/// <summary>
/// Parses input data to database friendly format an includes them in it.
/// If there is any error in the given data, process is aborted and empty object is returned.
/// </summary>
/// <param name="reader">Text reader. Must be set to read STDIN.</param>
/// <param name="wrongInput">Flag that carries information of error in data loading / parsing.</param>
/// <returns>Database object if the data were correct. NULL if they were not.</returns>
public static ModelStore LoadFrom(TextReader reader, out bool wrongInput)
{
var store = new ModelStore();
wrongInput = true;
try {
if (reader.ReadLine() != "DATA-BEGIN")
{
return(null);
}
while (true)
{
wrongInput = true;
string line = reader.ReadLine();
if (line == null)
{
return(null);
}
else if (line == "DATA-END")
{
wrongInput = false;
break;
}
string[] tokens = line.Split(';');
switch (tokens[0])
{
case "BOOK":
if (Book.TryParse(tokens, out Book book))
{
//is this book original?
if (store.GetBook(book.Id) == null)
{
store.books.Add(book);
wrongInput = false;
}
}
break;
case "CUSTOMER":
if (Customer.TryParse(tokens, out Customer customer))
{
//is this customer new?
if (store.GetCustomer(customer.Id) == null)
{
store.customers.Add(customer);
wrongInput = false;
}
}
break;
case "CART-ITEM":
if (ShoppingCartItem.TryParse(tokens, out ShoppingCartItem shoppingCartItem, out int userID))
{
//does this customer exist?
if (store.GetCustomer(userID) == null)
{
break;
}
//does the book exist?
if (store.GetBook(shoppingCartItem.BookId) == null)
{
break;
}
Customer existingCustomer = store.GetCustomer(userID);
existingCustomer.ShoppingCart.AddItem(shoppingCartItem);
wrongInput = false;
}
break;
default:
break;
}
if (wrongInput)
{
return(default(ModelStore));
}
}
} catch (Exception ex) {
if (ex is FormatException || ex is IndexOutOfRangeException)
{
return(null);
}
throw;
}
return(store);
}
/// <summary>
/// Adds item to its customer's shoping cart.
/// </summary>
/// <param name="shoppingCartItem">Book object to be added.</param>
public void AddItem(ShoppingCartItem shoppingCartItem)
{
Items.Add(shoppingCartItem);
}