// #797 / #1839 extends row 252's signed-in Console answers to ordinary decisions. Two POSTs.
// /confirmation asks the bus for authoritative answers and digest and returns a one-use
// confirmation bound to this session, business,
// decision, choice and digest. /resolve takes only that choice and confirmation, consumes the
// confirmation before it awaits the bus, and asks the bus to resolve with the digest. The bus
// rechecks everything in the resolve transaction. Nothing here retries.
import { createHash, randomBytes } from 'node:crypto';
import { BusReadError, subjectOk } from './bus.mjs';

export const DECISION_ROUTE = /^\/api\/decisions\/([^/]*)\/(confirmation|resolve|start|templates)$/;
// The endpoint contract, design section 4. Each refusal is one of these, never a 200.
export const DECISION_REFUSALS = Object.freeze({
  'sign-in-required': [401, 'Sign in again before answering.'],
  'read-only': [403, 'Console decision answers are not enabled. Use mosaic decide.'],
  'cross-origin': [403, 'Answer from the signed-in Console page.'],
  'not-found': [404, 'Not found.'],
  'human-required': [403, 'The bus refused this human identity.'],
  'peercred-required': [403, 'The bus could not verify this connection.'],
  'method-not-allowed': [405, 'Use POST.'],
  'invalid-request': [400, 'Invalid decision answer.'],
  'request-too-large': [413, 'Decision answer is too large.'],
  'decision-not-found': [404, 'This decision is unavailable.'],
  'decision-not-eligible': [403, 'Answer this decision with mosaic decide.'],
  'decision-closed': [409, 'This decision is no longer open. Refresh the inbox.'],
  'hire-owner-required': [403, 'Only the owner may approve these grants or a root agent.'],
  'right-required': [403, 'This decision needs org.hire.'],
  'decision-expired': [409, 'This decision expired. Ask for a fresh proposal.'],
  'hire-resolution-required': [403, 'Use the hire approval path.'],
  'decision-stale': [409, 'The choices changed. Review the decision again.'],
  'confirmation-required': [409, 'Review and confirm this answer again.'],
  'confirmation-unavailable': [503, 'Confirmation is unavailable. Try again later.'],
  'outcome-unknown': [503, 'The answer may have reached the bus. Refresh before trying again.'],
});
// Bus codes by name. A bus that refuses this caller is human-required, whatever its code. Any
// other code, or no answer, is confirmation-unavailable at the preview and outcome-unknown at the
// resolve, which the page reads as "refresh first".
const BUS_CODES = {
  'human-required': 'human-required', unauthenticated: 'human-required', 'unknown-business': 'human-required',
  'access-refused': 'human-required', 'access-revoked': 'human-required', 'agent-required': 'human-required',
  'peercred-required': 'peercred-required',
  'decision-not-found': 'decision-not-found', 'decision-not-eligible': 'decision-not-eligible',
  'decision-closed': 'decision-closed', 'decision-stale': 'decision-stale', 'invalid-choice': 'decision-stale',
  'invalid-request': 'invalid-request', 'hire-owner-required':'hire-owner-required','right-required':'right-required','decision-expired':'decision-expired','hire-resolution-required':'hire-resolution-required',
};
// D4 (#1873, P1-2): a hire, fire or change start the bus definitely refused keeps its own code,
// but only for codes the broker raises before it records the decision: the proposal checks in
// hire-decisions.mjs prepare(), which #raiseHire runs before its INSERT. hire.start.console then
// resolves the decision and applies it in #hireConsole, and those steps can raise other codes (and
// some of the same generic ones) after the decision exists or is consumed, so every code not listed
// here stays outcome-unknown. Review P3: an allowlist, not a pass-through of any well-formed code.
