/**
 * Phase 3b post-review — admin mutations drop per-key Prometheus
 * gauge labels so the registry doesn't grow unbounded over the key
 * lifecycle (issue → revoke → issue → revoke … leaves a permanent
 * `budgetUsedRatio{team, key_prefix}` series for every dead key
 * without this fix).
 */
import { describe, it, expect, beforeEach, afterEach } from 'vitest';
import express, { type Request, type RequestHandler } from 'express';
import request from 'supertest';
import { mkdtempSync, rmSync } from 'fs';
import { join } from 'path';
import { tmpdir } from 'os';
import { Registry } from 'prom-client';
import { Repository } from '../db/repository.js';
import { createAdminGatewayApi } from './admin-gateway-api.js';
import { createGatewayMetrics, type GatewayMetrics } from '../metrics/gateway-metrics.js';

function buildApp(repo: Repository, metrics: GatewayMetrics): express.Application {
  const app = express();
  app.use(express.json({ limit: '4kb' }));
  const guard: RequestHandler = (req, _res, next) => {
    (req as Request & { user?: unknown }).user = { id: 'admin-1', role: 'admin', status: 'active' };
    next();
  };
  const router = createAdminGatewayApi({
    repo,
    requireAdmin: guard,
    getUserId: (req) => {
      const u = (req as Request & { user?: { id?: string } }).user;
      return u?.id ?? null;
    },
    gatewayMetrics: metrics,
  });
  app.use('/api/admin/gateway/keys', router);
  return app;
}

describe('admin-gateway-api metric label removal (Phase 3b post-review)', () => {
  let tmpDir: string;
  let repo: Repository;
  let reg: Registry;
  let metrics: GatewayMetrics;
  let app: express.Application;

  beforeEach(() => {
    tmpDir = mkdtempSync(join(tmpdir(), 'admin-gw-metrics-'));
    repo = new Repository(join(tmpDir, 'test.db'));
    reg = new Registry();
    metrics = createGatewayMetrics(reg, 'aao_gateway_ml');
    app = buildApp(repo, metrics);
  });

  afterEach(() => {
    repo.close();
    rmSync(tmpDir, { recursive: true, force: true });
  });

  it('revoke removes the budgetUsedRatio label for the revoked key', async () => {
    const create = await request(app).post('/api/admin/gateway/keys').send({ team: 'alpha' });
    expect(create.status).toBe(201);
    const id = create.body.id as string;
    const prefix = id.slice(0, 8);
    // Simulate the gauge being set as it would by the bootstrap recordUsage callback.
    metrics.budgetUsedRatio.labels({ team: 'alpha', key_prefix: prefix }).set(0.42);
    let dump = await reg.metrics();
    expect(dump).toMatch(
      new RegExp(`aao_gateway_ml_virtual_key_budget_used_ratio\\{team="alpha",key_prefix="${prefix}"\\} 0\\.42`),
    );
    // Now revoke.
    const rev = await request(app).post(`/api/admin/gateway/keys/${id}/revoke`);
    expect(rev.status).toBe(200);
    // After remove() the label series should no longer appear.
    dump = await reg.metrics();
    expect(dump).not.toMatch(new RegExp(`key_prefix="${prefix}"`));
  });

  it('rotate removes the OLD key prefix label (new key creates its own on next usage)', async () => {
    const create = await request(app).post('/api/admin/gateway/keys').send({ team: 'beta' });
    const oldId = create.body.id as string;
    const oldPrefix = oldId.slice(0, 8);
    metrics.budgetUsedRatio.labels({ team: 'beta', key_prefix: oldPrefix }).set(0.55);
    let dump = await reg.metrics();
    expect(dump).toMatch(new RegExp(`key_prefix="${oldPrefix}"`));
    const rot = await request(app).post(`/api/admin/gateway/keys/${oldId}/rotate`);
    expect(rot.status).toBe(201);
    dump = await reg.metrics();
    expect(dump).not.toMatch(new RegExp(`key_prefix="${oldPrefix}"`));
  });

  it('delete removes the label too', async () => {
    const create = await request(app).post('/api/admin/gateway/keys').send({ team: 'gamma' });
    const id = create.body.id as string;
    const prefix = id.slice(0, 8);
    metrics.budgetUsedRatio.labels({ team: 'gamma', key_prefix: prefix }).set(0.7);
    const del = await request(app).delete(`/api/admin/gateway/keys/${id}`);
    expect(del.status).toBe(204);
    const dump = await reg.metrics();
    expect(dump).not.toMatch(new RegExp(`key_prefix="${prefix}"`));
  });

  it('revoke without an existing gauge label is a safe no-op', async () => {
    const create = await request(app).post('/api/admin/gateway/keys').send({ team: 'delta' });
    const id = create.body.id as string;
    // Don't pre-set the gauge — remove() of an unknown label is a noop.
    const rev = await request(app).post(`/api/admin/gateway/keys/${id}/revoke`);
    expect(rev.status).toBe(200);
  });

  it('missing gatewayMetrics handle (cross-process deploy) does not block mutations', async () => {
    // Build a separate app without a metrics handle to verify the
    // admin API stays functional when the gateway runs in a different
    // process.
    const app2 = express();
    app2.use(express.json({ limit: '4kb' }));
    const guard: RequestHandler = (req, _res, next) => {
      (req as Request & { user?: unknown }).user = { id: 'admin-1', role: 'admin', status: 'active' };
      next();
    };
    const router = createAdminGatewayApi({
      repo,
      requireAdmin: guard,
      getUserId: (req) => {
        const u = (req as Request & { user?: { id?: string } }).user;
        return u?.id ?? null;
      },
      // No gatewayMetrics. dropKeyMetricLabels is a no-op.
    });
    app2.use('/api/admin/gateway/keys', router);
    const create = await request(app2).post('/api/admin/gateway/keys').send({ team: 'eps' });
    expect(create.status).toBe(201);
    const id = create.body.id as string;
    const rev = await request(app2).post(`/api/admin/gateway/keys/${id}/revoke`);
    expect(rev.status).toBe(200);
  });
});