import {
  WORKSHOP_CHALLENGE_IDS,
  WORKSHOP_HONEYPOT_FIELD,
  WORKSHOP_MEMBER_COUNTS,
  WORKSHOP_ORGANIZATION_KINDS,
  WORKSHOP_ROLES,
  WORKSHOP_STARTED_AT_FIELD,
  type WorkshopFieldErrors,
  type WorkshopFormValues,
} from "../../workshopSignup";

const CHALLENGE_SET = new Set<string>(WORKSHOP_CHALLENGE_IDS);
const KIND_SET = new Set<string>(WORKSHOP_ORGANIZATION_KINDS);
const MEMBER_SET = new Set<string>(WORKSHOP_MEMBER_COUNTS);
const ROLE_SET = new Set<string>(WORKSHOP_ROLES);

const EMAIL_PATTERN = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;

export interface ParsedWorkshopSignup {
  values: WorkshopFormValues;
  fieldErrors: WorkshopFieldErrors;
  honeypot: string;
  startedAt: number | null;
}

function asString(value: unknown): string {
  return typeof value === "string" ? value : "";
}

function asStringList(value: unknown): string[] {
  if (Array.isArray(value)) {
    return value.filter((item): item is string => typeof item === "string");
  }
  if (typeof value === "string" && value.trim().length > 0) {
    return [value];
  }
  return [];
}

export function parseWorkshopSignupPayload(raw: unknown): ParsedWorkshopSignup {
  const record =
    raw && typeof raw === "object" ? (raw as Record<string, unknown>) : {};

  const challenges = [
    ...new Set(asStringList(record.challenges).map((item) => item.trim())),
  ].filter((item) => CHALLENGE_SET.has(item));

  const values: WorkshopFormValues = {
    challenges,
    challengeOther: asString(record.challengeOther).trim().slice(0, 200),
    unspokenQuestion: asString(record.unspokenQuestion).trim(),
    organizationName: asString(record.organizationName).trim(),
    organizationKind: asString(record.organizationKind).trim(),
    memberCount: asString(record.memberCount).trim(),
    contactName: asString(record.contactName).trim(),
    email: asString(record.email).trim().toLowerCase(),
    role: asString(record.role).trim(),
    sourcePage: asString(record.sourcePage).trim() || "/workshops",
    sourceUrl: asString(record.sourceUrl).trim().slice(0, 2000),
  };

  const fieldErrors: WorkshopFieldErrors = {};

  if (values.challenges.length === 0) fieldErrors.challenges = "required";
  if (
    values.challenges.includes("something-else") &&
    values.challengeOther.length === 0
  ) {
    fieldErrors.challengeOther = "required";
  }
  if (values.unspokenQuestion.length > 1000) fieldErrors.unspokenQuestion = "tooLong";
  if (values.organizationName.length === 0) fieldErrors.organizationName = "required";
  else if (values.organizationName.length > 150) fieldErrors.organizationName = "tooLong";
  if (!KIND_SET.has(values.organizationKind)) fieldErrors.organizationKind = "required";
  if (!MEMBER_SET.has(values.memberCount)) fieldErrors.memberCount = "required";
  if (values.contactName.length === 0) fieldErrors.contactName = "required";
  else if (values.contactName.length > 100) fieldErrors.contactName = "tooLong";
  if (values.email.length === 0 || !EMAIL_PATTERN.test(values.email) || values.email.length > 254) {
    fieldErrors.email = values.email.length === 0 ? "required" : "invalid";
  }
  if (values.role.length > 0 && !ROLE_SET.has(values.role)) fieldErrors.role = "invalid";

  const startedRaw = record[WORKSHOP_STARTED_AT_FIELD];
  const startedAt =
    typeof startedRaw === "number"
      ? startedRaw
      : typeof startedRaw === "string" && startedRaw.trim().length > 0
        ? Number(startedRaw)
        : null;

  return {
    values,
    fieldErrors,
    honeypot: asString(record[WORKSHOP_HONEYPOT_FIELD]).trim(),
    startedAt: startedAt !== null && Number.isFinite(startedAt) ? startedAt : null,
  };
}

export function workshopSignupFromFormData(formData: FormData): ParsedWorkshopSignup {
  return parseWorkshopSignupPayload({
    challenges: formData.getAll("challenges"),
    challengeOther: formData.get("challengeOther"),
    unspokenQuestion: formData.get("unspokenQuestion"),
    organizationName: formData.get("organizationName"),
    organizationKind: formData.get("organizationKind"),
    memberCount: formData.get("memberCount"),
    contactName: formData.get("contactName"),
    email: formData.get("email"),
    role: formData.get("role"),
    sourcePage: formData.get("sourcePage"),
    sourceUrl: formData.get("sourceUrl"),
    [WORKSHOP_STARTED_AT_FIELD]: formData.get(WORKSHOP_STARTED_AT_FIELD),
    [WORKSHOP_HONEYPOT_FIELD]: formData.get(WORKSHOP_HONEYPOT_FIELD),
  });
}