concinnity-dev 0.19.16

// src/editor/form_panel.rs
//
// The editor's add / edit form, in its own floating panel (separate from the
// Assets browse panel, which stays on its list while this is open). Spawned by
// clicking an asset in the browse list (or picking a type from the "+" picker):
// a draggable title bar ("Edit <type>" / "New <type>") with an "X" close button
// in its top-right corner, then a header row with the asset's editable NAME as a
// large heading and the Apply button pinned to the panel's top-right, then the
// scrollable arg-field area. Like the rest of the editor HUD it is plain
// `Sprite` / `TextLabel` / `TextInput` components at reserved ids driven each
// frame by the hook; the field model itself lives in `form.rs` and the hook owns
// all state.
//
// The field area renders a scrolling window over ALL of the type's fields into
// a fixed pool of `form::FIELD_POOL` control slots: visible slot `r` shows
// logical field `form_scroll + r`, and hit-test actions carry the LOGICAL index.
// An enum / ref field with a large variant set opens a floating value dropdown
// below the field (its own row pool here, so it can coexist with the Assets
// panel's combo).

use crate::components::TextAlign;
use crate::ecs::World;
use crate::ecs::asset_id::AssetId;

use super::form::{self, FieldKind, FormField};
use super::overrides::FieldOrigin;
use super::registry::{self, PanelKey};
use super::theme;
use super::widget::{self, place_rounded, point_in};

// An enum / ref field with this many variants or fewer cycles in place on click
// (fast for small sets); more than this opens a floating value dropdown anchored
// below the field (a long list is tedious to cycle through). A reference field's
// count includes its `(none)` option.
pub(crate) const CYCLE_MAX: usize = 5;

// Visible rows in an open field-value dropdown before it scrolls.
pub(crate) const MAX_DROP_ROWS: usize = 8;
// A field-value dropdown option row's height.
const DROP_ROW_H: f32 = 28.0;
// The most options an override / entity menu holds (Revert-all, Apply-all,
// Materialize, Minimize).
pub(crate) const MAX_OVR_ROWS: usize = 4;
const OVR_ROW_H: f32 = 26.0;
const OVR_MENU_W: f32 = 340.0;

const EDIT: u32 = registry::base(PanelKey::Edit);
pub(crate) const EDIT_BG: AssetId = AssetId(EDIT);
pub(crate) const TITLE_LABEL: AssetId = AssetId(EDIT + 2);
pub(crate) const APPLY_BG: AssetId = AssetId(EDIT + 3);
pub(crate) const APPLY_LABEL: AssetId = AssetId(EDIT + 4);
// The "X" close button in the title bar's top-right corner.
pub(crate) const CLOSE_BG: AssetId = AssetId(EDIT + 5);
pub(crate) const CLOSE_LABEL: AssetId = AssetId(EDIT + 6);
// The asset-name heading: a real editable TextInput drawn a step larger.
pub(crate) const NAME_INPUT: AssetId = AssetId(EDIT + 7);
pub(crate) const FORM_STATUS: AssetId = AssetId(EDIT + 8);
pub(crate) const FORM_TRACK: AssetId = AssetId(EDIT + 9);
pub(crate) const FORM_THUMB: AssetId = AssetId(EDIT + 10);
pub(crate) const DROP_BG: AssetId = AssetId(EDIT + 11);
pub(crate) const DROP_TRACK: AssetId = AssetId(EDIT + 12);
pub(crate) const DROP_THUMB: AssetId = AssetId(EDIT + 13);

// The per-slot control pool (`form::FIELD_POOL` of each). `form_row_label(r)` is
// the caption of visible slot `r`; `form_input(r)` its text control;
// `form_toggle_bg(r)` its checkbox / cycle-button / array-add background;
// `form_swatch(r)` its colour swatch / array-remove button;
// `form_enum_label(r)` its enum-value / array-count caption.
pub(crate) fn form_row_label(r: usize) -> AssetId {
    AssetId(EDIT + 0x20 + r as u32)
}
pub(crate) fn form_input(r: usize) -> AssetId {
    AssetId(EDIT + 0x40 + r as u32)
}
pub(crate) fn form_toggle_bg(r: usize) -> AssetId {
    AssetId(EDIT + 0x60 + r as u32)
}
pub(crate) fn form_swatch(r: usize) -> AssetId {
    AssetId(EDIT + 0x80 + r as u32)
}
pub(crate) fn form_enum_label(r: usize) -> AssetId {
    AssetId(EDIT + 0xA0 + r as u32)
}
// The value dropdown's own option rows (the Assets panel's combo pool can be in
// use at the same time now that the two are separate panels).
pub(crate) fn drop_row_bg(r: usize) -> AssetId {
    AssetId(EDIT + 0xC0 + r as u32)
}
pub(crate) fn drop_row_label(r: usize) -> AssetId {
    AssetId(EDIT + 0xE0 + r as u32)
}
// Override chrome for a template-derived asset: a per-slot accent bar +
// action button on overridden rows, a header summary chip + entity-menu
// button, and a floating Revert / Apply menu.
pub(crate) fn ovr_bar(r: usize) -> AssetId {
    AssetId(EDIT + 0x100 + r as u32)
}
pub(crate) fn ovr_btn_bg(r: usize) -> AssetId {
    AssetId(EDIT + 0x120 + r as u32)
}
pub(crate) fn ovr_btn_label(r: usize) -> AssetId {
    AssetId(EDIT + 0x140 + r as u32)
}
pub(crate) const OVR_CHIP_BG: AssetId = AssetId(EDIT + 0x160);
pub(crate) const OVR_CHIP_LABEL: AssetId = AssetId(EDIT + 0x161);
pub(crate) const ENT_BTN_BG: AssetId = AssetId(EDIT + 0x162);
pub(crate) const ENT_BTN_LABEL: AssetId = AssetId(EDIT + 0x163);
pub(crate) const OVR_MENU_BG: AssetId = AssetId(EDIT + 0x164);
pub(crate) fn ovr_menu_row_bg(r: usize) -> AssetId {
    AssetId(EDIT + 0x170 + r as u32)
}
pub(crate) fn ovr_menu_row_label(r: usize) -> AssetId {
    AssetId(EDIT + 0x180 + r as u32)
}

// Which of the form's inputs holds keyboard focus (re-asserted each frame so the
// opening click cannot blur it; only the focused input re-asserts, so N text
// fields do not fight).
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum FormFocus {
    Name,
    Field(usize),
}

// Geometry, in window pixels. A wider column than the Assets panel so field
// names and values read comfortably; every rect derives from the panel origin
// `o` (the title bar's top-left), so dragging the title bar moves the panel.
pub(crate) const EDIT_W: f32 = 480.0;
const PAD: f32 = 10.0;
const GAP: f32 = 8.0;
// The header row: the name heading and the Apply button.
const NAME_H: f32 = 34.0;
const BTN_W: f32 = 84.0;
// The validation status line reserved under the header row.
const STATUS_H: f32 = 22.0;
// One arg-field row; the caption column on its left.
const FIELD_H: f32 = 34.0;
const LABEL_COL: f32 = 190.0;
// Left inset per nesting level for a flattened nested (dotted-path) leaf caption.
const NEST_INDENT: f32 = 10.0;
const SCROLLBAR_W: f32 = 5.0;
// The name heading draws larger than the body text.
const NAME_SCALE: f32 = 1.05;

const BTN_TINT: [f32; 4] = [0.22, 0.40, 0.56, 1.0];
const BTN_TINT_HOVER: [f32; 4] = [0.28, 0.48, 0.66, 1.0];
const CYCLE_TINT: [f32; 4] = theme::BUTTON_TINT;
const OPTION_TINT: [f32; 4] = [0.16, 0.16, 0.20, 0.0];
const OPTION_TINT_HOVER: [f32; 4] = theme::HOVER_TINT;
const OPTION_TINT_SELECTED: [f32; 4] = theme::SELECTED_TINT;
const DROP_BG_TINT: [f32; 4] = [0.09, 0.09, 0.12, 1.0];
const TRACK_TINT: [f32; 4] = [0.12, 0.12, 0.15, 0.9];
const THUMB_TINT: [f32; 4] = [0.40, 0.44, 0.56, 0.95];
const CHECK_ON: [f32; 4] = [0.30, 0.66, 0.34, 1.0];
const CHECK_OFF: [f32; 4] = [0.30, 0.30, 0.34, 1.0];
const ADD_BTN_TINT: [f32; 4] = [0.24, 0.52, 0.32, 1.0];
const REMOVE_BTN_TINT: [f32; 4] = [0.52, 0.26, 0.26, 1.0];
const LABEL: [f32; 3] = [0.90, 0.90, 0.92];
const LABEL_DIM: [f32; 3] = [0.60, 0.60, 0.66];
const LABEL_WHITE: [f32; 3] = [1.0, 1.0, 1.0];
const ERROR_LABEL: [f32; 3] = [0.95, 0.55, 0.55];
// Override chrome: the accent marks an overridden row; instance-only fields
// (no template counterpart) read dimmer.
const OVERRIDE_LABEL: [f32; 3] = [0.62, 0.76, 1.0];
const INSTANCE_ONLY_TINT: [f32; 4] = [0.55, 0.58, 0.68, 1.0];

// Where the panel sits until the user drags it: to the left of the Assets
// panel's default anchor, below the top bar.
pub(crate) fn default_origin(vw: f32) -> [f32; 2] {
    [
        vw - super::panel::PANEL_W - GAP - EDIT_W,
        super::hud::body_top(),
    ]
}

