import { desc, eq, inArray } from "drizzle-orm";
import { apiJson } from "@/lib/api";
import { db, User, UsersCurrency } from "@/lib/db";
import { apiCacheKey, redisCache } from "@/lib/redis-cache";

// Public REST API — leaderboard. Mirrors src/app/leaderboard/page.tsx.
// AtomCMS-faithful currency type ids (see UsersCurrency):
//   Credits = -1 (lives on users.credits), Duckets = 0, Diamonds = 5.

type LeaderboardType = "credits" | "diamonds" | "duckets";

const CURRENCY_TYPE: Record<Exclude<LeaderboardType, "credits">, number> = {
	diamonds: 5,
	duckets: 0,
};

type Row = { rank: number; username: string; look: string; value: number };

async function loadCreditsRows(): Promise<Row[]> {
	const users = await db
		.select({
			username: User.username,
			look: User.look,
			credits: User.credits,
		})
		.from(User)
		.orderBy(desc(User.credits))
		.limit(20);
	return users.map((u, i) => ({
		rank: i + 1,
		username: u.username,
		look: u.look,
		value: u.credits,
	}));
}

async function loadCurrencyRows(type: number): Promise<Row[]> {
	const top = await db
		.select({
			userId: UsersCurrency.userId,
			amount: UsersCurrency.amount,
		})
		.from(UsersCurrency)
		.where(eq(UsersCurrency.type, type))
		.orderBy(desc(UsersCurrency.amount))
		.limit(20);
	if (top.length === 0) return [];

	const users = await db
		.select({ id: User.id, username: User.username, look: User.look })
		.from(User)
		.where(
			inArray(
				User.id,
				top.map((t) => t.userId),
			),
		);
	const byId = new Map(users.map((u) => [u.id, u]));

	return top
		.map((t) => {
			const u = byId.get(t.userId);
			if (!u) return null;
			return { username: u.username, look: u.look, value: t.amount };
		})
		.filter((r): r is Omit<Row, "rank"> => r !== null)
		.map((r, i) => ({ rank: i + 1, ...r }));
}

export async function GET(req: Request) {
	try {
		const sp = new URL(req.url).searchParams;
		const requested = sp.get("type");
		const type: LeaderboardType =
			requested === "diamonds" || requested === "duckets"
				? requested
				: "credits";

		const rows = await redisCache(
			apiCacheKey(`leaderboard:${type}`),
			60,
			async () =>
				type === "credits"
					? await loadCreditsRows()
					: // eslint-disable-next-line security/detect-object-injection -- type validated to "diamonds"|"duckets"
						await loadCurrencyRows(CURRENCY_TYPE[type]),
		);

		return apiJson({ type, data: rows }, { status: 200 });
	} catch {
		return apiJson({ type: "credits", data: [] }, { status: 200 });
	}
}