const CURP_RE =
  /^[A-Z][AEIOUX][A-Z]{2}\d{2}(?:0[1-9]|1[0-2])(?:0[1-9]|[12]\d|3[01])[HMX](?:AS|BC|BS|CC|CS|CH|CL|CM|DF|DG|GT|GR|HG|JC|MC|MN|MS|NT|NL|OC|PL|QT|QR|SP|SL|SR|TC|TS|TL|VZ|YN|ZS|NE)[B-DF-HJ-NP-TV-Z]{3}[A-Z\d]\d$/;

const RFC_PF = /^[A-ZÑ&]{4}\d{6}[A-Z0-9]{3}$/;
const RFC_PM = /^[A-ZÑ&]{3}\d{6}[A-Z0-9]{3}$/;

export function normUpper(value: string | null | undefined): string {
  return (value ?? "").toString().trim().toUpperCase().replace(/\s+/g, "");
}

export function normName(value: string | null | undefined): string {
  return (value ?? "").toString().trim().replace(/\s+/g, " ");
}

const NAME_PARTICLES = new Set([
  "de", "del", "la", "las", "los", "el", "y", "e", "da", "das", "do", "dos", "di", "du", "le", "van", "von",
]);

function capPiece(piece: string): string {
  if (!piece) return piece;
  return piece.replace(/(^|['’])(\p{L})/gu, (_m, sep: string, ch: string) => sep + ch.toLocaleUpperCase("es-MX"));
}

/** Nombre propio: Héctor de la Cruz. No guarda TODO EN MAYÚSCULAS. */
export function titleCase(value: string | null | undefined): string {
  const raw = normName(value);
  if (!raw) return "";
  return raw
    .toLocaleLowerCase("es-MX")
    .split(" ")
    .map((word, i) => {
      if (!word) return word;
      if (i > 0 && NAME_PARTICLES.has(word)) return word;
      return word.split("-").map(capPiece).join("-");
    })
    .join(" ");
}

/** Oración: primera letra y después de . ? ! */
export function sentenceCase(value: string | null | undefined): string {
  const raw = normName(value);
  if (!raw) return "";
  return raw
    .toLocaleLowerCase("es-MX")
    .replace(/(^|[.!?]\s+)(\p{L})/gu, (_m, sep: string, ch: string) => sep + ch.toLocaleUpperCase("es-MX"));
}

export function looksAllCaps(value: string | null | undefined): boolean {
  const letters = [...(value ?? "")].filter((ch) => /\p{L}/u.test(ch)).join("");
  if (letters.length < 2) return false;
  const up = letters.toLocaleUpperCase("es-MX");
  const low = letters.toLocaleLowerCase("es-MX");
  return letters === up && letters !== low;
}

export function validateCurp(raw: string): string | null {
  const curp = normUpper(raw);
  if (!CURP_RE.test(curp)) return "CURP inválida (18 caracteres, formato oficial)";
  return null;
}

export function validateRfc(raw: string): string | null {
  const rfc = normUpper(raw).replace(/Ñ/g, "Ñ");
  if (!RFC_PF.test(rfc) && !RFC_PM.test(rfc)) {
    return "RFC inválido (12 o 13 caracteres, formato SAT)";
  }
  return null;
}

/** Dígito verificador IMSS (11 dígitos). */
export function validateNss(raw: string): string | null {
  const nss = (raw ?? "").toString().replace(/\D/g, "");
  if (nss.length !== 11) return "NSS inválido (11 dígitos)";
  const digits = nss.split("").map(Number);
  let sum = 0;
  for (let i = 0; i < 10; i++) {
    let n = digits[i] * (i % 2 === 1 ? 2 : 1);
    if (n > 9) n -= 9;
    sum += n;
  }
  const check = (10 - (sum % 10)) % 10;
  if (check !== digits[10]) return "NSS inválido (dígito verificador)";
  return null;
}

export function formatNss(raw: string): string {
  return (raw ?? "").toString().replace(/\D/g, "");
}

