// library tree keyboard navigation manager

class LibrarySelection {
	constructor(options = {}) {
		this.currentFocusedItem = null;
		this.currentSection = "artists"; // "artists" or "playlists"
	}

	getFocusableItems() {
		// get all focusable items in library (organized by section for natural navigation)
		const items = [];
		const sections = [
			{
				selector: '[data-section="artists"]',
				containerId: DOM_IDS.LIBRARY_TREE,
			},
			{
				selector: '[data-section="playlists"]',
				containerId: DOM_IDS.PLAYLISTS_TREE,
			},
		];

		sections.forEach(({ selector, containerId }) => {
			const toggle = document.querySelector(selector);
			if (toggle) {
				items.push(toggle);
				const sectionItems = Array.from(
					document.querySelectorAll(
						`#${containerId} .${CLASSES.TREE_TOGGLE}, #${containerId} .${CLASSES.TREE_NAME}`,
					),
				);
				items.push(...sectionItems);
			}
		});

		return items;
	}

	focusItem(element) {
		// set focus to specific item
		if (this.currentFocusedItem) {
			this.currentFocusedItem.classList.remove(CLASSES.FOCUSED);
		}
		if (element) {
			element.classList.add(CLASSES.FOCUSED);
			element.scrollIntoView({ block: "nearest" });
			this.currentFocusedItem = element;
		}
	}

	_navigateTo(calcNewIndex) {
		// navigate with direction and optional offset (for page navigation)
		const items = this.getFocusableItems();
		if (items.length === 0) return;

		if (!this.currentFocusedItem) {
			this.focusItem(items[0]);
			return;
		}

		const currentIndex = items.indexOf(this.currentFocusedItem);
		const newIndex = calcNewIndex(currentIndex, items.length);
		if (newIndex >= 0 && newIndex < items.length) {
			this.focusItem(items[newIndex]);
		}
	}

	navigate(direction) {
		// navigate up/down through items
		this._navigateTo((idx) => idx + direction);
	}

	navigatePageUp(pageSize = 10) {
		// navigate by page (jump multiple items)
		this._navigateTo((idx) => Math.max(0, idx - pageSize));
	}

	navigatePageDown(pageSize = 10) {
		// navigate by page down (jump multiple items)
		this._navigateTo((idx, len) => Math.min(len - 1, idx + pageSize));
	}

	getCurrentItemData() {
		// get data (item id and type) from currently focused item
		if (!this.currentFocusedItem) return null;
		const li = this.currentFocusedItem.closest("li");
		if (!li) return null;
		const inArtists =
			this.currentFocusedItem.closest(`#${DOM_IDS.LIBRARY_TREE}`) !== null;
		return {
			itemId: li.dataset.itemId,
			section: inArtists ? "artists" : "playlists",
		};
	}
}

const librarySelection = new LibrarySelection();