import { loadAllPolls, savePoll, deletePoll as dbDeletePoll, loadPoll } from '$lib/db.js';
import type { Poll, PollOption, Vote, RoleAssignment } from '$lib/types.js';
import { getUserId } from '$lib/crypto.js';

let polls = $state<Poll[]>([]);
let loading = $state(true);

export function getPolls() {
	return {
		get all() { return polls; },
		get loading() { return loading; },
		get owned() {
			const id = currentUserId;
			return id ? polls.filter((p) => p.ownerId === id) : [];
		},
		get participating() {
			const id = currentUserId;
			return id ? polls.filter((p) => p.ownerId !== id) : [];
		}
	};
}

let currentUserId: string | null = null;

export async function initPolls(): Promise<void> {
	loading = true;
	currentUserId = await getUserId();
	polls = await loadAllPolls();
	loading = false;
}

export async function createPoll(data: {
	title: string;
	description: string;
	anonymous: boolean;
	visibility: Poll['visibility'];
	options?: string[];
}): Promise<Poll> {
	const userId = await getUserId();
	const now = Date.now();

	const poll: Poll = {
		id: crypto.randomUUID(),
		ownerId: userId,
		title: data.title,
		description: data.description,
		anonymous: data.anonymous,
		status: 'draft',
		visibility: data.visibility,
		createdAt: now,
		options: (data.options ?? []).map((text) => ({
			id: crypto.randomUUID(),
			text,
			addedBy: userId,
			addedAt: now
		})),
		votes: [],
		roles: []
	};

	await savePoll(poll);
	polls = [...polls, poll];
	return poll;
}

export async function updatePollInStore(poll: Poll): Promise<void> {
	await savePoll(poll);
	polls = polls.map((p) => (p.id === poll.id ? poll : p));
}

export function getPollById(id: string): Poll | undefined {
	return polls.find((p) => p.id === id);
}

export async function refreshPoll(id: string): Promise<Poll | undefined> {
	const poll = await loadPoll(id);
	if (poll) {
		polls = polls.map((p) => (p.id === id ? poll : p));
		if (!polls.find((p) => p.id === id)) {
			polls = [...polls, poll];
		}
	}
	return poll;
}

export async function deletePollFromStore(id: string): Promise<void> {
	await dbDeletePoll(id);
	polls = polls.filter((p) => p.id !== id);
}

export async function addOptionToPoll(pollId: string, text: string): Promise<PollOption | null> {
	const poll = getPollById(pollId);
	if (!poll || poll.status !== 'open') return null;

	const userId = await getUserId();
	const option: PollOption = {
		id: crypto.randomUUID(),
		text,
		addedBy: userId,
		addedAt: Date.now()
	};

	const updated = { ...poll, options: [...poll.options, option] };
	await updatePollInStore(updated);
	return option;
}

export async function castVote(pollId: string, optionId: string): Promise<Vote | null> {
	const poll = getPollById(pollId);
	if (!poll || poll.status !== 'open') return null;

	const userId = await getUserId();
	const vote: Vote = {
		optionId,
		voterId: poll.anonymous ? null : userId,
		timestamp: Date.now()
	};

	// Remove previous vote by this user (for vote changes)
	const filteredVotes = poll.anonymous
		? poll.votes // Can't deduplicate anonymous votes by voterId
		: poll.votes.filter((v) => v.voterId !== userId);

	const updated = { ...poll, votes: [...filteredVotes, vote] };
	await updatePollInStore(updated);
	return vote;
}

export async function setPollStatus(pollId: string, status: Poll['status']): Promise<void> {
	const poll = getPollById(pollId);
	if (!poll) return;

	const updated = {
		...poll,
		status,
		...(status === 'closed' ? { closedAt: Date.now() } : {})
	};
	await updatePollInStore(updated);
}

export async function setRole(pollId: string, userId: string, role: RoleAssignment['role']): Promise<void> {
	const poll = getPollById(pollId);
	if (!poll) return;

	const roles = poll.roles.filter((r) => r.userId !== userId);
	roles.push({ userId, role });
	const updated = { ...poll, roles };
	await updatePollInStore(updated);
}

export async function removeRole(pollId: string, userId: string): Promise<void> {
	const poll = getPollById(pollId);
	if (!poll) return;

	const updated = { ...poll, roles: poll.roles.filter((r) => r.userId !== userId) };
	await updatePollInStore(updated);
}