// The chrome height around the field band (title bar + header row + status line
// + pads); the field rows stack below it.
const CHROME_H: f32 = widget::TITLE_H + PAD + NAME_H + 4.0 + STATUS_H + PAD;

fn panel_height(rows: usize) -> f32 {
    CHROME_H + rows as f32 * FIELD_H
}

// The default (minimum) on-screen field slots: the field count capped at the
// default window.
fn visible_rows(n_fields: usize) -> usize {
    n_fields.clamp(1, form::FIELD_POOL)
}

// The number of field slots that fit panel height `h`, capped at the pool.
pub(crate) fn rows_for_height(h: f32) -> usize {
    (((h - CHROME_H) / FIELD_H).floor() as usize).clamp(1, form::FIELD_POOL_MAX)
}

// The panel footprint for `n_fields` total fields (the field area tracks the
// count, capped at the default window; a wider form scrolls). Origin-independent;
// the hook's drag clamp uses this, and it is the minimum resize size.
pub(crate) fn size(n_fields: usize) -> [f32; 2] {
    [EDIT_W, panel_height(visible_rows(n_fields))]
}

// The tallest the panel resizes to for a form of `n_fields`: its fields shown in
// full, capped at the injected pool. Width is unbounded (capped by the screen).
pub(crate) fn max_size(n_fields: usize) -> [f32; 2] {
    [
        f32::INFINITY,
        panel_height(n_fields.clamp(1, form::FIELD_POOL_MAX)),
    ]
}

// The "X" close button, a square flush in the title bar's top-right corner. The
// hook checks this before the title-bar drag, so clicking the X closes the form
// rather than starting a drag.
pub(crate) fn close_rect(o: [f32; 2], w: f32) -> [f32; 4] {
    widget::close_rect(widget::title_rect(o, w))
}

// The header row under the title bar: name heading + the pinned Apply button.
pub(crate) fn name_rect(o: [f32; 2], w: f32) -> [f32; 4] {
    [
        o[0] + PAD,
        widget::header_y(o, PAD),
        w - 2.0 * PAD - (BTN_W + GAP),
        NAME_H,
    ]
}
pub(crate) fn apply_rect(o: [f32; 2], w: f32) -> [f32; 4] {
    [
        o[0] + w - PAD - BTN_W,
        widget::header_y(o, PAD),
        BTN_W,
        NAME_H,
    ]
}

// Where the scrollable field area begins (below the header + status line).
fn fields_top(o: [f32; 2]) -> f32 {
    widget::header_y(o, PAD) + NAME_H + 4.0 + STATUS_H
}

// The full-width rect of visible field slot `r` at the effective width `w`.
fn field_row_rect(o: [f32; 2], w: f32, r: usize) -> [f32; 4] {
    [o[0], fields_top(o) + r as f32 * FIELD_H, w, FIELD_H]
}
// The control (text field / checkbox area) on the right of slot `r`; it widens
// with the panel while the caption column stays fixed.
pub(crate) fn form_control_rect(o: [f32; 2], w: f32, r: usize) -> [f32; 4] {
    let row = field_row_rect(o, w, r);
    [
        row[0] + LABEL_COL,
        row[1] + 3.0,
        w - LABEL_COL - PAD - 2.0,
        FIELD_H - 8.0,
    ]
}
// The checkbox box for a bool field on slot `r`.
pub(crate) fn form_toggle_rect(o: [f32; 2], w: f32, r: usize) -> [f32; 4] {
    let c = form_control_rect(o, w, r);
    let s = FIELD_H - 12.0;
    [c[0], c[1], s, s]
}
// The `[+]` add and `[-]` remove buttons of an array header on slot `r`.
fn array_add_rect(o: [f32; 2], w: f32, r: usize) -> [f32; 4] {
    let c = form_control_rect(o, w, r);
    let s = FIELD_H - 12.0;
    [c[0] + c[2] - s, c[1], s, s]
}
fn array_remove_rect(o: [f32; 2], w: f32, r: usize) -> [f32; 4] {
    let a = array_add_rect(o, w, r);
    [a[0] - a[2] - 4.0, a[1], a[2], a[3]]
}

// An open value dropdown for the enum / ref field on slot `r`: it floats
// directly below that field's control, aligned to it.
fn field_option_rect(o: [f32; 2], w: f32, slot: usize, r: usize) -> [f32; 4] {
    let c = form_control_rect(o, w, slot);
    [c[0], c[1] + c[3] + r as f32 * DROP_ROW_H, c[2], DROP_ROW_H]
}
// The dropdown's opaque backing. Its height is rounded out to a field-row
// boundary: an overlay whose edge lands mid-row leaves that row's control half
// drawn, which reads as the two clashing rather than as one sitting over the
// other.
fn field_dropdown_backing(o: [f32; 2], w: f32, slot: usize, shown: usize) -> [f32; 4] {
    let c = form_control_rect(o, w, slot);
    let top = c[1] + c[3];
    let h = shown as f32 * DROP_ROW_H + 4.0;
    let rows = ((top + h - fields_top(o)) / FIELD_H).ceil();
    [
        c[0],
        top,
        c[2],
        (fields_top(o) + rows * FIELD_H - top).max(h),
    ]
}

// How many field slots are on screen at effective size `s`: the field count
// capped at the height-derived window.
fn visible_field_count(view: &FormView, s: [f32; 2]) -> usize {
    view.form_fields.len().min(rows_for_height(s[1]))
}

// The accent bar down an overridden row's left edge.
fn ovr_bar_rect(o: [f32; 2], w: f32, r: usize) -> [f32; 4] {
    let row = field_row_rect(o, w, r);
    [row[0] + 3.0, row[1] + 5.0, 3.0, FIELD_H - 10.0]
}

// The per-row override-menu button, tucked into the caption column's right
// edge (never under a control, so a text field's opaque background cannot
// cover it).
fn ovr_btn_rect(o: [f32; 2], w: f32, r: usize) -> [f32; 4] {
    let row = field_row_rect(o, w, r);
    let side = 16.0;
    [
        row[0] + LABEL_COL - side - 6.0,
        row[1] + (FIELD_H - side) * 0.5,
        side,
        side,
    ]
}

// The entity-menu button on the status line's right end.
fn ent_btn_rect(o: [f32; 2], w: f32) -> [f32; 4] {
    [
        o[0] + w - PAD - 18.0,
        widget::header_y(o, PAD) + NAME_H + 4.0,
        18.0,
        18.0,
    ]
}

// The "N overridden" summary chip to the entity button's left.
fn ovr_chip_rect(o: [f32; 2], w: f32) -> [f32; 4] {
    let ent = ent_btn_rect(o, w);
    [ent[0] - GAP - 110.0, ent[1], 110.0, 18.0]
}

// One option row of the floating override / entity menu anchored at `anchor`
// (a row button or the entity button), clamped inside the panel.
fn ovr_menu_option_rect(o: [f32; 2], w: f32, anchor: [f32; 4], r: usize) -> [f32; 4] {
    let menu_w = OVR_MENU_W.min(w - 2.0 * PAD);
    let x = (anchor[0]).min(o[0] + w - PAD - menu_w).max(o[0] + PAD);
    [
        x,
        anchor[1] + anchor[3] + 2.0 + r as f32 * OVR_ROW_H,
        menu_w,
        OVR_ROW_H,
    ]
}

// The menu's opaque backing behind `shown` option rows.
fn ovr_menu_backing(o: [f32; 2], w: f32, anchor: [f32; 4], shown: usize) -> [f32; 4] {
    let first = ovr_menu_option_rect(o, w, anchor, 0);
    [
        first[0] - 2.0,
        first[1] - 2.0,
        first[2] + 4.0,
        shown as f32 * OVR_ROW_H + 4.0,
    ]
}

// Where the open override / entity menu anchors this frame, if any: the field
// menu hangs off its row's button (gone when its row scrolls out), the entity
// menu off the header button.
fn ovr_menu_anchor(view: &FormView, o: [f32; 2], w: f32, window: usize) -> Option<[f32; 4]> {
    let ovr = view.overrides.as_ref()?;
    if let Some((field, _)) = ovr.field_menu {
        let slot = field_slot(view, window, field)?;
        return Some(ovr_btn_rect(o, w, slot));
    }
    ovr.entity_menu.is_some().then(|| ent_btn_rect(o, w))
}

// The open override / entity menu's option labels, if any.
fn ovr_menu_options<'a>(view: &'a FormView) -> Option<&'a [String]> {
    let ovr = view.overrides.as_ref()?;
    if let Some((_, options)) = ovr.field_menu {
        return Some(options);
    }
    ovr.entity_menu
}

// The slot showing logical field `j`, if it is inside the scroll window of
// `window` rows.
fn field_slot(view: &FormView, window: usize, j: usize) -> Option<usize> {
    let scroll = view.form_scroll;
    (j >= scroll && j < scroll + window).then(|| j - scroll)
}

// The element count of a vector field (0 for any other kind).
fn vec_len(kind: FieldKind) -> usize {
    match kind {
        FieldKind::Vec { len, .. } => len,
        _ => 0,
    }
}

// Whether the non-colour vector at logical field `j` is currently disclosed: its
// element leaves (`key.0` ..) follow it directly in the field list, so the next
// field carrying that prefix means it is expanded.
fn vec_expanded(fields: &[FormField], j: usize) -> bool {
    let Some(field) = fields.get(j) else {
        return false;
    };
    let prefix = format!("{}.", field.key);
    fields
        .get(j + 1)
        .is_some_and(|next| next.key.starts_with(&prefix))
}

