import type { ScreenName } from "./types";
import { openDB, getProgress, saveProgress } from "./storage/db";
import { initWelcomeScreen, initLessonScreen } from "./ui/screens";
import { initForestScreen } from "./forest/scene";

let db: IDBDatabase;
let lessonCleanup: (() => void) | null = null;

export function showScreen(name: ScreenName): void {
	document.querySelectorAll(".screen").forEach((el) => {
		el.classList.remove("screen--active");
	});
	const target = document.getElementById(`screen-${name}`);
	if (target) {
		target.classList.add("screen--active");
	}
}

export function getDB(): IDBDatabase {
	return db;
}

async function handleLessonComplete(completedLevel: number): Promise<void> {
	// Update progress after lesson completion
	const progress = await getProgress(db);
	if (!progress) return;

	// Add level to completedLevels if not already there
	if (!progress.completedLevels.includes(completedLevel)) {
		progress.completedLevels.push(completedLevel);
	}

	// Advance to next level if this was the current level (LEVL-02, LEVL-03)
	if (completedLevel === progress.currentLevel) {
		progress.currentLevel = completedLevel + 1;
	}

	// Increment session count
	progress.totalSessions++;

	// Add today's date if not already recorded
	const today = new Date().toISOString().split("T")[0]!;
	if (!progress.sessionDates.includes(today)) {
		progress.sessionDates.push(today);
	}

	await saveProgress(db, progress);

	// Re-init forest screen with updated progress, then navigate
	await initForestScreen(db, startLessonFromForest);
	showScreen("forest");
}

function startLessonFromForest(level: number): void {
	// Clean up previous lesson if any
	if (lessonCleanup) {
		lessonCleanup();
		lessonCleanup = null;
	}

	// Get layout from progress (already loaded)
	getProgress(db).then((progress) => {
		const layout = progress?.selectedLayout ?? "de";

		showScreen("lesson");

		lessonCleanup = initLessonScreen(
			db,
			level,
			layout,
			handleLessonComplete,
		);
	});
}

export async function initApp(): Promise<void> {
	db = await openDB();
	const progress = await getProgress(db);
	if (progress && progress.selectedCharacter) {
		// Returning user -- init forest and go there
		await initForestScreen(db, startLessonFromForest);
		showScreen("forest");
	} else {
		// First time -- show welcome, then forest after setup
		initWelcomeScreen(db, async (screen: ScreenName) => {
			showScreen(screen);
			if (screen === "forest") {
				await initForestScreen(db, startLessonFromForest);
			}
		});
		showScreen("welcome");
	}
}