feat: deliver Riverside Schedule seven-day grid and school HTML import

mobile/lib/features/school/school_page_adapter.dart

@@ -1,16 +1,177 @@
+import 'dart:convert';
+
+import 'package:html/dom.dart' as dom;
+import 'package:html/parser.dart' as html;
+
 import '../../data/json_schedule_import.dart';
+import '../../domain/course.dart';
 import 'school_navigation_policy.dart';
 
 class UnsupportedSchoolLayout implements Exception {
   @override
-  String toString() => '学校课表识别待联调，当前课表保持不变。';
+  String toString() => '未识别到完整的学校课表，当前课表保持不变。请在课表查询页面保存 HTML 后重试。';
 }
 
+/// Reads the supplied graduate-system table as data; never executes its scripts.
 class SchoolPageAdapter {
-  ImportDraft extract(String html, Uri source) {
-    // A real authenticated timetable fixture is required before registering a parser.
-    // Unknown HTML must never erase the student's last valid imported timetable.
-    throw UnsupportedSchoolLayout();
+  ImportDraft extract(
+    String content,
+    Uri origin, {
+    CourseSource source = CourseSource.school,
+  }) {
+    try {
+      if (!SchoolNavigationPolicy.isTimetable(origin) ||
+          source == CourseSource.demo ||
+          utf8.encode(content).length > 2 * 1024 * 1024) {
+        throw UnsupportedSchoolLayout();
+      }
+      final document = html.parse(content);
+      final table = document.querySelector('#tbl');
+      final selected = document.querySelector('#drpxq option[selected]');
+      final term = selected?.attributes['value'];
+      if (table == null ||
+          term == null ||
+          !RegExp(r'^\d+$').hasMatch(term) ||
+          selected!.text.trim().isEmpty) {
+        throw UnsupportedSchoolLayout();
+      }
+      final rows = table.querySelectorAll('tr');
+      const weekdays = ['节次', '星期一', '星期二', '星期三', '星期四', '星期五', '星期六', '星期日'];
+      if (rows.length != 6 || rows.first.children.length != 8) {
+        throw UnsupportedSchoolLayout();
+      }
+      for (var i = 0; i < 8; i++) {
+        if (rows.first.children[i].text.trim() != weekdays[i]) {
+          throw UnsupportedSchoolLayout();
+        }
+      }
+      final courses = <String, Course>{};
+      final ids = <String>{};
+      const starts = [1, 3, 5, 7, 9];
+      for (var row = 0; row < starts.length; row++) {
+        final first = starts[row], last = first == 9 ? 11 : first + 1;
+        final cells = rows[row + 1].children;
+        if (cells.length != 8 ||
+            cells.first.id != 't0$first' ||
+            cells.first.text.trim() != '$first-$last节') {
+          throw UnsupportedSchoolLayout();
+        }
+        for (var day = 1; day <= 7; day++) {
+          final cell = cells[day];
+          if (cell.id != 't$day$first') throw UnsupportedSchoolLayout();
+          for (final line in _lines(cell)) {
+            final record = RegExp(
+              r'^(\d+)/(.+?)/(\d+(?:\.\d+)?)/(\d+(?:\.\d+)?)/([^/]+)/([^/]+)周/(\d+)[~～-](\d+)节/(.+)$',
+            ).firstMatch(line);
+            if (record == null ||
+                int.parse(record[7]!) != first ||
+                int.parse(record[8]!) != last) {
+              throw UnsupportedSchoolLayout();
+            }
+            final code = record[1]!,
+                name = record[2]!.trim(),
+                teacher = record[5]!.trim(),
+                room = record[9]!.trim();
+            final weeks = _weeks(record[6]!);
+            final identity = jsonEncode([
+              term,
+              code,
+              name,
+              teacher,
+              room,
+              day,
+              first,
+              last,
+            ]);
+            final previous = courses[identity];
+            final id =
+                previous?.id ??
+                'uestc-$term-$code-$day-$first-$last-${_hash(identity)}';
+            if (previous == null && !ids.add(id)) {
+              throw UnsupportedSchoolLayout();
+            }
+            courses[identity] = Course(
+              id: id,
+              name: name,
+              teacher: teacher,
+              room: room,
+              weekday: day,
+              startPeriod: first,
+              endPeriod: last,
+              weeks: {...?previous?.weeks, ...weeks},
+              source: source,
+            );
+          }
+        }
+      }
+      // An empty DOM can be an expired session or an incomplete response.
+      if (courses.isEmpty) throw UnsupportedSchoolLayout();
+      return ImportDraft(
+        courses: List.unmodifiable(courses.values),
+        explicitlyEmpty: false,
+        source: source,
+        parserVersion: 'uestc-graduate-html-v1',
+        semesterLabel: selected.text.trim(),
+      );
+    } on UnsupportedSchoolLayout {
+      rethrow;
+    } catch (_) {
+      throw UnsupportedSchoolLayout();
+    }
+  }
+
+  List<String> _lines(dom.Element cell) {
+    final buffer = StringBuffer();
+    void visit(dom.Node node) {
+      if (node is dom.Text) {
+        buffer.write(node.text);
+      } else if (node is dom.Element) {
+        if (node.localName == 'br') {
+          buffer.write('\n');
+        } else {
+          if (node.localName == 'script' || node.localName == 'style') {
+            throw UnsupportedSchoolLayout();
+          }
+          for (final child in node.nodes) {
+            visit(child);
+          }
+        }
+      }
+    }
+
+    for (final node in cell.nodes) {
+      visit(node);
+    }
+    return buffer
+        .toString()
+        .split('\n')
+        .map((s) => s.trim())
+        .where((s) => s.isNotEmpty)
+        .toList();
+  }
+
+  Set<int> _weeks(String text) {
+    final result = <int>{};
+    for (final part in text.split(RegExp('[,，、]'))) {
+      final range = RegExp(r'^\s*(\d+)(?:\s*[-~～]\s*(\d+))?\s*$')
+          .firstMatch(part);
+      if (range == null) throw UnsupportedSchoolLayout();
+      final first = int.parse(range[1]!),
+          last = int.parse(range[2] ?? range[1]!);
+      if (first < 1 || last > 30 || last < first) {
+        throw UnsupportedSchoolLayout();
+      }
+      result.addAll(List.generate(last - first + 1, (i) => first + i));
+    }
+    return result;
+  }
+
+  String _hash(String value) {
+    var hash = 2166136261;
+    for (final byte in utf8.encode(value)) {
+      hash = ((hash ^ byte) * 16777619) & 0xffffffff;
+    }
+    return hash.toRadixString(16).padLeft(8, '0');
   }
 }
 
