import 'package:currency_picker/currency_picker.dart';
import 'package:json_annotation/json_annotation.dart';
import 'package:prasule/api/category.dart';
import 'package:prasule/api/recurring_entry.dart';
import 'package:prasule/api/wallet_entry.dart';
import 'package:prasule/api/wallet_manager.dart';
part 'wallet.g.dart';

Currency _currencyFromJson(Map<String, dynamic> data) =>
    Currency.from(json: data);

/// Represents a single wallet
///
/// A wallet stores [WalletSingleEntry]s categorized under [WalletCategory]s
@JsonSerializable()
class Wallet {
  /// A wallet stores [WalletSingleEntry]s categorized under [WalletCategory]s
  Wallet({
    required this.name,
    required this.currency,
    this.categories = const [],
    this.entries = const [],
    this.recurringEntries = const [],
    this.starterBalance = 0,
  });

  /// Connects generated fromJson method
  factory Wallet.fromJson(Map<String, dynamic> json) => _$WalletFromJson(json);

  /// A list of all [RecurringWalletEntry]s
  final List<RecurringWalletEntry> recurringEntries;

  /// Name of the wallet
  final String name;

  /// A list of available categories
  final List<WalletCategory> categories;

  /// List of saved entries
  final List<WalletSingleEntry> entries;

  /// The starting balance of the wallet
  ///
  /// Used to calculate current balance
  double starterBalance;

  /// Selected currency
  @JsonKey(fromJson: _currencyFromJson)
  final Currency currency;

  /// Connects generated toJson method
  Map<String, dynamic> toJson() => _$WalletToJson(this);

  /// Getter for the next unused unique number ID in the wallet's **entry** list
  int get nextId {
    var id = 1;
    while (entries.where((element) => element.id == id).isNotEmpty) {
      id++; // create unique ID
    }
    return id;
  }

  /// Getter for the next unused unique number ID in the wallet's **category**
  /// list
  int get nextCategoryId {
    var id = 0;
    while (categories.where((element) => element.id == id).isNotEmpty) {
      id++; // create unique ID
    }
    return id;
  }

  /// Removes the specified category.
  ///
  /// All [WalletSingleEntry]s will have their category reassigned
  /// to the default *No category*
  Future<void> removeCategory(WalletCategory category) async {
    // First remove the category from existing entries
    for (final entryToChange
        in entries.where((element) => element.category.id == category.id)) {
      entryToChange.category =
          categories.where((element) => element.id == 0).first;
    }
    // Remove the category
    categories.removeWhere((element) => element.id == category.id);
    // Save
    await WalletManager.saveWallet(this);
  }

  /// Empty wallet used for placeholders
  static final Wallet empty = Wallet(
    name: "Empty",
    currency: Currency.from(
      json: {
        "code": "USD",
        "name": "United States Dollar",
        "symbol": r"$",
        "flag": "USD",
        "decimal_digits": 2,
        "number": 840,
        "name_plural": "US dollars",
        "thousands_separator": ",",
        "decimal_separator": ".",
        "space_between_amount_and_symbol": false,
        "symbol_on_left": true,
      },
    ),
  );
}