/* SPDX-License-Identifier: GPL-3.0-or-later */
/* Copyright (C) 2024 Marco Groß <mgross@sw-gross.de> */
import 'dart:io';

import 'package:calorimeter/food_entry/food_entry_bloc.dart';
import 'package:calorimeter/utils/date_time_helper.dart';
import 'package:path_provider/path_provider.dart';
import 'package:universal_platform/universal_platform.dart';

class FoodStorage {
  static late FoodStorage _instance;
  late String path;
  final Map<String, int> _foodLookupDatabase = {};

  FoodStorage._create();

  static Future<FoodStorage> create() async {
    var storage = FoodStorage._create();

    Directory dir = Directory('');

    if (UniversalPlatform.isDesktop) {
      dir = await getApplicationCacheDirectory();
    } else if (UniversalPlatform.isAndroid) {
      dir = await getApplicationDocumentsDirectory();
    }

    storage.path = dir.path;
    _instance = storage;

    return _instance;
  }

  static FoodStorage getInstance() => _instance;

  Future<List<FoodEntryState>> getEntriesForDate(DateTime date) async {
    List<FoodEntryState> entries = [];
    var filePath = '$path/${date.year}/${date.month}/${date.day}';

    var file = File(filePath);
    var exists = await file.exists();

    if (!exists) return [];

    var lines = await file.readAsLines();

    for (var line in lines) {
      var fields = line.splitWithIgnore(',', ignoreIn: '"');
      int mass = 0;
      int kcalPerMass = 0;

      try {
        mass = int.parse(fields[2]);
      } catch (e) {
        mass = double.parse(fields[2]).toInt();
      }

      try {
        kcalPerMass = int.parse(fields[3]);
      } catch (e) {
        kcalPerMass = double.parse(fields[3]).toInt();
      }

      var entry = FoodEntryState(
        name: fields[1].replaceAll('"', ""),
        mass: mass,
        kcalPer100: kcalPerMass,
        waitingForNetwork: false,
        isSelected: false,
      );
      entries.add(entry);
    }

    return entries;
  }

  Future<void> writeEntriesForDate(
      DateTime date, List<FoodEntryState> foodEntries) async {
    var filePath = '$path/${date.year}/${date.month}/${date.day}';
    var file = File(filePath);

    var exists = await file.exists();

    if (!exists) {
      await file.create(recursive: true);
    }

    String fullString = '';
    for (var entry in foodEntries) {
      fullString += '${entry.toString()}\n';
    }

    await file.writeAsString(fullString);
  }

  Future<void> updateLimit(double limit) async {
    var filePath = '$path/limit';
    var file = File(filePath);

    var exists = await file.exists();
    if (!exists) {
      await file.create();
    }

    await file.writeAsString(limit.toString());
  }

  Future<double> readLimit() async {
    var filePath = '$path/limit';
    var file = File(filePath);
    var exists = await file.exists();

    if (!exists) {
      return 2000;
    }

    var line = await file.readAsLines();

    double limit;
    try {
      limit = double.parse(line[0]);
    } catch (e) {
      limit = 2000;
    }

    return limit;
  }

  Future<String> readBrightness() async {
    var filePath = '$path/brightness';
    var file = File(filePath);
    var exists = await file.exists();

    if (!exists) {
      return 'dark';
    }

    var line = await file.readAsLines();

    if (line.isEmpty || (line[0] != 'dark' && line[0] != 'light')) {
      return 'dark';
    }

    return line[0];
  }

  Future<void> writeBrightness(String brightness) async {
    var filePath = '$path/brightness';
    var file = File(filePath);
    var exists = await file.exists();

    if (!exists) {
      file.create();
    }

    await file.writeAsString(brightness);
  }

  Future<void> buildFoodLookupDatabase() async {
    // get a list of dates of the last 365 days
    var dates = List<DateTime>.generate(365, (idx) {
      var durationToPast = Duration(days: idx);
      return DateTimeHelper.now().subtract(durationToPast);
    });

    for (var date in dates.reversed) {
      addFoodEntryToLookupDatabaseFor(date);
    }
  }

  Future<void> addFoodEntryToLookupDatabaseFor(DateTime date) async {
    var entriesForDate = await getEntriesForDate(date);

    for (var entry in entriesForDate) {
      _foodLookupDatabase[entry.name] = entry.kcalPer100;
    }
  }

  void addFoodEntryToLookupDatabase(FoodEntryState entry) {
    _foodLookupDatabase[entry.name] = entry.kcalPer100;
  }

  Map<String, int> get getFoodEntryLookupDatabase => _foodLookupDatabase;
}

extension SplitWithIgnore on String {
  List<String> splitWithIgnore(String delimiter, {String? ignoreIn}) {
    List<String> parts = [];

    if (ignoreIn == null) {
      return split(delimiter);
    }

    int index = -1;
    int indexCharAfterDelimiter = 0;
    bool inIgnore = false;
    for (var rune in runes) {
      var char = String.fromCharCode(rune);

      index += 1;

      if (char == ignoreIn) {
        inIgnore = !inIgnore;
        continue;
      }

      if (inIgnore) {
        continue;
      }

      if (char == delimiter) {
        parts.add(substring(indexCharAfterDelimiter, index));
        indexCharAfterDelimiter = index + 1;
      }

      if (index + 1 == length) {
        parts.add(substring(indexCharAfterDelimiter, length));
      }
    }

    return parts;
  }
}