import Event from '../../../models/event';

export default defineEventHandler(async (event) => {
  const id = getRouterParam(event, 'id');
  const body = await readBody(event);
  const { email } = body;

  if (!email) {
    throw createError({
      statusCode: 400,
      statusMessage: 'Email is required'
    });
  }

  try {
    // Check if id is a valid ObjectId or treat as slug
    const isObjectId = /^[0-9a-fA-F]{24}$/.test(id);
    const query = isObjectId
      ? { $or: [{ _id: id }, { slug: id }] }
      : { slug: id };

    const eventDoc = await Event.findOne(query);

    if (!eventDoc) {
      throw createError({
        statusCode: 404,
        statusMessage: 'Event not found'
      });
    }

    // Find the registration index
    const registrationIndex = eventDoc.registrations.findIndex(
      registration => registration.email.toLowerCase() === email.toLowerCase()
    );

    if (registrationIndex === -1) {
      throw createError({
        statusCode: 404,
        statusMessage: 'Registration not found'
      });
    }

    // Remove the registration
    eventDoc.registrations.splice(registrationIndex, 1);

    // Update registered count
    eventDoc.registeredCount = eventDoc.registrations.length;

    await eventDoc.save();

    return {
      success: true,
      message: 'Registration cancelled successfully',
      registeredCount: eventDoc.registeredCount
    };
  } catch (error) {
    console.error('Error cancelling registration:', error);

    // Re-throw known errors
    if (error.statusCode) {
      throw error;
    }

    throw createError({
      statusCode: 500,
      statusMessage: 'Failed to cancel registration'
    });
  }
});