OpenIsle/backend/src/main/java/com/openisle/model/Reaction.java

package com.openisle.model;

import jakarta.persistence.*;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import org.hibernate.annotations.CreationTimestamp;

/**
 * Reaction entity representing a user's reaction to a post, comment or message.
 */
@Entity
@Getter
@Setter
@NoArgsConstructor
@Table(name = "reactions",
       uniqueConstraints = {
           @UniqueConstraint(columnNames = {"user_id", "post_id", "type"}),
           @UniqueConstraint(columnNames = {"user_id", "comment_id", "type"}),
           @UniqueConstraint(columnNames = {"user_id", "message_id", "type"})
       })
public class Reaction {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Enumerated(EnumType.STRING)
    @Column(nullable = false)
    private ReactionType type;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "user_id")
    private User user;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "post_id")
    private Post post;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "comment_id")
    private Comment comment;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "message_id")
    private Message message;

    @CreationTimestamp
    @Column(nullable = false, updatable = false,
            columnDefinition = "DATETIME(6) DEFAULT CURRENT_TIMESTAMP(6)")
    private java.time.LocalDateTime createdAt;
}