// The display caption for a field: a disclosed vector element (`position.0`) reads
// as its axis (x / y / z / w); every other field keeps its leaf name.
fn field_caption(fields: &[FormField], field: &FormField) -> String {
    element_axis_label(fields, &field.key).unwrap_or_else(|| {
        field
            .key
            .rsplit('.')
            .next()
            .unwrap_or(&field.key)
            .to_string()
    })
}

// The axis label for `key` when it is an element leaf of a non-colour vector
// (`parent.<idx>` with `parent` a non-colour vector field), else `None`.
fn element_axis_label(fields: &[FormField], key: &str) -> Option<String> {
    let (parent, last) = key.rsplit_once('.')?;
    let idx: usize = last.parse().ok()?;
    let is_vec_parent = fields
        .iter()
        .any(|f| f.key == parent && matches!(f.kind, FieldKind::Vec { color: false, .. }));
    is_vec_parent.then(|| axis_letter(idx))
}

// A vector element's axis label: x / y / z / w for the first four, else `[i]`.
fn axis_letter(i: usize) -> String {
    ["x", "y", "z", "w"]
        .get(i)
        .map(|s| s.to_string())
        .unwrap_or_else(|| format!("[{i}]"))
}

// A resolved form-panel click. Field actions carry the LOGICAL field index.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum FormAction {
    // Focus the name heading, or arg text field `i`.
    FocusName,
    FocusField(usize),
    // Toggle the bool arg field `i`.
    ToggleField(usize),
    // Advance the enum / ref arg field `i` to its next variant (small sets).
    CycleField(usize),
    // Open (or, if already open, close) the value dropdown for field `i`.
    OpenFieldDropdown(usize),
    // Pick option `i` from the open field-value dropdown.
    PickFieldOption(usize),
    // Append / drop the last element of array arg field `i`.
    AddArrayElement(usize),
    RemoveArrayElement(usize),
    // Expand / collapse the disclosure of non-colour vector arg field `i` (its
    // per-element leaves).
    ToggleVecExpand(usize),
    // Open (or close) the override menu of the marked field `i`.
    OpenOverrideMenu(usize),
    // Pick option `i` from the open per-field override menu.
    PickOverrideOption(usize),
    // Open (or close) the entity-level override menu in the header.
    OpenEntityMenu,
    // Pick option `i` from the open entity-level menu.
    PickEntityOption(usize),
    // The header summary chip: scroll to the next overridden field.
    JumpOverride,
    // The Apply / Add button: validate + commit.
    Confirm,
    // The Cancel button: close the panel, discarding the form.
    Close,
    // Dismiss the open value dropdown without picking.
    CloseOverlays,
    // A click inside the panel that hits no control (swallowed).
    Consume,
}

// Override state for a template-derived asset's form, borrowed from the
// hook's per-tick data.
pub(crate) struct OverridesView<'a> {
    // Per-field origin, parallel to `form_fields`.
    pub marks: &'a [FieldOrigin],
    // How many fields diverge from the template.
    pub count: usize,
    // The open per-field menu: (logical field index, option labels).
    pub field_menu: Option<(usize, &'a [String])>,
    // The open entity-level menu's option labels.
    pub entity_menu: Option<&'a [String]>,
}

// The per-frame data the hook hands to `apply` / `hit_test`.
pub(crate) struct FormView<'a> {
    // The title-bar heading ("Edit Camera3D" / "New PointLight").
    pub title: &'a str,
    // Whether an existing entry is being edited (confirm says "Apply", and the
    // hook highlights the entry's browse row) vs a new asset ("Add").
    pub editing: bool,
    // The editable arg fields; the panel renders a `form::FIELD_POOL` window.
    pub form_fields: &'a [FormField],
    // First visible field of the scroll window.
    pub form_scroll: usize,
    // Which input holds keyboard focus.
    pub form_focus: FormFocus,
    // The field whose value dropdown is open, and its scroll offset.
    pub field_dropdown: Option<usize>,
    pub field_dropdown_scroll: usize,
    // A validation error from the last rejected commit.
    pub form_error: Option<&'a str>,
    // Per-field override state when the form edits a template-derived asset.
    pub overrides: Option<OverridesView<'a>>,
    pub mouse: [f32; 2],
}

// Whether the cursor is over the panel (for wheel-scrolling the field window).
pub(crate) fn cursor_over(mx: f32, my: f32, o: [f32; 2], s: [f32; 2]) -> bool {
    point_in(mx, my, widget::outer_rect(o, s))
}

// Resolve a click against the open form panel at origin `o`, effective size `s`.
// `None` means the click missed the panel (the caller lets it fall through).
// Title-bar presses never reach this: the hook intercepts them first to drag.
pub(crate) fn hit_test(
    view: &FormView,
    mx: f32,
    my: f32,
    o: [f32; 2],
    s: [f32; 2],
) -> Option<FormAction> {
    let w = s[0];
    let window = rows_for_height(s[1]);
    // An open override / entity menu is modal over the panel: its option rows
    // pick, anything else dismisses it.
    if let (Some(anchor), Some(options)) =
        (ovr_menu_anchor(view, o, w, window), ovr_menu_options(view))
    {
        let picking_field = view
            .overrides
            .as_ref()
            .is_some_and(|ovr| ovr.field_menu.is_some());
        for k in 0..options.len().min(MAX_OVR_ROWS) {
            if point_in(mx, my, ovr_menu_option_rect(o, w, anchor, k)) {
                return Some(if picking_field {
                    FormAction::PickOverrideOption(k)
                } else {
                    FormAction::PickEntityOption(k)
                });
            }
        }
        return Some(FormAction::CloseOverlays);
    }
    // An open value dropdown is modal over the panel: its option rows pick,
    // anything else dismisses it.
    if let Some(open) = view.field_dropdown
        && let Some(field) = view.form_fields.get(open)
        && let Some(slot) = field_slot(view, window, open)
    {
        let total = field.variants.len();
        let scroll = view.field_dropdown_scroll.min(total.saturating_sub(1));
        for r in 0..MAX_DROP_ROWS {
            let idx = scroll + r;
            if idx >= total {
                break;
            }
            if point_in(mx, my, field_option_rect(o, w, slot, r)) {
                return Some(FormAction::PickFieldOption(idx));
            }
        }
        return Some(FormAction::CloseOverlays);
    }

    if !point_in(mx, my, widget::outer_rect(o, s)) {
        return None;
    }
    // The "X" in the title bar closes the form. (The hook checks this before the
    // title-bar drag; resolved here too so the pure hit test stays complete.)
    if point_in(mx, my, close_rect(o, w)) {
        return Some(FormAction::Close);
    }
    if point_in(mx, my, apply_rect(o, w)) {
        return Some(FormAction::Confirm);
    }
    if point_in(mx, my, name_rect(o, w)) {
        return Some(FormAction::FocusName);
    }
    // The override chrome of a template-derived asset: the entity-menu button,
    // the summary chip, and each marked row's menu button (in the caption
    // column, so it never contends with a control).
    if let Some(ovr) = &view.overrides {
        if point_in(mx, my, ent_btn_rect(o, w)) {
            return Some(FormAction::OpenEntityMenu);
        }
        if ovr.count > 0 && point_in(mx, my, ovr_chip_rect(o, w)) {
            return Some(FormAction::JumpOverride);
        }
        for r in 0..visible_field_count(view, s) {
            let j = view.form_scroll + r;
            let marked = ovr
                .marks
                .get(j)
                .is_some_and(|m| *m != FieldOrigin::Inherited);
            if marked && point_in(mx, my, ovr_btn_rect(o, w, r)) {
                return Some(FormAction::OpenOverrideMenu(j));
            }
        }
    }

    // Arg field controls over the visible window: slot `r` is logical field
    // `form_scroll + r`. A bool toggles, an enum cycles / opens a dropdown, an
    // array grows / shrinks, a text field takes focus.
    let scroll = view.form_scroll;
    for r in 0..visible_field_count(view, s) {
        let j = scroll + r;
        let Some(f) = view.form_fields.get(j) else {
            break;
        };
        match f.kind {
            FieldKind::Bool => {
                if point_in(mx, my, form_toggle_rect(o, w, r)) {
                    return Some(FormAction::ToggleField(j));
                }
            }
            FieldKind::Enum | FieldKind::Ref { .. } => {
                if point_in(mx, my, form_control_rect(o, w, r)) {
                    // A small variant set cycles in place; a large one opens a
                    // floating dropdown instead of forcing many clicks.
                    if f.variants.len() > CYCLE_MAX {
                        return Some(FormAction::OpenFieldDropdown(j));
                    }
                    return Some(FormAction::CycleField(j));
                }
            }
            FieldKind::Array => {
                if point_in(mx, my, array_add_rect(o, w, r)) {
                    return Some(FormAction::AddArrayElement(j));
                }
                if point_in(mx, my, array_remove_rect(o, w, r)) {
                    return Some(FormAction::RemoveArrayElement(j));
                }
            }
            FieldKind::Vec { color: false, .. } => {
                // The disclosure button toggles the per-element leaves.
                if point_in(mx, my, form_control_rect(o, w, r)) {
                    return Some(FormAction::ToggleVecExpand(j));
                }
            }
            _ => {
                if point_in(mx, my, form_control_rect(o, w, r)) {
                    return Some(FormAction::FocusField(j));
                }
            }
        }
    }
    // Empty panel space: swallow so it does not fall through to the world.
    Some(FormAction::Consume)
}

