import 'dart:io';

import 'package:test/test.dart';

/// halkyon.li at home, published through ramiel (ADR 0039): TLS passes
/// through ramiel by name, unopened (D3, D10, D11), and the tunnel between
/// them carries what each side needs and nothing else (D8, D9, D17). None of
/// it runs in CI, so its rules are held here, refusals first.
void main() {
  String read(String path) => File(path).readAsStringSync();

  /// The lines of [text] without comments and blank lines, trimmed.
  List<String> lines(String text) => [
    for (final line in text.split('\n'))
      if (line.trim().isNotEmpty && !line.trim().startsWith('#')) line.trim(),
  ];

  const names = [
    'halkyon.li',
    'learn.halkyon.li',
    'todo.halkyon.li',
    'train.halkyon.li',
    'meditate.halkyon.li',
    'jellyfin.halkyon.li',
  ];

  group("ramiel's HAProxy (D3, D10)", () {
    final config = lines(read('deploy/forward/haproxy.cfg'));

    test('logs nothing, so no visitor of halkyon.li is kept on ramiel', () {
      expect(config.where((line) => line.startsWith('log ')), isEmpty);
      expect(config, isNot(contains('option tcplog')));
    });

    test('passes TLS on unopened: no certificate, no HTTP', () {
      expect(config.where((line) => line.contains('crt ')), isEmpty);
      expect(config, isNot(contains('mode http')));
      expect(config, contains('mode tcp'));
    });

    test("sends halkyon.li's names alone through the tunnel", () {
      final acl = config.singleWhere(
        (line) => line.startsWith('acl halkyon_li '),
      );
      expect(acl, 'acl halkyon_li req.ssl_sni -i ${names.join(' ')}');
      expect(config, contains('use_backend home if halkyon_li'));
    });

    test('sends everything else to the local Caddy', () {
      expect(config, contains('default_backend local'));
      expect(config, contains('server caddy 127.0.0.1:8443 send-proxy-v2'));
    });

    test("reaches home's Caddy at its tunnel address alone, with the "
        "visitor's address", () {
      expect(
        config.where((line) => line.startsWith('server ')),
        unorderedEquals([
          'server caddy 127.0.0.1:8443 send-proxy-v2',
          'server balthasar 10.61.97.2:443 send-proxy-v2',
        ]),
      );
    });

    test('listens on 443 over IPv4 and IPv6', () {
      expect(config, contains('bind :::443 v4v6'));
    });
  });

  group("ramiel's Caddy (D3, D11)", () {
    final caddy = read('deploy/forward/Caddyfile.halkyon-li');

    test('leaves 443 to HAProxy, trusting its PROXY header from the loopback '
        'alone', () {
      expect(caddy, contains('https_port 8443'));
      expect(caddy, contains('allow 127.0.0.1/32 ::1/128'));
    });

    test('speaks no HTTP/3, which HAProxy would not route', () {
      expect(caddy, contains('protocols h1 h2'));
      expect(caddy, isNot(contains('h3')));
    });

    test('sends plain HTTP for halkyon.li on to HTTPS, and serves none of '
        'it itself', () {
      expect(caddy, contains('http://halkyon.li, http://*.halkyon.li {'));
      expect(caddy, contains('redir https://{host}{uri} 308'));
      expect(caddy, isNot(contains('reverse_proxy')));
    });

    test("redirects its own names to HTTPS by hand, so Caddy's automatic "
        'redirects never point at 8443', () {
      expect(
        caddy,
        contains(
          'http://code.halkyon.app, http://halkyon.app, '
          'http://learn.halkyon.app {',
        ),
      );
      expect(
        RegExp(
          r'^\s*redir (\S+)',
          multiLine: true,
        ).allMatches(caddy).map((match) => match[1]),
        everyElement('https://{host}{uri}'),
      );
    });
  });

  group("ramiel's end of the tunnel (D8, D9)", () {
    final config = read('deploy/forward/wg-halkyon.conf');
    final rules = lines(read('deploy/forward/wg-halkyon.nft'));

