/**
 * tests/DSLRuntime.test.js — higher-order DSL+Core wrapper.
 *
 * Covers:
 *   - schema indexing (types, relations, injectable facts, dependency graph)
 *   - typed inserts/updates (addNode / updateNodeData / addRelation / updateRelation)
 *     reject unknown types, wrong node types, and mistyped field values
 *   - DSL-informed check: derives partial-graph requirements, retrieves missing
 *     injectable facts through providers, injects them, and delegates
 *   - missing-fact reporting
 *
 * NOTE: referencing a derived evidence relation as a sub-rule of another rule
 * (e.g. `WHEN can_read(user, doc)` where can_read is an evidence) lowers to a
 * direct edge lookup and does NOT re-derive the evidence's config. Evidence
 * composition across rules is a documented gap (use fusion or facts).
 */
import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { Arbiter } from '@arbiter/core';
import { DSLRuntime } from '../src/runtime/DSLRuntime.js';

const BASE_DSL = `
  definition Employee { id: string? level: number? active: boolean? }
  definition Group { id: string? }
  definition Doc { id: string? }
  fact member_of(user: Employee, group: Group)
  fact *owns(user: Employee, doc: Doc)
  fact *user_score(user: Employee, value: number)
  fact *granted(user: Employee, doc: Doc)
  fact can_access(group: Group, doc: Doc)
  evidence can_read(user: Employee, doc: Doc) { owns(user, doc) }
  evidence can_enter(user: Employee, doc: Doc) { member_of(user, *g) { can_access(g, doc) } }
  evidence can_borrow(user: Employee, doc: Doc) { WHEN granted(user, doc) UNLESS user_score(user, 1) }
`;

function makeRuntime() {
  return new DSLRuntime(new Arbiter()).compile(BASE_DSL, 'rt-test');
}

describe('DSLRuntime', () => {
  it('indexes the DSL schema', () => {
    const rt = makeRuntime();
    assert.ok(rt.types.has('Employee'));
    assert.equal(rt.types.get('Employee').fields.get('level').type, 'number');
    assert.equal(rt.relations.get('owns').kind, 'fact');
    assert.equal(rt.relations.get('owns').injectable, true);
    assert.equal(rt.relations.get('member_of').injectable, false);
    assert.equal(rt.relations.get('can_read').kind, 'evidence');
    assert.deepEqual(rt.requiredFacts('can_read'), ['owns']);
  });

  it('validates typed node inserts', () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', { level: 3, active: true });
    assert.throws(() => rt.addNode('g:1', 'Ghost', {}), /unknown type/);
    assert.throws(() => rt.addNode('u:2', 'Employee', { level: 'high' }), /must be number/);
    assert.throws(() => rt.addNode('u:3', 'Employee', { active: 'yes' }), /must be boolean/);
  });

  it('validates node updates against the declared type', () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', { level: 3, active: true });
    rt.updateNodeData('u:1', { level: 5 });
    assert.throws(() => rt.updateNodeData('u:1', { level: 'x' }), /must be number/);
  });

  it('validates relation endpoints against declared param types', () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('g:1', 'Group', {});
    rt.addNode('doc:9', 'Doc', {});
    rt.addRelation('u:1', 'member_of', 'g:1', { possibility: 1.0 });
    assert.throws(() => rt.addRelation('u:1', 'member_of', 'doc:9', {}), /expected 'Group'/);
    assert.throws(() => rt.addRelation('u:1', 'ghost_relation', 'g:1', {}), /unknown relation/);
    // value-param fact: second param is a number value, dst must be the subject
    rt.addRelation('u:1', 'user_score', 'u:1', { possibility: 1.0, value: 5 });
    assert.throws(() => rt.addRelation('u:1', 'user_score', 'g:1', { possibility: 1.0, value: 5 }), /self-edge/);
    assert.throws(() => rt.addRelation('u:1', 'user_score', 'u:1', { possibility: 1.0, value: 'high' }), /must be number/);
  });

  it('updateRelation validates and replaces', () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('g:1', 'Group', {});
    rt.addNode('doc:9', 'Doc', {});
    rt.addRelation('u:1', 'member_of', 'g:1', { possibility: 0.5 });
    rt.updateRelation('u:1', 'member_of', 'g:1', { possibility: 1.0 });
    assert.equal(rt.arbiter.check('u:1', 'member_of', 'g:1').possibility, 1.0);
    assert.throws(() => rt.updateRelation('u:1', 'member_of', 'doc:9', {}), /expected 'Group'/);
  });

  it('DSL-informed check retrieves injectable facts via providers', async () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('doc:9', 'Doc', {});
    const res = await rt.check('u:1', 'can_read', 'doc:9', {
      factProviders: { owns: async () => 0.8 }
    });
    assert.equal(res.possibility, 0.8);
    assert.equal(res.reason, 'allow_rule_matched');
    assert.deepEqual(res.requiredFacts, ['owns']);
    assert.deepEqual(res.providedFacts, ['owns']);
    assert.deepEqual(res.missingFacts, []);
  });