const HIRE_START_REFUSALS = {
  'model-provider-unavailable': [409, 'The model proxy does not offer this model, or its catalogue is not ready. Pick a model it offers, or ask the owner to check Settings > Model proxy. Nothing was applied.'],
  'model-catalogue-unavailable': [503, 'The model catalogue could not be read, so this model could not be checked. Check Settings > Model proxy, then try again. Nothing was applied.'],
  'model-harness-incompatible': [409, 'This model does not run on the chosen harness. Pick another model or harness. Nothing was applied.'],
  'thinking-unsupported': [409, 'The chosen harness does not apply this thinking level. Clear Thinking or pick a level it applies. Nothing was applied.'],
  'definition-not-hireable': [409, 'This organization does not hire agents from this role template. Pick another template. Nothing was applied.'],
  'definition-shared': [409, 'Another agent uses the same role definition, so this change cannot replace it. Nothing was applied.'],
  'no-chief-of-staff': [409, 'This organization has no chief of staff, so a hire, fire or change cannot be checked against it. Nothing was applied.'],
};
// #1873 CB5: the owner's next step once a copy credential binding decision is approved, fixed text
// (design section 6 and its three steps). Nothing in it comes from the decision, the bus or a token.
export const BINDING_NEXT = Object.freeze({
  bind: "Binding approved. Issue the copy's token with mosaic credentials issue, then restart the organization bus. The copy's status on the Agents grid names each next step.",
  unbind: "Unbind approved. The bus stops the copy's runs and revokes its credential. The copy's status on the Agents grid shows when the revoke finishes.",
});
// A binding decision's preview names its copy and whether it binds or unbinds. Only those two leave
// this server: the copy id, incarnation, definition pin and services stay with the bus. The owner's
// preview verb is the one bus answer that carries them; the inbox and the trail send the same two.
const bindingOf = (v) => (v?.binding && typeof v.binding === 'object' && subjectOk(v.binding.instance) &&
  (v.binding.after === null || (typeof v.binding.after === 'object' && !Array.isArray(v.binding.after)))
  ? { instance: v.binding.instance, change: v.binding.after === null ? 'unbind' : 'bind' } : null);
const BODY_MAX = 4096;
const TOKEN = /^[a-f0-9]{64}$/;
const DIGEST = /^[a-f0-9]{64}$/;
const one = (req, name) => (req.headersDistinct[name]?.length === 1 ? req.headersDistinct[name][0] : null);
const hash = (token) => createHash('sha256').update(token).digest('hex');
export function decisionRefuse(res, code) {
  const [status, message] = DECISION_REFUSALS[code];
  res.writeHead(status, { 'content-type': 'application/json', 'cache-control': 'no-store' });
  res.end(JSON.stringify({ error: code, message }));
}

// The confirmations, in this process's memory only and stored by hash. 120 seconds, at most 1024
// live. A full store refuses a new one rather than drop a live one. An expired one is swept.
export function createConfirmations({ ttlMs = 120000, max = 1024, now = Date.now } = {}) {
  const live = new Map();
  const sweep = () => { const t = now(); for (const [k, v] of live) if (v.expires <= t) live.delete(k); };
  return {
    issue(binding) {
      sweep();
      if (live.size >= max) return null;
      const token = randomBytes(32).toString('hex');
      live.set(hash(token), { ...binding, expires: now() + ttlMs });
      return token;
    },
    // One use: a token found is gone, whether or not it matches.