    test('lets home send from its own address alone', () {
      expect(
        RegExp(
          r'^AllowedIPs = (.+)$',
          multiLine: true,
        ).allMatches(config).map((match) => match[1]),
        ['10.61.97.2/32'],
      );
    });

    test('holds no endpoint, so it never names the home address', () {
      expect(config, isNot(contains('Endpoint')));
    });

    test('keeps its key out of the file', () {
      expect(config, isNot(contains('PrivateKey')));
      expect(
        config,
        contains(
          'PostUp = wg set %i private-key /etc/wireguard/wg-halkyon.key',
        ),
      );
    });

    test('sets its rules as it comes up and takes them away as it goes', () {
      expect(config, contains('PostUp = nft -f /etc/wireguard/wg-halkyon.nft'));
      expect(
        config,
        contains('PreDown = nft delete table inet halkyon_tunnel'),
      );
    });

    test('accepts no new connection from home', () {
      expect(_chain(rules, 'input'), [
        'iifname "wg-halkyon" ct state established,related accept',
        'iifname "wg-halkyon" drop',
      ]);
    });

    test("opens to home only HAProxy's 443 and the jump's 22 (D17)", () {
      expect(_chain(rules, 'output'), [
        'oifname "wg-halkyon" ct state established,related accept',
        'oifname "wg-halkyon" ip daddr 10.61.97.2 tcp dport { 22, 443 } accept',
        'oifname "wg-halkyon" drop',
      ]);
    });

    test('forwards nothing through the tunnel', () {
      final forward = _chain(rules, 'forward');
      expect(forward, contains('iifname "wg-halkyon" drop'));
      expect(forward, contains('oifname "wg-halkyon" drop'));
      expect(forward.where((line) => line.endsWith('accept')), isEmpty);
    });
  });

  group("home's end of the tunnel (D8, D9, D12, D17)", () {
    final config = read('deploy/host/wg-halkyon.conf');
    final rules = lines(read('deploy/host/wg-halkyon.nft'));

    test('lets ramiel send from its own address alone', () {
      expect(
        RegExp(
          r'^AllowedIPs = (.+)$',
          multiLine: true,
        ).allMatches(config).map((match) => match[1]),
        ['10.61.97.1/32'],
      );
    });

    test('dials ramiel by its address and keeps the way open', () {
      expect(config, contains('Endpoint = 45.129.181.128:51820'));
      expect(config, contains('PersistentKeepalive = 25'));
    });

    test('keeps its key out of the file', () {
      expect(config, isNot(contains('PrivateKey')));
      expect(
        config,
        contains(
          'PostUp = wg set %i private-key /etc/wireguard/wg-halkyon.key',
        ),
      );
    });

    test('accepts from ramiel only the jump to sshd, nothing else on the '
        'host', () {
      expect(_chain(rules, 'input'), [
        'iifname "wg-halkyon" ct state established,related accept',
        'iifname "wg-halkyon" ip saddr 10.61.97.1 tcp dport 22 accept',
        'iifname "wg-halkyon" drop',
      ]);
    });

    test("passes from ramiel only to Caddy's 443, nothing else of the home "
        'network or the containers', () {
      expect(_chain(rules, 'forward'), [
        'iifname "wg-halkyon" ct state established,related accept',
        _caddyFromRamiel,
        'iifname "wg-halkyon" drop',
        'oifname "wg-halkyon" ct state established,related accept',
        'oifname "wg-halkyon" drop',
      ]);
    });

    test('opens nothing towards ramiel', () {
      expect(_chain(rules, 'output'), [
        'oifname "wg-halkyon" ct state established,related accept',
        'oifname "wg-halkyon" drop',
      ]);
    });

    test('comes up before Docker, which publishes on its address', () {
      final dropIn = read('deploy/host/wg-quick-before-docker.conf');
      expect(dropIn, contains('Before=docker.service'));
    });

