PR for OOP Concepts

app/src/main/kotlin/org/example/Book.kt

@@ -0,0 +1,14 @@
+package org.example
+
+class Book(
+    id: String,
+    title: String,
+    val author: String,
+    val isbn: String,
+    val pages: Int
+) : LibraryItem(id, title) {
+    override fun getItemType(): String = "Book"
+    override fun calculateLateFee(daysLate: Int): Double {
+        return daysLate * 0.5
+    }
+}

app/src/main/kotlin/org/example/DVD.kt

@@ -0,0 +1,14 @@
+package org.example
+
+class DVD(
+    id: String,
+    title: String,
+    val director: String,
+    val duration: Int,
+    val genre: String
+) : LibraryItem(id, title) {
+    override fun getItemType(): String = "DVD"
+    override fun calculateLateFee(daysLate: Int): Double {
+        return daysLate * 1.0
+    }
+}

app/src/main/kotlin/org/example/LibraryItem.kt

@@ -0,0 +1,16 @@
+package org.example
+
+abstract class LibraryItem(
+    val id: String,
+    val title: String,
+    var isAvailable: Boolean = true
+) {
+    abstract fun getItemType(): String
+    abstract fun calculateLateFee(daysLate: Int): Double
+
+    open fun displayInfo(): String {
+        return "ID: $id, Title: $title, Available: $isAvailable"
+    }
+
+
+}

app/src/main/kotlin/org/example/Magazine.kt

@@ -0,0 +1,13 @@
+package org.example
+
+class Magazine(
+    id: String,
+    title: String,
+    val issueNumber: Int,
+    val publisher: String
+) : LibraryItem(id, title) {
+    override fun getItemType(): String = "Magazine"
+    override fun calculateLateFee(daysLate: Int): Double {
+        return daysLate * 0.25
+    }
+}

app/src/main/kotlin/org/example/Main.kt

@@ -0,0 +1,24 @@
+/*
+ * This source file was generated by the Gradle 'init' task
+ */
+package org.example
+
+fun main() {
+    val member1= Member("M1", "S", "s")
+    member1.setName("Smith")
+    member1.setEmail("smith.com")
+    member1.setEmail("smith@gmail.com")
+
+    val book1 = Book("B1", "Harry Potter", "JK", "1111-222", 122)
+    member1.borrowItem(book1)
+
+    val member2 = Member("M2", "John", "john@gmail.com")
+    member2.borrowItem(book1)
+
+    member2.returnItem(book1)
+    member1.returnItem(book1)
+    member2.borrowItem(book1)
+    member1.totalLateFees(15)
+    member2.totalLateFees(15)
+
+}

app/src/main/kotlin/org/example/Member.kt

@@ -0,0 +1,64 @@
+package org.example
+
+class Member(
+    private val memberId: String,
+    private var name: String,
+    private var email: String
+) {
+    private val borrowedItems = mutableListOf<LibraryItem>()
+
+    fun getMemberId(): String = memberId
+    fun getName(): String = name
+    fun getEmail(): String = email
+
+    fun setName(memberName: String) {
+        name = memberName
+        println("Member Name set to $name")
+    }
+    fun setEmail(memberEmail: String) {
+        if(
+            memberEmail.contains('@')
+            &&
+            memberEmail.contains('.')
+            ) {
+            email = memberEmail
+            println("Member Email set to $email")
+        } else {
+            println("invalid email")
+        }
+    }
+
+    fun borrowItem(item: LibraryItem) {
+        if(item.isAvailable) {
+            borrowedItems.add(item)
+            item.isAvailable = false
+            println("Member $memberId $name borrowed item ${item.id} ${item.title}")
+        }
+        else {
+            println("item unavailable")
+        }
+    }
+
+    fun returnItem(item: LibraryItem) {
+        if(borrowedItems.contains(item)) {
+            borrowedItems.remove(item)
+            item.isAvailable = true
+            println("Member $memberId $name returned item ${item.id} ${item.title}")
+        } else {
+            println("Member $memberId $name did not borrow this item")
+        }
+    }
+
+    fun totalLateFees(daysLate: Int) {
+        if(borrowedItems.isEmpty()) {
+            println("no items borrowed")
+        }
+        else {
+            var total = 0.0
+            borrowedItems.forEach { item ->
+                total += item.calculateLateFee(daysLate)
+            }
+            println("Total Late Fees = $$total")
+        }
+    }
+}