/**
 * Tests for caddy-upstream-watcher.
 *
 * Mock-driven: we stub fs (for /etc/caddy/sites scan + state file) and http/https
 * (for the probe). Tests cover site parsing, probe happy/sad path, the 5-minute
 * "dead" threshold, mute toggle, and incident integration with healthChecker.
 */

const path = require('path');
const Module = require('module');

// Mock fs with controllable behavior.
const fsState = {
  files: {},          // path -> string content
  exists: {},         // path -> bool
  writeLog: [],       // writes
};

jest.mock('fs', () => {
  const real = jest.requireActual('fs');
  return {
    ...real,
    existsSync: jest.fn((p) => fsState.exists[p] !== undefined ? fsState.exists[p] : (fsState.files[p] !== undefined)),
    readFileSync: jest.fn((p) => {
      if (fsState.files[p] === undefined) {
        const e = new Error(`ENOENT: ${p}`);
        e.code = 'ENOENT';
        throw e;
      }
      return fsState.files[p];
    }),
    readdirSync: jest.fn((p) => Object.keys(fsState.files).filter(f => f.startsWith(p + '/')).map(f => f.substring(p.length + 1))),
    writeFileSync: jest.fn((p, content) => {
      fsState.writeLog.push({ p, content });
      fsState.files[p] = content;
      fsState.exists[p] = true;
    }),
    mkdirSync: jest.fn(),
    renameSync: jest.fn((src, dst) => {
      fsState.files[dst] = fsState.files[src];
      fsState.exists[dst] = true;
      delete fsState.files[src];
      delete fsState.exists[src];
    })
  };
});

// Mock http/https request to control probe responses.
const probeQueue = []; // each entry: { kind: 'ok'|'err'|'timeout'|'code', statusCode? }
jest.mock('http', () => ({
  request: jest.fn((opts, cb) => {
    const entry = probeQueue.shift() || { kind: 'ok', statusCode: 200 };
    const handlers = {};
    const res = {
      statusCode: entry.statusCode || 200,
      headers: { server: 'mock' },
      resume: () => {},
      on: (e, fn) => { handlers[e] = fn; }
    };
    const req = {
      on: jest.fn((e, fn) => { handlers[e] = fn; }),
      end: jest.fn(() => {
        if (entry.kind === 'err') {
          handlers.error && handlers.error(new Error(entry.message || 'connect ECONNREFUSED'));
          return;
        }
        if (entry.kind === 'timeout') {
          handlers.timeout && handlers.timeout();
          return;
        }
        cb(res);
        if (handlers.end) handlers.end();
      }),
      destroy: jest.fn()
    };
    return req;
  })
}));
jest.mock('https', () => ({
  request: jest.fn((opts, cb) => {
    const entry = probeQueue.shift() || { kind: 'ok', statusCode: 200 };
    const handlers = {};
    const res = {
      statusCode: entry.statusCode || 200,
      headers: { server: 'mock-https' },
      resume: () => {},
      on: (e, fn) => { handlers[e] = fn; }
    };
    const req = {
      on: jest.fn((e, fn) => { handlers[e] = fn; }),
      end: jest.fn(() => {
        if (entry.kind === 'err') {
          handlers.error && handlers.error(new Error(entry.message || 'TLS error'));
          return;
        }
        cb(res);
        if (handlers.end) handlers.end();
      }),
      destroy: jest.fn()
    };
    return req;
  })
}));

// Reset fs mock state between tests.
beforeEach(() => {
  fsState.files = {};
  fsState.exists = {};
  fsState.writeLog = [];
  probeQueue.length = 0;
  jest.clearAllMocks();
  jest.resetModules();
});

describe('CaddyUpstreamWatcher', () => {
  const SITES = '/etc/caddy/sites';
  const STATE = '/tmp/caddy-upstreams-test.json';

  function seedSites(files) {
    for (const [name, content] of Object.entries(files)) {
      fsState.files[SITES + '/' + name] = content;
      fsState.exists[SITES + '/' + name] = true;
    }
  }

  function loadWatcher() {
    process.env.CADDY_UPSTREAMS_STATE_FILE = STATE;
    process.env.CADDY_SITES_DIR = SITES;
    // Disable the singleton's auto-write so we can call _saveState manually.
    const mod = require('../src/monitoring/caddy-upstream-watcher');
    return { mod, w: mod.CaddyUpstreamWatcher ? new mod.CaddyUpstreamWatcher() : mod };
  }

