// most keyboard and input control
// TODO: kinda a monolith file, maybe should split into separate modules later? idk :p

// tab order

// selector for all interactive elements that should be non-tabbable
const INTERACTIVE_SELECTOR =
	"button, a, input, select, textarea, [role='button'], tr, li, ul, .section-toggle";

// apply `tabIndex=-1` to ALL interactive elements, only queue and library get tabIndex=0
function lockTabOrder() {
	document.querySelectorAll(INTERACTIVE_SELECTOR).forEach((el) => {
		// skip queue and library which are always tabbable
		if (el.id === "queue" || el.id === "library") return;

		// skip if element is inside a modal
		const modal = el.closest(".modal:not(.hidden)");
		if (modal) return;

		// lock all other interactive elements
		el.tabIndex = -1;
	});
}

// watch for dynamically added elements and lock their tab order
function setupTabOrderObserver() {
	let isUpdating = false;

	const observer = new MutationObserver((mutations) => {
		const hasAddedNodes = mutations.some(
			(m) => m.type === "childList" && m.addedNodes.length,
		);
		if (hasAddedNodes && !isUpdating) lockTabOrder();
	});

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

	// expose flag so queue operations can pause observer during DOM updates
	return {
		pauseUpdates: () => {
			isUpdating = true;
		},
		resumeUpdates: () => {
			isUpdating = false;
		},
	};
}

let tabOrderObserver;

// queue navigation

// navigate queue selection with arrow keys
const navigateSelection = (offset, extend = false) => {
	if (!selectionManager) return;
	const currentIdx = selectionManager.lastSelected ?? 0;
	const nextIdx =
		offset < 0
			? Math.max(0, currentIdx - 1)
			: Math.min(state.queue.length - 1, currentIdx + 1);

	if (extend) {
		selectionManager.select(nextIdx, { shift: true });
	} else {
		selectionManager.select(nextIdx);
	}

	// ensure queue container has focus for keyboard navigation
	ui.queueList.focus();
};

// cache element references at module scope to avoid repeated lookups
const elementCache = { queue: null, library: null };

// get cached element by id, refresh if detached from DOM
function getCachedElement(type) {
	const id = type === "queue" ? "queue" : "library";
	if (!elementCache[type] || !document.body.contains(elementCache[type])) {
		elementCache[type] = document.getElementById(id);
	}
	return elementCache[type];
}

function getMainEl() {
	return getCachedElement("queue");
}

function getLibraryEl() {
	return getCachedElement("library");
}

// refocus the container after an action to keep keyboard shortcuts working
function refocusContext(isInMain, isInSidebar) {
	if (isInMain) {
		const mainEl = getMainEl();
		if (mainEl && document.activeElement !== mainEl) {
			mainEl.focus();
		}
	} else if (isInSidebar) {
		const libraryEl = getLibraryEl();
		if (libraryEl && document.activeElement !== libraryEl) {
			libraryEl.focus();
		}
	}
}

// action handlers for keyboard shortcuts and selection manager
const keyboardActionHandlers = {
	play: (selectedIndices) => {
		if (!selectedIndices || selectedIndices.length === 0) return;
		playQueueTrack(selectedIndices[0]);
		updateQueue();
		refocusContext(true, false);
	},
	moveUp: (selectedIndices) => {
		const firstIdx = Math.min(...selectedIndices);
		if (firstIdx > 0) {
			moveQueueItems(
				state.queue,
				selectedIndices,
				firstIdx - 1,
				queueCallbacks,
			);
		}
		refocusContext(true, false);
	},
	moveDown: (selectedIndices) => {
		const lastIdx = Math.max(...selectedIndices);
		if (lastIdx < state.queue.length - 1) {
			moveQueueItems(state.queue, selectedIndices, lastIdx + 2, queueCallbacks);
		}
		refocusContext(true, false);
	},
	showContextMenu: (selectedIndices) => {
		// show context menu at the last selected row's position
		const lastIdx = selectedIndices[selectedIndices.length - 1];
		const row = ui.queueList.querySelector(
			`tr[${DATA_ATTRS.INDEX}="${lastIdx}"]`,
		);
		if (row) {
			const rect = row.getBoundingClientRect();
			showQueueContextMenuAtSelection(
				rect.left,
				rect.top + rect.height,
				selectedIndices,
			);
		}
		refocusContext(true, false);
	},
};

