import { prisma } from '../prisma.js';
import type { CreateGroupInput, UpdateGroupInput } from '$lib/types/group.js';

export async function findAll() {
	return prisma.group.findMany({
		orderBy: { name: 'asc' },
		include: {
			_count: { select: { users: true } }
		}
	});
}

export async function findById(id: string) {
	const group = await prisma.group.findUnique({
		where: { id },
		include: {
			_count: { select: { users: true } }
		}
	});
	if (!group) {
		throw new Error(`Group not found: ${id}`);
	}
	return group;
}

export async function findByName(name: string) {
	return prisma.group.findUnique({
		where: { name }
	});
}

export async function findDefaultGroups() {
	return prisma.group.findMany({
		where: { isDefault: true }
	});
}

export async function create(input: CreateGroupInput) {
	const existing = await prisma.group.findUnique({
		where: { name: input.name }
	});
	if (existing) {
		throw new Error(`Group with name "${input.name}" already exists`);
	}

	return prisma.group.create({
		data: {
			name: input.name,
			description: input.description ?? null,
			isDefault: input.isDefault ?? false
		}
	});
}

export async function update(id: string, input: UpdateGroupInput) {
	await findById(id);

	if (input.name) {
		const existing = await prisma.group.findFirst({
			where: { name: input.name, NOT: { id } }
		});
		if (existing) {
			throw new Error(`Group with name "${input.name}" already exists`);
		}
	}

	return prisma.group.update({
		where: { id },
		data: {
			...(input.name !== undefined ? { name: input.name } : {}),
			...(input.description !== undefined ? { description: input.description } : {}),
			...(input.isDefault !== undefined ? { isDefault: input.isDefault } : {})
		}
	});
}

export async function remove(id: string) {
	await findById(id);
	await prisma.group.delete({ where: { id } });
}

export async function addUser(groupId: string, userId: string) {
	const existing = await prisma.userGroup.findUnique({
		where: { userId_groupId: { userId, groupId } }
	});
	if (existing) {
		return existing;
	}

	return prisma.userGroup.create({
		data: { userId, groupId }
	});
}

export async function removeUser(groupId: string, userId: string) {
	await prisma.userGroup.deleteMany({
		where: { userId, groupId }
	});
}

export async function getGroupMembers(groupId: string) {
	const memberships = await prisma.userGroup.findMany({
		where: { groupId },
		include: {
			user: {
				select: {
					id: true,
					email: true,
					displayName: true,
					role: true,
					avatarUrl: true
				}
			}
		}
	});
	return memberships.map((m) => m.user);
}

export async function addUserToDefaultGroups(userId: string) {
	const defaultGroups = await findDefaultGroups();
	const results = await Promise.all(
		defaultGroups.map((group) => addUser(group.id, userId))
	);
	return results;
}