/**
 * What the site's two forms send — the general contact and an application to
 * a call — checked before it costs a round trip.
 *
 * Pure, so the two server routes share it and it can be tested without a
 * request: the API would answer 422 with the same verdict, and its throttle
 * counts the attempt either way.
 */
import type { SubmissionPayload } from './api';

export interface SubmissionBody {
  name?: string;
  email?: string;
  message?: string;
  organisation?: string | null;
  hours_per_week?: number | string | null;
  kind?: 'contribute' | 'request';
  consent?: boolean;
  links?: Record<string, string>;
  /** Honeypot. Never rendered visibly; a bot that fills it is filed as spam. */
  website?: string | null;
}

export type SubmissionCheck =
  | { errors: Record<string, string[]>; payload?: undefined }
  | { errors?: undefined; payload: SubmissionPayload };

/**
 * @param forCall An application to a call is always an offer of time: the API
 *   refuses a `kind` on it, so none is sent, and no organisation is asked for.
 */
export function checkSubmission(
  body: SubmissionBody,
  { forCall = false } = {},
): SubmissionCheck {
  const kind = !forCall && body.kind === 'request' ? 'request' : 'contribute';

  const name = body.name?.trim() ?? '';
  const email = body.email?.trim() ?? '';
  const message = body.message?.trim() ?? '';
  const organisation = body.organisation?.trim() ?? '';

  const errors: Record<string, string[]> = {};

  if (name.length < 2) {
    errors['name'] = ['required'];
  }

  if (!/^[^@\s]+@[^@\s]+\.[^@\s]+$/.test(email)) {
    errors['email'] = ['required'];
  }

  // The API rejects anything shorter, and rightly: a one-word submission is
  // never anything but noise.
  if (message.length < 20) {
    errors['message'] = ['min'];
  }

  if (kind === 'request' && organisation.length === 0) {
    errors['organisation'] = ['required'];
  }

  if (body.consent !== true) {
    errors['consent'] = ['required'];
  }

  if (Object.keys(errors).length > 0) {
    return { errors };
  }

  const hours = Number(body.hours_per_week);

  return {
    payload: {
      name,
      email,
      message,
      consent: true,
      ...(forCall ? {} : { kind }),
      organisation: organisation || null,
      hours_per_week: Number.isFinite(hours) && hours > 0 ? hours : null,
      ...(body.links && Object.keys(body.links).length > 0
        ? { links: body.links }
        : {}),
      ...(body.website ? { website: body.website } : {}),
    },
  };
}