itpdp/api/src/party/question-utils.ts

import type { db as Db } from "../db";

export type PartyQuestionMember = {
	userId: string;
	name: string;
};

export type PartyAnalytics = {
	groupSummary?: {
		mostSharedGenres?: { name: string }[];
	};
	storyClusters?: {
		tracks?: {
			name: string;
			artists?: { name: string }[];
			albumName?: string;
			memberScores?: { userId: string; score: number }[];
		}[];
		artists?: { name: string }[];
		genres?: { name: string }[];
	}[];
	memberProfiles?: { userId: string }[];
	pairwise?: { userIdA: string; userIdB: string }[];
} | null;

export const QUESTION_DURATION_MS = 60_000;
export const MIN_PARTY_SIZE = 2;
export const MAX_PARTY_SIZE = 4;

export async function fetchPartyMembers(
	db: typeof Db,
	partyId: string,
): Promise<PartyQuestionMember[]> {
	const members = await db.query.partyMember.findMany({
		where: {
			partyId,
		},
		with: {
			user: true,
		},
	});

	return members.map((member) => ({
		userId: member.userId,
		name: member.user?.name ?? member.userId,
	}));
}

export function getPartySize(memberCount: number): number {
	return Math.max(MIN_PARTY_SIZE, Math.min(MAX_PARTY_SIZE, memberCount));
}

export function buildQuestionWindow<T extends object>(
	question: T,
	timestamp = Date.now(),
): T & { startTimestamp: number; endTimestamp: number } {
	return {
		...question,
		startTimestamp: timestamp,
		endTimestamp: timestamp + QUESTION_DURATION_MS,
	};
}

export function getQuestionDistanceScore(
	selectedValue: number,
	correctValue: number,
	maxDistance: number,
	points: number,
): number {
	if (!Number.isFinite(selectedValue)) return 0;
	if (maxDistance <= 0) return selectedValue === correctValue ? points : 0;
	const distance = Math.abs(selectedValue - correctValue);
	const ratio = Math.max(0, 1 - distance / maxDistance);
	return Math.round(points * ratio);
}

export function getQuestionRange(
	correctValue: number,
	tolerance: number,
	randomness: number,
): { min: number; max: number } {
	const min = Math.floor(correctValue - tolerance);
	const max = Math.ceil(correctValue + tolerance);
	const range = max - min;
	return {
		min: min + Math.floor(Math.random() * range * randomness),
		max: max - Math.floor(Math.random() * range * randomness),
	};
}

export function getMostSharedGenreNames(analytics: PartyAnalytics): string[] {
	return (analytics?.groupSummary?.mostSharedGenres ?? []).map(
		(genre) => genre.name,
	);
}

export function getTopClusterArtists(analytics: PartyAnalytics): string[] {
	return (analytics?.storyClusters?.[0]?.artists ?? []).map(
		(artist) => artist.name,
	);
}

export function getTopClusterTracks(analytics: PartyAnalytics): Array<{
	name: string;
	artists?: { name: string }[];
	albumName?: string;
	memberScores?: { userId: string; score: number }[];
}> {
	return analytics?.storyClusters?.[0]?.tracks ?? [];
}

export function getTopTrackListener(
	track: { memberScores?: { userId: string; score: number }[] },
	members: PartyQuestionMember[],
): PartyQuestionMember | null {
	const topMember = (track.memberScores ?? [])
		.slice()
		.sort((a, b) => b.score - a.score)
		.at(0);

	if (!topMember) return null;
	return members.find((member) => member.userId === topMember.userId) ?? null;
}

export function buildOrderedOptions(
	values: Array<string | undefined>,
	desiredCount: number,
): string[] | null {
	const options = uniqueStrings(
		values.filter((value): value is string => Boolean(value)),
	);
	return options.length >= desiredCount ? options.slice(0, desiredCount) : null;
}

export function buildOptionsWithCorrect(
	correct: string,
	candidates: string[],
	desiredCount: number,
): string[] | null {
	const options = uniqueStrings([
		correct,
		...candidates.filter((c) => c !== correct),
	]);
	return options.length >= desiredCount ? options.slice(0, desiredCount) : null;
}

export function pickRandom<T>(items: T[]): T | null {
	if (items.length === 0) return null;
	const index = Math.floor(Math.random() * items.length);
	return items[index] ?? null;
}

export function getCurrentLeader(
	quizState: { scores: Record<string, number> },
	members: PartyQuestionMember[],
): PartyQuestionMember {
	const leaderId = Object.entries(quizState.scores)
		.sort(([, a], [, b]) => b - a)
		.at(0)?.[0];

	return (
		members.find((member) => member.userId === leaderId) ??
		members[0] ?? { userId: "", name: "Player A" }
	);
}

export function hasClearLeader(quizState: {
	scores: Record<string, number>;
}): boolean {
	const scores = Object.values(quizState.scores);
	if (scores.length < 2) return false;
	const ordered = scores.slice().sort((a, b) => b - a);
	const [first, second] = ordered;
	if (first === undefined || second === undefined) return false;
	return first > second;
}

export function getMostDiverseMember(
	analytics: PartyAnalytics,
	members: PartyQuestionMember[],
): PartyQuestionMember {
	const userId = analytics?.memberProfiles?.[0]?.userId;
	return (
		members.find((member) => member.userId === userId) ??
		members[1] ??
		members[0] ?? { userId: "", name: "Player B" }
	);
}

export function getMostAlignedMember(
	analytics: PartyAnalytics,
	members: PartyQuestionMember[],
): PartyQuestionMember {
	const userId = analytics?.pairwise?.[0]?.userIdA;
	return (
		members.find((member) => member.userId === userId) ??
		members[2] ??
		members[0] ?? { userId: "", name: "Player C" }
	);
}

export function buildMemberOptions(
	correctMember: PartyQuestionMember,
	members: PartyQuestionMember[],
): string[] {
	const desiredCount = getPartySize(members.length);
	const options = uniqueStrings([
		correctMember.name,
		...members.map((member) => member.name),
	]);

	if (options.length < desiredCount) {
		for (const fallback of fallbackPlayerNames(desiredCount)) {
			if (options.length >= desiredCount) break;
			if (!options.includes(fallback)) options.push(fallback);
		}
	}

	const ordered = [
		correctMember.name,
		...options.filter((name) => name !== correctMember.name),
	];
	return ordered.slice(0, desiredCount);
}

function uniqueStrings(values: string[]): string[] {
	return values.filter((value, index, list) => list.indexOf(value) === index);
}

function fallbackPlayerNames(count: number): string[] {
	return Array.from(
		{ length: count },
		(_, index) => `Player ${String.fromCharCode(65 + index)}`,
	);
}

export function buildMemberPairOptions(
	members: PartyQuestionMember[],
	correctPair: string,
): string[] | null {
	if (members.length < 3) return null;
	const pairs: string[] = [correctPair];
	for (let i = 0; i < members.length; i++) {
		for (let j = i + 1; j < members.length; j++) {
			const pair = `${members[i]!.name} & ${members[j]!.name}`;
			if (pair !== correctPair) pairs.push(pair);
		}
	}
	return pairs.length >= 2 ? pairs.slice(0, 4) : null;
}