import { context, type WithRefOpts } from '../../provider';
import { boolToEmptyStrOrUndef, boolToStr } from '$adom';
import {
	readableActive,
	state,
	type Active,
	type ActiveProps,
	type StateProps
} from '$libs/reactive';
import type { SomaKeyboardEvent, SomaMouseEvent } from '../../types';
import { untrack } from 'svelte';
import { KEYS, getDirectionalKeys } from '../../keyboard';

function dbg(_label: string, _payload?: unknown): void {}

import { Soma } from '../../core/soma.svelte';
import { COMMAND_LANGS } from './langs';
import type { CommandFilterFn, CommandSnippetProps } from './types';

import { commandMorfo } from '../../../morfo/components/command';
import type { SomaRuntime, SomaRuntimePart } from '../../runtime.svelte';

// ── Registry shapes ──────────────────────────────────────────────────────────

interface ItemEntry {
	value: string;
	keywords: readonly string[];
	forceMount: boolean;
	disabled: boolean;
	groupValue: string | undefined;
	element: HTMLElement | null;
	score: number;
}

/** Shallow-equal for keyword arrays (identical length + same entries in order). */
function stringArrayEqual(
	a: readonly string[] | undefined,
	b: readonly string[] | undefined
): boolean {
	if (a === b) return true;
	if (!a || !b) return false;
	if (a.length !== b.length) return false;
	for (let i = 0; i < a.length; i++) if (a[i] !== b[i]) return false;
	return true;
}

/**
 * True when a patch would leave the entry unchanged. Compares primitives by
 * identity and `keywords` by content (since consumers often re-spread the
 * array on every render).
 */
function isEntryPatchNoop(entry: ItemEntry, patch: Partial<ItemEntry>): boolean {
	for (const key of Object.keys(patch) as (keyof ItemEntry)[]) {
		const next = patch[key];
		const prev = entry[key];
		if (key === 'keywords') {
			if (!stringArrayEqual(prev as readonly string[], next as readonly string[])) return false;
		} else if (next !== prev) {
			return false;
		}
	}
	return true;
}

interface GroupEntry {
	value: string;
	forceMount: boolean;
	itemValues: Set<string>;
}

// ── Root ─────────────────────────────────────────────────────────────────────

interface CommandOpts
	extends
		WithRefOpts,
		StateProps<{ value: string; search: string }>,
		ActiveProps<{
			label: string | undefined;
			shouldFilter: boolean;
			filter: CommandFilterFn;
			loop: boolean;
			vimBindings: boolean;
			columns: number;
			disablePointerSelection: boolean;
			dir: 'ltr' | 'rtl';
		}> {}

export class CommandProvider {
	readonly opts: CommandOpts;
	readonly runtimePart: SomaRuntimePart;
	readonly soma: Soma;
	readonly runtime: SomaRuntime;
	static readonly ctx = context<CommandProvider>('Command');
	static get(): CommandProvider | undefined {
		return this.ctx.getOr(undefined) as CommandProvider | undefined;
	}
	static require(): CommandProvider {
		return this.ctx.get();
	}

	static create(opts: CommandOpts) {
		return new CommandProvider(opts);
	}

	/**
	 * Plain storage + a version counter that increments synchronously on each
	 * mutation. Synchronous = consumer event handlers (clicks) see up-to-date
	 * state immediately. `isEntryPatchNoop` still short-circuits the patch
	 * effect to avoid loops when consumers pass new array literals for
	 * `keywords` on every render.
	 */
	private readonly _items: ItemEntry[] = [];
	private readonly itemIndex = new Map<string, number>();
	private readonly _groups: GroupEntry[] = [];
	private readonly groupIndex = new Map<string, number>();
	itemsVersion = $state(0);
	groupsVersion = $state(0);

	inputId = state('');
	listId = state('');

	private constructor(opts: CommandOpts) {
		this.opts = opts;
		this.soma = Soma.require();
		this.runtime = this.soma.runtime(commandMorfo, {});
		this.runtimePart = this.runtime.part('provider', {
			id: opts.id,
			ref: opts.ref,
			owner: this,
			context: CommandProvider.ctx
		});
		dbg('Provider.ctor');

