/**
 * rigor/dsl-mutation-parity.test.js — js-rigor property tests that a
 * DSL-compiled arbiter and an equivalent hand-written arbiter stay in
 * lock-step through identical MUTATION SEQUENCES.
 *
 * Properties verified:
 *
 *   - SEQUENCE PARITY: starting from the same graph, apply the same random
 *     add/remove sequence to both the DSL-compiled and the hand-written
 *     arbiter; after EVERY mutation the check() answers agree exactly.
 *     This exercises compiled configs (dependency indexes, caches,
 *     invalidation) under mutation, not just static evaluation.
 *   - GRANT/REVOKE CYCLES: interleaved add/remove of the same tuple keeps
 *     both arbiters consistent (no stale compiled state).
 */
import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { rigor } from '@rigor/core';
import { Arbiter } from '../../src/index.js';
import { DSLCompiler } from '../../src/ast/DSLCompiler.js';

const EPS = 1e-9;
const POS = [0, 0.25, 0.5, 0.75, 1];

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

const DSL = `
  definition Doc { id: string }
  definition Dept { id: string }
  fact owns(user: User, doc: Doc)
  fact works_in(user: User, dept: Dept)
  fact has_access(dept: Dept, doc: Doc)
  evidence can_read(user: User, doc: Doc) { owns(user, doc) }
  evidence can_access(user: User, doc: Doc) { works_in(user, *d) { has_access(d, doc) } }
`;

function buildCompiledArbiter() {
  const arbiter = new Arbiter();
  arbiter.addNode('user:alice', 'user');
  arbiter.addNode('dept:eng', 'group');
  arbiter.addNode('doc:1', 'doc');
  const compiler = new DSLCompiler(arbiter);
  const result = compiler.compile(DSL, 'mutation-parity');
  if (!result.success) {
    throw new Error(`DSL compile failed: ${result.errors.join('; ')}`);
  }
  return arbiter;
}

function buildManualArbiter() {
  const arbiter = new Arbiter();
  arbiter.addNode('user:alice', 'user');
  arbiter.addNode('dept:eng', 'group');
  arbiter.addNode('doc:1', 'doc');
  arbiter.setRelationConfig('can_read', { type: 'direct', relation: 'owns' });
  arbiter.setRelationConfig('can_access', {
    type: 'chain',
    steps: [
      { relation: 'works_in', direction: 'out' },
      { relation: 'has_access', direction: 'out' }
    ]
  });
  return arbiter;
}

const RELATIONS = ['owns', 'works_in', 'has_access'];
const SUBJECTS = ['user:alice', 'dept:eng'];

function applyMutation(arbiter, op) {
  const [kind, src, rel, dst, p] = op;
  if (kind === 'add') {
    arbiter.addRelation(src, rel, dst, { possibility: p });
  } else {
    arbiter.removeRelation(src, rel, dst);
  }
}

describe('DSL-compiled vs hand-written parity under mutation (rigor)', () => {
  it('SEQUENCE PARITY: identical mutation sequences keep compiled and manual arbiters in lock-step', async () => {
    async function check(operations) {
      const compiled = buildCompiledArbiter();
      const manual = buildManualArbiter();

      // Same starting graph on both
      for (const arb of [compiled, manual]) {
        arb.addRelation('user:alice', 'owns', 'doc:1', { possibility: 0.5 });
        arb.addRelation('user:alice', 'works_in', 'dept:eng', { possibility: 1 });
        arb.addRelation('dept:eng', 'has_access', 'doc:1', { possibility: 0.75 });
      }

      for (const op of operations) {
        applyMutation(compiled, op);
        applyMutation(manual, op);

        for (const rel of ['can_read', 'can_access']) {
          const c = compiled.check('user:alice', rel, 'doc:1');
          const m = manual.check('user:alice', rel, 'doc:1');
          if (Math.abs(c.possibility - m.possibility) > EPS) {
            fail(`parity ${rel} after ${JSON.stringify(op)}: compiled=${c.possibility}, manual=${m.possibility}`);
          }
        }
      }
      return { ops: operations.length };
    }

    const mutationGen = rigor.gen.oneOf([
      rigor.gen.tuple(
        rigor.gen.constant('add'),
        rigor.gen.oneOf(SUBJECTS),
        rigor.gen.oneOf(RELATIONS),
        rigor.gen.oneOf(SUBJECTS),
        rigor.gen.oneOf(POS)
      ),
      rigor.gen.tuple(
        rigor.gen.constant('remove'),
        rigor.gen.oneOf(SUBJECTS),
        rigor.gen.oneOf(RELATIONS),
        rigor.gen.oneOf(SUBJECTS),
        rigor.gen.constant(0)
      )
    ]);

    const report = await rigor.campaign(
      [
        rigor.fn('check', check, rigor.args(
          rigor.gen.array(mutationGen, 1, 10)
        ))
      ],
      rigor.crucible([
        rigor.invariant('sequence-parity', ({ error, errorMessage }) => !error && !errorMessage)
      ])
    ).run({ effort: 400, seed: 'dsl-mutation-parity' });

    const inv = report.crucibleVerdict?.invariants?.find(i => i.name === 'sequence-parity');
    assert.ok(inv);
    assert.equal(inv.passed, true, `SEQUENCE PARITY violated in ${inv.failureCount} cases`);
  });

  it('GRANT/REVOKE CYCLES: repeated add/remove of the same tuple never desyncs', async () => {
    async function check({ cycles, p }) {
      const compiled = buildCompiledArbiter();
      const manual = buildManualArbiter();

      for (let i = 0; i < cycles; i++) {
        for (const arb of [compiled, manual]) {
          arb.addRelation('user:alice', 'owns', 'doc:1', { possibility: p });
        }
        for (const rel of ['can_read', 'can_access']) {
          const c = compiled.check('user:alice', rel, 'doc:1');
          const m = manual.check('user:alice', rel, 'doc:1');
          if (Math.abs(c.possibility - m.possibility) > EPS) {
            fail(`grant cycle ${i} ${rel}: compiled=${c.possibility}, manual=${m.possibility}`);
          }
        }
        for (const arb of [compiled, manual]) {
          arb.removeRelation('user:alice', 'owns', 'doc:1');
        }
        const c = compiled.check('user:alice', 'can_read', 'doc:1');
        const m = manual.check('user:alice', 'can_read', 'doc:1');
        if (Math.abs(c.possibility - m.possibility) > EPS) {
          fail(`revoke cycle ${i}: compiled=${c.possibility}, manual=${m.possibility}`);
        }
        if (c.possibility !== 0) {
          fail(`revoke cycle ${i}: grant survived removal (${c.possibility})`);
        }
      }
      return { cycles };
    }

    const report = await rigor.campaign(
      [
        rigor.fn('check', check, rigor.args(
          rigor.gen.object({
            cycles: rigor.gen.int(2, 8),
            p: rigor.gen.oneOf([0.25, 0.5, 1])
          })
        ))
      ],
      rigor.crucible([
        rigor.invariant('grant-revoke-cycles', ({ error, errorMessage }) => !error && !errorMessage)
      ])
    ).run({ effort: 300, seed: 'dsl-grant-revoke-cycles' });

    const inv = report.crucibleVerdict?.invariants?.find(i => i.name === 'grant-revoke-cycles');
    assert.ok(inv);
    assert.equal(inv.passed, true, `GRANT/REVOKE CYCLES violated in ${inv.failureCount} cases`);
  });
});