export type WorkerInput = {
  first_name?: string;
  middle_name?: string | null;
  last_name_p?: string;
  last_name_m?: string;
  curp?: string;
  rfc?: string;
  nss?: string;
  phone?: string;
  email?: string;
  address?: string;
  blood_type?: string | null;
  hire_type?: string;
  company_id?: number | null;
  position?: string;
  risk_code?: string;
  work_type?: string;
  daily_wage?: number;
  needs_badge?: boolean | number;
  status?: string;
};

export function validateWorkerFields(body: WorkerInput): Record<string, string> {
  const errors: Record<string, string> = {};
  if (!normName(body.first_name)) errors.first_name = "Nombre obligatorio";
  if (!normName(body.last_name_p)) errors.last_name_p = "Apellido paterno obligatorio";
  if (!normName(body.last_name_m)) errors.last_name_m = "Apellido materno obligatorio";

  const curpErr = validateCurp(body.curp ?? "");
  if (curpErr) errors.curp = curpErr;
  const rfcErr = validateRfc(body.rfc ?? "");
  if (rfcErr) errors.rfc = rfcErr;
  const nssErr = validateNss(body.nss ?? "");
  if (nssErr) errors.nss = nssErr;

  if (!normName(body.phone)) errors.phone = "Teléfono obligatorio";
  if (!normName(body.email)) errors.email = "Correo obligatorio";
  if (!normName(body.address)) errors.address = "Dirección obligatoria";

  // Empresa / patrón se asigna solo con el alta IMSS; no es obligatoria en el padrón.
  if (!normName(body.position)) errors.position = "Cargo obligatorio";
  if (!normName(body.risk_code)) errors.risk_code = "Riesgo obligatorio";
  const wt = (body.work_type ?? "").toUpperCase();
  if (!["N", "D"].includes(wt)) errors.work_type = "Tipo de trabajo N o D";
  if (body.daily_wage === undefined || body.daily_wage === null || Number.isNaN(Number(body.daily_wage))) {
    errors.daily_wage = "Jornal obligatorio";
  }
  return errors;
}

export function canonicalRiskCode(raw?: string) {
  const c = (raw ?? "").toLowerCase().trim();
  if (c === "alto") return "rojo";
  if (c === "medio") return "amarillo";
  if (c === "bajo") return "verde";
  return c;
}

export function pipelineLabelFor(status: string): string {
  const labels: Record<string, string> = {
    incompleto: "Falta expediente",
    listo_gafete: "Listo gafete",
    impreso: "Gafete impreso",
    activo: "Activo en proyecto",
    baja: "Baja",
  };
  return labels[status] ?? status;
}

export function normalizeWorker(body: WorkerInput) {
  return {
    first_name: titleCase(body.first_name),
    middle_name: titleCase(body.middle_name) || null,
    last_name_p: titleCase(body.last_name_p),
    last_name_m: titleCase(body.last_name_m),
    curp: normUpper(body.curp),
    rfc: normUpper(body.rfc),
    nss: formatNss(body.nss ?? ""),
    phone: normName(body.phone),
    email: (body.email ?? "").toString().trim().toLowerCase(),
    address: sentenceCase(body.address),
    blood_type: normUpper(body.blood_type) || null,
    hire_type: (body.hire_type ?? "").toUpperCase(),
    position: titleCase(body.position),
    risk_code: canonicalRiskCode(body.risk_code),
    work_type: (body.work_type ?? "").toUpperCase(),
    daily_wage: Number(body.daily_wage ?? 0),
    needs_badge: body.needs_badge === false || body.needs_badge === 0 ? 0 : 1,
    status: body.status === "baja" ? "baja" : "activo",
  };
}

export function fullName(w: {
  first_name: string;
  middle_name?: string | null;
  last_name_p: string;
  last_name_m: string;
}): string {
  return [w.first_name, w.middle_name, w.last_name_p, w.last_name_m]
    .filter(Boolean)
    .join(" ");
}

export function frontName(w: { first_name: string; last_name_p: string }): string {
  return `${w.first_name} ${w.last_name_p}`.trim();
}