// Position + show the panel's elements for this frame at origin `o`, effective
// size `s`, or hide them all when the form is closed (`view` is `None`).
pub(crate) fn apply(world: &mut World, view: Option<&FormView>, o: [f32; 2], s: [f32; 2]) {
    let Some(view) = view else {
        hide_all(world);
        return;
    };

    // Blank everything, then re-show what this frame needs.
    hide_all(world);

    let w = s[0];
    let window = rows_for_height(s[1]);
    widget::place_panel(world, EDIT_BG, widget::outer_rect(o, s));
    widget::place_heading(world, TITLE_LABEL, widget::title_rect(o, w), view.title);

    // The "X" close button in the title bar's top-right corner (blends into the
    // title bar until hovered; shared look across every panel).
    let close_hover = point_in(view.mouse[0], view.mouse[1], close_rect(o, w));
    widget::place_close(
        world,
        CLOSE_BG,
        CLOSE_LABEL,
        widget::title_rect(o, w),
        close_hover,
    );

    // The header row: the asset-name heading (drawn larger) and the pinned Apply
    // button at the panel's top right.
    show_name_heading(world, o, w, view.form_focus == FormFocus::Name);
    let apply_btn = apply_rect(o, w);
    let hover = point_in(view.mouse[0], view.mouse[1], apply_btn);
    place_rounded(
        world,
        APPLY_BG,
        apply_btn,
        if hover { BTN_TINT_HOVER } else { BTN_TINT },
        theme::CONTROL_RADIUS,
        true,
    );
    let confirm = if view.editing { "Apply" } else { "Add" };
    place_center_label(world, APPLY_LABEL, apply_btn, confirm, LABEL_WHITE, true);

    // A validation error, if the last commit was rejected (a reserved line, so
    // showing it never shifts the fields below).
    if let Some(err) = view.form_error {
        widget::place_left_label(
            world,
            FORM_STATUS,
            [o[0] + PAD, widget::header_y(o, PAD) + NAME_H + 6.0],
            err,
            ERROR_LABEL,
            true,
        );
    }

    // The arg fields over the visible window, drawn into the slot-indexed pool.
    let scroll = view.form_scroll;
    for r in 0..visible_field_count(view, s) {
        let j = scroll + r;
        let Some(field) = view.form_fields.get(j) else {
            break;
        };
        let row = field_row_rect(o, w, r);
        // A nested (dotted-path) field shows its indented caption; a disclosed
        // vector element reads as its axis (x / y / z / w).
        let depth = field.key.matches('.').count();
        let caption = field_caption(view.form_fields, field);
        widget::place_left_label(
            world,
            form_row_label(r),
            [
                row[0] + PAD + depth as f32 * NEST_INDENT,
                row[1] + FIELD_H * 0.5 - theme::TEXT_HALF,
            ],
            &caption,
            LABEL,
            true,
        );
        match field.kind {
            FieldKind::Bool => {
                let t = form_toggle_rect(o, w, r);
                let tint = if field.boolval { CHECK_ON } else { CHECK_OFF };
                place_rounded(world, form_toggle_bg(r), t, tint, 4.0, true);
            }
            FieldKind::Enum | FieldKind::Ref { .. } => {
                // A cycling button spanning the control, captioned with the
                // current selection.
                let c = form_control_rect(o, w, r);
                let hover = point_in(view.mouse[0], view.mouse[1], c);
                let tint = if hover { OPTION_TINT_HOVER } else { CYCLE_TINT };
                place_rounded(
                    world,
                    form_toggle_bg(r),
                    c,
                    tint,
                    theme::CONTROL_RADIUS,
                    true,
                );
                let value = field
                    .variants
                    .get(field.variant_idx)
                    .map(String::as_str)
                    .unwrap_or("");
                place_center_label(world, form_enum_label(r), c, value, LABEL, true);
            }
            FieldKind::Array => {
                // A header for a variable-length array: its element count and a
                // red `[-]` remove + green `[+]` add button.
                let c = form_control_rect(o, w, r);
                widget::place_left_label(
                    world,
                    form_enum_label(r),
                    [c[0], c[1] + c[3] * 0.5 - theme::TEXT_HALF],
                    &format!("({})", field.variant_idx),
                    LABEL_DIM,
                    true,
                );
                place_rounded(
                    world,
                    form_swatch(r),
                    array_remove_rect(o, w, r),
                    REMOVE_BTN_TINT,
                    4.0,
                    true,
                );
                place_rounded(
                    world,
                    form_toggle_bg(r),
                    array_add_rect(o, w, r),
                    ADD_BTN_TINT,
                    4.0,
                    true,
                );
            }
            FieldKind::Vec { color: false, .. } => {
                // A disclosure button spanning the control, captioned with the
                // element count and a caret (`>` collapsed, `v` expanded). Clicking
                // it toggles the per-element leaves below.
                let c = form_control_rect(o, w, r);
                let hover = point_in(view.mouse[0], view.mouse[1], c);
                let tint = if hover { OPTION_TINT_HOVER } else { CYCLE_TINT };
                place_rounded(
                    world,
                    form_toggle_bg(r),
                    c,
                    tint,
                    theme::CONTROL_RADIUS,
                    true,
                );
                let open = vec_expanded(view.form_fields, j);
                let caption = format!("[{}] {}", vec_len(field.kind), if open { "v" } else { ">" });
                widget::place_left_label(
                    world,
                    form_enum_label(r),
                    [c[0] + 8.0, c[1] + c[3] * 0.5 - theme::TEXT_HALF],
                    &caption,
                    LABEL_DIM,
                    true,
                );
            }
            kind => {
                let control = form_control_rect(o, w, r);
                // A colour vector reserves a right-hand strip for a live preview
                // swatch and narrows its field to clear it. The swatch must sit
                // OUTSIDE the field rect: a `TextInput`'s opaque background box
                // is synthesised after every authored sprite (the swatch
                // included), so a swatch drawn under the field would be painted
                // over.
                let swatch = matches!(kind, FieldKind::Vec { color: true, .. }).then(|| {
                    let s = FIELD_H - 14.0;
                    [
                        control[0] + control[2] - s,
                        control[1] + (control[3] - s) * 0.5,
                        s,
                        s,
                    ]
                });
                let rect = match swatch {
                    Some(sw) => [control[0], control[1], sw[0] - control[0] - 4.0, control[3]],
                    None => control,
                };
                widget::show_field(
                    world,
                    form_input(r),
                    rect,
                    view.form_focus == FormFocus::Field(j),
                );
                if let Some(sw) = swatch {
                    let rgb = swatch_rgb(&widget::field_text(world, form_input(r)));
                    place_rounded(world, form_swatch(r), sw, rgb, 4.0, true);
                }
            }
        }
    }

    // Override chrome for a template-derived asset: per-row accent bars +
    // menu buttons, and the header summary chip + entity-menu button.
    if let Some(ovr) = &view.overrides {
        for r in 0..visible_field_count(view, s) {
            let j = scroll + r;
            let Some(mark) = ovr.marks.get(j) else {
                break;
            };
            if *mark == FieldOrigin::Inherited {
                continue;
            }
            let tint = match mark {
                FieldOrigin::InstanceOnly => INSTANCE_ONLY_TINT,
                _ => theme::ACCENT_TINT,
            };
            place_rounded(world, ovr_bar(r), ovr_bar_rect(o, w, r), tint, 1.5, true);
            let btn = ovr_btn_rect(o, w, r);
            let hover = point_in(view.mouse[0], view.mouse[1], btn);
            let open_here = view
                .overrides
                .as_ref()
                .and_then(|v| v.field_menu)
                .is_some_and(|(f, _)| f == j);
            let bg = if hover || open_here {
                theme::HOVER_TINT
            } else {
                CYCLE_TINT
            };
            place_rounded(world, ovr_btn_bg(r), btn, bg, 4.0, true);
            place_center_label(world, ovr_btn_label(r), btn, "*", OVERRIDE_LABEL, true);
        }

        let ent = ent_btn_rect(o, w);
        let hover = point_in(view.mouse[0], view.mouse[1], ent);
        let bg = if hover || ovr.entity_menu.is_some() {
            theme::HOVER_TINT
        } else {
            CYCLE_TINT
        };
        place_rounded(world, ENT_BTN_BG, ent, bg, 4.0, true);
        place_center_label(world, ENT_BTN_LABEL, ent, "...", LABEL, true);
        if ovr.count > 0 {
            let chip = ovr_chip_rect(o, w);
            let hover = point_in(view.mouse[0], view.mouse[1], chip);
            let bg = if hover { theme::HOVER_TINT } else { CYCLE_TINT };
            place_rounded(world, OVR_CHIP_BG, chip, bg, 4.0, true);
            let caption = format!("{} overridden", ovr.count);
            place_center_label(world, OVR_CHIP_LABEL, chip, &caption, OVERRIDE_LABEL, true);
        }
    }

    // A scrollbar down the field region's right edge when the form overflows the
    // visible window.
    layout_form_scrollbar(world, view.form_fields.len(), scroll, o, w, window);

    // The open value dropdown draws last so it floats over the slots below it.
    if let Some(open) = view.field_dropdown {
        layout_field_dropdown(world, view, o, w, window, open);
    }

