feat: Post entity and endpoint to create posts

backend/src/main/java/online/wesal/wesal/controller/PostController.java

@@ -0,0 +1,61 @@
+package online.wesal.wesal.controller;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import online.wesal.wesal.dto.ApiResponse;
+import online.wesal.wesal.dto.PostCreateRequestDTO;
+import online.wesal.wesal.dto.PostResponseDTO;
+import online.wesal.wesal.entity.Post;
+import online.wesal.wesal.service.PostService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/posts")
+@CrossOrigin(origins = "*")
+@Tag(name = "Posts", description = "Post management endpoints")
+public class PostController {
+    
+    @Autowired
+    private PostService postService;
+    
+    @PostMapping(value = "/create", consumes = "application/json", produces = "application/json")
+    @Operation(summary = "Create post", description = "Create a new post")
+    public ResponseEntity<ApiResponse<PostResponseDTO>> createPost(
+            @Valid @RequestBody PostCreateRequestDTO request,
+            BindingResult bindingResult,
+            Authentication authentication) {
+        
+        if (bindingResult.hasErrors()) {
+            String errorMessage = bindingResult.getFieldErrors().stream()
+                .map(error -> {
+                    String field = error.getField();
+                    if ("body".equals(field)) return "Post body is required and cannot exceed 2000 characters";
+                    return error.getDefaultMessage();
+                })
+                .findFirst()
+                .orElse("Invalid input");
+            return ResponseEntity.badRequest().body(ApiResponse.error(errorMessage));
+        }
+        
+        try {
+            Post post = postService.createPost(request.getBody());
+            PostResponseDTO response = new PostResponseDTO(post);
+            return ResponseEntity.ok(ApiResponse.success(response));
+        } catch (RuntimeException e) {
+            String message;
+            if (e.getMessage().contains("User not found")) {
+                message = "Authentication error. Please log in again.";
+            } else {
+                message = "Something went wrong.. We're sorry but try again later";
+            }
+            return ResponseEntity.badRequest().body(ApiResponse.error(message));
+        } catch (Exception e) {
+            return ResponseEntity.status(500).body(ApiResponse.error("Something went wrong.. We're sorry but try again later"));
+        }
+    }
+}

backend/src/main/java/online/wesal/wesal/dto/PostCreateRequestDTO.java

@@ -0,0 +1,25 @@
+package online.wesal.wesal.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Size;
+
+public class PostCreateRequestDTO {
+    
+    @NotBlank(message = "Post body cannot be empty")
+    @Size(max = 2000, message = "Post body cannot exceed 2000 characters")
+    private String body;
+    
+    public PostCreateRequestDTO() {}
+    
+    public PostCreateRequestDTO(String body) {
+        this.body = body;
+    }
+    
+    public String getBody() {
+        return body;
+    }
+    
+    public void setBody(String body) {
+        this.body = body;
+    }
+}

backend/src/main/java/online/wesal/wesal/dto/PostResponseDTO.java

@@ -0,0 +1,73 @@
+package online.wesal.wesal.dto;
+
+import online.wesal.wesal.entity.Post;
+import java.time.LocalDateTime;
+
+public class PostResponseDTO {
+    
+    private String id;
+    private String creatorId;
+    private String body;
+    private String likes;
+    private String comments;
+    private LocalDateTime creationDate;
+    
+    public PostResponseDTO() {}
+    
+    public PostResponseDTO(Post post) {
+        this.id = String.valueOf(post.getId());
+        this.creatorId = String.valueOf(post.getCreatorId());
+        this.body = post.getBody();
+        this.likes = String.valueOf(post.getLikes());
+        this.comments = String.valueOf(post.getComments());
+        this.creationDate = post.getCreationDate();
+    }
+    
+    public String getId() {
+        return id;
+    }
+    
+    public void setId(String id) {
+        this.id = id;
+    }
+    
+    public String getCreatorId() {
+        return creatorId;
+    }
+    
+    public void setCreatorId(String creatorId) {
+        this.creatorId = creatorId;
+    }
+    
+    public String getBody() {
+        return body;
+    }
+    
+    public void setBody(String body) {
+        this.body = body;
+    }
+    
+    public String getLikes() {
+        return likes;
+    }
+    
+    public void setLikes(String likes) {
+        this.likes = likes;
+    }
+    
+    public String getComments() {
+        return comments;
+    }
+    
+    public void setComments(String comments) {
+        this.comments = comments;
+    }
+    
+    public LocalDateTime getCreationDate() {
+        return creationDate;
+    }
+    
+    public void setCreationDate(LocalDateTime creationDate) {
+        this.creationDate = creationDate;
+    }
+}

backend/src/main/java/online/wesal/wesal/entity/Post.java

@@ -0,0 +1,85 @@
+package online.wesal.wesal.entity;
+
+import jakarta.persistence.*;
+import jakarta.validation.constraints.NotBlank;
+import java.time.LocalDateTime;
+
+@Entity
+@Table(name = "posts")
+public class Post {
+    
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+    
+    @Column(nullable = false)
+    private Long creatorId;
+    
+    @Column(nullable = false, length = 2000)
+    @NotBlank
+    private String body;
+    
+    @Column(nullable = false)
+    private int likes = 0;
+    
+    @Column(nullable = false)
+    private int comments = 0;
+    
+    @Column(nullable = false)
+    private LocalDateTime creationDate = LocalDateTime.now();
+    
+    public Post() {}
+    
+    public Post(Long creatorId, String body) {
+        this.creatorId = creatorId;
+        this.body = body;
+    }
+    
+    public Long getId() {
+        return id;
+    }
+    
+    public void setId(Long id) {
+        this.id = id;
+    }
+    
+    public Long getCreatorId() {
+        return creatorId;
+    }
+    
+    public void setCreatorId(Long creatorId) {
+        this.creatorId = creatorId;
+    }
+    
+    public String getBody() {
+        return body;
+    }
+    
+    public void setBody(String body) {
+        this.body = body;
+    }
+    
+    public int getLikes() {
+        return likes;
+    }
+    
+    public void setLikes(int likes) {
+        this.likes = likes;
+    }
+    
+    public int getComments() {
+        return comments;
+    }
+    
+    public void setComments(int comments) {
+        this.comments = comments;
+    }
+    
+    public LocalDateTime getCreationDate() {
+        return creationDate;
+    }
+    
+    public void setCreationDate(LocalDateTime creationDate) {
+        this.creationDate = creationDate;
+    }
+}

backend/src/main/java/online/wesal/wesal/repository/PostRepository.java

@@ -0,0 +1,12 @@
+package online.wesal.wesal.repository;
+
+import online.wesal.wesal.entity.Post;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface PostRepository extends JpaRepository<Post, Long> {
+    List<Post> findByCreatorIdOrderByCreationDateDesc(Long creatorId);
+}

backend/src/main/java/online/wesal/wesal/service/PostService.java

@@ -0,0 +1,23 @@
+package online.wesal.wesal.service;
+
+import online.wesal.wesal.entity.Post;
+import online.wesal.wesal.entity.User;
+import online.wesal.wesal.repository.PostRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class PostService {
+    
+    @Autowired
+    private PostRepository postRepository;
+    
+    @Autowired
+    private UserService userService;
+    
+    public Post createPost(String body) {
+        User currentUser = userService.getCurrentUser();
+        Post post = new Post(currentUser.getId(), body);
+        return postRepository.save(post);
+    }
+}