feat: NOTAM client + parser (M5a)

packages/zones_api_client/lib/src/notam_client.dart

@@ -0,0 +1,87 @@
+import 'package:http/http.dart' as http;
+import 'package:zones_api_client/src/models/zone_data.dart';
+import 'package:zones_api_client/src/notam_parser.dart';
+
+/// Thrown when the NOTAM feed cannot be fetched.
+class NotamException implements Exception {
+  const NotamException(this.message);
+  final String message;
+  @override
+  String toString() => 'NotamException: $message';
+}
+
+/// Fetches live Argentine NOTAMs from EANA's public `POST /notam/pib` endpoint
+/// and parses them into time-bounded zones.
+///
+/// The endpoint is an AJAX form behind a session cookie: a GET on the NOTAM
+/// page establishes the session, then a form-urlencoded POST with the FIR
+/// `indicador` returns an HTML `<table>`. This is an undocumented scrape
+/// (HTML shape can change) and is reference-only — never present it as an
+/// official PIB.
+class NotamClient {
+  NotamClient({Uri? baseUrl, http.Client? httpClient})
+      : _base = baseUrl ?? Uri.parse('https://ais.anac.gob.ar'),
+        _httpClient = httpClient ?? http.Client();
+
+  /// FIR-wide indicator codes (EANA-internal, not ICAO): Ezeiza, Córdoba,
+  /// Comodoro, Mendoza, Resistencia.
+  static const firCodes = ['-EF', '-CF', '-VF', '-MF', '-RR'];
+
+  final Uri _base;
+  final http.Client _httpClient;
+
+  /// Fetches and parses NOTAMs for a single FIR [indicador] (e.g. `-EF`).
+  Future<NotamParseResult> fetchFir(String indicador) async {
+    final cookie = await _establishSession();
+    final response = await _post(indicador, cookie);
+    if (response.statusCode != 200) {
+      throw NotamException('HTTP ${response.statusCode} for $indicador');
+    }
+    return NotamParser.parse(response.body);
+  }
+
+  /// Fetches every FIR in [firCodes] and merges the results. A FIR that fails
+  /// is skipped so one outage doesn't blank the whole feed.
+  Future<NotamParseResult> fetchAllFirs() async {
+    final zones = <ZoneData>[];
+    final ungeocodable = <UngeocodableNotam>[];
+    for (final code in firCodes) {
+      try {
+        final result = await fetchFir(code);
+        zones.addAll(result.zones);
+        ungeocodable.addAll(result.ungeocodable);
+      } on Object {
+        // Skip this FIR; partial coverage beats none.
+      }
+    }
+    return NotamParseResult(zones: zones, ungeocodable: ungeocodable);
+  }
+
+  Future<String?> _establishSession() async {
+    try {
+      final response = await _httpClient
+          .get(_base.replace(path: '/notam'))
+          .timeout(const Duration(seconds: 12));
+      return response.headers['set-cookie'];
+    } catch (e) {
+      throw NotamException('session error: $e');
+    }
+  }
+
+  Future<http.Response> _post(String indicador, String? cookie) async {
+    try {
+      return await _httpClient.post(
+        _base.replace(path: '/notam/pib'),
+        headers: {
+          'Content-Type': 'application/x-www-form-urlencoded',
+          'X-Requested-With': 'XMLHttpRequest',
+          'Referer': _base.replace(path: '/notam').toString(),
+          if (cookie != null) 'Cookie': cookie,
+        },
+        body: {'indicador': indicador},
+      ).timeout(const Duration(seconds: 15));
+    } catch (e) {
+      throw NotamException('network error: $e');
+    }
+  }
+}