    consume(token, { session, decision, choice }) {
      sweep();
      if (typeof token !== 'string' || !TOKEN.test(token)) return null;
      const k = hash(token), v = live.get(k);
      if (!v) return null;
      live.delete(k);
      return v.session === session && v.decision === decision && v.choice === choice ? v : null;
    },
    get size() { sweep(); return live.size; },
  };
}

async function readBody(req, max = BODY_MAX) {
  if (one(req, 'content-type')?.split(';')[0].trim().toLowerCase() !== 'application/json') return { code: 'invalid-request' };
  const chunks = [];
  let size = 0;
  for await (const chunk of req) {
    size += chunk.length;
    if (size > max) return { code: 'request-too-large' };
    chunks.push(chunk);
  }
  try {
    const value = JSON.parse(Buffer.concat(chunks).toString('utf8'));
    return value && typeof value === 'object' && !Array.isArray(value) ? { value } : { code: 'invalid-request' };
  } catch { return { code: 'invalid-request' }; }
}
const option = o => o && typeof o.key === 'string' && o.key.length > 0 && typeof o.text === 'string' && o.text.length > 0;
const options = list => Array.isArray(list) && list.length >= 2 && list.length <= 9 && list.every(option) && new Set(list.map(o => o.key)).size === list.length;
function preview(v, id) {
  if (!v || v.id !== id || typeof v.business !== 'string' || !DIGEST.test(v.digest ?? '')) return false;
  if(v.kind==='hire')return options(v.options) && Array.isArray(v.flagged) && Array.isArray(v.credentialLines) && typeof v.expiresAt==='string';
  if (v.kind === 'decision') return options(v.options) && !['grant', 'approve', 'deny'].some(k => k in v);
  // Retain the existing grant preview fields, including previews from an older pinned broker.
  return (v.kind === undefined || v.kind === 'grant') && option(v.approve) && option(v.deny) &&
    v.approve.key !== v.deny.key && v.grant && typeof v.grant.method === 'string' &&
    (v.options === undefined || (options(v.options) && v.options.length === 2 &&
      [v.approve, v.deny].every(o => v.options.some(x => x.key === o.key && x.text === o.text))));
}

// `session` is the live sign-in session object this request passed, and `live()` reads it again
// right before each spawn. `call(verb, args, { subject, business })` is the console transport.
export async function decisionHTTP(req, res, { path, decide, session, live, confirmations, log }) {
  const [, raw, step] = DECISION_ROUTE.exec(path);
  let id = null;
  try { id = decodeURIComponent(raw); } catch { /* refused below */ }
  if (req.method !== 'POST') return decisionRefuse(res, 'method-not-allowed');
  if (!decide) return decisionRefuse(res, 'read-only');
  if (!session) return decisionRefuse(res, 'sign-in-required');
  if (one(req, 'origin') !== decide.origin || one(req, 'sec-fetch-site') !== 'same-origin') return decisionRefuse(res, 'cross-origin');
  const line = (outcome) => log(`${new Date().toISOString()} decide user=${JSON.stringify(String(session.name ?? '').slice(0, 64))} decision=${JSON.stringify(String(id ?? '').slice(0, 64))} step=${step} ${outcome}`);
  const refuse = (code) => { line(`error=${code}`); return decisionRefuse(res, code); };
  const { value, code } = await readBody(req, step==='start'?32768:BODY_MAX);
  if (code) return refuse(code);
  if (!subjectOk(id)) return refuse('decision-not-found');
  const subject = { provider: session.provider, iss: session.iss, sub: session.sub };
  const busCode = (err, open) => {
    const c = err instanceof BusReadError ? BUS_CODES[err.code] : undefined;
    return c ?? open;
  };
  if(step==='start' || step==='templates') {
    const allowed=step==='start'?['business','hire']:['business'];
    if(id!=='hire' || Object.keys(value).length!==allowed.length || Object.keys(value).some(k=>!allowed.includes(k)) || !subjectOk(value.business))return refuse('invalid-request');
    if(live()!==session)return refuse('sign-in-required');
    try {
      const result=await decide.call(step==='start'?'hire.start.console':'hire.templates.console',step==='start'?value.hire:{},{subject,business:value.business});
      if(step==='start' && (typeof result?.id!=='string'||result.op!=='resolved'||result.choice!=='yes'))return refuse('outcome-unknown');
      if(step==='templates' && !Array.isArray(result?.templates))return refuse('confirmation-unavailable');
      line(step==='start'?'hire=recorded':'templates=read');
      // CB5: an approved binding start says what the owner does next, fixed text by its shape.