    // The open override / entity menu draws over everything else.
    if let (Some(anchor), Some(options)) =
        (ovr_menu_anchor(view, o, w, window), ovr_menu_options(view))
    {
        let shown = options.len().min(MAX_OVR_ROWS);
        place_rounded(
            world,
            OVR_MENU_BG,
            ovr_menu_backing(o, w, anchor, shown),
            DROP_BG_TINT,
            theme::CONTROL_RADIUS,
            true,
        );
        for (k, option) in options.iter().take(MAX_OVR_ROWS).enumerate() {
            let rect = ovr_menu_option_rect(o, w, anchor, k);
            let hovered = point_in(view.mouse[0], view.mouse[1], rect);
            let tint = if hovered {
                OPTION_TINT_HOVER
            } else {
                OPTION_TINT
            };
            place_rounded(
                world,
                ovr_menu_row_bg(k),
                theme::highlight_rect(rect),
                tint,
                theme::CONTROL_RADIUS,
                true,
            );
            widget::place_left_label(
                world,
                ovr_menu_row_label(k),
                [rect[0] + PAD, rect[1] + OVR_ROW_H * 0.5 - theme::TEXT_HALF],
                option,
                LABEL,
                true,
            );
        }
    }
}

// The name heading: the editable TextInput under the title bar, drawn larger
// than the body text.
fn show_name_heading(world: &mut World, o: [f32; 2], w: f32, focused: bool) {
    widget::show_field(world, NAME_INPUT, name_rect(o, w), focused);
    if let Some(t) = widget::input_mut(world, NAME_INPUT) {
        t.scale = NAME_SCALE;
    }
}

// The form's scrollbar thumb, sizing the visible window against the total field
// count. Shown only when the form overflows the visible window of `window` rows.
fn layout_form_scrollbar(
    world: &mut World,
    total: usize,
    scroll: usize,
    o: [f32; 2],
    w: f32,
    window: usize,
) {
    if total <= window {
        return;
    }
    let region_top = fields_top(o);
    let track_h = window as f32 * FIELD_H;
    let track = [o[0] + w - SCROLLBAR_W, region_top, SCROLLBAR_W, track_h];
    place_rounded(
        world,
        FORM_TRACK,
        track,
        TRACK_TINT,
        SCROLLBAR_W * 0.5,
        true,
    );
    let frac_visible = window as f32 / total as f32;
    let thumb_h = (track_h * frac_visible).max(20.0);
    let max_scroll = (total - window) as f32;
    let t = if max_scroll > 0.0 {
        scroll.min(total - window) as f32 / max_scroll
    } else {
        0.0
    };
    let thumb_y = region_top + t * (track_h - thumb_h);
    place_rounded(
        world,
        FORM_THUMB,
        [track[0], thumb_y, SCROLLBAR_W, thumb_h],
        THUMB_TINT,
        SCROLLBAR_W * 0.5,
        true,
    );
}

// The floating value dropdown for an open enum / ref field: an opaque backing
// plus its option rows (the current selection highlighted) and, when it
// overflows, its own thin scrollbar.
fn layout_field_dropdown(
    world: &mut World,
    view: &FormView,
    o: [f32; 2],
    w: f32,
    window: usize,
    open: usize,
) {
    let Some(field) = view.form_fields.get(open) else {
        return;
    };
    let Some(slot) = field_slot(view, window, open) else {
        return;
    };
    let total = field.variants.len();
    let scroll = view.field_dropdown_scroll.min(total.saturating_sub(1));
    let shown = total.saturating_sub(scroll).clamp(1, MAX_DROP_ROWS);
    place_rounded(
        world,
        DROP_BG,
        field_dropdown_backing(o, w, slot, shown),
        DROP_BG_TINT,
        theme::CONTROL_RADIUS,
        true,
    );
    for r in 0..MAX_DROP_ROWS {
        let idx = scroll + r;
        if idx >= total {
            break;
        }
        let rect = field_option_rect(o, w, slot, r);
        let hovered = point_in(view.mouse[0], view.mouse[1], rect);
        let tint = if hovered {
            OPTION_TINT_HOVER
        } else if idx == field.variant_idx {
            OPTION_TINT_SELECTED
        } else {
            OPTION_TINT
        };
        place_rounded(
            world,
            drop_row_bg(r),
            theme::highlight_rect(rect),
            tint,
            theme::CONTROL_RADIUS,
            true,
        );
        widget::place_left_label(
            world,
            drop_row_label(r),
            [rect[0] + PAD, rect[1] + DROP_ROW_H * 0.5 - theme::TEXT_HALF],
            &field.variants[idx],
            LABEL,
            true,
        );
    }
    if total > MAX_DROP_ROWS {
        let back = field_dropdown_backing(o, w, slot, shown);
        let track = [
            back[0] + back[2] - SCROLLBAR_W,
            back[1],
            SCROLLBAR_W,
            back[3],
        ];
        place_rounded(
            world,
            DROP_TRACK,
            track,
            TRACK_TINT,
            SCROLLBAR_W * 0.5,
            true,
        );
        let frac = MAX_DROP_ROWS as f32 / total as f32;
        let thumb_h = (back[3] * frac).max(20.0);
        let max_scroll = (total - MAX_DROP_ROWS) as f32;
        let t = if max_scroll > 0.0 {
            scroll as f32 / max_scroll
        } else {
            0.0
        };
        let thumb_y = back[1] + t * (back[3] - thumb_h);
        place_rounded(
            world,
            DROP_THUMB,
            [track[0], thumb_y, SCROLLBAR_W, thumb_h],
            THUMB_TINT,
            SCROLLBAR_W * 0.5,
            true,
        );
    }
}

// Parse a colour field's live text ("r, g, b" / "r, g, b, a") into an opaque RGB
// tint for its preview swatch, clamped to the displayable 0..=1 range. Falls
// back to a neutral dark swatch until three components parse.
fn swatch_rgb(text: &str) -> [f32; 4] {
    let nums: Vec<f32> = text
        .split(|c: char| c == ',' || c.is_whitespace())
        .filter(|s| !s.is_empty())
        .filter_map(|s| s.parse::<f32>().ok())
        .take(3)
        .collect();
    if nums.len() < 3 {
        return [0.15, 0.15, 0.18, 1.0];
    }
    [
        nums[0].clamp(0.0, 1.0),
        nums[1].clamp(0.0, 1.0),
        nums[2].clamp(0.0, 1.0),
        1.0,
    ]
}

fn place_center_label(
    world: &mut World,
    id: AssetId,
    rect: [f32; 4],
    content: &str,
    color: [f32; 3],
    visible: bool,
) {
    if let Some(l) = widget::label_mut(world, id) {
        l.x = rect[0] + rect[2] * 0.5;
        l.y = rect[1] + rect[3] * 0.5 - theme::TEXT_HALF;
        l.align = TextAlign::Center;
        l.color = color;
        l.visible = visible;
        l.content = content.to_string();
    }
}

// Hide every panel element, including the typed fields (and blur them so a
// hidden field cannot keep keyboard focus).
pub(crate) fn hide_all(world: &mut World) {
    widget::hide_all(world, &all_sprite_ids(), &all_label_ids(), &all_field_ids());
}

// Every panel sprite id. THE ORDER OF THIS VEC IS THE DRAW ORDER (inject.rs
// inserts in this sequence; the overlay draws in insertion order): background,
// title, buttons, per-slot chrome, then the floating overlays (scrollbar, value
// dropdown) which must sit above the slot chrome.
// The value dropdown's own elements, which draw above the rest of the panel
// while it is open so its backing occludes the field rows it covers.
pub(crate) fn dropdown_ids() -> Vec<AssetId> {
    let mut ids = vec![DROP_BG, DROP_TRACK, DROP_THUMB];
    ids.extend((0..MAX_DROP_ROWS).map(drop_row_bg));
    ids.extend((0..MAX_DROP_ROWS).map(drop_row_label));
    ids
}

// The open override / entity menu's elements, raised above the rest of the
// panel while one is open (same contract as `dropdown_ids`).
pub(crate) fn override_menu_ids() -> Vec<AssetId> {
    let mut ids = vec![OVR_MENU_BG];
    ids.extend((0..MAX_OVR_ROWS).map(ovr_menu_row_bg));
    ids.extend((0..MAX_OVR_ROWS).map(ovr_menu_row_label));
    ids
}

pub(crate) fn all_sprite_ids() -> Vec<AssetId> {
    let mut ids = vec![EDIT_BG, CLOSE_BG, APPLY_BG, OVR_CHIP_BG, ENT_BTN_BG];
    ids.extend((0..form::FIELD_POOL_MAX).map(form_toggle_bg));
    ids.extend((0..form::FIELD_POOL_MAX).map(form_swatch));
    ids.extend((0..form::FIELD_POOL_MAX).map(ovr_bar));
    ids.extend((0..form::FIELD_POOL_MAX).map(ovr_btn_bg));
    ids.extend([FORM_TRACK, FORM_THUMB, DROP_BG]);
    ids.extend((0..MAX_DROP_ROWS).map(drop_row_bg));
    ids.extend([DROP_TRACK, DROP_THUMB, OVR_MENU_BG]);
    ids.extend((0..MAX_OVR_ROWS).map(ovr_menu_row_bg));
    ids
}
// Same draw-order contract; the dropdown's option captions come last so they
// draw above the slot captions the dropdown floats over.
pub(crate) fn all_label_ids() -> Vec<AssetId> {
    let mut ids = vec![
        TITLE_LABEL,
        CLOSE_LABEL,
        APPLY_LABEL,
        FORM_STATUS,
        OVR_CHIP_LABEL,
        ENT_BTN_LABEL,
    ];
    ids.extend((0..form::FIELD_POOL_MAX).map(form_row_label));
    ids.extend((0..form::FIELD_POOL_MAX).map(form_enum_label));
    ids.extend((0..form::FIELD_POOL_MAX).map(ovr_btn_label));
    ids.extend((0..MAX_DROP_ROWS).map(drop_row_label));
    ids.extend((0..MAX_OVR_ROWS).map(ovr_menu_row_label));
    ids
}
// Every typed field: the name heading and the arg-field text inputs.
pub(crate) fn all_field_ids() -> Vec<AssetId> {
    let mut ids = vec![NAME_INPUT];
    ids.extend((0..form::FIELD_POOL_MAX).map(form_input));
    ids
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::components::{Sprite, TextInput, TextLabel};

    fn test_origin() -> [f32; 2] {
        default_origin(1280.0)
    }

    fn field(key: &str, kind: FieldKind) -> FormField {
        FormField {
            key: key.into(),
            kind,
            initial: "0".into(),
            boolval: false,
            variants: Vec::new(),
            variant_idx: 0,
        }
    }

    fn float_fields(n: usize) -> Vec<FormField> {
        (0..n)
            .map(|i| field(&format!("f{i}"), FieldKind::Float))
            .collect()
    }