		// Build the stable snippet props object. Getters read reactive state
		// lazily so the snapshot identity never changes across renders.
		const self = this;
		this.snippetProps = {
			get value() {
				return self.opts.value.current;
			},
			get search() {
				return self.opts.search.current;
			},
			get visible() {
				return self.visibleOrderedValues;
			},
			get isEmpty() {
				return self.isEmpty;
			},
			next: (step?: number) => self.next(step),
			prev: (step?: number) => self.prev(step),
			first: () => self.first(),
			last: () => self.last(),
			select: () => self.selectCurrent(),
			setValue: (value: string) => self.setValue(value),
			setSearch: (value: string) => {
				self.opts.search.current = value;
			},
			clearSearch: () => {
				self.opts.search.current = '';
			},
			isVisible: (value: string) => self.isVisible(value),
			isSelected: (value: string) => self.isSelected(value)
		};

		// When the filter changes (items added/removed or search changes), if
		// the current highlight falls out of the visible set, move it to the
		// first visible item. `$effect` + `untrack` avoids re-triggering on the
		// write we perform inside.
		$effect(() => {
			const values = this.visibleOrderedValues;
			dbg('Provider.autoSelect', { n: values.length });
			if (values.length === 0) return;
			untrack(() => {
				if (!values.includes(this.opts.value.current)) {
					this.opts.value.current = values[0];
				}
			});
		});
	}

	// ── Registration ──────────────────────────────────────────────────────────

	registerItem(entry: ItemEntry): void {
		dbg('registerItem', entry.value);
		this.itemIndex.set(entry.value, this._items.length);
		this._items.push(entry);
		this.itemsVersion++;
	}

	unregisterItem(value: string): void {
		dbg('unregisterItem', value);
		const idx = this.itemIndex.get(value);
		if (idx === undefined) return;
		this._items.splice(idx, 1);
		this.itemIndex.delete(value);
		for (let i = idx; i < this._items.length; i++) this.itemIndex.set(this._items[i].value, i);
		if (this.opts.value.current === value) {
			const visible = this.visibleOrderedValues;
			this.opts.value.current = visible[0] ?? '';
		}
		this.itemsVersion++;
	}

	registerGroup(entry: GroupEntry): void {
		this.groupIndex.set(entry.value, this._groups.length);
		this._groups.push(entry);
		this.groupsVersion++;
	}

	unregisterGroup(value: string): void {
		const idx = this.groupIndex.get(value);
		if (idx === undefined) return;
		this._groups.splice(idx, 1);
		this.groupIndex.delete(value);
		for (let i = idx; i < this._groups.length; i++) this.groupIndex.set(this._groups[i].value, i);
		this.groupsVersion++;
	}

	updateItem(value: string, patch: Partial<ItemEntry>): void {
		dbg('updateItem:call', value);
		const idx = this.itemIndex.get(value);
		if (idx === undefined) return;
		const entry = this._items[idx];
		if (isEntryPatchNoop(entry, patch)) {
			dbg('updateItem:noop', value);
			return;
		}
		dbg('updateItem:mutate', value);
		this._items[idx] = { ...entry, ...patch };
		this.itemsVersion++;
	}

	private findItem(value: string): ItemEntry | undefined {
		const idx = this.itemIndex.get(value);
		return idx !== undefined ? this._items[idx] : undefined;
	}

	private findGroup(value: string): GroupEntry | undefined {
		const idx = this.groupIndex.get(value);
		return idx !== undefined ? this._groups[idx] : undefined;
	}

	// ── Derived state ─────────────────────────────────────────────────────────

	/** Map of value → score after running the current filter. */
	readonly scores = $derived.by(() => {
		void this.itemsVersion;
		dbg('scores.derive', { items: this._items.length });
		const search = this.opts.search.current;
		const shouldFilter = this.opts.shouldFilter.current;
		const filterFn = this.opts.filter.current;
		const result = new Map<string, number>();
		for (const entry of this._items) {
			if (!shouldFilter || search === '') {
				result.set(entry.value, 1);
			} else {
				result.set(entry.value, filterFn(entry.value, search, entry.keywords));
			}
		}
		return result;
	});

