import { useDb } from '~~/server/database/client';
import { expenseParticipants, expenses } from '~~/server/database/schema';

export default defineEventHandler(async (event) => {
  const slug = getRouterParam(event, 'slug')!;
  await getPotOrThrow(slug);

  const body = await readBody(event);
  const fromId = Number(body?.fromId);
  const toId = Number(body?.toId);
  const amountCents = Number(body?.amountCents);

  if (!Number.isInteger(amountCents) || amountCents <= 0) {
    throw createError({
      statusCode: 400,
      statusMessage: 'amountCents must be a positive integer',
    });
  }
  if (fromId === toId) {
    throw createError({
      statusCode: 400,
      statusMessage: 'fromId and toId must differ',
    });
  }

  const potParticipants = await getParticipants(slug);
  const validIds = new Set(potParticipants.map((p) => p.id));
  if (!validIds.has(fromId) || !validIds.has(toId)) {
    throw createError({
      statusCode: 400,
      statusMessage: 'fromId and toId must reference participants of this Pot',
    });
  }

  const db = useDb(event);
  const [payment] = await db
    .insert(expenses)
    .values({
      potSlug: slug,
      type: 'payment',
      description: 'Settlement',
      amountCents,
      payerId: fromId,
    })
    .returning();
  await db
    .insert(expenseParticipants)
    .values({ expenseId: payment!.id, participantId: toId });

  return { ...payment, participantIds: [toId] };
});