    test('lets sshd take keys alone, for two users alone', () {
      final sshd = lines(read('deploy/host/sshd-halkyon.conf'));
      expect(sshd, contains('PasswordAuthentication no'));
      expect(sshd, contains('KbdInteractiveAuthentication no'));
      expect(sshd, contains('PermitRootLogin no'));
      expect(sshd, contains('AllowUsers raisondetredev deploy'));
    });
  });

  group('the host at home (D12, D20)', () {
    test('unlocks its disk over SSH at boot, on a port of its own, and runs '
        'nothing else there', () {
      final dropbear = read('deploy/host/dropbear.conf');
      final options = RegExp(
        r'^DROPBEAR_OPTIONS="(.+)"$',
        multiLine: true,
      ).firstMatch(dropbear)![1]!.split(' ');
      // No password, no forwarding of any kind, nothing but the unlock.
      expect(options, containsAll(['-p', '2222', '-s', '-j', '-k']));
      expect(options, containsAll(['-c', 'cryptroot-unlock']));
    });

    test("loads the USB network adapter's driver at boot", () {
      expect(lines(read('deploy/host/initramfs-modules')), contains('cdc_ncm'));
    });

    test("keeps Docker's data on the HDD, which Docker waits for", () {
      final fstab = lines(read('deploy/host/fstab-docker'))
          .map((line) => line.split(RegExp(r'\s+')).take(2).join(' '));
      expect(fstab, [
        '/data/docker /var/lib/docker',
        '/data/containerd /var/lib/containerd',
      ]);
      expect(
        read('deploy/host/docker-after-data.conf'),
        contains('RequiresMountsFor=/var/lib/docker /var/lib/containerd'),
      );
    });
  });

  group("home's Caddy behind the forward (D10, D11, D12)", () {
    final compose = read('deploy/compose.forwarded.yaml');
    final global = read('deploy/forwarded.caddy');

    test('publishes 443 on the tunnel address alone, and neither 80 nor '
        'HTTP/3', () {
      final ports = RegExp(r'ports: !override\n((?:\s+- .+\n)+)')
          .firstMatch(compose)![1]!
          .split('\n')
          .map((line) => line.trim())
          .where((line) => line.isNotEmpty);
      expect(ports, ['- "10.61.97.2:443:443"']);
    });

    test("trusts the PROXY header from ramiel's tunnel address alone", () {
      expect(global, contains('allow 10.61.97.1/32'));
      expect(RegExp('allow (.+)').allMatches(global).map((match) => match[1]), [
        '10.61.97.1/32',
      ]);
    });

    test('gets its certificates through TLS alone, and speaks no HTTP/3', () {
      expect(global, contains('disable_http_challenge'));
      expect(global, contains('protocols h1 h2'));
    });

    test("is mounted into Caddy's global options", () {
      expect(
        compose,
        contains('./forwarded.caddy:/etc/caddy/global/forwarded.caddy:ro'),
      );
      expect(read('deploy/Caddyfile'), contains('import global/*.caddy'));
    });

    test('recreates Caddy when it changes, as a sidecar site does', () {
      expect(read('deploy/redeploy.sh'), contains('forwarded.caddy'));
    });
  });
}

/// home's one rule passing anything from ramiel on: to Caddy's 443.
const _caddyFromRamiel =
    'iifname "wg-halkyon" ip saddr 10.61.97.1 ip daddr 172.30.80.2 '
    'tcp dport 443 accept';

/// The rules of [rules]' chain [name], from its first rule to its closing
/// brace, without its `type … hook …` line.
List<String> _chain(List<String> rules, String name) {
  final start = rules.indexOf('chain $name {');
  expect(start, isNot(-1), reason: 'no chain $name');
  final chain = <String>[];
  for (final line in rules.skip(start + 1)) {
    if (line == '}') {
      break;
    }
    if (!line.startsWith('type ')) {
      chain.add(line);
    }
  }
  return chain;
}