	/** Ordered list of visible item values (score > 0 or forceMount). */
	readonly visibleOrderedValues = $derived.by(() => {
		void this.itemsVersion;
		dbg('visible.derive', { items: this._items.length });
		const result: string[] = [];
		for (const entry of this._items) {
			const score = this.scores.get(entry.value) ?? 0;
			if (entry.forceMount || score > 0) result.push(entry.value);
		}
		return result;
	});

	/**
	 * Precomputed visibility set — the hot path for per-item `isVisible`.
	 *
	 * Items consult this with `visibleSet.has(value)` (O(1)) instead of calling
	 * `provider.isVisible(value)` per item. Calling the method meant every
	 * Item's `$derived` subscribed to `itemsVersion` directly, so each bump
	 * re-ran *all* items' derivations (O(N²) cascade). With the Set, items
	 * subscribe to a single signal and each derivation is an O(1) lookup;
	 * Svelte only invalidates an Item's dependents when its boolean result
	 * actually flips.
	 */
	readonly visibleSet = $derived.by(() => {
		void this.itemsVersion;
		const scores = this.scores;
		const result = new Set<string>();
		for (const entry of this._items) {
			if (entry.forceMount || (scores.get(entry.value) ?? 0) > 0) result.add(entry.value);
		}
		return result;
	});

	/** True when no item survives the filter. */
	readonly isEmpty = $derived.by(() => {
		dbg('isEmpty.derive');
		return this.visibleOrderedValues.length === 0;
	});

	/**
	 * Imperative visibility query (used by the snippet API and navigation
	 * helpers). Reads from the precomputed `visibleSet` so callers subscribe
	 * to a single signal and the per-call cost is O(1).
	 */
	isVisible(value: string): boolean {
		return this.visibleSet.has(value);
	}

	isSelected(value: string): boolean {
		return this.opts.value.current === value;
	}

	/**
	 * True when the group contains at least one visible item.
	 *
	 * Note: we intentionally walk `_items` (not `group.itemValues`) because the
	 * registration order is not guaranteed. Items can register BEFORE the
	 * group exists — e.g. when Svelte runs child effects before parent ones.
	 * In that case `group.itemValues` would stay empty and the group would
	 * never show its children. Iterating items keeps this robust regardless
	 * of mount order.
	 */
	groupHasVisibleItems(groupValue: string): boolean {
		void this.groupsVersion;
		void this.itemsVersion;
		const gIdx = this.groupIndex.get(groupValue);
		if (gIdx === undefined) return false;
		const group = this._groups[gIdx];
		if (!group) return false;
		if (group.forceMount) return true;
		const visible = this.visibleSet;
		for (const item of this._items) {
			if (item.groupValue === groupValue && visible.has(item.value)) return true;
		}
		return false;
	}

	// ── Navigation ────────────────────────────────────────────────────────────

	private indexOfSelected(): number {
		return this.visibleOrderedValues.indexOf(this.opts.value.current);
	}

	private setSelectedByIndex(i: number): void {
		const values = this.visibleOrderedValues;
		if (values.length === 0) return;
		const clamped = this.opts.loop.current
			? ((i % values.length) + values.length) % values.length
			: Math.max(0, Math.min(values.length - 1, i));
		const next = values[clamped];
		if (next && next !== this.opts.value.current) this.opts.value.current = next;
	}

	next(step = 1): void {
		const idx = this.indexOfSelected();
		this.setSelectedByIndex(idx === -1 ? 0 : idx + step);
	}
	prev(step = 1): void {
		const idx = this.indexOfSelected();
		this.setSelectedByIndex(idx === -1 ? 0 : idx - step);
	}
	first(): void {
		this.setSelectedByIndex(0);
	}
	last(): void {
		this.setSelectedByIndex(this.visibleOrderedValues.length - 1);
	}
	setValue(value: string): void {
		if (this.isVisible(value)) this.opts.value.current = value;
	}

