Fixed RandomFiller multiple unwanted events being created

Library/DataLayer/API/IDataFiller.cs

@@ -0,0 +1,7 @@
+namespace DataLayer.API
+{
+    public interface IDataFiller
+    {
+        void Fill(IDataContext context);
+    }
+}

Library/DataLayer/Implementations/DataFillers/PresetFiller.cs

@@ -0,0 +1,37 @@
+using DataLayer.API;
+using DataLayer.Implementations.Events;
+
+namespace DataLayer.Implementations
+{
+    public class PresetFiller : IDataFiller 
+    {
+        public void Fill(IDataContext context)
+        {
+            context.Users.Add(new User("John", "Doe", "johndoe@email", 100, 123456789, null));
+            context.Users.Add(new User("Jane", "Doe", "janedoe@email", 200, 111111111, null));
+            context.Users.Add(new User("Alice", "Smith", "alicesmith@email", 300, 121212121, null));
+            context.Users.Add(new User("Bob", "Smith", "bobsmith@email", 400, 987654321, null));
+            context.Users.Add(new User("Charlie", "Brown", "charliebrown@email", 500, 999999999, null));
+
+            context.Products.Add(new Book("Old Man and the Sea", 10, "Ernest Hemingway", "Charles Sons", 300, new DateTime(1952, 1, 1)));
+            context.Products.Add(new Book("The Great Gatsby", 20, "F. Scott Fitzgerald", "Charles Sons", 400, new DateTime(1925, 1, 1)));
+            context.Products.Add(new Book("To Kill a Mockingbird", 30, "Harper Lee", "Charles Sons", 500, new DateTime(1960, 1, 1)));
+            context.Products.Add(new Book("1984", 40, "George Orwell", "Charles Sons", 600, new DateTime(1949, 1, 1)));
+            context.Products.Add(new Book("Brave New World", 50, "Aldous Huxley", "Charles Sons", 700, new DateTime(1932, 1, 1)));
+
+            context.States.Add(new State(context.Products[0], 5));
+            context.States.Add(new State(context.Products[1], 5));
+            context.States.Add(new State(context.Products[2], 5));
+            context.States.Add(new State(context.Products[3], 5));
+            context.States.Add(new State(context.Products[4], 5));
+
+            context.Events.Add(new Borrow(context.Users[0], context.States[0]));
+            context.Events.Add(new Borrow(context.Users[1], context.States[1]));
+            context.Events.Add(new Borrow(context.Users[3], context.States[3]));
+            context.Events.Add(new Return(context.Users[0], context.States[0]));
+            context.Events.Add(new Return(context.Users[1], context.States[1]));
+            context.Events.Add(new Return(context.Users[3], context.States[3]));
+            context.Events.Add(new Delivery(context.Users[4], context.States[4], 10));
+        }
+    }
+}