@@ -18,17 +179,36 @@ class SchoolReader {
   SchoolReader(this.adapter);
   final SchoolPageAdapter adapter;
   Future<ImportDraft>? _pending;
+  int _generation = 0;
+  Uri? _origin;
   bool get busy => _pending != null;
+  void invalidate() {
+    _generation++;
+    _pending = null;
+    _origin = null;
+  }
+
   Future<ImportDraft> read(Uri origin, Future<String> Function() getHtml) {
+    if (!SchoolNavigationPolicy.isTimetable(origin) ||
+        (_pending != null && origin != _origin)) {
+      return Future.error(UnsupportedSchoolLayout());
+    }
     if (_pending != null) return _pending!;
+    final generation = _generation;
+    _origin = origin;
     _pending = Future<ImportDraft>(() async {
       try {
         if (!SchoolNavigationPolicy.isTimetable(origin)) {
           throw UnsupportedSchoolLayout();
         }
-        return adapter.extract(await getHtml(), origin);
+        final content = await getHtml();
+        if (generation != _generation) throw UnsupportedSchoolLayout();
+        return adapter.extract(content, origin);
       } finally {
-        _pending = null;
+        if (generation == _generation) {
+          _pending = null;
+          _origin = null;
+        }
       }
     });
     return _pending!;