    // A ref field with `n` options past `(none)`. With `n > CYCLE_MAX` it opens
    // a dropdown rather than cycling.
    fn ref_field(n: usize) -> FormField {
        let mut variants = vec![form::NONE_LABEL.to_string()];
        variants.extend((0..n).map(|i| format!("tex_{i}")));
        FormField {
            key: "texture".into(),
            kind: FieldKind::Ref { target: "Texture" },
            initial: String::new(),
            boolval: false,
            variants,
            variant_idx: 0,
        }
    }

    fn view<'a>(fields: &'a [FormField]) -> FormView<'a> {
        FormView {
            title: "New PointLight",
            editing: false,
            form_fields: fields,
            form_scroll: 0,
            form_focus: FormFocus::Name,
            field_dropdown: None,
            field_dropdown_scroll: 0,
            form_error: None,
            overrides: None,
            mouse: [0.0, 0.0],
        }
    }

    fn injected_world() -> World {
        let mut world = World::new();
        for id in all_sprite_ids() {
            world.add_component(Sprite {
                asset_id: id,
                ..Default::default()
            });
        }
        for id in all_label_ids() {
            world.add_component(TextLabel {
                asset_id: id,
                ..Default::default()
            });
        }
        for id in all_field_ids() {
            world.add_component(TextInput {
                asset_id: id,
                ..Default::default()
            });
        }
        world
    }

    fn sprite(world: &World, id: AssetId) -> Sprite {
        world
            .query::<Sprite>()
            .find(|s| s.asset_id == id)
            .cloned()
            .expect("sprite present")
    }
    fn sprite_visible(world: &World, id: AssetId) -> bool {
        sprite(world, id).visible
    }
    fn label(world: &World, id: AssetId) -> TextLabel {
        world
            .query::<TextLabel>()
            .find(|l| l.asset_id == id)
            .cloned()
            .expect("label present")
    }
    fn input(world: &World, id: AssetId) -> TextInput {
        world
            .query::<TextInput>()
            .find(|t| t.asset_id == id)
            .cloned()
            .expect("input present")
    }

    // The X close sits in the title bar's top-right corner; the header row pins the
    // name heading and the Apply button under the title bar.
    #[test]
    fn header_pins_name_and_button_under_the_title_bar() {
        let o = test_origin();
        let title = widget::title_rect(o, EDIT_W);
        assert_eq!(title, [o[0], o[1], EDIT_W, widget::TITLE_H]);
        let close = close_rect(o, EDIT_W);
        assert_eq!(close[1], o[1], "the X sits in the title bar");
        assert_eq!(
            close[0] + close[2],
            o[0] + EDIT_W,
            "the X is flush to the panel's right edge"
        );
        let name = name_rect(o, EDIT_W);
        let apply_btn = apply_rect(o, EDIT_W);
        assert_eq!(name[1], o[1] + widget::TITLE_H + PAD, "under the title bar");
        assert_eq!(
            name[1], apply_btn[1],
            "the name and Apply share the header row"
        );
        assert!(
            name[0] + name[2] <= apply_btn[0],
            "the name heading ends left of Apply"
        );
        assert_eq!(
            apply_btn[0] + apply_btn[2],
            o[0] + EDIT_W - PAD,
            "Apply flush to the panel's right pad"
        );
        // The whole panel follows its origin.
        let v = view(&[]);
        let moved = widget::outer_rect([40.0, 60.0], size(v.form_fields.len()));
        assert_eq!((moved[0], moved[1]), (40.0, 60.0));
    }

    // The panel height tracks the field count up to the pool cap; `size` is what
    // the hook's drag clamp uses.
    #[test]
    fn panel_height_tracks_fields_and_caps_at_the_pool() {
        let short = size(2);
        let tall = size(form::FIELD_POOL + 20);
        assert!(short[1] < tall[1]);
        assert_eq!(
            tall[1],
            size(form::FIELD_POOL)[1],
            "a form past the pool scrolls instead of growing"
        );
        let fields = float_fields(2);
        let v = view(&fields);
        assert_eq!(
            widget::outer_rect(test_origin(), size(v.form_fields.len()))[3],
            short[1]
        );
    }

    // Growing the panel taller reveals more field rows (up to the pool); a short
    // form is height-locked; growing it wider stretches the control column while
    // the caption column stays fixed.
    #[test]
    fn taller_reveals_more_fields_and_wider_grows_the_control_column() {
        // A form past the default window: the default height shows FIELD_POOL rows,
        // taller reveals more up to FIELD_POOL_MAX.
        assert_eq!(rows_for_height(size(40)[1]), form::FIELD_POOL);
        assert_eq!(
            rows_for_height(size(40)[1] + 5.0 * FIELD_H),
            form::FIELD_POOL + 5
        );
        assert_eq!(rows_for_height(max_size(40)[1]), form::FIELD_POOL_MAX);
        assert_eq!(
            rows_for_height(10_000.0),
            form::FIELD_POOL_MAX,
            "capped at the pool"
        );
        // A short form's height is locked (max == default): no vertical grab.
        assert_eq!(max_size(3)[1], size(3)[1]);
        // Wider widens the control column; the caption column start is fixed.
        let o = [40.0, 60.0];
        let narrow = form_control_rect(o, EDIT_W, 0);
        let wide = form_control_rect(o, EDIT_W + 200.0, 0);
        assert_eq!(narrow[0], wide[0], "the control column starts at a fixed x");
        assert!(
            wide[2] > narrow[2] + 150.0,
            "the control widens with the panel"
        );
    }

    // A taller panel draws field rows past the default window that a default one
    // would never show.
    #[test]
    fn taller_panel_draws_fields_past_the_default_window() {
        let mut world = injected_world();
        let fields = float_fields(form::FIELD_POOL_MAX);
        let tall = [EDIT_W, max_size(fields.len())[1]];
        apply(&mut world, Some(&view(&fields)), [20.0, 20.0], tall);
        assert!(
            input(&world, form_input(form::FIELD_POOL)).visible,
            "a row past the default window shows only because we grew"
        );
    }

    #[test]
    fn buttons_and_name_hit_test() {
        let fields = float_fields(1);
        let v = view(&fields);
        let o = test_origin();
        let a = apply_rect(o, EDIT_W);
        let x = close_rect(o, EDIT_W);
        let n = name_rect(o, EDIT_W);
        assert_eq!(
            hit_test(&v, a[0] + 5.0, a[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::Confirm)
        );
        assert_eq!(
            hit_test(&v, x[0] + 5.0, x[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::Close),
            "the title-bar X closes the form"
        );
        assert_eq!(
            hit_test(&v, n[0] + 5.0, n[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::FocusName)
        );
        // A title-bar click off the X is consumed (the hook grabs drags before this).
        let t = widget::title_rect(o, EDIT_W);
        assert_eq!(
            hit_test(&v, t[0] + 5.0, t[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::Consume)
        );
        // A miss falls through.
        assert_eq!(
            hit_test(&v, 10.0, 700.0, o, size(v.form_fields.len())),
            None
        );
    }

    // The title bar carries the heading, the confirm button is captioned "Apply"
    // while editing and "Add" for a new asset, and the name heading draws larger.
    #[test]
    fn apply_shows_title_confirm_caption_and_scaled_name() {
        let fields = float_fields(1);
        let mut world = injected_world();
        let o = test_origin();
        apply(&mut world, Some(&view(&fields)), o, size(fields.len()));
        assert_eq!(label(&world, TITLE_LABEL).content, "New PointLight");
        assert_eq!(label(&world, APPLY_LABEL).content, "Add");
        assert_eq!(
            label(&world, CLOSE_LABEL).content,
            "X",
            "the title-bar close"
        );
        let name = input(&world, NAME_INPUT);
        assert!(name.visible);
        assert!(name.scale > 1.0, "the name heading draws larger");
        let mut editing = view(&fields);
        editing.editing = true;
        editing.title = "Edit Camera3D";
        apply(
            &mut world,
            Some(&editing),
            o,
            size(editing.form_fields.len()),
        );
        assert_eq!(label(&world, TITLE_LABEL).content, "Edit Camera3D");
        assert_eq!(label(&world, APPLY_LABEL).content, "Apply");
    }