Library/DataLayer/Implementations/DataFillers/RandomFiller.cs

@@ -0,0 +1,158 @@
+using System;
+using DataLayer.API;
+using DataLayer.Implementations.Events;
+
+namespace DataLayer.Implementations
+{
+    public class RandomFiller : IDataFiller
+    {
+        private Random random = new Random();
+        public void Fill(IDataContext context)
+        {
+            int usersCount = random.Next(5, 11);
+            for (int i = 0; i < usersCount; i++)
+            {
+                context.Users.Add(new User(
+                    GetRandomFirstName(),
+                    GetRandomLastName(),
+                    $"{GetRandomFirstName().ToLower()}{GetRandomLastName().ToLower()}@email.com",
+                    random.Next(100, 1000),
+                    GetRandomPhoneNumber(),
+                    null
+                ));
+            }
+
+            int productsCount = random.Next(5, 11);
+            for (int i = 0; i < productsCount; i++)
+            {
+                context.Products.Add(new Book(
+                    GetRandomTitle(),
+                    random.Next(10, 100),
+                    GetRandomAuthor(),
+                    GetRandomPublisher(),
+                    random.Next(50, 1000),
+                    GetRandomDate()
+                ));
+            }
+
+            int statesCount = context.Products.Count;
+            for (int i = 0; i < statesCount; i++)
+            {
+                context.States.Add(new State(
+                    context.Products[i],
+                    random.Next(1, 10)
+                ));
+            }
+
+            int eventsCount = random.Next(5, 11);
+            int borrowsCount = 0;
+            List<IUser> usersBorrowing = new List<IUser>();
+            List<IState> statesBorrowed = new List<IState>();
+            for (int i = 0; i < eventsCount; i++)
+            {
+                int userIndex = random.Next(context.Users.Count);
+                int stateIndex = random.Next(context.States.Count);
+                int randomEvent = random.Next(3);
+                if (randomEvent == 0)
+                {
+                    context.Events.Add(new Borrow(context.Users[userIndex], context.States[stateIndex]));
+                    borrowsCount++;
+                    usersBorrowing.Add(context.Users[userIndex]);
+                    statesBorrowed.Add(context.States[stateIndex]);
+                }
+                else if (randomEvent == 1 && borrowsCount > 0)
+                {
+                    context.Events.Add(new Return(usersBorrowing[borrowsCount-1], statesBorrowed[borrowsCount-1]));
+                    borrowsCount--;
+                    usersBorrowing.RemoveAt(borrowsCount);
+                    statesBorrowed.RemoveAt(borrowsCount);
+                }
+                else if (randomEvent == 1 && borrowsCount == 0)
+                {
+                    i--;
+                }
+                else if (randomEvent == 2)
+                {
+                    context.Events.Add(new Delivery(context.Users[userIndex], context.States[stateIndex], random.Next(1, 10)));
+                }
+            }
+        }
+        private string GetRandomFirstName()
+        {
+            string[] firstNames = {
+                "John", "Jane", "Alice", "Bob", "Charlie",
+                "Michael", "Emily", "David", "Sarah", "Daniel",
+                "Matthew", "Jessica", "Andrew", "Jennifer", "James",
+                "Linda", "William", "Karen", "Joseph", "Maria",
+                "Robert", "Susan", "Christopher", "Nancy", "Daniel",
+                "Karen", "Thomas", "Lisa", "Brian", "Margaret",
+                "Steven", "Betty", "Timothy", "Dorothy", "Kevin",
+                "Sandra", "Richard", "Ashley", "Mark", "Kimberly",
+                "Jeffrey", "Donna", "Scott", "Emily", "Charles",
+                "Carol", "Paul", "Michelle", "Anthony", "Laura"
+            };
+            return firstNames[random.Next(firstNames.Length)];
+        }
+        private string GetRandomLastName()
+        {
+            string[] lastNames = {
+                "Smith", "Johnson", "Williams", "Brown", "Jones",
+                "Garcia", "Miller", "Davis", "Rodriguez", "Martinez",
+                "Hernandez", "Lopez", "Gonzalez", "Wilson", "Anderson",
+                "Thomas", "Taylor", "Moore", "Jackson", "Martin",
+                "Lee", "Perez", "Thompson", "White", "Harris",
+                "Sanchez", "Clark", "Ramirez", "Lewis", "Robinson",
+                "Walker", "Young", "Allen", "King", "Wright",
+                "Scott", "Torres", "Nguyen", "Hill", "Flores",
+                "Green", "Adams", "Nelson", "Baker", "Hall",
+                "Rivera", "Campbell", "Mitchell", "Carter", "Roberts"
+            };
+            return lastNames[random.Next(lastNames.Length)];
+        }
+        private int GetRandomPhoneNumber()
+        {
+            return random.Next(100000000, 1000000000); // 9-digit random number
+        }
+        private string GetRandomTitle()
+        {
+            string[] titles = {
+                "The Catcher in the Rye", "To Kill a Mockingbird", "1984", "The Great Gatsby", "Pride and Prejudice",
+                "Harry Potter and the Philosopher's Stone", "The Hobbit", "The Lord of the Rings", "The Hunger Games", "The Da Vinci Code",
+                "The Chronicles of Narnia", "Twilight", "The Alchemist", "The Fault in Our Stars", "The Kite Runner",
+                "A Song of Ice and Fire", "The Hitchhiker's Guide to the Galaxy", "The Shining", "The Girl with the Dragon Tattoo", "Gone Girl",
+                "Brave New World", "Animal Farm", "The Adventures of Huckleberry Finn", "Moby-Dick", "Frankenstein",
+                "Dracula", "Alice's Adventures in Wonderland", "The War of the Worlds", "The Picture of Dorian Gray", "The Bell Jar"
+            };
+            return titles[random.Next(titles.Length)];
+        }
+        private string GetRandomAuthor()
+        {
+            string[] authors = {
+                "J.D. Salinger", "Harper Lee", "George Orwell", "F. Scott Fitzgerald", "Jane Austen",
+                "J.K. Rowling", "J.R.R. Tolkien", "George R.R. Martin", "Suzanne Collins", "Dan Brown",
+                "C.S. Lewis", "Stephenie Meyer", "Paulo Coelho", "John Green", "Khaled Hosseini",
+                "George R.R. Martin", "Douglas Adams", "Stephen King", "Stieg Larsson", "Gillian Flynn",
+                "Aldous Huxley", "George Orwell", "Mark Twain", "Herman Melville", "Mary Shelley",
+                "Bram Stoker", "Lewis Carroll", "H.G. Wells", "Oscar Wilde", "Sylvia Plath"
+            };
+            return authors[random.Next(authors.Length)];
+        }
+        private string GetRandomPublisher()
+        {
+            string[] publishers = {
+                "Random House", "Penguin Books", "HarperCollins", "Simon & Schuster", "Hachette Livre",
+                "Macmillan Publishers", "Scholastic Corporation", "Pearson Education", "Bloomsbury Publishing", "Oxford University Press",
+                "Cambridge University Press", "Wiley", "Springer Nature", "McGraw-Hill Education", "Cengage",
+                "Houghton Mifflin Harcourt", "Elsevier", "Taylor & Francis", "Harvard University Press", "MIT Press"
+            };
+            return publishers[random.Next(publishers.Length)];
+        }
+        private DateTime GetRandomDate()
+        {
+            // Random date between 1900 and now
+            DateTime start = new DateTime(1900, 1, 1);
+            int range = (DateTime.Today - start).Days;
+            return start.AddDays(random.Next(range));
+        }
+    }
+}

