/* The part the client actually cares about: personalization that is not made up.

   The rule is structural, not a polite instruction in a prompt. A message is
   generated from a Signal object. If no Signal survives validation there is
   nothing to generate from, so the prospect is flagged and no copy is written.
   A model cannot talk its way past a missing argument. */

export const MAX_AGE_DAYS = 120;

/* Signal kinds we accept, roughly in the order a salesperson would rank them.
   Weight feeds the personalization score. */
export const KINDS = {
  funding: 5, acquisition: 5, launch: 4, partnership: 4,
  licence: 4, expansion: 3, exec_hire: 3, media: 2, conference: 2
};

export class Signal {
  constructor({ kind, summary, url, published, quote }) {
    this.kind = kind;
    this.summary = summary;
    this.url = url;
    this.published = published;
    this.quote = quote || null;
  }
}

/* Every one of these has to pass. Anything that fails is not a signal, it is
   a guess wearing a source. */
export function validate(sig, today = new Date()) {
  const fail = [];
  if (!KINDS[sig?.kind]) fail.push('unknown_kind');
  if (!sig?.url || !/^https?:\/\//.test(sig.url)) fail.push('no_source_url');
  if (!sig?.published || Number.isNaN(Date.parse(sig.published))) fail.push('no_publish_date');
  else {
    const age = (today - new Date(sig.published)) / 864e5;
    if (age > MAX_AGE_DAYS) fail.push(`stale_${Math.round(age)}d`);
    if (age < -1) fail.push('future_dated');
  }
  if (!sig?.summary || sig.summary.length < 25) fail.push('summary_too_thin');
  /* the summary has to be about this company, not the sector */
  return { ok: fail.length === 0, fail };
}

/* ICP score is mechanical: it comes from fields Apollo already gave us, so it
   is reproducible and arguable. No model opinion in here. */
export function icpScore(p, icp) {
  let s = 0;
  if (icp.titles.some((t) => (p.title || '').toLowerCase().includes(t.toLowerCase()))) s += 2;
  else if (['founder', 'c_suite', 'owner', 'vp'].includes(p.seniority)) s += 1;
  const n = p.headcount || 0;
  if (n >= icp.min_headcount && n <= icp.max_headcount) s += 1;
  if ((p.city || '').toLowerCase() === icp.city.toLowerCase()) s += 1;
  if (p.linkedin_url) s += 1;
  return Math.max(1, Math.min(5, s));
}

/* Personalization score is the strength of the evidence, not the prose. */
export function persScore(sig, today = new Date()) {
  if (!sig) return 1;
  const age = (today - new Date(sig.published)) / 864e5;
  let s = KINDS[sig.kind] || 1;
  if (age > 60) s -= 1;
  if (sig.quote) s += 1;
  return Math.max(1, Math.min(5, s));
}

/* The gate. Returns either a writable prospect or a flagged one. */
export function decide(p, sig, icp, today = new Date()) {
  const v = validate(sig, today);
  const icp_score = icpScore(p, icp);
  if (!v.ok) {
    return {
      ...p, icp_score, personalization_score: 1,
      status: 'flagged', flag_reason: v.fail.join(', '),
      icebreaker: null, email_body: null, linkedin_message: null
    };
  }
  return {
    ...p, icp_score,
    personalization_score: persScore(sig, today),
    status: 'ready',
    trigger_kind: sig.kind,
    trigger_summary: sig.summary,
    trigger_source: sig.url,
    trigger_date: sig.published
  };
}

/* Length rules from the brief, checked after generation rather than hoped for
   in a prompt. Anything out of range goes back once, then gets flagged. */
export const LIMITS = { email: [60, 100], linkedin: [30, 60] };
export const words = (t) => (t || '').trim().split(/\s+/).filter(Boolean).length;
export function inRange(kind, text) {
  const [lo, hi] = LIMITS[kind];
  const n = words(text);
  return { n, ok: n >= lo && n <= hi };
}