import type { JSX } from "@solidjs/web";
import { type Accessor, createContext, createMemo, useContext } from "solid-js";
import { createPopupCore } from "../internals/create-popup-core";
import { type MaybeAccessor, readOption } from "../internals/maybe-accessor";
import {
	SNAPSHOT_KEYS,
	type Snapshottable,
	snapshotKeys,
} from "../internals/observability/snapshot";

/**
 * Why the popover's open state changed.
 *
 * - `"trigger-press"` — trigger was clicked or keyboard-activated.
 * - `"escape-key"` — Escape dismissed the popover.
 * - `"outside-press"` — pointer pressed outside.
 * - `"close-button"` — `<Popover.Close>` was pressed.
 * - `"imperative"` — `p.setOpen()` called programmatically.
 */
export type PopoverChangeReason =
	| "trigger-press"
	| "escape-key"
	| "outside-press"
	| "close-button"
	| "imperative";

import type { PopoverModalKind } from "./popover-root-context";

export type { PopoverModalKind };

/**
 * Options for {@link createPopover}.
 */
export interface CreatePopoverOptions {
	/**
	 * Open state. Consumer-owned signal.
	 */
	open: MaybeAccessor<boolean>;
	/**
	 * Whether interaction is suppressed.
	 * @default false
	 */
	disabled?: MaybeAccessor<boolean>;
	/**
	 * Modal surface kind.
	 * @default false
	 */
	modal?: MaybeAccessor<PopoverModalKind>;
	/**
	 * Pre-change callback fired via `runWithOwner(null, ...)`.
	 */
	onOpenChange?: (
		open: boolean,
		event: Event,
		reason: PopoverChangeReason,
	) => void;
}

/**
 * Public API returned by {@link createPopover}.
 */
export interface PopoverApi {
	/** Reactive accessor for the current open state. */
	open: Accessor<boolean>;
	/** Whether interaction is suppressed. */
	disabled: Accessor<boolean>;
	/** Modal surface kind. */
	modal: Accessor<PopoverModalKind>;

	/** Imperative open setter. */
	setOpen: (next: boolean, event?: Event, reason?: PopoverChangeReason) => void;
	/** Flip open (no-op when disabled). */
	toggle: (event?: Event, reason?: PopoverChangeReason) => void;

	/** Context provider. */
	Provider: (props: { children: JSX.Element }) => JSX.Element;
}

const PopoverContext = createContext<PopoverApi | null>(null);

/**
 * Read the nearest {@link PopoverApi}. Throws unless `optional` is true.
 */
export function usePopover(): PopoverApi;
export function usePopover(optional: true): PopoverApi | null;
export function usePopover(optional?: boolean): PopoverApi | null {
	const ctx = useContext(PopoverContext);
	if (ctx == null && !optional) {
		throw new Error(
			"Base UI: usePopover() must be called inside a <p.Provider>.",
		);
	}
	return ctx;
}

/**
 * Headless primitive for a popover compound. Owns logical state — open,
 * disabled, modal kind. DOM machinery lives in `<Popover.Root>`.
 */
export function createPopover(options: CreatePopoverOptions): PopoverApi {
	const core = createPopupCore<PopoverChangeReason>({
		open: options.open,
		disabled: options.disabled,
		onOpenChange: options.onOpenChange,
	});

	const modal = createMemo<PopoverModalKind>(
		() => readOption(options.modal) ?? false,
		{ name: "popover.modal" },
	);

	const api: PopoverApi = {
		open: core.open,
		disabled: core.disabled,
		modal,
		setOpen: core.setOpen,
		toggle: core.toggle,
		Provider: (props) => (
			<PopoverContext value={api}>{props.children}</PopoverContext>
		),
	};

	(api as PopoverApi & Snapshottable)[SNAPSHOT_KEYS] = POPOVER_SNAPSHOT_KEYS;

	return api;
}

const POPOVER_SNAPSHOT_KEYS = snapshotKeys<PopoverApi>(
	"open",
	"disabled",
	"modal",
);