Library/Tests/DataLayerTests.cs

@@ -174,4 +174,28 @@ public void DataRepositoryTests()
         Assert.IsFalse(dataRepository.GetAllProducts().Contains(product));
         Assert.IsFalse(dataRepository.GetAllStates().Contains(state));
     }
+
+    [TestMethod]
+    public void DataFillerTests()
+    {
+        IDataContext dataContext = new DataContext();
+        IDataFiller dataFiller = new PresetFiller();
+
+        dataFiller.Fill(dataContext);
+
+        Assert.AreEqual(5, dataContext.Users.Count);
+        Assert.AreEqual(5, dataContext.Products.Count);
+        Assert.AreEqual(5, dataContext.States.Count);
+        Assert.AreEqual(7, dataContext.Events.Count);
+
+        dataContext = new DataContext();
+        dataFiller = new RandomFiller();
+
+        dataFiller.Fill(dataContext);
+
+        Assert.IsTrue(dataContext.Users.Count >= 5 && dataContext.Users.Count <= 11);
+        Assert.IsTrue(dataContext.Products.Count >= 5 && dataContext.Products.Count <= 11);
+        Assert.AreEqual(dataContext.Products.Count, dataContext.States.Count);
+        Assert.IsTrue(dataContext.Events.Count >= 5 && dataContext.Events.Count <= 11);
+    }
 }