
+  <https://bezel.gallery/docs/color.md>, <https://bezel.gallery/docs/layout.md>,
+  <https://bezel.gallery/docs/typography.md>
+- bezel source (copy constants from here):
+  `crates/theme/src/theme/{mod,palettes,layout,typography,syntax}.rs`,
+  `crates/theme/src/{lib,paint,brand}.rs`
+- Current coop theme: `crates/theme/src/{lib,colors,scale,theme,registry}.rs`
+- Current coop components: `crates/ui/src/`