// keyboard shortcuts

// setup keyboard shortcuts
function setupKeyboardShortcuts() {
	// setup keyboard help close button
	const closeKeyboardHelpBtn = document.getElementById(
		"close-keyboard-help-btn",
	);
	if (closeKeyboardHelpBtn) {
		closeKeyboardHelpBtn.onclick = () => hideModal("keyboard-help-modal");
	}

	document.addEventListener("keydown", (e) => {
		// skip if user is typing in an input field
		if (document.activeElement.matches("input, textarea")) return;

		// skip keyboard shortcuts if a modal is open (let modal handle it)
		if (isModalOpen()) return;

		// cache element lookups for this event to avoid repeated DOM queries
		const mainEl = getMainEl();
		const libraryEl = getLibraryEl();
		const isInMain = mainEl && mainEl.contains(document.activeElement);
		const isInSidebar = libraryEl && libraryEl.contains(document.activeElement);

		if (!isInMain && !isInSidebar) return;

		switch (e.code) {
			case "Space": {
				e.preventDefault();
				togglePlayback();
				break;
			}

			case "Delete":
			case "Backspace": {
				if (!isInMain) return; // queue only
				e.preventDefault();
				if (selectionManager?.count() > 0) {
					const selected = selectionManager.getSelected();
					const nextIdx = Math.min(
						selected[0],
						state.queue.length - selected.length - 1,
					);
					clearSelectedRows();
					if (nextIdx >= 0 && state.queue.length > 0) {
						selectionManager.select(nextIdx);
					}
				}
				refocusContext(true, false);
				break;
			}

			case "ArrowUp": {
				e.preventDefault();
				if (isInSidebar) {
					LibraryNavigator.navigate(-1);
				} else if (e.altKey) {
					selectionManager?.executeAction("moveUp", keyboardActionHandlers);
				} else {
					navigateSelection(-1, e.shiftKey);
				}
				refocusContext(isInMain, isInSidebar);
				break;
			}

			case "ArrowDown": {
				e.preventDefault();
				if (isInSidebar) {
					LibraryNavigator.navigate(1);
				} else if (e.altKey) {
					selectionManager?.executeAction("moveDown", keyboardActionHandlers);
				} else {
					navigateSelection(1, e.shiftKey);
				}
				refocusContext(isInMain, isInSidebar);
				break;
			}

			case "Home": {
				e.preventDefault();
				if (isInSidebar) {
					LibraryNavigator.navigateFirst();
				} else {
					if (e.shiftKey) {
						selectionManager?.select(0, { shift: true });
					} else {
						selectionManager?.navigateFirst();
					}
				}
				refocusContext(isInMain, isInSidebar);
				break;
			}

			case "End": {
				e.preventDefault();
				if (isInSidebar) {
					LibraryNavigator.navigateLast();
				} else {
					const lastIdx = (state?.queue?.length || 0) - 1;
					if (e.shiftKey) {
						selectionManager?.select(lastIdx, { shift: true });
					} else {
						selectionManager?.navigateLast();
					}
				}
				refocusContext(isInMain, isInSidebar);
				break;
			}

			case "PageUp": {
				e.preventDefault();
				if (isInMain) {
					const currentIdx = selectionManager.lastSelected ?? 0;
					const nextIdx = Math.max(0, currentIdx - 10);
					if (e.shiftKey) {
						selectionManager?.select(nextIdx, { shift: true });
					} else {
						selectionManager?.navigatePageUp(10);
					}
				} else if (isInSidebar) {
					LibraryNavigator.navigatePageUp(10);
				}
				refocusContext(isInMain, isInSidebar);
				break;
			}