      const change=step==='start' && value.hire?.binding && typeof value.hire.binding==='object' && 'services' in value.hire.binding
        ? (value.hire.binding.services===null?'unbind':'bind') : null;
      return json(res,200,step==='start'?{id:result.id,op:result.op,choice:result.choice,...(change?{next:BINDING_NEXT[change]}:{})}:result);
    } catch(err) {
      if(step!=='start' || !(err instanceof BusReadError) || !Object.hasOwn(HIRE_START_REFUSALS,err.code))
        return refuse(busCode(err,step==='start'?'outcome-unknown':'confirmation-unavailable'));
      const [status,message]=HIRE_START_REFUSALS[err.code];
      line(`error=${err.code}`);
      return json(res,status,{error:err.code,message});
    }
  }
  if (step === 'confirmation') {
    if (Object.keys(value).some(k=>!['choice','adjust'].includes(k)) || typeof value.choice !== 'string') return refuse('invalid-request');
    if (live() !== session) return refuse('sign-in-required');
    let v;
    try { v = await decide.call(value.adjust===undefined?'decision.preview.console':'hire.preview.console', { id,...(value.adjust===undefined?{}:{adjust:value.adjust}) }, { subject }); } catch (err) { return refuse(busCode(err, 'confirmation-unavailable')); }
    if (!preview(v, id)) return refuse('confirmation-unavailable');
    const ordinary = v.kind === 'decision' || v.kind === 'hire';
    const chosen = (ordinary ? v.options : [v.approve, v.deny]).find(o => o.key === value.choice);
    if (!chosen) return refuse('decision-stale');
    const action = ordinary ? 'answer' : value.choice === v.approve.key ? 'approve' : 'deny';
    if (live() !== session) return refuse('sign-in-required');
    if(value.adjust!==undefined && v.kind!=='hire')return refuse('invalid-request');
    const binding = v.kind === 'hire' ? bindingOf(v) : null;
    const confirmation = confirmations.issue({ session, business: v.business, decision: id, choice: value.choice, digest: v.digest, ...(v.kind==='hire'?{kind:'hire',...(value.adjust===undefined?{}:{adjust:structuredClone(value.adjust)}),...(binding?{change:binding.change}:{})}:{}) });
    if (!confirmation) return refuse('confirmation-unavailable');
    line(`action=${action}`);
    return json(res, 200, { id, question: typeof v.question === 'string' ? v.question : '', action, choice: value.choice, text: chosen.text,
      ...(v.kind==='hire'?{kind:'hire',flagged:v.flagged,credentialLines:v.credentialLines,expiresAt:v.expiresAt,...(binding?{binding}:{})}:ordinary ? { kind: 'decision' } : { grant: v.grant }), confirmation });
  }
  const keys = Object.keys(value);
  if (keys.length !== 2 || !keys.includes('choice') || !keys.includes('confirmation') || typeof value.choice !== 'string') return refuse('invalid-request');
  // Consumed before any await on the bus, so a second click finds nothing (J12).
  const held = confirmations.consume(value.confirmation, { session, decision: id, choice: value.choice });
  if (!held) return refuse('confirmation-required');
  if (live() !== session) return refuse('sign-in-required');
  let r;
  try {
    r = await decide.call(held.kind==='hire'?'hire.resolve.console':'decision.resolve.console', { id, choice: held.choice, digest: held.digest,...(held.adjust===undefined?{}:{adjust:held.adjust}) }, { subject, business: held.business });
  } catch (err) { return refuse(busCode(err, 'outcome-unknown')); }
  if (r?.id !== id || r.op !== 'resolved' || r.choice !== held.choice) return refuse('outcome-unknown');
  line(`choice=${JSON.stringify(held.choice.slice(0, 64))}${r.grant ? ` grant=${r.grant}` : ''}`);
  return json(res, 200, { id, op: 'resolved', choice: r.choice, ...(r.grant === 'started' ? { grant: 'started' } : {}),
    ...(held.change && r.choice === 'yes' ? { next: BINDING_NEXT[held.change] } : {}) });
}
function json(res, status, body) {
  res.writeHead(status, { 'content-type': 'application/json', 'cache-control': 'no-store' });
  res.end(JSON.stringify(body));
}