'use strict';

const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');
const test = require('node:test');
const { withFixture, write, update } = require('./helpers/context-fixture');
const { resolveTaskContext, resolveDeclinedFallback } = require('../../scripts/lib/context-selection');

const task = (values = {}) => ({ sessionId: 'session-1', taskId: 'task-1', revision: 1,
  phase: 'implement', query: '', explicitIds: [], proposedIds: [], ...values });
const resolve = (repoRoot, input, values = {}) => resolveTaskContext({ repoRoot, task: task(input), ...values });

test('Auto loads exact requested context and preserves the Lean base', () => withFixture(repoRoot => {
  const result = resolve(repoRoot, { explicitIds: ['skill:feature'] }, { load: true });
  assert.deepEqual(result.selectedIds, ['skill:feature']);
  assert.deepEqual(result.loadedIds, ['skill:feature']);
  assert.equal(result.profileId, 'lean@1');
  assert.equal(result.activation, 'context-returned');
  assert.match(result.resources[0].content, /# feature/);
  assert.equal(result.nativeInvocation, 'unobserved');
}));

test('simple tasks return an empty successful selection', () => withFixture(repoRoot => {
  const result = resolve(repoRoot, { noWorkflow: true, query: 'hello' }, { load: true });
  assert.deepEqual(result.selectedIds, []);
  assert.equal(result.reason, 'no-workflow-needed');
}));

test('suggest returns candidates without loading and manual ignores proposals', () => withFixture(repoRoot => {
  assert.deepEqual(resolve(repoRoot, { proposedIds: ['skill:feature'] }, { selectionMode: 'manual', load: true }).selectedIds, []);
  const suggestion = resolve(repoRoot, { proposedIds: ['skill:feature'] }, { selectionMode: 'suggest', load: true });
  assert.deepEqual(suggestion.selectedIds, ['skill:feature']);
  assert.deepEqual(suggestion.loadedIds, []);
}));

test('exclusions cannot be bypassed by explicit IDs or dependencies', () => withFixture(repoRoot => {
  assert.throws(() => resolve(repoRoot, { explicitIds: ['skill:feature'] }, { exclude: ['skill:feature'] }), /excluded/);
  update(repoRoot, 'manifests/context-packs/skill-registry@1.json', value => ({ ...value,
    overrides: [{ id: 'skill:feature', dependencies: ['skill:shared'], requiredResources: ['skills/feature/references/details.md'] }] }));
  assert.throws(() => resolve(repoRoot, { explicitIds: ['skill:feature'] }, { exclude: ['skill:shared'] }), /excluded/);
  const result = resolve(repoRoot, { explicitIds: ['skill:feature'] }, { load: true });
  assert.deepEqual(result.loadedIds, ['skill:feature', 'skill:shared']);
  assert.ok(result.resources.some(resource => resource.path.endsWith('details.md')));
}));

test('manual-only native policy rejects implicit proposals and allows explicit request', () => withFixture(repoRoot => {
  write(repoRoot, 'skills/feature/SKILL.md', '---\nname: feature\ndescription: Feature work\ndisable-model-invocation: true\n---\nFeature instructions');
  assert.throws(() => resolve(repoRoot, { proposedIds: ['skill:feature'] }, { load: true }), /manual-only/);
  assert.deepEqual(resolve(repoRoot, { explicitIds: ['skill:feature'] }, { load: true }).loadedIds, ['skill:feature']);
}));

test('manual-only dependencies require their own explicit request', () => withFixture(repoRoot => {
  write(repoRoot, 'skills/shared/agents/openai.yaml', 'policy:\n  allow_implicit_invocation: false\n');
  update(repoRoot, 'manifests/context-packs/skill-registry@1.json', value => ({ ...value,
    overrides: [{ id: 'skill:feature', dependencies: ['skill:shared'] }] }));
  assert.throws(() => resolve(repoRoot, { explicitIds: ['skill:feature'] }, { load: true }), /manual-only.*skill:shared/);
  const result = resolve(repoRoot, { explicitIds: ['skill:feature', 'skill:shared'] }, { load: true });
  assert.deepEqual(result.loadedIds, ['skill:feature', 'skill:shared']);
}));