	selectCurrent(): void {
		const value = this.opts.value.current;
		const entry = this.findItem(value);
		if (!entry || entry.disabled || !this.isVisible(value)) return;
		this.onSelectHandlers.get(value)?.(value);
		// Morfo: commit-submit-invoke on `item`. Look up the item element
		// by data-value so the cascade matches this specific item (Enter
		// key path — onclick handler emits independently for mouse path).
		const itemEl = this.opts.ref?.current?.querySelector<HTMLElement>(
			`[${attrs.item}][data-value="${CSS.escape(value)}"]`
		);
		if (itemEl) {
			void this.runtime.trigger('commit-submit-invoke', { fallbackTarget: itemEl });
		}
	}

	private onSelectHandlers = new Map<string, (v: string) => void>();
	registerOnSelect(value: string, fn: (v: string) => void): void {
		this.onSelectHandlers.set(value, fn);
	}
	unregisterOnSelect(value: string): void {
		this.onSelectHandlers.delete(value);
	}

	/**
	 * Snippet props surface. Reactive fields are exposed via getters so the
	 * snapshot object itself is a stable reference — only the individual
	 * getters notify consumers. This avoids invalidating `snippetProps`
	 * whenever `value` / `search` / `visible` changes, which would otherwise
	 * cause the `children` snippet to re-run on every tick.
	 */
	readonly snippetProps: CommandSnippetProps;

	readonly props = $derived.by(() =>
		this.runtimePart.assert({ ...this.runtimePart.props, dir: this.opts.dir.current } as const)
	);
}

// ── Input (role="combobox") ──────────────────────────────────────────────────

interface CommandInputOpts extends WithRefOpts {}

export class CommandInputProvider {
	readonly opts: CommandInputOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandInputOpts) {
		return new CommandInputProvider(opts);
	}

	readonly provider: CommandProvider;

	private constructor(opts: CommandInputOpts) {
		this.opts = opts;
		this.provider = CommandProvider.require();
		this.runtimePart = this.provider.runtime.part('input', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
		this.provider.inputId.current = opts.id.current;
	}

	readonly oninput = (e: Event) => {
		const target = e.currentTarget as HTMLInputElement;
		this.provider.opts.search.current = target.value;
	};

	readonly onkeydown = (e: SomaKeyboardEvent<HTMLInputElement>) => {
		const columns = Math.max(1, this.provider.opts.columns.current);
		const vim = this.provider.opts.vimBindings.current;
		// In RTL, ArrowLeft moves forward and ArrowRight moves backward.
		const { nextKey: horizNext, prevKey: horizPrev } = getDirectionalKeys(
			this.provider.opts.dir.current,
			'horizontal'
		);

		if (e.key === KEYS.ARROW_DOWN) {
			e.preventDefault();
			this.provider.next(columns);
			return;
		}
		if (e.key === KEYS.ARROW_UP) {
			e.preventDefault();
			this.provider.prev(columns);
			return;
		}
		if (e.key === horizNext && columns > 1) {
			e.preventDefault();
			this.provider.next(1);
			return;
		}
		if (e.key === horizPrev && columns > 1) {
			e.preventDefault();
			this.provider.prev(1);
			return;
		}
		if (e.key === KEYS.HOME && !e.shiftKey) {
			e.preventDefault();
			this.provider.first();
			return;
		}
		if (e.key === KEYS.END && !e.shiftKey) {
			e.preventDefault();
			this.provider.last();
			return;
		}
		if (e.key === KEYS.ENTER) {
			e.preventDefault();
			this.provider.selectCurrent();
			return;
		}
		if (vim && e.ctrlKey) {
			if (e.key === 'n' || e.key === 'j') {
				e.preventDefault();
				this.provider.next(1);
				return;
			}
			if (e.key === 'p' || e.key === 'k') {
				e.preventDefault();
				this.provider.prev(1);
				return;
			}
		}
	};

