/*
 * 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/8f2f2acb3d5850382ebe631f055f88c704aa7d17/packages/@react-aria/selection/src/ListKeyboardDelegate.ts
 */

import type { Accessor } from "solid-js";

import type { Collection, CollectionNode } from "../primitives";
import type { KeyboardDelegate } from "../selection";

export class ListKeyboardDelegate implements KeyboardDelegate {
	private collection: Accessor<Collection<CollectionNode>>;
	private ref?: Accessor<HTMLElement | undefined>;
	private collator?: Accessor<Intl.Collator | undefined>;

	constructor(
		collection: Accessor<Collection<CollectionNode>>,
		ref?: Accessor<HTMLElement | undefined>,
		collator?: Accessor<Intl.Collator | undefined>,
	) {
		this.collection = collection;
		this.ref = ref;
		this.collator = collator;
	}

	getKeyBelow(key: string) {
		let keyAfter = this.collection().getKeyAfter(key);

		while (keyAfter != null) {
			const item = this.collection().getItem(keyAfter);

			if (item && item.type === "item" && !item.disabled) {
				return keyAfter;
			}

			keyAfter = this.collection().getKeyAfter(keyAfter);
		}
	}

	getKeyAbove(key: string) {
		let keyBefore = this.collection().getKeyBefore(key);

		while (keyBefore != null) {
			const item = this.collection().getItem(keyBefore);

			if (item && item.type === "item" && !item.disabled) {
				return keyBefore;
			}

			keyBefore = this.collection().getKeyBefore(keyBefore);
		}
	}

	getFirstKey() {
		let key = this.collection().getFirstKey();

		while (key != null) {
			const item = this.collection().getItem(key);

			if (item && item.type === "item" && !item.disabled) {
				return key;
			}

			key = this.collection().getKeyAfter(key);
		}
	}

	getLastKey() {
		let key = this.collection().getLastKey();

		while (key != null) {
			const item = this.collection().getItem(key);

			if (item && item.type === "item" && !item.disabled) {
				return key;
			}

			key = this.collection().getKeyBefore(key);
		}
	}

	private getItem(key: string): HTMLElement | null {
		return this.ref?.()?.querySelector(`[data-key="${key}"]`) ?? null;
	}

	// TODO: not working correctly
	getKeyPageAbove(key: string) {
		const menu = this.ref?.();
		let item = this.getItem(key);

		if (!menu || !item) {
			return;
		}

		const pageY = Math.max(
			0,
			item.offsetTop + item.offsetHeight - menu.offsetHeight,
		);

		let keyAbove: string | undefined = key;

		while (keyAbove && item && item.offsetTop > pageY) {
			keyAbove = this.getKeyAbove(keyAbove);
			item = keyAbove != null ? this.getItem(keyAbove) : null;
		}

		return keyAbove;
	}

	// TODO: not working correctly
	getKeyPageBelow(key: string) {
		const menu = this.ref?.();
		let item = this.getItem(key);

		if (!menu || !item) {
			return;
		}

		const pageY = Math.min(
			menu.scrollHeight,
			item.offsetTop - item.offsetHeight + menu.offsetHeight,
		);

		let keyBelow: string | undefined = key;

		while (keyBelow && item && item.offsetTop < pageY) {
			keyBelow = this.getKeyBelow(keyBelow);
			item = keyBelow != null ? this.getItem(keyBelow) : null;
		}

		return keyBelow;
	}

	getKeyForSearch(search: string, fromKey?: string) {
		const collator = this.collator?.();

		if (!collator) {
			return;
		}

		// Prevent from getting the same key twice
		let key = fromKey != null ? this.getKeyBelow(fromKey) : this.getFirstKey();

		while (key != null) {
			const item = this.collection().getItem(key);

			if (item) {
				const substring = item.textValue.slice(0, search.length);

				if (item.textValue && collator.compare(substring, search) === 0) {
					return key;
				}
			}

			key = this.getKeyBelow(key);
		}
	}
}