for (const load of [false, true]) {
  test(`policy resource drift after registry compilation rejects selection (load=${load})`, context => withFixture(repoRoot => {
    const relative = 'skills/feature/agents/openai.yaml';
    write(repoRoot, relative, 'policy:\n  allow_implicit_invocation: false\n');
    const policyPath = path.join(fs.realpathSync(repoRoot), relative);
    const originalOpen = fs.openSync;
    const originalRead = fs.readSync;
    let policyOpens = 0;
    let changedDescriptor;
    let alteredReads = 0;
    context.mock.method(fs, 'openSync', (filename, ...args) => {
      const descriptor = originalOpen(filename, ...args);
      // First compile the profile, then reload the canonical registry. Only
      // the subsequent policy read observes replacement bytes.
      if (filename === policyPath && ++policyOpens === 3) changedDescriptor = descriptor;
      return descriptor;
    });
    context.mock.method(fs, 'readSync', (descriptor, buffer, offset, length, position) => {
      const count = originalRead(descriptor, buffer, offset, length, position);
      if (descriptor === changedDescriptor && count > 0) {
        const source = buffer.toString('utf8', offset, offset + count);
        const replacement = source.replace('false', 'true ');
        assert.notEqual(replacement, source);
        buffer.write(replacement, offset, count, 'utf8');
        alteredReads++;
      }
      return count;
    });
    try {
      assert.throws(() => resolve(repoRoot, { proposedIds: ['skill:feature'] }, { load }),
        /Context source changed during selection/);
      assert.equal(policyOpens, 3);
      assert.equal(alteredReads, 1);
    } finally { context.mock.restoreAll(); }
  }));
}

test('authority-bearing metadata cannot become automatic invocation', () => withFixture(repoRoot => {
  write(repoRoot, 'skills/feature/SKILL.md', '---\nname: feature\ndescription: Feature work\nallowed-tools: Bash\n---\nRun !`touch /tmp/never-run`');
  assert.throws(() => resolve(repoRoot, { proposedIds: ['skill:feature'] }, { load: true }), /authority|dynamic/);
}));

test('receipt pins source and task identity without retaining query text', () => withFixture(repoRoot => {
  const first = resolve(repoRoot, { proposedIds: ['skill:feature'], query: 'private task prose' });
  assert.ok(!JSON.stringify(first.receipt).includes('private task prose'));
  const second = resolve(repoRoot, { query: 'private task prose' }, { previous: first.receipt });
  assert.deepEqual(second.selectedIds, first.selectedIds);
  assert.equal(second.reused, true);
  const reworded = resolve(repoRoot, { query: 'reworded' }, { previous: first.receipt });
  assert.equal(reworded.reused, false);
  assert.notEqual(reworded.receipt.bindingDigest, first.receipt.bindingDigest);
  assert.throws(() => resolve(repoRoot, {}, { previous: { ...first.receipt, selectedIds: ['skill:shared'] } }), /receipt/);
  const changed = resolve(repoRoot, { sessionId: 'session-2' }, { previous: first.receipt });
  assert.equal(changed.reused, false);
}));

test('trigger changes invalidate a pinned Auto receipt', () => withFixture(repoRoot => {
  const first = resolve(repoRoot, { proposedIds: ['skill:feature'], query: 'feature work' });
  write(repoRoot, 'manifests/context-packs/skill-triggers@1.json', JSON.stringify({
    schemaVersion: 1, triggers: { 'skill:feature': ['feature work'] },
  }));
  const second = resolve(repoRoot, { query: 'feature work' }, { previous: first.receipt });
  assert.equal(second.reused, false);
  assert.notEqual(second.receipt.bindingDigest, first.receipt.bindingDigest);
}));

for (const [label, taskChanges, options] of [
  ['task', { taskId: 'task-2' }, {}],
  ['revision', { revision: 2 }, {}],
  ['phase', { phase: 'review' }, {}],
  ['manual mode', {}, { selectionMode: 'manual' }],
  ['suggest mode', {}, { selectionMode: 'suggest' }],
  ['profile', {}, { profileId: 'full@1' }],
  ['target', {}, { target: 'claude-project' }],
  ['exclusions', {}, { exclude: ['skill:feature'] }],
  ['inclusions', {}, { include: ['skill:shared'] }],
]) {
  test(`changing ${label} invalidates a pinned task selection`, () => withFixture(repoRoot => {
    const first = resolve(repoRoot, { explicitIds: ['skill:feature'] }, { load: true });
    const second = resolve(repoRoot, taskChanges, { previous: first.receipt, load: true, ...options });
    assert.equal(second.reused, false);
    assert.deepEqual(second.selectedIds, []);
    assert.deepEqual(second.loadedIds, []);
    assert.notEqual(second.receipt.bindingDigest, first.receipt.bindingDigest);
    assert.throws(() => resolve(repoRoot, taskChanges, { previous: first.receipt,
      expectedDigest: first.receipt.selectionDigest, load: true, ...options }), /stale/);
  }));
}

