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 dialog's open state changed.
 *
 * - `"trigger-press"` — trigger was clicked or keyboard-activated.
 * - `"escape-key"` — Escape dismissed the dialog.
 * - `"outside-press"` — pointer pressed outside (when enabled).
 * - `"close-button"` — `<Dialog.Close>` was pressed.
 * - `"imperative"` — `d.setOpen()` called programmatically.
 */
export type DialogChangeReason =
	| "trigger-press"
	| "escape-key"
	| "outside-press"
	| "close-button"
	| "imperative";

import type { DialogModalKind } from "./dialog-root-context";

export type { DialogModalKind };

/**
 * Options for {@link createDialog}.
 */
export interface CreateDialogOptions {
	/**
	 * Open state. Consumer-owned signal.
	 */
	open: MaybeAccessor<boolean>;
	/**
	 * Whether interaction is suppressed.
	 * @default false
	 */
	disabled?: MaybeAccessor<boolean>;
	/**
	 * Modal surface kind.
	 * @default true
	 */
	modal?: MaybeAccessor<DialogModalKind>;
	/**
	 * When true, outside-press dismissal is disabled.
	 * @default false
	 */
	disablePointerDismissal?: MaybeAccessor<boolean>;
	/**
	 * Pre-change callback fired via `runWithOwner(null, ...)`.
	 */
	onOpenChange?: (
		open: boolean,
		event: Event,
		reason: DialogChangeReason,
	) => void;
}

/**
 * Public API returned by {@link createDialog}.
 */
export interface DialogApi {
	/** Reactive accessor for the current open state. */
	open: Accessor<boolean>;
	/** Whether interaction is suppressed. */
	disabled: Accessor<boolean>;
	/** Modal surface kind. */
	modal: Accessor<DialogModalKind>;
	/** Whether outside-press dismissal is disabled. */
	disablePointerDismissal: Accessor<boolean>;

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

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

const DialogContext = createContext<DialogApi | null>(null);

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

/**
 * Headless primitive for a dialog compound. Modal by default. Configurable
 * outside-press dismissal. DOM machinery lives in `<Dialog.Root>`.
 */
export function createDialog(options: CreateDialogOptions): DialogApi {
	const core = createPopupCore<DialogChangeReason>({
		open: options.open,
		disabled: options.disabled,
		onOpenChange: options.onOpenChange,
	});

	const modal = createMemo<DialogModalKind>(
		() => readOption(options.modal) ?? true,
		{ name: "dialog.modal" },
	);

	const disablePointerDismissal = createMemo<boolean>(
		() => Boolean(readOption(options.disablePointerDismissal)),
		{ name: "dialog.disablePointerDismissal" },
	);

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

	(api as DialogApi & Snapshottable)[SNAPSHOT_KEYS] = DIALOG_SNAPSHOT_KEYS;

	return api;
}

const DIALOG_SNAPSHOT_KEYS = snapshotKeys<DialogApi>(
	"open",
	"disabled",
	"modal",
	"disablePointerDismissal",
);