import type { JSX } from "@solidjs/web";

import { type Accessor, createContext, useContext } from "solid-js";
import type { MutableRef } from "../../internals/floating-ui/types";

/** `side` values reported by floating-ui's `placement.split('-')[0]`. */
export type PopoverSide =
	| "top"
	| "right"
	| "bottom"
	| "left"
	| "inline-start"
	| "inline-end";

/** `align` values mapped from floating-ui's placement suffix. */
export type PopoverAlign = "start" | "center" | "end";

/**
 * Shared positioning state produced by the positioner and consumed by the
 * arrow + popup for their own reactive `side` / `align` data-attrs and for
 * the arrow's absolute-position styles.
 *
 * Mirrors Base UI React's `PopoverPositionerContext`.
 */
export interface PopoverPositionerContextValue {
	/** Resolved side (`'top'`, `'bottom'`, ...) from the placement. */
	side: Accessor<PopoverSide>;
	/** Resolved align (`'start'`, `'center'`, `'end'`) from the placement. */
	align: Accessor<PopoverAlign>;
	/** Whether the anchor has been scrolled out of view. */
	anchorHidden: Accessor<boolean>;
	/**
	 * Arrow element ref slot. `<Popover.Arrow>` writes to this on mount so
	 * the arrow middleware can read the element dimensions on next update.
	 */
	arrowRef: MutableRef<HTMLElement | null>;
	/** Reactive absolute-position styles for the arrow element. */
	arrowStyles: Accessor<JSX.CSSProperties>;
	/** Whether the arrow is visually off-center (too close to a collision edge). */
	arrowUncentered: Accessor<boolean>;
}

export const PopoverPositionerContext =
	createContext<PopoverPositionerContextValue | null>(null);

/**
 * Read the current `<Popover.Positioner>` context. Throws unless the
 * consumer is rendered inside a positioner.
 */
export function usePopoverPositionerContext(): PopoverPositionerContextValue {
	const context = useContext(PopoverPositionerContext);
	if (context == null) {
		throw new Error(
			"Base UI: PopoverPositionerContext is missing. Popover.Arrow and Popover.Popup must be placed inside <Popover.Positioner>.",
		);
	}
	return context;
}