	readonly props = $derived.by(() => {
		const selected = this.provider.opts.value.current;
		const listId = this.provider.listId.current;
		return this.runtimePart.assert({
			...this.runtimePart.props,
			type: 'text' as const,
			role: 'combobox' as const,
			autocomplete: 'off' as const,
			autocorrect: 'off' as const,
			spellcheck: false,
			'aria-autocomplete': 'list' as const,
			'aria-expanded': true as const,
			'aria-controls': listId || undefined,
			'aria-activedescendant': selected ? `${listId}-item-${cssSafe(selected)}` : undefined,
			value: this.provider.opts.search.current,
			oninput: this.oninput,
			onkeydown: this.onkeydown
		} as const);
	});
}

// Escape a value to produce a deterministic id suffix.
function cssSafe(v: string): string {
	return v.replace(/[^a-zA-Z0-9_-]/g, '_');
}

// ── List (role="listbox") ───────────────────────────────────────────────────

interface CommandListOpts extends WithRefOpts {}

export class CommandListProvider {
	readonly opts: CommandListOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandListOpts) {
		return new CommandListProvider(opts);
	}

	readonly provider: CommandProvider;

	private constructor(opts: CommandListOpts) {
		this.opts = opts;
		this.provider = CommandProvider.require();
		this.runtimePart = this.provider.runtime.part('list', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
		this.provider.listId.current = opts.id.current;
	}

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			role: 'listbox' as const,
			'aria-label':
				this.provider.opts.label.current ?? this.provider.soma.langs.ts(COMMAND_LANGS.LIST)
		} as const)
	);
}

// ── Viewport — exposes --command-list-height ───────────────────────────

interface CommandViewportOpts extends WithRefOpts {}

export class CommandViewportProvider {
	readonly opts: CommandViewportOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandViewportOpts) {
		return new CommandViewportProvider(opts);
	}

	height = $state<number | undefined>(undefined);

	private constructor(opts: CommandViewportOpts) {
		this.opts = opts;
		const provider = CommandProvider.require();
		this.runtimePart = provider.runtime.part('viewport', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});

		$effect(() => {
			const el = opts.ref.current;
			if (!el) return;
			const child = el.firstElementChild as HTMLElement | null;
			if (!child) return;
			return provider.soma.dom.observeResize(child, ([entry]) => {
				this.height = entry?.borderBoxSize?.[0]?.blockSize ?? entry?.contentRect.height;
			});
		});
	}

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			style: this.height !== undefined ? `--command-list-height: ${this.height}px;` : undefined
		} as const)
	);
}

// ── Item (role="option") ────────────────────────────────────────────────────

interface CommandItemOpts
	extends
		WithRefOpts,
		ActiveProps<{
			value: string;
			keywords: readonly string[] | string[];
			disabled: boolean;
			forceMount: boolean;
			onSelect: ((v: string) => void) | undefined;
		}> {}

export class CommandItemProvider {
	readonly opts: CommandItemOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandItemOpts) {
		return new CommandItemProvider(opts);
	}

	readonly provider: CommandProvider;
	readonly group: CommandGroupProvider | undefined;

	private constructor(opts: CommandItemOpts) {
		this.opts = opts;
		this.provider = CommandProvider.require();
		this.group = CommandGroupProvider.get();
		this.runtimePart = this.provider.runtime.part('item', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
		dbg('Item.ctor', opts.value.current);

		const groupValue = this.group?.opts.value.current;

		// Register ONCE per item identity. EVERYTHING except `opts.value.current`
		// must go through `untrack` — including the `registerItem` call itself,
		// because its internal reads (items.length, items.push) are reactive
		// reads on the $state array. Without untrack, the effect subscribes to
		// items.length; pushing this very item then re-runs the effect →
		// cleanup → re-register → loop.
		$effect(() => {
			const value = opts.value.current;
			dbg('Item.fx1.register', value);
			untrack(() => {
				const initial = {
					keywords: opts.keywords.current,
					forceMount: opts.forceMount.current,
					disabled: opts.disabled.current,
					element: opts.ref.current
				};
				this.provider.registerItem({ value, groupValue, score: 0, ...initial });
				const handler = opts.onSelect.current;
				if (handler) this.provider.registerOnSelect(value, handler);
			});

			return () => {
				dbg('Item.fx1.cleanup', value);
				untrack(() => {
					this.provider.unregisterItem(value);
					this.provider.unregisterOnSelect(value);
				});
			};
		});

