#!/usr/bin/env node
/* eslint-disable no-console */
require('dotenv').config();

const http = require('http');
const fs = require('fs');
const path = require('path');

const BASE_URL = process.env.BENCH_BASE_URL || `http://127.0.0.1:${process.env.PORT || 8082}`;
const SAMPLES = Number(process.env.BENCH_SAMPLES || 15);
const CONCURRENCY = Number(process.env.BENCH_CONCURRENCY || 3);
const MATRICULE = process.env.BENCH_MATRICULE || 'S601153';
const REPORT_DIR = process.env.BENCH_REPORT_DIR
  ? path.resolve(process.env.BENCH_REPORT_DIR)
  : path.resolve(__dirname, 'reports');

function request(method, path, token, body = null, responseType = 'json') {
  return new Promise((resolve, reject) => {
    const url = new URL(path, BASE_URL);
    const payload = body ? JSON.stringify(body) : null;
    const req = http.request({
      method,
      hostname: url.hostname,
      port: url.port,
      path: `${url.pathname}${url.search}`,
      headers: {
        ...(token ? { Authorization: `Bearer ${token}` } : {}),
        ...(payload ? { 'Content-Type': 'application/json', 'Content-Length': Buffer.byteLength(payload) } : {})
      }
    }, (res) => {
      let raw = '';
      res.on('data', (chunk) => { raw += chunk.toString(); });
      res.on('end', () => {
        if (res.statusCode >= 400) {
          return reject(new Error(`${method} ${path} failed (${res.statusCode}) ${raw.slice(0, 300)}`));
        }
        if (responseType === 'text') {
          return resolve(raw);
        }
        if (responseType === 'json') {
          try {
            const parsed = raw ? JSON.parse(raw) : {};
            return resolve(parsed);
          } catch (error) {
            return reject(new Error(`Invalid JSON response for ${method} ${path}: ${error.message}`));
          }
        }
        return reject(new Error(`Unsupported responseType '${responseType}' for ${method} ${path}`));
      });
    });
    req.on('error', reject);
    if (payload) req.write(payload);
    req.end();
  });
}

async function getToken() {
  if (process.env.BENCH_TOKEN) return process.env.BENCH_TOKEN;
  const auth = await request('GET', `/auth/verifyMatricule/${encodeURIComponent(MATRICULE)}`, null);
  if (!auth.valid || !auth.token) {
    throw new Error(`Unable to get token for matricule ${MATRICULE}`);
  }
  return auth.token;
}

function percentile(values, p) {
  if (!values.length) return 0;
  const sorted = [...values].sort((a, b) => a - b);
  const idx = Math.ceil((p / 100) * sorted.length) - 1;
  return sorted[Math.max(0, Math.min(sorted.length - 1, idx))];
}

async function benchmarkEndpoint(token, endpoint) {
  const durations = [];
  const runOne = async () => {
    const started = process.hrtime.bigint();
    await request(
      endpoint.method,
      endpoint.path,
      token,
      endpoint.body || null,
      endpoint.responseType || 'json'
    );
    const ended = process.hrtime.bigint();
    durations.push(Number(ended - started) / 1_000_000);
  };

  await runOne(); // warm-up

  let running = [];
  for (let i = 0; i < SAMPLES; i += 1) {
    running.push(runOne());
    if (running.length >= CONCURRENCY) {
      await Promise.all(running);
      running = [];
    }
  }
  if (running.length) await Promise.all(running);

  return {
    endpoint: endpoint.path,
    samples: durations.length,
    p50Ms: Number(percentile(durations, 50).toFixed(2)),
    p95Ms: Number(percentile(durations, 95).toFixed(2)),
    avgMs: Number((durations.reduce((acc, x) => acc + x, 0) / durations.length).toFixed(2)),
    maxMs: Number(Math.max(...durations).toFixed(2))
  };
}

async function main() {
  const token = await getToken();
  const endpoints = [
    { method: 'GET', path: '/advalo/historique?page=1&pageSize=20' },
    { method: 'GET', path: '/advalo/cumul?page=1&pageSize=20' },
    { method: 'GET', path: '/advalo/reporting?page=1&pageSize=20' },
    { method: 'GET', path: '/advalo/export?page=1&pageSize=100', responseType: 'text' }
  ];

  const results = [];
  for (const endpoint of endpoints) {
    console.log(`Benchmarking ${endpoint.path} ...`);
    const result = await benchmarkEndpoint(token, endpoint);
    results.push(result);
  }

  const summary = {
    baseUrl: BASE_URL,
    samples: SAMPLES,
    concurrency: CONCURRENCY,
    generatedAt: new Date().toISOString(),
    results,
    acceptance: {
      allP95Lt2000: results.every((item) => item.p95Ms < 2000)
    }
  };

  fs.mkdirSync(REPORT_DIR, { recursive: true });
  const reportPath = path.join(REPORT_DIR, `advalo-bench-${Date.now()}.json`);
  fs.writeFileSync(reportPath, `${JSON.stringify(summary, null, 2)}\n`, 'utf8');

  console.log(JSON.stringify(summary, null, 2));
  console.log(`Report saved: ${reportPath}`);
}

main().catch((error) => {
  console.error(error.stack || error.message || String(error));
  process.exit(1);
});