  test('parses reverse_proxy directives from /etc/caddy/sites/*', async () => {
    seedSites({
      'arch.sami': `arch.sami {\n    reverse_proxy 100.120.159.34:5000 { health_uri /api/stats }\n}`,
      'appt.sami': `appt.sami {\n    reverse_proxy http://100.81.59.99:5232\n}`,
      'zap.sami': `zap.sami {\n    reverse_proxy 10.0.0.5:8080\n    reverse_proxy 10.0.0.6:8080  # multiple upstreams in same site block\n}`
    });
    const { w } = loadWatcher();
    await w.scanSites();
    const snap = w.snapshot();
    const hosts = snap.upstreams.map(u => u.host).sort();
    expect(hosts).toEqual(['10.0.0.5:8080', '10.0.0.6:8080', '100.120.159.34:5000', '100.81.59.99:5232']);
    expect(snap.upstreams.find(u => u.host === '100.120.159.34:5000').site).toBe('arch.sami');
    expect(snap.upstreams.find(u => u.host === '100.81.59.99:5232').site).toBe('appt.sami');
  });

  test('ignores non-site files and unparseable entries', async () => {
    seedSites({
      'README.md': '# documentation\nreverse_proxy 1.2.3.4:9999\n', // not a site file
      'garbage.sami': 'not a caddyfile\n', // no reverse_proxy
      'good.sami': 'good.sami {\n  reverse_proxy 1.2.3.4:9999\n}\n'
    });
    const { w } = loadWatcher();
    await w.scanSites();
    const hosts = w.snapshot().upstreams.map(u => u.host);
    expect(hosts).toEqual(['1.2.3.4:9999']);
  });

  test('handles real prod-style filenames: zap.sami-ahmed.net, samitest.space, blocks.cryptographic-triangles.org', async () => {
    // These are the actual file names in production /etc/caddy/sites/ —
    // extension is .net / .space / .org, NOT .sami/.caddy/.conf. The old
    // file-extension filter would skip them silently.
    seedSites({
      'zap.sami-ahmed.net': 'zap.sami-ahmed.net {\n    reverse_proxy localhost:8088\n}\n',
      'samitest.space': 'samitest.space {\n    reverse_proxy 100.120.159.34:8080 {}\n}\n',
      'blocks.cryptographic-triangles.org': 'blocks.cryptographic-triangles.org {\n\treverse_proxy localhost:3052 {}\n}\n'
    });
    const { w } = loadWatcher();
    await w.scanSites();
    const snap = w.snapshot();
    const byHost = Object.fromEntries(snap.upstreams.map(u => [u.host, u.site]));
    expect(byHost['localhost:8088']).toBe('zap.sami-ahmed.net');
    expect(byHost['100.120.159.34:8080']).toBe('samitest.space');
    expect(byHost['localhost:3052']).toBe('blocks.cryptographic-triangles.org');
  });

  test('drops upstreams that disappear from the sites dir', async () => {
    seedSites({
      'arch.sami': 'arch.sami {\n  reverse_proxy 1.1.1.1:5000\n}\n'
    });
    const { w } = loadWatcher();
    await w.scanSites();
    expect(w.upstreams.size).toBe(1);
    fsState.files = {}; // wipe
    fsState.exists = {};
    await w.scanSites();
    expect(w.upstreams.size).toBe(0);
  });

  test('healthy probe updates state and does not open an incident', async () => {
    seedSites({ 'good.sami': 'good.sami { reverse_proxy 1.1.1.1:80 }\n' });
    probeQueue.push({ kind: 'ok', statusCode: 200 });
    const { w } = loadWatcher();
    const fakeHealthChecker = { createIncident: jest.fn(), incidents: [] };
    w.healthChecker = fakeHealthChecker;
    await w.scanSites();
    await w._probeOne(w.upstreams.values().next().value);
    const snap = w.snapshot();
    expect(snap.upstreams[0].status).toBe('up');
    expect(snap.upstreams[0].lastSuccessAt).toBeTruthy();
    expect(fakeHealthChecker.createIncident).not.toHaveBeenCalled();
  });

  test('auth-walled 4xx counts as healthy (proves the upstream answered)', async () => {
    seedSites({ 'auth.sami': 'auth.sami { reverse_proxy 1.1.1.1:80 }\n' });
    probeQueue.push({ kind: 'ok', statusCode: 401 });
    const { w } = loadWatcher();
    await w.scanSites();
    await w._probeOne(w.upstreams.values().next().value);
    expect(w.snapshot().upstreams[0].status).toBe('up');
  });