test('new explicit IDs replace a pinned selection and noWorkflow clears it', () => withFixture(repoRoot => {
  const first = resolve(repoRoot, { explicitIds: ['skill:feature'] });
  const next = resolve(repoRoot, { explicitIds: ['skill:shared'] }, { previous: first.receipt, load: true });
  assert.equal(next.reused, false);
  assert.deepEqual(next.loadedIds, ['skill:shared']);
  const cleared = resolve(repoRoot, { noWorkflow: true }, { previous: first.receipt, load: true });
  assert.equal(cleared.reused, false);
  assert.deepEqual(cleared.selectedIds, []);
  assert.deepEqual(cleared.loadedIds, []);
}));

test('source changes invalidate reuse and source-bound load preview', () => withFixture(repoRoot => {
  const first = resolve(repoRoot, { explicitIds: ['skill:feature'] });
  write(repoRoot, 'skills/feature/references/details.md', 'changed');
  assert.equal(resolve(repoRoot, {}, { previous: first.receipt }).reused, false);
  assert.throws(() => resolve(repoRoot, { explicitIds: ['skill:feature'] }, { load: true, expectedDigest: first.receipt.selectionDigest }), /stale/);
}));

test('bounded search uses canonical IDs and deterministic order', () => withFixture(repoRoot => {
  const result = resolve(repoRoot, { query: 'feature' });
  assert.equal(result.candidates[0].id, 'skill:feature');
  // A bare name mention ranks the skill but is not a directive citation.
  assert.deepEqual(result.selectedIds, []);
  assert.equal(result.reason, 'agent-selection-required');
  assert.ok(result.candidates.length <= 5);
}));

test('generic lexical relevance requests agent selection instead of loading the top score', () => withFixture(repoRoot => {
  write(repoRoot, 'skills/feature/SKILL.md', '---\nname: feature\ndescription: Diagnose memory leak symptoms\n---\nFeature instructions');
  const result = resolve(repoRoot, { query: 'Diagnose memory leak symptoms' }, { load: true });
  assert.equal(result.candidates[0].id, 'skill:feature');
  assert.deepEqual(result.selectedIds, []);
  assert.deepEqual(result.loadedIds, []);
  assert.equal(result.reason, 'agent-selection-required');
}));

test('a single complete canonical or native name auto-selects the cited skill', () => withFixture(repoRoot => {
  write(repoRoot, 'skills/feature/SKILL.md', '---\nname: native-feature\ndescription: Feature workflow\n---\nFeature instructions');
  for (const query of ['Use skill:feature.', 'Use the native-feature skill.', 'Use Native Feature guidance.']) {
    const result = resolve(repoRoot, { query }, { load: true });
    assert.deepEqual(result.loadedIds, ['skill:feature']);
    assert.equal(result.candidates[0].id, 'skill:feature');
    assert.equal(result.reason, 'auto-selection');
    assert.equal(result.receipt.autoSelection.exact, true);
  }
}));

test('multiple directive citations defer to an explicit agent proposal', () => withFixture(repoRoot => {
  const result = resolve(repoRoot, { query: 'Use feature and use shared guidance.' }, { load: true });
  assert.deepEqual(result.selectedIds, []);
  assert.equal(result.reason, 'agent-selection-required');
}));

test('name anchors require complete word boundaries', () => withFixture(repoRoot => {
  const result = resolve(repoRoot, { query: 'featurette sharedness' }, { load: true });
  assert.deepEqual(result.loadedIds, []);
}));

test('candidate descriptions stay useful and bounded with explicit truncation', () => withFixture(repoRoot => {
  const description = `Feature workflow ${'x'.repeat(3000)}`;
  write(repoRoot, 'skills/feature/SKILL.md', `---\nname: feature\ndescription: ${description}\n---\nFeature instructions`);
  const result = resolve(repoRoot, { query: 'feature' });
  assert.equal(result.candidates[0].description, description.slice(0, 2048));
  assert.equal(result.candidates[0].descriptionTruncated, true);
  const shared = resolve(repoRoot, { query: 'shared' }).candidates[0];
  assert.equal(shared.descriptionTruncated, false);
  assert.ok(shared.description.length < 2048);
}));

test('normalization cannot turn a native name into an empty-query anchor', () => withFixture(repoRoot => {
  write(repoRoot, 'skills/feature/SKILL.md', '---\nname: 日本語\ndescription: Japanese guidance\n---\nFeature instructions');
  assert.deepEqual(resolve(repoRoot, {}).selectedIds, []);
}));