    // Field slots map logical fields through the scroll window; a form past the
    // pool shows its scrollbar and keeps the buttons pinned in the header.
    #[test]
    fn a_form_past_the_pool_scrolls_a_window() {
        let o = test_origin();
        let fields = float_fields(form::FIELD_POOL + 4);
        let mut world = injected_world();
        let v = view(&fields);
        apply(&mut world, Some(&v), o, size(v.form_fields.len()));
        assert!(
            sprite_visible(&world, FORM_THUMB),
            "the form scrollbar shows"
        );
        // Slot 0 resolves to logical field 0.
        let c0 = form_control_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&v, c0[0] + 5.0, c0[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::FocusField(0))
        );
        // Scrolled by three: slot 0 shows logical field 3; the last slot shows
        // the window's last field.
        let mut vs = view(&fields);
        vs.form_scroll = 3;
        assert_eq!(
            hit_test(&vs, c0[0] + 5.0, c0[1] + 5.0, o, size(vs.form_fields.len())),
            Some(FormAction::FocusField(3))
        );
        let last = form_control_rect(o, EDIT_W, form::FIELD_POOL - 1);
        assert_eq!(
            hit_test(
                &vs,
                last[0] + 5.0,
                last[1] + 5.0,
                o,
                size(vs.form_fields.len())
            ),
            Some(FormAction::FocusField(3 + form::FIELD_POOL - 1))
        );
        // The Apply button stays pinned in the header regardless.
        let a = apply_rect(o, EDIT_W);
        assert_eq!(
            hit_test(&vs, a[0] + 5.0, a[1] + 5.0, o, size(vs.form_fields.len())),
            Some(FormAction::Confirm)
        );
    }

    #[test]
    fn a_form_within_the_pool_has_no_scrollbar() {
        let fields = float_fields(1);
        let mut world = injected_world();
        apply(
            &mut world,
            Some(&view(&fields)),
            test_origin(),
            size(fields.len()),
        );
        assert!(!sprite_visible(&world, FORM_THUMB));
    }

    // A colour-vector arg field renders its text control plus a live preview
    // swatch tinted from the field's current text; the swatch sits outside the
    // field rect (a TextInput's opaque background box is synthesised after every
    // authored sprite, so a swatch under the field would be painted over).
    #[test]
    fn colour_vector_field_shows_a_live_swatch() {
        let mut world = injected_world();
        for t in world.query_mut::<TextInput>() {
            if t.asset_id == form_input(0) {
                t.content = "1, 0, 0".into();
            }
        }
        let fields = [FormField {
            key: "color".into(),
            kind: FieldKind::Vec {
                len: 3,
                color: true,
            },
            initial: "1, 0, 0".into(),
            boolval: false,
            variants: Vec::new(),
            variant_idx: 0,
        }];
        apply(
            &mut world,
            Some(&view(&fields)),
            test_origin(),
            size(fields.len()),
        );
        let sw = sprite(&world, form_swatch(0));
        assert!(sw.visible, "the colour field draws a swatch");
        assert_eq!(sw.tint, [1.0, 0.0, 0.0, 1.0], "swatch tint is the RGB text");
        let ti = input(&world, form_input(0));
        assert!(ti.visible, "the editable text field still shows");
        assert!(
            sw.x >= ti.x + ti.width,
            "the swatch sits outside the field's opaque background box"
        );
    }

    // A plain (non-colour) vector renders as a collapsed disclosure button, not an
    // editable text field or a swatch; clicking it toggles its per-element leaves.
    #[test]
    fn plain_vector_field_is_a_disclosure() {
        let o = test_origin();
        let mut world = injected_world();
        let fields = [FormField {
            key: "position".into(),
            kind: FieldKind::Vec {
                len: 3,
                color: false,
            },
            initial: "0, 0, 0".into(),
            boolval: false,
            variants: Vec::new(),
            variant_idx: 0,
        }];
        let v = view(&fields);
        apply(&mut world, Some(&v), o, size(v.form_fields.len()));
        assert!(!sprite_visible(&world, form_swatch(0)), "no colour swatch");
        assert!(
            !input(&world, form_input(0)).visible,
            "a collapsed vector has no editable comma field"
        );
        assert!(
            sprite_visible(&world, form_toggle_bg(0)),
            "the disclosure button shows"
        );
        let cap = label(&world, form_enum_label(0));
        assert!(
            cap.visible && cap.content == "[3] >",
            "collapsed count + caret"
        );
        let c = form_control_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&v, c[0] + 5.0, c[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::ToggleVecExpand(0))
        );
    }

    // An expanded vector shows its element leaves labelled by axis (x / y / z), each
    // an editable field, and the header caret flips to `v`.
    #[test]
    fn expanded_vector_shows_axis_labelled_element_fields() {
        let o = test_origin();
        let mut world = injected_world();
        let elem = |axis: &str| FormField {
            key: format!("position.{axis}"),
            kind: FieldKind::Float,
            initial: "0".into(),
            boolval: false,
            variants: Vec::new(),
            variant_idx: 0,
        };
        let fields = [
            FormField {
                key: "position".into(),
                kind: FieldKind::Vec {
                    len: 3,
                    color: false,
                },
                initial: String::new(),
                boolval: false,
                variants: Vec::new(),
                variant_idx: 0,
            },
            elem("0"),
            elem("1"),
            elem("2"),
        ];
        let v = view(&fields);
        apply(&mut world, Some(&v), o, size(v.form_fields.len()));
        // The header caret is now `v` (its element leaves follow it).
        assert_eq!(label(&world, form_enum_label(0)).content, "[3] v");
        // Slots 1..=3 are the axis-labelled element fields.
        assert_eq!(label(&world, form_row_label(1)).content, "x");
        assert_eq!(label(&world, form_row_label(2)).content, "y");
        assert_eq!(label(&world, form_row_label(3)).content, "z");
        assert!(
            input(&world, form_input(1)).visible,
            "an element leaf is an editable field"
        );
        // Clicking an element focuses it; clicking the header collapses again.
        let c1 = form_control_rect(o, EDIT_W, 1);
        assert_eq!(
            hit_test(&v, c1[0] + 5.0, c1[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::FocusField(1))
        );
        let c0 = form_control_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&v, c0[0] + 5.0, c0[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::ToggleVecExpand(0))
        );
    }

    // An enum / ref field renders as a cycling button captioned with the current
    // variant and hit-tests to a cycle; a large variant set opens a dropdown.
    #[test]
    fn choice_fields_cycle_or_open_a_dropdown() {
        let o = test_origin();
        let mut world = injected_world();
        let small = [FormField {
            key: "align".into(),
            kind: FieldKind::Enum,
            initial: String::new(),
            boolval: false,
            variants: vec!["left".into(), "center".into(), "right".into()],
            variant_idx: 1,
        }];
        let v = view(&small);
        apply(&mut world, Some(&v), o, size(v.form_fields.len()));
        assert!(
            sprite_visible(&world, form_toggle_bg(0)),
            "cycle button shows"
        );
        let cap = label(&world, form_enum_label(0));
        assert!(cap.visible && cap.content == "center");
        assert!(
            !input(&world, form_input(0)).visible,
            "an enum has no editable text field"
        );
        let c = form_control_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&v, c[0] + 5.0, c[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::CycleField(0))
        );
        let big = [ref_field(CYCLE_MAX + 1)];
        let vb = view(&big);
        assert_eq!(
            hit_test(&vb, c[0] + 5.0, c[1] + 5.0, o, size(vb.form_fields.len())),
            Some(FormAction::OpenFieldDropdown(0)),
            "a large variant set opens a dropdown"
        );
    }

    // An open value dropdown is modal: its option rows pick (through the scroll
    // offset), anything else closes it.
    #[test]
    fn open_field_dropdown_picks_options_and_is_modal() {
        let o = test_origin();
        let fields = [ref_field(CYCLE_MAX + 3)];
        let mut v = view(&fields);
        v.field_dropdown = Some(0);
        let opt = field_option_rect(o, EDIT_W, 0, 2);
        assert_eq!(
            hit_test(&v, opt[0] + 5.0, opt[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::PickFieldOption(2))
        );
        let n = name_rect(o, EDIT_W);
        assert_eq!(
            hit_test(&v, n[0] + 5.0, n[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::CloseOverlays),
            "a click off the option list dismisses it"
        );
        v.field_dropdown_scroll = 3;
        let r0 = field_option_rect(o, EDIT_W, 0, 0);
        assert_eq!(
            hit_test(&v, r0[0] + 5.0, r0[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::PickFieldOption(3)),
            "visible row 0 is option `scroll + 0`"
        );
    }

    // Laying out an open dropdown shows its backing + option rows and hides the
    // slots it floats over (their opaque TextInput boxes would paint over it).
    #[test]
    fn open_dropdown_draws_over_the_slots_it_covers() {
        let mut world = injected_world();
        let fields = [
            ref_field(CYCLE_MAX + 2),
            field("intensity", FieldKind::Float),
        ];
        let mut v = view(&fields);
        v.field_dropdown = Some(0);
        apply(
            &mut world,
            Some(&v),
            test_origin(),
            size(v.form_fields.len()),
        );
        assert!(sprite_visible(&world, DROP_BG), "dropdown backing shows");
        assert!(sprite_visible(&world, drop_row_bg(0)), "option row shows");
        let opt0 = label(&world, drop_row_label(0));
        assert!(opt0.visible && opt0.content == form::NONE_LABEL);
        assert!(
            sprite_visible(&world, form_toggle_bg(0)),
            "the open field's button stays"
        );
        // The covered rows keep drawing: the dropdown is on its own layer (see
        // `overlay_ids`) and its opaque backing hides them.
        assert!(
            label(&world, form_row_label(1)).visible,
            "the covered slot was blanked instead of being drawn under the dropdown"
        );
        let declared = dropdown_ids();
        for id in [DROP_BG, drop_row_bg(0), drop_row_label(0)] {
            assert!(declared.contains(&id), "{id:?} is not declared an overlay");
        }
    }