		// Patch mutable props. Item identity (`opts.value`) is read via
		// `untrack` so a value change doesn't call `updateItem` with the new
		// id (there's no entry for it yet — the registration effect handles
		// it).
		$effect(() => {
			const keywords = opts.keywords.current;
			const disabled = opts.disabled.current;
			const forceMount = opts.forceMount.current;
			dbg('Item.fx2.patch');
			untrack(() => {
				this.provider.updateItem(opts.value.current, { keywords, disabled, forceMount });
			});
		});

		// Keep the onSelect handler fresh without re-registering the item.
		$effect(() => {
			const handler = opts.onSelect.current;
			const value = untrack(() => opts.value.current);
			dbg('Item.fx3.handler', value);
			if (handler) this.provider.registerOnSelect(value, handler);
			else this.provider.unregisterOnSelect(value);
		});
	}

	readonly isSelected = $derived.by(() => this.provider.isSelected(this.opts.value.current));
	readonly isVisible = $derived.by(() => this.provider.visibleSet.has(this.opts.value.current));

	readonly onclick = (e: SomaMouseEvent<HTMLElement>) => {
		if (this.opts.disabled.current) return;
		this.provider.setValue(this.opts.value.current);
		this.opts.onSelect.current?.(this.opts.value.current);
		// Morfo: commit-submit-invoke on `item` (affirm). Fire with the
		// clicked element so the cascade matches this specific item.
		void this.provider.runtime.trigger('commit-submit-invoke', {
			fallbackTarget: e.currentTarget
		});
	};

	readonly onpointermove = () => {
		if (this.provider.opts.disablePointerSelection.current) return;
		if (this.opts.disabled.current) return;
		this.provider.setValue(this.opts.value.current);
	};

	readonly idForAria = $derived.by(
		() => `${this.provider.listId.current}-item-${cssSafe(this.opts.value.current)}`
	);

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			id: this.idForAria,
			role: 'option' as const,
			'aria-selected': this.isSelected,
			'aria-disabled': boolToStr(this.opts.disabled.current),
			'data-selected': boolToEmptyStrOrUndef(this.isSelected),
			'data-disabled': boolToEmptyStrOrUndef(this.opts.disabled.current),
			'data-value': this.opts.value.current,
			onclick: this.onclick,
			onpointermove: this.onpointermove
		} as const)
	);
}

// ── LinkItem — same semantics but renders <a> ───────────────────────────────

interface CommandLinkItemOpts
	extends
		WithRefOpts,
		ActiveProps<{
			value: string;
			keywords: readonly string[] | string[];
			disabled: boolean;
			forceMount: boolean;
			href: string;
			onSelect: ((v: string) => void) | undefined;
		}> {}

export class CommandLinkItemProvider {
	readonly opts: CommandLinkItemOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandLinkItemOpts) {
		return new CommandLinkItemProvider(opts);
	}

	readonly provider: CommandProvider;
	readonly group: CommandGroupProvider | undefined;

	private constructor(opts: CommandLinkItemOpts) {
		this.opts = opts;
		this.provider = CommandProvider.require();
		this.group = CommandGroupProvider.get();
		this.runtimePart = this.provider.runtime.part('link-item', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
		const groupValue = this.group?.opts.value.current;

		// See the matching block in CommandItemProvider: register once per
		// identity, with the whole register/unregister call wrapped in untrack
		// so the effect doesn't subscribe to items.length via the internal
		// $state array reads (that would loop).
		$effect(() => {
			const value = opts.value.current;
			untrack(() => {
				const initial = {
					keywords: opts.keywords.current,
					forceMount: opts.forceMount.current,
					disabled: opts.disabled.current,
					element: opts.ref.current
				};
				this.provider.registerItem({ value, groupValue, score: 0, ...initial });
				const handler = opts.onSelect.current;
				if (handler) this.provider.registerOnSelect(value, handler);
			});
			return () => {
				untrack(() => {
					this.provider.unregisterItem(value);
					this.provider.unregisterOnSelect(value);
				});
			};
		});

