import 'package:collection/collection.dart';
import 'package:flutter/material.dart';

import '../../../state/app/modules/timetable/bloc/timetable_state.dart';
import '../queries/get_rooms/get_rooms_response.dart';
import '../queries/get_subjects/get_subjects_response.dart';

/// Resolves Webuntis IDs (subject, room) against the cached `TimetableState`.
/// When a record is missing the resolver returns a placeholder fallback
/// instead of `null` so call sites stay branch-free.
class LessonResolver {
  static GetSubjectsResponseObject resolveSubject(
    TimetableState state,
    int? id,
  ) {
    final fallback = GetSubjectsResponseObject(0, '?', 'Unbekannt', '?', true);
    if (id == null) return fallback;
    return state.subjects?.result.firstWhereOrNull((s) => s.id == id) ??
        fallback;
  }

  static GetRoomsResponseObject resolveRoom(TimetableState state, int? id) {
    final fallback = GetRoomsResponseObject(0, '?', 'Unbekannt', true, '');
    if (id == null) return fallback;
    return state.rooms?.result.firstWhereOrNull((r) => r.id == id) ?? fallback;
  }
}

/// Pure formatting/labelling helpers for Webuntis lessons (status code →
/// icon/label, "Name (Longname) · Extra" lines, subject prefix). No widgets,
/// safe to unit-test.
class LessonFormatter {
  static IconData iconForCode(String? code) {
    switch (code) {
      case 'cancelled':
        return Icons.event_busy_outlined;
      case 'irregular':
        return Icons.swap_horiz;
      default:
        return Icons.school_outlined;
    }
  }

  static String statusLabel(String? code) {
    switch (code) {
      case null:
      case '':
        return 'Regulär';
      case 'cancelled':
        return 'Entfällt';
      case 'irregular':
        return 'Geändert';
      default:
        return code;
    }
  }

  static String codePrefix(String? code) {
    if (code == 'cancelled') return 'Entfällt: ';
    if (code == 'irregular') return 'Änderung: ';
    return code ?? '';
  }

  /// Builds a single display line from the typical Webuntis triple of name,
  /// optional longname (rendered in parentheses if it differs from `name`),
  /// and optional extra info (joined with `·`).
  static String formatLine(String name, {String? longname, String? extra}) {
    final parts = <String>[if (name.isNotEmpty) name else '?'];
    final ln = (longname ?? '').trim();
    if (ln.isNotEmpty && ln != name) parts.add('($ln)');
    final ex = (extra ?? '').trim();
    if (ex.isNotEmpty) parts.add('· $ex');
    return parts.join(' ');
  }
}