  it('reports missing facts when a provider declines', async () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('doc:9', 'Doc', {});
    const res = await rt.check('u:1', 'can_read', 'doc:9', {
      factProviders: { owns: async () => null }
    });
    assert.equal(res.possibility, 0);
    assert.deepEqual(res.missingFacts, [{ relation: 'owns', reason: 'not_provided' }]);
  });

  it('merges caller-supplied partial graphs with provider results', async () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('doc:9', 'Doc', {});
    const res = await rt.check('u:1', 'can_read', 'doc:9', {
      partialGraph: { relations: [{ src: 'u:1', relation: 'owns', dst: 'doc:9', possibility: 1.0 }] },
      factProviders: { owns: async () => null }
    });
    assert.equal(res.possibility, 1.0);
  });

  it('unary condition inside binary evidence (subject-as-object) defeats the grant', async () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('doc:9', 'Doc', {});
    // can_borrow: WHEN granted(user, doc) UNLESS user_score(user, 1).
    // user_score is injectable+unary; the provider injects a user self-edge
    // with value 1 -> the unless fires and defeats the grant.
    const res = await rt.check('u:1', 'can_borrow', 'doc:9', {
      factProviders: {
        granted: async () => 0.9,
        user_score: async () => ({ possibility: 1.0, value: 1 })
      }
    });
    assert.equal(res.possibility, 0);
    assert.equal(res.reason, 'defeated_by_unless');
    assert.deepEqual(res.requiredFacts, ['granted', 'user_score']);
  });

  it('chain evidence across an intermediate validates and checks', async () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('g:1', 'Group', {});
    rt.addNode('doc:9', 'Doc', {});
    rt.addRelation('u:1', 'member_of', 'g:1', { possibility: 1.0 });
    rt.addRelation('g:1', 'can_access', 'doc:9', { possibility: 0.7 });
    // can_enter: member_of(user, *g) { can_access(g, doc) } — chain [member_of, can_access]
    const res = await rt.check('u:1', 'can_enter', 'doc:9', {});
    assert.equal(res.possibility, 0.7);
  });

  it('rejects checks against unknown relations in strict mode', async () => {
    const rt = makeRuntime();
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('doc:9', 'Doc', {});
    await assert.rejects(() => rt.check('u:1', 'does_not_exist', 'doc:9'), /unknown relation/);
  });

  it('derives transitive required facts through evidence composition', async () => {
    const dsl = `
      definition Employee { id: string? }
      definition Doc { id: string? }
      fact *owns(user: Employee, doc: Doc)
      fact *banned(user: Employee)
      evidence can_read(user: Employee, doc: Doc) { owns(user, doc) }
      evidence can_open(user: Employee, doc: Doc) { WHEN can_read(user, doc) UNLESS banned(user) }
    `;
    const rt = new DSLRuntime(new Arbiter()).compile(dsl, 'rt-comp');
    rt.addNode('u:1', 'Employee', {});
    rt.addNode('doc:9', 'Doc', {});
    // can_open composes can_read, so its requirements reach through to owns.
    assert.deepEqual(rt.requiredFacts('can_open'), ['owns', 'banned']);
    const granted = await rt.check('u:1', 'can_open', 'doc:9', {
      factProviders: { owns: async () => 0.9, banned: async () => 0 }
    });
    assert.equal(granted.possibility, 0.9);
    assert.equal(granted.reason, 'allow_rule_matched');
    assert.deepEqual(granted.providedFacts, ['owns', 'banned']);
    const denied = await rt.check('u:1', 'can_open', 'doc:9', {
      factProviders: { owns: async () => 0.9, banned: async () => 1 }
    });
    assert.equal(denied.possibility, 0);
    assert.equal(denied.reason, 'defeated_by_unless');
  });

  it('derives transitive required facts through a condition-step chain', () => {
    const dsl = `
      definition Employee { id: string? }
      definition Group { id: string? }
      definition Doc { id: string? }
      fact *member_of(user: Employee, group: Group)
      fact *can_view(group: Group, doc: Doc)
      fact *banned(group: Group)
      evidence gated(group: Group, doc: Doc) { WHEN can_view(group, doc) UNLESS banned(group) }
      evidence can_via(user: Employee, doc: Doc) { member_of(user, *g) { gated(g, doc) } }
    `;
    const rt = new DSLRuntime(new Arbiter()).compile(dsl, 'rt-cond');
    // The condition step's facts (can_view, banned) reach through to the
    // evidence's requirements, alongside the edge-traversal fact.
    assert.deepEqual(rt.requiredFacts('can_via'), ['member_of', 'can_view', 'banned']);
  });
});