    // An overlay that stops mid-row leaves the row under it half drawn, which
    // reads as clashing text rather than as one thing sitting over another.
    #[test]
    fn the_dropdown_backing_ends_on_a_field_row_boundary() {
        let o = test_origin();
        let w = EDIT_W;
        for slot in 0..4 {
            for shown in 1..=MAX_DROP_ROWS {
                let b = field_dropdown_backing(o, w, slot, shown);
                let bottom = b[1] + b[3];
                let rows = (bottom - fields_top(o)) / FIELD_H;
                assert!(
                    (rows - rows.round()).abs() < 0.01,
                    "slot {slot} shown {shown}: bottom {bottom} is {rows} rows down",
                );
                // Still tall enough for every option it draws.
                assert!(b[3] >= shown as f32 * DROP_ROW_H, "{b:?}");
            }
        }
    }

    // An array header renders its element count + red remove / green add buttons,
    // and the buttons hit-test to the add / remove actions.
    #[test]
    fn array_header_renders_count_and_buttons_and_hit_tests() {
        let o = test_origin();
        let mut world = injected_world();
        let fields = [FormField {
            key: "waves".into(),
            kind: FieldKind::Array,
            initial: String::new(),
            boolval: false,
            variants: Vec::new(),
            variant_idx: 3,
        }];
        let v = view(&fields);
        apply(&mut world, Some(&v), o, size(v.form_fields.len()));
        assert!(
            sprite_visible(&world, form_toggle_bg(0)),
            "add button shows"
        );
        assert!(
            sprite_visible(&world, form_swatch(0)),
            "remove button shows"
        );
        let cap = label(&world, form_enum_label(0));
        assert!(cap.visible && cap.content == "(3)");
        assert!(!input(&world, form_input(0)).visible);
        let add = array_add_rect(o, EDIT_W, 0);
        let rem = array_remove_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&v, add[0] + 3.0, add[1] + 3.0, o, size(v.form_fields.len())),
            Some(FormAction::AddArrayElement(0))
        );
        assert_eq!(
            hit_test(&v, rem[0] + 3.0, rem[1] + 3.0, o, size(v.form_fields.len())),
            Some(FormAction::RemoveArrayElement(0))
        );
    }

    // A validation error shows on the reserved status line; hiding the panel
    // blanks everything including the typed fields.
    #[test]
    fn error_line_shows_and_hide_all_blanks() {
        let fields = float_fields(1);
        let mut world = injected_world();
        let mut v = view(&fields);
        v.form_error = Some("Invalid argument");
        apply(
            &mut world,
            Some(&v),
            test_origin(),
            size(v.form_fields.len()),
        );
        let status = label(&world, FORM_STATUS);
        assert!(status.visible);
        assert_eq!(status.content, "Invalid argument");
        apply(&mut world, None, [0.0, 0.0], size(0));
        assert!(world.query::<Sprite>().all(|s| !s.visible));
        assert!(world.query::<TextLabel>().all(|l| !l.visible));
        assert!(world.query::<TextInput>().all(|t| !t.visible));
    }

    // The floating value dropdown draws above the slot chrome (insertion order).
    #[test]
    fn dropdown_is_injected_after_the_slot_chrome() {
        let sprites = all_sprite_ids();
        let spos = |id: AssetId| sprites.iter().position(|&x| x == id).unwrap();
        let last_slot = (0..form::FIELD_POOL_MAX)
            .map(form_toggle_bg)
            .chain((0..form::FIELD_POOL_MAX).map(form_swatch))
            .map(spos)
            .max()
            .unwrap();
        assert!(
            spos(DROP_BG) > last_slot,
            "dropdown backing above the slots"
        );
        let first_drop_row = (0..MAX_DROP_ROWS).map(drop_row_bg).map(spos).min().unwrap();
        assert!(spos(DROP_BG) < first_drop_row, "backing under its rows");
        let labels = all_label_ids();
        let lpos = |id: AssetId| labels.iter().position(|&x| x == id).unwrap();
        let last_slot_label = (0..form::FIELD_POOL_MAX)
            .map(form_row_label)
            .chain((0..form::FIELD_POOL_MAX).map(form_enum_label))
            .map(lpos)
            .max()
            .unwrap();
        for r in 0..MAX_DROP_ROWS {
            assert!(lpos(drop_row_label(r)) > last_slot_label);
        }
    }

    // A FormView with the value dropdown for logical field `open` disclosed.
    fn view_with_dropdown<'a>(
        fields: &'a [FormField],
        open: usize,
        mouse: [f32; 2],
    ) -> FormView<'a> {
        FormView {
            field_dropdown: Some(open),
            mouse,
            ..view(fields)
        }
    }

    // An enum field with a small (cycle-in-place) variant set.
    fn enum_field(key: &str, variants: &[&str]) -> FormField {
        FormField {
            key: key.into(),
            kind: FieldKind::Enum,
            initial: String::new(),
            boolval: false,
            variants: variants.iter().map(|s| s.to_string()).collect(),
            variant_idx: 0,
        }
    }

    #[test]
    fn open_dropdown_renders_its_options_and_a_scrollbar() {
        // 11 variants ((none) + tex_0..tex_9) overflow the 8-row window, so the
        // dropdown draws its scrollbar too.
        let fields = vec![ref_field(10)];
        let mut world = injected_world();
        let o = test_origin();
        apply(
            &mut world,
            Some(&view_with_dropdown(&fields, 0, [0.0, 0.0])),
            o,
            size(fields.len()),
        );
        assert!(sprite_visible(&world, DROP_BG));
        assert_eq!(label(&world, drop_row_label(0)).content, form::NONE_LABEL);
        assert!(sprite_visible(&world, DROP_TRACK), "scrollbar track shows");
        assert!(sprite_visible(&world, DROP_THUMB), "scrollbar thumb shows");
    }

    #[test]
    fn open_dropdown_hit_test_picks_or_dismisses() {
        // A short (non-scrolling) dropdown so the option scan reaches its end.
        let fields = vec![ref_field(2)];
        let o = test_origin();
        let v = view_with_dropdown(&fields, 0, [0.0, 0.0]);
        // Clicking an option row picks that variant.
        let opt = field_option_rect(o, EDIT_W, 0, 1);
        assert_eq!(
            hit_test(&v, opt[0] + 5.0, opt[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::PickFieldOption(1))
        );
        // Clicking off every option dismisses the dropdown.
        assert_eq!(
            hit_test(&v, 0.0, 0.0, o, size(v.form_fields.len())),
            Some(FormAction::CloseOverlays)
        );
    }

    #[test]
    fn control_click_opens_a_large_variant_dropdown() {
        // A ref field with more than CYCLE_MAX options opens a dropdown rather
        // than cycling in place.
        let fields = vec![ref_field(10)];
        let o = test_origin();
        let v = view(&fields);
        let c = form_control_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&v, c[0] + 5.0, c[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::OpenFieldDropdown(0))
        );
    }

    #[test]
    fn bool_enum_and_array_controls_hit_test() {
        let o = test_origin();

        // A bool field toggles from its checkbox rect.
        let bools = vec![field("flag", FieldKind::Bool)];
        let vb = view(&bools);
        let t = form_toggle_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&vb, t[0] + 3.0, t[1] + 3.0, o, size(vb.form_fields.len())),
            Some(FormAction::ToggleField(0))
        );

        // A small enum cycles in place from its control rect.
        let enums = vec![enum_field("mode", &["a", "b"])];
        let ve = view(&enums);
        let c = form_control_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&ve, c[0] + 5.0, c[1] + 5.0, o, size(ve.form_fields.len())),
            Some(FormAction::CycleField(0))
        );

        // An array header grows / shrinks from its + / - buttons.
        let arrays = vec![field("waves", FieldKind::Array)];
        let va = view(&arrays);
        let add = array_add_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(
                &va,
                add[0] + 3.0,
                add[1] + 3.0,
                o,
                size(va.form_fields.len())
            ),
            Some(FormAction::AddArrayElement(0))
        );
        let rem = array_remove_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(
                &va,
                rem[0] + 3.0,
                rem[1] + 3.0,
                o,
                size(va.form_fields.len())
            ),
            Some(FormAction::RemoveArrayElement(0))
        );
    }

    #[test]
    fn hit_test_consumes_a_click_past_the_scrolled_field_window() {
        // A scroll offset past the only field leaves the visible slot empty, so a
        // click there is swallowed rather than resolving to a control.
        let fields = float_fields(1);
        let v = FormView {
            form_scroll: 1,
            ..view(&fields)
        };
        let o = test_origin();
        let c = form_control_rect(o, EDIT_W, 0);
        assert_eq!(
            hit_test(&v, c[0] + 5.0, c[1] + 5.0, o, size(v.form_fields.len())),
            Some(FormAction::Consume)
        );
    }

    #[test]
    fn swatch_rgb_falls_back_and_clamps() {
        // Fewer than three parsed components yields the neutral placeholder.
        assert_eq!(swatch_rgb("1"), [0.15, 0.15, 0.18, 1.0]);
        assert_eq!(swatch_rgb("nope"), [0.15, 0.15, 0.18, 1.0]);
        // Three components clamp into the displayable range.
        assert_eq!(swatch_rgb("2, -1, 0.5"), [1.0, 0.0, 0.5, 1.0]);
    }
}