			case "PageDown": {
				e.preventDefault();
				if (isInMain) {
					const currentIdx = selectionManager.lastSelected ?? 0;
					const lastIdx = (state?.queue?.length || 0) - 1;
					const nextIdx = Math.min(lastIdx, currentIdx + 10);
					if (e.shiftKey) {
						selectionManager?.select(nextIdx, { shift: true });
					} else {
						selectionManager?.navigatePageDown(10);
					}
				} else if (isInSidebar) {
					LibraryNavigator.navigatePageDown(10);
				}
				refocusContext(isInMain, isInSidebar);
				break;
			}

			case "KeyA": {
				if (!isInMain) return; // queue only
				if (!e.ctrlKey && !e.metaKey) return; // Ctrl+A (or Cmd+A on Mac)
				e.preventDefault();
				if (state.queue.length > 0) {
					selectionManager?.setSelection(
						Array.from({ length: state.queue.length }, (_, i) => i),
					);
				}
				refocusContext(true, false);
				break;
			}

			case "Enter": {
				e.preventDefault();
				if (isInSidebar) {
					LibraryNavigator.toggleCurrent();
					refocusContext(false, true);
				} else {
					selectionManager?.executeAction("play", keyboardActionHandlers);
				}
				break;
			}

			case "Escape": {
				e.preventDefault();
				cleanupContextMenu();
				// clear selection only in focused container
				if (isInMain) {
					selectionManager.clear();
				} else if (isInSidebar) {
					if (LibraryNavigator.currentFocusedItem) {
						LibraryNavigator.currentFocusedItem.classList.remove(
							"library-focused",
						);
						LibraryNavigator.currentFocusedItem = null;
					}
				}
				refocusContext(isInMain, isInSidebar);
				break;
			}

			case "KeyP": {
				if (!isInSidebar) return; // library only
				if (e.altKey) {
					// Alt+P for add next in library
					e.preventDefault();
					addLibraryItem(true);
					updateQueue();
				} else {
					// P for add to queue
					e.preventDefault();
					addLibraryItem(false);
					updateQueue();
				}
				refocusContext(false, true);
				break;
			}

			case "Comma": {
				if (!(e.ctrlKey || e.metaKey)) return; // Ctrl+, for settings
				e.preventDefault();
				const settingsModal = document.getElementById("settings-modal");
				if (settingsModal) {
					showModal(settingsModal, {
						focusSelector: "input, button",
						closeOnClickOutside: true,
					});
				}
				break;
			}

			case "ContextMenu": {
				if (!isInMain) return; // queue only
				e.preventDefault();
				selectionManager?.executeAction(
					"showContextMenu",
					keyboardActionHandlers,
				);
				break;
			}

			case "Slash": {
				if (!e.shiftKey) return; // Shift+/ for keyboard help (?)
				e.preventDefault();
				const helpModalEl = document.getElementById("keyboard-help-modal");
				if (!helpModalEl) break;

				if (helpModalEl.classList.contains("hidden")) {
					showModal(helpModalEl, {
						focusSelector: "button, input",
						closeOnClickOutside: true,
					});
				} else {
					hideModal("keyboard-help-modal");
				}
				break;
			}

			case "KeyR": {
				if (!e.shiftKey) return; // Shift+R for toggle loop (was Ctrl+R)
				e.preventDefault();
				state.loop = !state.loop;
				ui.loopBtn.classList.toggle("active", state.loop);
				break;
			}

			case "KeyJ": {
				if (!isInMain) return; // queue only
				e.preventDefault();
				if (e.altKey) {
					// Alt+J for previous track
					navigateTrack(-1);
				} else {
					// J for seek -10s
					ui.player.currentTime = Math.max(0, ui.player.currentTime - 10);
				}
				break;
			}

			case "KeyL": {
				if (!isInMain) return; // queue only
				e.preventDefault();
				if (e.altKey) {
					// Alt+L for next track
					navigateTrack(1);
				} else {
					// L for seek +10s
					ui.player.currentTime = Math.min(
						ui.player.duration,
						ui.player.currentTime + 10,
					);
				}
				break;
			}
		}
	});
}