IssuedBook.java

package models;

import java.io.Serializable;
import java.time.LocalDate;
import java.util.Objects;

/**
 * IssuedBook.java - Transaction record for book issues and returns
 * 
 * Purpose: Track when books are issued and returned
 * Maintains:
 * - Issue and due dates
 * - Return status
 * - Member information
 */
public class IssuedBook implements Serializable {
    
    private static final long serialVersionUID = 1L;
    
    // Transaction identifiers
    private int issueId;              // Unique transaction ID
    private int bookId;               // Foreign key to books table
    private String bookTitle;         // Denormalized for display
    
    // Date information
    private LocalDate issuedDate;     // Date book was issued
    private LocalDate dueDate;        // Expected return date
    private LocalDate returnDate;     // Actual return date (null if not returned)
    
    // Status and member info
    private String status;            // "ISSUED" or "RETURNED"
    private String memberName;        // Who issued the book
    private String memberContact;     // Phone/email for follow-up
    
    // Constants
    public static final String STATUS_ISSUED = "ISSUED";
    public static final String STATUS_RETURNED = "RETURNED";
    private static final int DEFAULT_ISSUE_DAYS = 14; // 2 weeks
    
    // Constructors
    
    /**
     * No-argument constructor for framework compatibility
     */
    public IssuedBook() {
        this.status = STATUS_ISSUED;
    }
    
    /**
     * Constructor for new issue (issueId is auto-generated)
     */
    public IssuedBook(int bookId, String bookTitle, LocalDate issuedDate, 
                      int issueDays, String memberName, String memberContact) {
        this.bookId = bookId;
        this.bookTitle = bookTitle;
        this.issuedDate = issuedDate;
        this.dueDate = issuedDate.plusDays(issueDays);
        this.returnDate = null;
        this.status = STATUS_ISSUED;
        this.memberName = memberName;
        this.memberContact = memberContact;
    }
    
    /**
     * Full constructor with all fields
     */
    public IssuedBook(int issueId, int bookId, String bookTitle, 
                      LocalDate issuedDate, LocalDate dueDate, 
                      LocalDate returnDate, String status, 
                      String memberName, String memberContact) {
        this.issueId = issueId;
        this.bookId = bookId;
        this.bookTitle = bookTitle;
        this.issuedDate = issuedDate;
        this.dueDate = dueDate;
        this.returnDate = returnDate;
        this.status = status;
        this.memberName = memberName;
        this.memberContact = memberContact;
    }
    
    // Getters and Setters (Encapsulation)
    
    public int getIssueId() {
        return issueId;
    }
    
    public void setIssueId(int issueId) {
        if (issueId < 0) {
            throw new IllegalArgumentException("Issue ID must be positive");
        }
        this.issueId = issueId;
    }
    
    public int getBookId() {
        return bookId;
    }
    
    public void setBookId(int bookId) {
        if (bookId <= 0) {
            throw new IllegalArgumentException("Book ID must be positive");
        }
        this.bookId = bookId;
    }
    
    public String getBookTitle() {
        return bookTitle;
    }
    
    public void setBookTitle(String bookTitle) {
        if (bookTitle == null || bookTitle.trim().isEmpty()) {
            throw new IllegalArgumentException("Book title cannot be empty");
        }
        this.bookTitle = bookTitle;
    }
    
    public LocalDate getIssuedDate() {
        return issuedDate;
    }
    
    public void setIssuedDate(LocalDate issuedDate) {
        if (issuedDate == null || issuedDate.isAfter(LocalDate.now())) {
            throw new IllegalArgumentException("Issued date cannot be in future");
        }
        this.issuedDate = issuedDate;
    }
    
    public LocalDate getDueDate() {
        return dueDate;
    }
    
    public void setDueDate(LocalDate dueDate) {
        if (dueDate == null) {
            throw new IllegalArgumentException("Due date cannot be null");
        }
        this.dueDate = dueDate;
    }
    
    public LocalDate getReturnDate() {
        return returnDate;
    }
    
    public void setReturnDate(LocalDate returnDate) {
        if (returnDate != null && returnDate.isAfter(LocalDate.now())) {
            throw new IllegalArgumentException("Return date cannot be in future");
        }
        if (returnDate != null && returnDate.isBefore(issuedDate)) {
            throw new IllegalArgumentException("Return date cannot be before issue date");
        }
        this.returnDate = returnDate;
    }
    
    public String getStatus() {
        return status;
    }
    
    public void setStatus(String status) {
        if (!status.equals(STATUS_ISSUED) && !status.equals(STATUS_RETURNED)) {
            throw new IllegalArgumentException("Status must be ISSUED or RETURNED");
        }
        this.status = status;
    }
    
    public String getMemberName() {
        return memberName;
    }
    
    public void setMemberName(String memberName) {
        if (memberName == null || memberName.trim().isEmpty()) {
            throw new IllegalArgumentException("Member name cannot be empty");
        }
        this.memberName = memberName;
    }
    
    public String getMemberContact() {
        return memberContact;
    }
    
    public void setMemberContact(String memberContact) {
        this.memberContact = memberContact != null ? memberContact : "";
    }
    
    // Business Logic Methods
    
    /**
     * Marks book as returned
     * Called when member returns the book
     */
    public void markAsReturned() {
        this.returnDate = LocalDate.now();
        this.status = STATUS_RETURNED;
    }
    
    /**
     * Checks if book is overdue
     * 
     * @return true if current date > due date and not returned
     */
    public boolean isOverdue() {
        return status.equals(STATUS_ISSUED) && LocalDate.now().isAfter(dueDate);
    }
    
    /**
     * Gets days overdue
     * 
     * @return number of days overdue, 0 if not overdue
     */
    public long getDaysOverdue() {
        if (!isOverdue()) {
            return 0;
        }
        return java.time.temporal.ChronoUnit.DAYS.between(dueDate, LocalDate.now());
    }
    
    /**
     * Gets fine amount based on overdue days
     * Example: ₹5 per day after due date
     * 
     * @return fine amount in rupees
     */
    public double calculateFine() {
        long overdueDay = getDaysOverdue();
        return overdueDay > 0 ? overdueDay * 5.0 : 0.0;
    }
    
    /**
     * Checks if book is currently issued (not returned)
     * 
     * @return true if status is ISSUED
     */
    public boolean isCurrentlyIssued() {
        return status.equals(STATUS_ISSUED);
    }
    
    // Object Methods
    
    @Override
    public String toString() {
        return "IssuedBook{" +
                "issueId=" + issueId +
                ", bookId=" + bookId +
                ", bookTitle='" + bookTitle + '\'' +
                ", issuedDate=" + issuedDate +
                ", dueDate=" + dueDate +
                ", returnDate=" + returnDate +
                ", status='" + status + '\'' +
                ", memberName='" + memberName + '\'' +
                ", memberContact='" + memberContact + '\'' +
                '}';
    }
    
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        IssuedBook that = (IssuedBook) o;
        return issueId == that.issueId;
    }
    
    @Override
    public int hashCode() {
        return Objects.hash(issueId);
    }
}