import 'dart:convert';
import 'dart:io';

import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';

class FetchMenu {
  static var lastFetch = DateTime.now();
  static var fetched = false;

  static Future<List<String>> get() async {
    List<String> menus = [];

    if (!fetched || DateTime.now().difference(lastFetch).inHours >= 2) {
      menus = await fromRequest();
      fetched = true;
    } else {
      menus = await fromCache();
    }

    return menus;
  }

  static Future<List<String>> fromCache() async {
    return await loadCache();
  }

  static Future<List<String>> fromRequest() async {
    List<String> menus = [];
    http.Response resp = await http.get(Uri.parse(
        "https://www.swfr.de/essen/mensen-cafes-speiseplaene/mensa-loerrach"));
    var content = resp.body.split("<h3>");
    var innerContent = content[1].split("\n");
    for (var s in innerContent) {
      if (s.contains("extra-text mb-15px")) {
        var name = (s.split("\">")[1].split("</")[0]).replaceAll("<br>", " ");
        menus.add(name);
      }
    }

    await storeCache(menus);

    lastFetch = DateTime.now();

    return menus;
  }

  static Future<void> storeCache(List<String> menus) async {
    var prefs = await SharedPreferences.getInstance();

    for (var i = 0; i < 4; i++) {
      prefs.setString("menuCache$i", "");
      if (i < menus.length) {
        prefs.setString("menuCache$i", menus[i]);
      }
    }


  }

  static Future<List<String>> loadCache() async {
    var prefs = await SharedPreferences.getInstance();

    List<String> menus = [];

    for (var i = 0; i < 4; i++) {
      var curr = prefs.getString("menuCache$i");
      if (curr != "") {
        menus.add(curr!);
      }
    }

    return menus;
  }
}