import type { InferSelectModel } from "drizzle-orm";
import type { db as Db } from "../db";
import type { track as trackTable } from "../db/schema";
import type { QuizRound } from "../party-types";

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

export type PartyAnalytics = {
	groupSummary?: {
		totalMembers?: number;
		mostSharedGenres?: { name: string }[];
		mostDiverseMember?: { userId: string; genreEntropy: number } | null;
		mostAlignedPair?: {
			userIdA: string;
			userIdB: string;
			similarity?: number;
		} | null;
	};
	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 type AnalyticsTrack = {
	name: string;
	artists?: { name: string }[];
	albumName?: string;
	memberScores?: { userId: string; score: number }[];
};
type QuestionLike = {
	text: string;
	questionKey?: string;
	subjectKey?: string;
};

export type QuestionCandidate<T extends QuestionLike = QuestionLike> = {
	key: string;
	subjectKey?: string;
	question: T;
};
export type QuestionSong = InferSelectModel<typeof trackTable>;

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,
): { min: number; max: number } {
	const min = Math.floor(correctValue - tolerance);
	const max = Math.ceil(correctValue + tolerance);
	return normalizeRange(min, max);
}

export function getReleaseYearRange(
	releaseYear: number,
	currentYear = new Date().getFullYear(),
	tolerance = 10,
	minSpan = 4,
): { min: number; max: number } {
	const cappedMax = Math.min(currentYear, Math.ceil(releaseYear + tolerance));
	const rawMin = Math.floor(releaseYear - tolerance);
	const minimumSpan = Math.max(1, minSpan);
	const expandedMin = Math.max(0, cappedMax - minimumSpan);
	const min = Math.min(rawMin, expandedMin, releaseYear);
	return normalizeRange(min, cappedMax);
}

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

export function pickQuestionCandidate<T extends QuestionLike>(
	candidates: QuestionCandidate<T>[],
	history: QuizRound[],
	index: number,
): T | null {
	const seenKeys = new Set<string>();
	const seenSubjects = new Set<string>();
	const seenTexts = new Set<string>();

	for (const round of history) {
		const question = round.question;
		seenTexts.add(normalizeQuestionKey(question.text));
		if (question.questionKey)
			seenKeys.add(normalizeQuestionKey(question.questionKey));
		if (question.subjectKey)
			seenSubjects.add(normalizeQuestionKey(question.subjectKey));
	}

	const fresh = candidates.filter((candidate) => {
		const key = normalizeQuestionKey(candidate.key);
		const subjectKey = candidate.subjectKey
			? normalizeQuestionKey(candidate.subjectKey)
			: null;
		const text = normalizeQuestionKey(candidate.question.text);

		if (seenKeys.has(key)) return false;
		if (subjectKey && seenSubjects.has(subjectKey)) return false;
		if (seenTexts.has(text)) return false;
		return true;
	});

	if (fresh.length === 0) return null;
	const pool = fresh;
	return pool[index % pool.length]?.question ?? null;
}

function normalizeQuestionKey(value: string): string {
	return value.trim().toLowerCase();
}

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

export function getTopClusterTracks(
	analytics: PartyAnalytics,
): AnalyticsTrack[] {
	return (analytics?.storyClusters?.[0]?.tracks ?? []).filter((track) =>
		isUsableText(track.name),
	);
}

export function pickRelevantTrack(
	analytics: PartyAnalytics,
	hints: {
		trackName?: string;
		artistNames?: string[];
		albumName?: string;
	} = {},
): AnalyticsTrack | null {
	const tracks = getTopClusterTracks(analytics);
	if (tracks.length === 0) return null;

	const scored = tracks.map((track) => {
		const trackArtistNames = track.artists?.map((artist) => artist.name) ?? [];
		const matchesTrackName = hints.trackName && track.name === hints.trackName;
		const matchesAlbum = hints.albumName && track.albumName === hints.albumName;
		const matchesArtist =
			hints.artistNames?.some((name) => trackArtistNames.includes(name)) ??
			false;

		return {
			track,
			score:
				(matchesTrackName ? 4 : 0) +
				(matchesAlbum ? 2 : 0) +
				(matchesArtist ? 2 : 0),
		};
	});

	const best = scored.sort((a, b) => b.score - a.score).at(0);
	return best?.track ?? tracks[0] ?? null;
}

export async function resolveQuestionSong(
	db: typeof Db,
	analytics: PartyAnalytics,
	hints: {
		trackName?: string;
		artistNames?: string[];
		albumName?: string;
	} = {},
): Promise<QuestionSong | null> {
	const trackHint = pickRelevantTrack(analytics, hints);
	if (!trackHint?.name) return null;

	const tracks = await db.query.track.findMany({
		where: { name: trackHint.name },
		with: { album: true, artists: true },
	});
	const usableTracks = tracks.filter((track) => isUsableText(track.name));
	if (usableTracks.length === 0) return null;

	const scoreTrack = (track: (typeof tracks)[number]) => {
		const artistNames = track.artists?.map((artist) => artist.name) ?? [];
		const matchesAlbum = trackHint.albumName
			? track.album?.name === trackHint.albumName
			: false;
		const matchesArtist =
			hints.artistNames?.some((name) => artistNames.includes(name)) ?? false;
		return (matchesAlbum ? 2 : 0) + (matchesArtist ? 2 : 0);
	};

	const chosen = usableTracks
		.slice()
		.sort((a, b) => scoreTrack(b) - scoreTrack(a))[0];
	if (!chosen) return null;
	const { album: _album, artists: _artists, ...song } = chosen;
	return song;
}

export function isUsableText(
	value: string | null | undefined,
): value is string {
	return typeof value === "string" && value.trim().length > 0;
}

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 => isUsableText(value)),
	);
	return options.length >= desiredCount ? options.slice(0, desiredCount) : null;
}

export function buildOptionsWithCorrect(
	correct: string,
	candidates: string[],
	desiredCount: number,
): string[] | null {
	if (!isUsableText(correct)) return null;
	const options = uniqueStrings([
		correct,
		...candidates.filter((c) => isUsableText(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 | null {
	const userId = analytics?.groupSummary?.mostDiverseMember?.userId;
	if (!userId) return null;
	return members.find((member) => member.userId === userId) ?? null;
}

export function getMostAlignedMember(
	analytics: PartyAnalytics,
	members: PartyQuestionMember[],
): PartyQuestionMember | null {
	const userId = analytics?.groupSummary?.mostAlignedPair?.userIdA;
	if (!userId) return null;
	return members.find((member) => member.userId === userId) ?? null;
}

export function buildMemberOptions(
	correctMember: PartyQuestionMember,
	members: PartyQuestionMember[],
): string[] | null {
	const desiredCount = getPartySize(members.length);
	if (!isUsableText(correctMember.name)) return null;
	const options = uniqueStrings([
		correctMember.name,
		...members.map((member) => member.name).filter(isUsableText),
	]);

	if (options.length < desiredCount) return null;

	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 normalizeRange(
	min: number,
	max: number,
): { min: number; max: number } {
	if (min <= max) return { min, max };
	return { min: max, max: min };
}

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