  test('first failure flips status to down but does NOT open an incident (under 5min)', async () => {
    seedSites({ 'bad.sami': 'bad.sami { reverse_proxy 1.1.1.1:80 }\n' });
    probeQueue.push({ kind: 'err', message: 'connect ECONNREFUSED' });
    const { w } = loadWatcher();
    const fakeHealthChecker = { createIncident: jest.fn(), incidents: [] };
    w.healthChecker = fakeHealthChecker;
    await w.scanSites();
    const u = w.upstreams.values().next().value;
    u.lastSuccessAt = new Date(Date.now() - 30000).toISOString(); // 30s ago it was healthy
    await w._probeOne(u);
    const snap = w.snapshot();
    expect(snap.upstreams[0].status).toBe('down');
    expect(snap.upstreams[0].failingForMs).toBeLessThan(5 * 60 * 1000);
    expect(fakeHealthChecker.createIncident).not.toHaveBeenCalled();
  });

  test('after 5 minutes of consecutive failures an incident is opened', async () => {
    seedSites({ 'dead.sami': 'dead.sami { reverse_proxy 1.1.1.1:80 }\n' });
    probeQueue.push({ kind: 'err', message: 'i/o timeout' });
    const { w } = loadWatcher();
    const incidents = [];
    const fakeHealthChecker = {
      createIncident: jest.fn((serviceId, type, message, status) => {
        incidents.push({ serviceId, type, message, status });
      }),
      incidents: []
    };
    w.healthChecker = fakeHealthChecker;
    await w.scanSites();
    const u = w.upstreams.values().next().value;
    // Simulate lastSuccessAt being 6 minutes ago so failingForMs exceeds DEAD_AFTER_MS.
    u.lastSuccessAt = new Date(Date.now() - 6 * 60 * 1000).toISOString();
    await w._probeOne(u);
    expect(fakeHealthChecker.createIncident).toHaveBeenCalledTimes(1);
    expect(fakeHealthChecker.createIncident.mock.calls[0][1]).toBe('caddy-upstream-dead');
    expect(w.openIncidents.has('1.1.1.1:80')).toBe(true);
  });

  test('does not duplicate incidents for the same upstream', async () => {
    seedSites({ 'dead.sami': 'dead.sami { reverse_proxy 1.1.1.1:80 }\n' });
    // Queue up 3 errors so each probe fails.
    probeQueue.push({ kind: 'err', message: 'i/o timeout' });
    probeQueue.push({ kind: 'err', message: 'i/o timeout' });
    probeQueue.push({ kind: 'err', message: 'i/o timeout' });
    const { w } = loadWatcher();
    const fakeHealthChecker = {
      createIncident: jest.fn(),
      incidents: []
    };
    w.healthChecker = fakeHealthChecker;
    await w.scanSites();
    const u = w.upstreams.values().next().value;
    u.lastSuccessAt = new Date(Date.now() - 6 * 60 * 1000).toISOString();
    await w._probeOne(u);
    await w._probeOne(u);
    await w._probeOne(u);
    expect(fakeHealthChecker.createIncident).toHaveBeenCalledTimes(1);
  });

  test('recovery resolves the open incident after RESOLVED_AFTER_MS', async () => {
    seedSites({ 'flap.sami': 'flap.sami { reverse_proxy 1.1.1.1:80 }\n' });
    probeQueue.push({ kind: 'err', message: 'i/o timeout' }); // trip dead
    probeQueue.push({ kind: 'ok', statusCode: 200 }); // recovery
    const { w } = loadWatcher();
    const fakeHealthChecker = {
      createIncident: jest.fn(),
      resolveIncident: jest.fn(),
      incidents: []
    };
    w.healthChecker = fakeHealthChecker;
    await w.scanSites();
    const u = w.upstreams.values().next().value;
    // Trip the dead state
    u.lastSuccessAt = new Date(Date.now() - 6 * 60 * 1000).toISOString();
    await w._probeOne(u);
    expect(w.openIncidents.has('1.1.1.1:80')).toBe(true);
    // Simulate a recovery — lastFailureAt is 2 min ago, now healthy
    u.lastFailureAt = new Date(Date.now() - 2 * 60 * 1000).toISOString();
    await w._probeOne(u);
    expect(fakeHealthChecker.resolveIncident).toHaveBeenCalledTimes(1);
    expect(w.openIncidents.has('1.1.1.1:80')).toBe(false);
  });

  test('mute suppresses probing and hides upstream in snapshot status', async () => {
    seedSites({ 'noisy.sami': 'noisy.sami { reverse_proxy 1.1.1.1:80 }\n' });
    const { w } = loadWatcher();
    await w.scanSites();
    w.setMuted('1.1.1.1:80', true);
    expect(w.isMuted('1.1.1.1:80')).toBe(true);
    const snap = w.snapshot();
    expect(snap.upstreams[0].status).toBe('muted');
    expect(snap.upstreams[0].muted).toBe(true);
    // probe tick should skip muted
    await w._tick();
    // lastCheckedAt should NOT have advanced because no probe was issued
    expect(snap.upstreams[0].lastCheckedAt).toBeNull();
  });