// [label, query, expected]. Expected 'auto' arms must auto-select the pinned
// skill (reason 'auto-selection'); 'agent' arms must defer to the bounded
// proposal path (reason 'agent-selection-required', nothing loaded).
const QUERY_CORPUS = [
  ['small Python defect', 'Fix an off-by-one bug in a Python function that indexes a list.', 'agent'],
  ['React keyboard accessibility', 'Fix keyboard navigation and focus handling in our React settings form.', 'auto', 'skill:frontend-a11y'],
  ['PostgreSQL migration review', 'Review a PostgreSQL migration that adds an indexed nullable column without downtime.', 'auto', 'skill:database-migrations'],
  ['read-only JavaScript review', 'Review this JavaScript pull request for input validation bugs without modifying the code.', 'agent'],
  ['RAG literature research', 'Find recent papers about retrieval augmented generation and compare their experimental evidence.', 'agent'],
  ['npm release verification', 'Prepare a release checklist for our npm package, verifying the packed archive and test results.', 'agent'],
  ['API documentation', 'Update the API documentation to explain the new pagination response fields and include an example.', 'agent'],
  ['Rust memory diagnosis', 'Diagnose a memory leak in a Rust background worker service.', 'agent'],
  ['mixed-stack feature', 'Add a React preferences form and a Django endpoint that saves preferences in PostgreSQL.', 'agent'],
];

for (const [label, query, arm, expectedId] of QUERY_CORPUS) {
  test(`actual registry: ${label} ${arm === 'auto' ? 'auto-selects its skill' : 'needs an agent decision before loading'}`, () => {
    const result = resolveTaskContext({ task: task({ query }), load: true });
    assert.ok(result.candidates.length > 0 && result.candidates.length <= 5);
    if (arm === 'auto') {
      assert.deepEqual(result.selectedIds, [expectedId]);
      assert.deepEqual(result.loadedIds, [expectedId]);
      assert.equal(result.reason, 'auto-selection');
      assert.equal(result.receipt.autoSelection.id, expectedId);
      assert.equal(result.receipt.decision, 'selected');
    } else {
      assert.deepEqual(result.selectedIds, []);
      assert.deepEqual(result.loadedIds, []);
      assert.equal(result.reason, 'agent-selection-required');
      assert.equal(result.receipt.decision, 'pending');
    }
  });
}

test('actual registry: a declined proposal exposes a tier-2 fallback candidate', () => {
  const { tasks } = require('../../docker/context-profiles/ai-corpus.json');
  const query = tasks.find(item => item.id === 'rbac-middleware').query;
  const result = resolveTaskContext({ task: task({ query }), load: false });
  assert.equal(result.reason, 'agent-selection-required');
  assert.ok(result.fallback, 'expected a tier-2 fallback for the rbac task');
  const resolved = resolveDeclinedFallback({ task: task({ query }), load: true }, result);
  assert.equal(resolved.reason, 'auto-selection-fallback');
  assert.deepEqual(resolved.selectedIds, [result.fallback.id]);
  assert.equal(resolved.receipt.fallbackApplied, true);
  const { receiptDigest, ...body } = resolved.receipt;
  assert.equal(require('../../scripts/lib/context-profile-support').digestObject(body), receiptDigest);
});

test('actual registry: a near-tied wrong top candidate exposes no fallback', () => {
  const { tasks } = require('../../docker/context-profiles/ai-corpus.json');
  const query = tasks.find(item => item.id === 'slugify-regression-tests').query;
  const result = resolveTaskContext({ task: task({ query }), load: false });
  assert.equal(result.reason, 'agent-selection-required');
  assert.equal(result.fallback, null);
});

test('actual registry: a simple factual question needs no context', () => {
  const result = resolveTaskContext({ task: task({ query: 'What is the capital of Japan?' }), load: true });
  assert.deepEqual(result.selectedIds, []);
  assert.deepEqual(result.candidates, []);
});

test('actual registry: the full Python patterns name auto-selects the cited skill', () => {
  const result = resolveTaskContext({ task: task({ query: 'Use Python patterns for this change.' }), load: true });
  assert.deepEqual(result.loadedIds, ['skill:python-patterns']);
  assert.equal(result.candidates[0].id, 'skill:python-patterns');
  assert.equal(result.reason, 'auto-selection');
  assert.equal(result.receipt.autoSelection.exact, true);
});

test('invalid input and oversized bodies fail closed', () => withFixture(repoRoot => {
  assert.throws(() => resolve(repoRoot, { surprise: true }), /Unknown/);
  assert.throws(() => resolve(repoRoot, { query: 'x'.repeat(9000) }), /limit/);
  assert.throws(() => resolve(repoRoot, { explicitIds: ['skill:missing'] }), /Unknown/);
  write(repoRoot, 'skills/feature/references/details.md', 'x'.repeat(40000));
  update(repoRoot, 'manifests/context-packs/skill-registry@1.json', value => ({ ...value,
    overrides: [{ id: 'skill:feature', requiredResources: ['skills/feature/references/details.md'] }] }));
  assert.throws(() => resolve(repoRoot, { explicitIds: ['skill:feature'] }, { load: true }), /budget/);
}));