/*
 * Portions of this file are based on code from react-spectrum.
 * Apache License Version 2.0, Copyright 2020 Adobe.
 *
 * Credits to the React Spectrum team:
 * https://github.com/adobe/react-spectrum/blob/bfce84fee12a027d9cbc38b43e1747e3e4b4b169/packages/@react-stately/selection/src/useMultipleSelectionState.ts
 */

import { type MaybeAccessor, access, mergeDefaultProps } from "@kobalte/utils";
import { createEffect, createMemo, createSignal } from "solid-js";

import { createControllableSelectionSignal } from "./create-controllable-selection-signal";
import {
	type MultipleSelection,
	type MultipleSelectionState,
	Selection,
	type SelectionBehavior,
} from "./types";
import { convertSelection, isSameSelection } from "./utils";

export interface CreateMultipleSelectionStateProps extends MultipleSelection {
	/** How multiple selection should behave in the collection. */
	selectionBehavior?: MaybeAccessor<SelectionBehavior | undefined>;

	/** Whether onSelectionChange should fire even if the new set of keys is the same as the last. */
	allowDuplicateSelectionEvents?: MaybeAccessor<boolean | undefined>;
}

/**
 * Manages state for multiple selection and focus in a collection.
 */
export function createMultipleSelectionState(
	props: CreateMultipleSelectionStateProps,
): MultipleSelectionState {
	const mergedProps = mergeDefaultProps(
		{
			selectionMode: "none",
			selectionBehavior: "toggle",
		},
		props,
	);

	const [isFocused, setFocused] = createSignal(false);
	const [focusedKey, setFocusedKey] = createSignal<string>();

	const selectedKeysProp = createMemo(() => {
		const selection = access(mergedProps.selectedKeys);

		if (selection != null) {
			return convertSelection(selection);
		}

		return selection;
	});

	const defaultSelectedKeys = createMemo(() => {
		const defaultSelection = access(mergedProps.defaultSelectedKeys);

		if (defaultSelection != null) {
			return convertSelection(defaultSelection);
		}

		return new Selection();
	});

	const [selectedKeys, _setSelectedKeys] = createControllableSelectionSignal({
		value: selectedKeysProp,
		defaultValue: defaultSelectedKeys,
		onChange: (value) => mergedProps.onSelectionChange?.(value),
	});

	const [selectionBehavior, setSelectionBehavior] =
		createSignal<SelectionBehavior>(access(mergedProps.selectionBehavior)!);

	const selectionMode = () => access(mergedProps.selectionMode)!;
	const disallowEmptySelection = () =>
		access(mergedProps.disallowEmptySelection) ?? false;

	const setSelectedKeys = (keys: Set<string>) => {
		if (
			access(mergedProps.allowDuplicateSelectionEvents) ||
			!isSameSelection(keys, selectedKeys())
		) {
			_setSelectedKeys(keys);
		}
	};

	// If the selectionBehavior prop is set to replace, but the current state is toggle (e.g. due to long press
	// to enter selection mode on touch), and the selection becomes empty, reset the selection behavior.
	createEffect(() => {
		const selection = selectedKeys();

		if (
			access(mergedProps.selectionBehavior) === "replace" &&
			selectionBehavior() === "toggle" &&
			typeof selection === "object" &&
			selection.size === 0
		) {
			setSelectionBehavior("replace");
		}
	});

	// If the selectionBehavior prop changes, update the state as well.
	createEffect(() => {
		setSelectionBehavior(access(mergedProps.selectionBehavior) ?? "toggle");
	});

	return {
		selectionMode,
		disallowEmptySelection,
		selectionBehavior,
		setSelectionBehavior,
		isFocused,
		setFocused,
		focusedKey,
		setFocusedKey,
		selectedKeys,
		setSelectedKeys,
	};
}