  test('unmute resets failure counters so a recently-recovered upstream is not immediately re-incidented', async () => {
    seedSites({ 'flap.sami': 'flap.sami { reverse_proxy 1.1.1.1:80 }\n' });
    const { w } = loadWatcher();
    await w.scanSites();
    const u = w.upstreams.values().next().value;
    u.consecutiveFailures = 42;
    u.lastError = 'old failure';
    u.lastFailureAt = new Date().toISOString();
    u.status = 'down';
    w.setMuted('1.1.1.1:80', true);
    w.setMuted('1.1.1.1:80', false);
    expect(u.consecutiveFailures).toBe(0);
    expect(u.status).toBe('unknown');
    expect(u.lastError).toBeNull();
  });

  test('snapshot sorts dead > down > muted > up > unknown', async () => {
    seedSites({
      'a.sami': 'a.sami { reverse_proxy 1.1.1.1:80 }\n',
      'b.sami': 'b.sami { reverse_proxy 2.2.2.2:80 }\n',
      'c.sami': 'c.sami { reverse_proxy 3.3.3.3:80 }\n',
      'd.sami': 'd.sami { reverse_proxy 4.4.4.4:80 }\n',
      'e.sami': 'e.sami { reverse_proxy 5.5.5.5:80 }\n'
    });
    const { w } = loadWatcher();
    await w.scanSites();
    const all = Array.from(w.upstreams.values());
    // 1.1.1.1:80 -> up (just succeeded)
    all.find(u => u.host === '1.1.1.1:80').status = 'up';
    all.find(u => u.host === '1.1.1.1:80').lastSuccessAt = new Date().toISOString();
    // 2.2.2.2:80 -> down (recent — last success 30s ago)
    all.find(u => u.host === '2.2.2.2:80').status = 'down';
    all.find(u => u.host === '2.2.2.2:80').lastSuccessAt = new Date(Date.now() - 30000).toISOString();
    // 3.3.3.3:80 -> muted
    w.muted.add('3.3.3.3:80');
    // 4.4.4.4:80 -> dead (last success 7min ago, never recovered)
    const dead = all.find(u => u.host === '4.4.4.4:80');
    dead.status = 'down';
    dead.lastSuccessAt = new Date(Date.now() - 7 * 60 * 1000).toISOString();
    // 5.5.5.5:80 -> unknown (no probes yet)
    const snap = w.snapshot();
    const order = snap.upstreams.map(u => u.host);
    // Expected: dead first, then down, then muted, then up, then unknown
    expect(order).toEqual(['4.4.4.4:80', '2.2.2.2:80', '3.3.3.3:80', '1.1.1.1:80', '5.5.5.5:80']);
  });

  test('persists muted list to state file', async () => {
    seedSites({ 'a.sami': 'a.sami { reverse_proxy 1.1.1.1:80 }\n' });
    const { w } = loadWatcher();
    await w.scanSites();
    w.setMuted('1.1.1.1:80', true);
    // _saveState writes to STATE + '.tmp' then renames. Look for the .tmp
    // write since that's the actual writeFileSync call (rename is silent).
    const writes = fsState.writeLog.filter(w => w.p === STATE + '.tmp' || w.p === STATE);
    expect(writes.length).toBeGreaterThan(0);
    const last = writes[writes.length - 1];
    const data = JSON.parse(last.content);
    expect(data.muted).toContain('1.1.1.1:80');
  });

  test('reload from state file restores muted list', async () => {
    // Pre-seed a state file with a muted host
    fsState.files[STATE] = JSON.stringify({
      muted: ['99.99.99.99:80'],
      upstreams: { '99.99.99.99:80': { ip: '99.99.99.99', port: '80', site: 'old.sami', siteFile: 'old.sami' } }
    });
    fsState.exists[STATE] = true;
    // And the matching site file
    seedSites({ 'old.sami': 'old.sami { reverse_proxy 99.99.99.99:80 }\n' });

    process.env.CADDY_UPSTREAMS_STATE_FILE = STATE;
    process.env.CADDY_SITES_DIR = SITES;
    const mod = require('../src/monitoring/caddy-upstream-watcher');
    const w = mod.CaddyUpstreamWatcher ? new mod.CaddyUpstreamWatcher() : mod;
    expect(w.isMuted('99.99.99.99:80')).toBe(true);
  });
});