		$effect(() => {
			const keywords = opts.keywords.current;
			const disabled = opts.disabled.current;
			const forceMount = opts.forceMount.current;
			untrack(() => {
				this.provider.updateItem(opts.value.current, { keywords, disabled, forceMount });
			});
		});

		$effect(() => {
			const handler = opts.onSelect.current;
			const value = untrack(() => opts.value.current);
			if (handler) this.provider.registerOnSelect(value, handler);
			else this.provider.unregisterOnSelect(value);
		});
	}

	readonly isSelected = $derived.by(() => this.provider.isSelected(this.opts.value.current));
	readonly isVisible = $derived.by(() => this.provider.visibleSet.has(this.opts.value.current));

	readonly onclick = (e: SomaMouseEvent<HTMLElement>) => {
		if (this.opts.disabled.current) {
			e.preventDefault();
			return;
		}
		this.opts.onSelect.current?.(this.opts.value.current);
	};

	readonly onpointermove = () => {
		if (this.provider.opts.disablePointerSelection.current) return;
		if (this.opts.disabled.current) return;
		this.provider.setValue(this.opts.value.current);
	};

	readonly idForAria = $derived.by(
		() => `${this.provider.listId.current}-item-${cssSafe(this.opts.value.current)}`
	);

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			id: this.idForAria,
			role: 'option' as const,
			href: this.opts.href.current,
			'aria-selected': this.isSelected,
			'aria-disabled': boolToStr(this.opts.disabled.current),
			'data-selected': boolToEmptyStrOrUndef(this.isSelected),
			'data-disabled': boolToEmptyStrOrUndef(this.opts.disabled.current),
			'data-value': this.opts.value.current,
			onclick: this.onclick,
			onpointermove: this.onpointermove
		} as const)
	);
}

// ── Group ────────────────────────────────────────────────────────────────────

interface CommandGroupOpts
	extends WithRefOpts, ActiveProps<{ value: string; forceMount: boolean }> {}

export class CommandGroupProvider {
	readonly opts: CommandGroupOpts;
	readonly runtimePart: SomaRuntimePart;
	static readonly ctx = context<CommandGroupProvider>('CommandGroup');
	static get(): CommandGroupProvider | undefined {
		return this.ctx.getOr(undefined) as CommandGroupProvider | undefined;
	}
	static require(): CommandGroupProvider {
		return this.ctx.get();
	}

	static create(opts: CommandGroupOpts) {
		return new CommandGroupProvider(opts);
	}

	readonly provider: CommandProvider;
	headingId = state('');

	private constructor(opts: CommandGroupOpts) {
		this.opts = opts;
		this.provider = CommandProvider.require();
		this.runtimePart = this.provider.runtime.part('group', {
			id: opts.id,
			ref: opts.ref,
			owner: this,
			context: CommandGroupProvider.ctx
		});

		// Register ONCE per group identity. The register/unregister calls read
		// from the reactive `groups` array internally, so wrap in untrack to
		// avoid subscribing this effect to items.length (would loop on mount).
		$effect(() => {
			const value = opts.value.current;
			untrack(() => {
				const forceMount = opts.forceMount.current;
				this.provider.registerGroup({ value, forceMount, itemValues: new Set() });
			});
			return () => untrack(() => this.provider.unregisterGroup(value));
		});
	}

	readonly hasVisibleItems = $derived.by(() =>
		this.provider.groupHasVisibleItems(this.opts.value.current)
	);

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			role: 'group' as const,
			'aria-labelledby': this.headingId.current || undefined,
			'data-empty': boolToEmptyStrOrUndef(!this.hasVisibleItems)
		} as const)
	);
}

