/* eslint-disable */
// @ts-nocheck
/*
 * Copyright 2020 Adobe. All rights reserved.
 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy
 * of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
 * OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

// Keeps a ref count of all hidden elements. Added to when hiding an element, and
// subtracted from when showing it again. When it reaches zero, aria-hidden is removed.
let refCountMap = new WeakMap<Element, number>();
let observerStack = [];

/**
 * Hides all elements in the DOM outside the given targets from screen readers using aria-hidden,
 * and returns a function to revert these changes. In addition, changes to the DOM are watched
 * and new elements outside the targets are automatically hidden.
 * @param targets - The elements that should remain visible.
 * @param root - Nothing will be hidden above this element.
 * @returns - A function to restore all hidden elements.
 */
export function ariaHideOutside(targets: Element[], root = document.body) {
    let visibleNodes = new Set<Element>(targets);
    let hiddenNodes = new Set<Element>();

    let walk = (root: Element) => {
        // Keep live announcer and top layer elements (e.g. toasts) visible.
        for (let element of root.querySelectorAll(
            "[data-live-announcer], [data-react-aria-top-layer]"
        )) {
            visibleNodes.add(element);
        }

        let acceptNode = (node: Element) => {
            // Skip this node and its children if it is one of the target nodes, or a live announcer.
            // Also skip children of already hidden nodes, as aria-hidden is recursive. An exception is
            // made for elements with role="row" since VoiceOver on iOS has issues hiding elements with role="row".
            // For that case we want to hide the cells inside as well (https://bugs.webkit.org/show_bug.cgi?id=222623).
            if (
                visibleNodes.has(node) ||
                // @ts-ignore
                (hiddenNodes.has(node.parentElement) &&
                    // @ts-ignore
                    node.parentElement.getAttribute("role") !== "row")
            ) {
                return NodeFilter.FILTER_REJECT;
            }

            // Skip this node but continue to children if one of the targets is inside the node.
            for (let target of visibleNodes) {
                if (node.contains(target)) {
                    return NodeFilter.FILTER_SKIP;
                }
            }

            return NodeFilter.FILTER_ACCEPT;
        };

        let walker = document.createTreeWalker(root, NodeFilter.SHOW_ELEMENT, {
            acceptNode,
        });

        // TreeWalker does not include the root.
        let acceptRoot = acceptNode(root);
        if (acceptRoot === NodeFilter.FILTER_ACCEPT) {
            hide(root);
        }

        if (acceptRoot !== NodeFilter.FILTER_REJECT) {
            let node = walker.nextNode() as Element;
            while (node != null) {
                hide(node);
                node = walker.nextNode() as Element;
            }
        }
    };

    let hide = (node: Element) => {
        let refCount = refCountMap.get(node) ?? 0;

        // If already aria-hidden, and the ref count is zero, then this element
        // was already hidden and there's nothing for us to do.
        if (node.getAttribute("aria-hidden") === "true" && refCount === 0) {
            return;
        }

        if (refCount === 0) {
            node.setAttribute("aria-hidden", "true");
        }

        hiddenNodes.add(node);
        refCountMap.set(node, refCount + 1);
    };

    // If there is already a MutationObserver listening from a previous call,
    // disconnect it so the new on takes over.
    if (observerStack.length) {
        // @ts-ignore
        observerStack[observerStack.length - 1].disconnect();
    }

    walk(root);

    let observer = new MutationObserver((changes) => {
        for (let change of changes) {
            if (change.type !== "childList" || change.addedNodes.length === 0) {
                continue;
            }

            // If the parent element of the added nodes is not within one of the targets,
            // and not already inside a hidden node, hide all of the new children.
            if (
                ![...visibleNodes, ...hiddenNodes].some((node) =>
                    node.contains(change.target)
                )
            ) {
                for (let node of change.removedNodes) {
                    if (node instanceof Element) {
                        visibleNodes.delete(node);
                        hiddenNodes.delete(node);
                    }
                }

                for (let node of change.addedNodes) {
                    if (
                        (node instanceof HTMLElement ||
                            node instanceof SVGElement) &&
                        (node.dataset.liveAnnouncer === "true" ||
                            node.dataset.reactAriaTopLayer === "true")
                    ) {
                        visibleNodes.add(node);
                    } else if (node instanceof Element) {
                        walk(node);
                    }
                }
            }
        }
    });

    observer.observe(root, { childList: true, subtree: true });

    let observerWrapper = {
        observe() {
            observer.observe(root, { childList: true, subtree: true });
        },
        disconnect() {
            observer.disconnect();
        },
    };

    // @ts-ignore
    observerStack.push(observerWrapper);

    return () => {
        observer.disconnect();

        for (let node of hiddenNodes) {
            let count = refCountMap.get(node);
            if (count === 1) {
                node.removeAttribute("aria-hidden");
                refCountMap.delete(node);
            } else {
                // @ts-ignore
                refCountMap.set(node, count - 1);
            }
        }

        // Remove this observer from the stack, and start the previous one.
        if (observerWrapper === observerStack[observerStack.length - 1]) {
            observerStack.pop();
            if (observerStack.length) {
                // @ts-ignore
                observerStack[observerStack.length - 1].observe();
            }
        } else {
            // @ts-ignore
            observerStack.splice(observerStack.indexOf(observerWrapper), 1);
        }
    };
}