/**
 * rigor/multi-object-independence.test.js — js-rigor property tests for
 * cross-object isolation.
 *
 * Shared groups connect multiple objects: alice is a member of group:eng,
 * and BOTH doc:1 and doc:2 have owner tuples pointing at group:eng.
 * Mutations affecting one object must never change another object's
 * checks.
 *
 * Properties verified:
 *
 *   - PER-OBJECT ORACLE PARITY: every check on every object equals the
 *     per-object oracle computed from the edge set (TTU:
 *     max over tuples of min(tupleP, memberP); chain: BFS per object).
 *   - MUTATION ISOLATION: after every mutation targeting one object, all
 *     OTHER objects' checks are unchanged (equal to their own oracles).
 */
import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { rigor } from '@rigor/core';
import { Arbiter } from '../../src/index.js';

const EPS = 1e-9;
const POS = [0, 0.25, 0.5, 0.75, 1];
const USERS = ['user:alice', 'user:bob'];
const DOCS = ['doc:1', 'doc:2', 'doc:3'];
const GROUPS = ['group:eng', 'group:design'];

function fail(message) {
  throw new Error(message);
}

function mulberry32(seed) {
  let a = seed >>> 0;
  return {
    next() {
      a |= 0; a = (a + 0x6D2B79F5) | 0;
      let t = Math.imul(a ^ (a >>> 15), 1 | a);
      t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
      return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
    }
  };
}

function buildArbiter() {
  const arb = new Arbiter();
  for (const k of [...USERS, ...DOCS, ...GROUPS]) {
    arb.addNode(k, k.startsWith('user') ? 'user' : k.startsWith('doc') ? 'doc' : 'group');
  }
  arb.setRelationConfig('owner', { type: 'direct' });
  arb.setRelationConfig('member_of', { type: 'direct' });
  arb.setRelationConfig('can_edit', { type: 'tuple_to_userset', tuplesetRelation: 'owner', computedRelation: 'member_of' });
  arb.setRelationConfig('viewer', { type: 'direct' });
  arb.setRelationConfig('member_of2', { type: 'direct' });
  return arb;
}

function randomState(rng) {
  // Random membership + tuple edges
  const edges = [];
  for (const user of USERS) {
    for (const grp of GROUPS) {
      if (rng.next() < 0.6) {
        const p = POS[Math.floor(rng.next() * POS.length)];
        edges.push(['member_of', user, grp, p]);
      }
    }
  }
  for (const doc of DOCS) {
    for (const grp of GROUPS) {
      if (rng.next() < 0.6) {
        const p = POS[Math.floor(rng.next() * POS.length)];
        edges.push(['owner', doc, grp, p]);
      }
    }
  }
  return edges;
}

function applyEdges(arb, edges) {
  for (const [rel, src, dst, p] of edges) arb.addRelation(src, rel, dst, { possibility: p });
}

function ttuOracle(user, doc, edges) {
  let best = 0;
  for (const [rel, src, dst, p] of edges) {
    if (rel !== 'owner' || src !== doc) continue;
    const member = edges.find(e => e[0] === 'member_of' && e[1] === user && e[2] === dst);
    best = Math.max(best, Math.min(p, member ? member[3] : 0));
  }
  return best;
}

function checkAll(arb, edges) {
  const results = {};
  for (const user of USERS) {
    for (const doc of DOCS) {
      results[`${user}|${doc}`] = {
        got: arb.check(user, 'can_edit', doc, {}).possibility,
        oracle: ttuOracle(user, doc, edges)
      };
    }
  }
  return results;
}

describe('Multi-object independence (rigor)', () => {
  it('PER-OBJECT ORACLE PARITY + MUTATION ISOLATION through random mutations', async () => {
    async function check({ seed, mutations }) {
      const rng = mulberry32(seed);
      const edges = randomState(rng);
      const arb = buildArbiter();
      applyEdges(arb, edges);

      const verify = (tag) => {
        const results = checkAll(arb, edges);
        for (const [key, r] of Object.entries(results)) {
          if (Math.abs(r.got - r.oracle) > EPS) {
            fail(`${tag} ${key}: got=${r.got} oracle=${r.oracle}`);
          }
        }
      };

      verify('initial');

      for (let i = 0; i < mutations; i++) {
        // Mutate a single edge; the target is one user/doc pair
        const rel = rng.next() < 0.5 ? 'owner' : 'member_of';
        const src = rel === 'owner' ? DOCS[Math.floor(rng.next() * DOCS.length)] : USERS[Math.floor(rng.next() * USERS.length)];
        const dst = GROUPS[Math.floor(rng.next() * GROUPS.length)];
        const idx = edges.findIndex(e => e[0] === rel && e[1] === src && e[2] === dst);
        if (idx !== -1) {
          arb.removeRelation(src, rel, dst);
          edges.splice(idx, 1);
        } else {
          const p = POS[Math.floor(rng.next() * POS.length)];
          arb.addRelation(src, rel, dst, { possibility: p });
          edges.push([rel, src, dst, p]);
        }
        verify(`mutation ${i}`);
      }
      return { edges: edges.length };
    }

    const report = await rigor.campaign(
      [
        rigor.fn('check', check, rigor.args(
          rigor.gen.object({
            seed: rigor.gen.int(1, 80000),
            mutations: rigor.gen.int(3, 10)
          })
        ))
      ],
      rigor.crucible([
        rigor.invariant('multi-object-isolation', ({ error, errorMessage }) => !error && !errorMessage)
      ])
    ).run({ effort: 1000, seed: 'multi-object-independence' });

    const inv = report.crucibleVerdict?.invariants?.find(i => i.name === 'multi-object-isolation');
    assert.ok(inv, 'invariant missing');
    assert.equal(inv.passed, true, `multi-object isolation violated in ${inv.failureCount} cases`);
  });
});