// ── GroupHeading ─────────────────────────────────────────────────────────────

interface CommandGroupHeadingOpts extends WithRefOpts {}

export class CommandGroupHeadingProvider {
	readonly opts: CommandGroupHeadingOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandGroupHeadingOpts) {
		return new CommandGroupHeadingProvider(opts);
	}

	readonly group: CommandGroupProvider;

	private constructor(opts: CommandGroupHeadingOpts) {
		this.opts = opts;
		this.group = CommandGroupProvider.require();
		this.runtimePart = this.group.provider.runtime.part('group-heading', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
		this.group.headingId.current = opts.id.current;
	}

	readonly props = $derived.by(() =>
		this.runtimePart.assert({ ...this.runtimePart.props, 'aria-hidden': true as const } as const)
	);
}

// ── GroupItems ───────────────────────────────────────────────────────────────

interface CommandGroupItemsOpts extends WithRefOpts {}

export class CommandGroupItemsProvider {
	readonly opts: CommandGroupItemsOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandGroupItemsOpts) {
		return new CommandGroupItemsProvider(opts);
	}

	private constructor(opts: CommandGroupItemsOpts) {
		this.opts = opts;
		const group = CommandGroupProvider.require();
		this.runtimePart = group.provider.runtime.part('group-items', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
	}

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			role: 'presentation' as const
		} as const)
	);
}

// ── Empty ────────────────────────────────────────────────────────────────────

interface CommandEmptyOpts extends WithRefOpts {}

export class CommandEmptyProvider {
	readonly opts: CommandEmptyOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandEmptyOpts) {
		return new CommandEmptyProvider(opts);
	}

	readonly provider: CommandProvider;

	private constructor(opts: CommandEmptyOpts) {
		this.opts = opts;
		this.provider = CommandProvider.require();
		this.runtimePart = this.provider.runtime.part('empty', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
	}

	readonly shouldRender = $derived.by(() => this.provider.isEmpty);

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			role: 'status' as const,
			'aria-live': 'polite' as const
		} as const)
	);
}

// ── Loading ──────────────────────────────────────────────────────────────────

interface CommandLoadingOpts extends WithRefOpts, ActiveProps<{ progress: number | undefined }> {}

export class CommandLoadingProvider {
	readonly opts: CommandLoadingOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandLoadingOpts) {
		return new CommandLoadingProvider(opts);
	}

	private constructor(opts: CommandLoadingOpts) {
		this.opts = opts;
		const provider = CommandProvider.require();
		this.runtimePart = provider.runtime.part('loading', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
	}

	readonly percent: Active<number | undefined> = readableActive(() => {
		const v = this.opts.progress.current;
		if (v === undefined) return undefined;
		return Math.min(100, Math.max(0, v));
	});

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			role: 'progressbar' as const,
			'aria-valuemin': 0,
			'aria-valuemax': 100,
			'aria-valuenow': this.percent.current,
			'data-value': this.percent.current
		} as const)
	);
}

// ── Separator ────────────────────────────────────────────────────────────────

interface CommandSeparatorOpts extends WithRefOpts, ActiveProps<{ forceMount: boolean }> {}

export class CommandSeparatorProvider {
	readonly opts: CommandSeparatorOpts;
	readonly runtimePart: SomaRuntimePart;
	static create(opts: CommandSeparatorOpts) {
		return new CommandSeparatorProvider(opts);
	}

	readonly provider: CommandProvider;

	private constructor(opts: CommandSeparatorOpts) {
		this.opts = opts;
		this.provider = CommandProvider.require();
		this.runtimePart = this.provider.runtime.part('separator', {
			id: opts.id,
			ref: opts.ref,
			owner: this
		});
	}

	/** Hide the separator when the palette has no visible items, unless forced. */
	readonly shouldRender = $derived.by(() => this.opts.forceMount.current || !this.provider.isEmpty);

	readonly props = $derived.by(() =>
		this.runtimePart.assert({
			...this.runtimePart.props,
			role: 'separator' as const,
			'aria-orientation': 'horizontal' as const
		} as const)
	);
}