feat: Admin Area Blog and Blog Page

backend/src/modules/blog/admin-blog.service.ts

@@ -0,0 +1,82 @@
+import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { v4 as uuid } from 'uuid';
+import { BlogPostEntity } from '../../database/entities/blog-post.entity';
+import { ApiError } from '../../common/errors/api-error';
+import { AdminBlogPost, CreatePostPayload, UpdatePostPayload } from './dto/blog.dto';
+
+@Injectable()
+export class AdminBlogService {
+  constructor(
+    @InjectRepository(BlogPostEntity)
+    private readonly posts: Repository<BlogPostEntity>,
+  ) {}
+
+  async listAll(): Promise<AdminBlogPost[]> {
+    const rows = await this.posts.find({ order: { updatedAt: 'DESC' } });
+    return rows.map((r) => this.toView(r));
+  }
+
+  async getById(id: string): Promise<AdminBlogPost> {
+    const row = await this.posts.findOne({ where: { id } });
+    if (!row) throw ApiError.notFound('Post not found');
+    return this.toView(row);
+  }
+
+  async create(payload: CreatePostPayload): Promise<AdminBlogPost> {
+    const status = payload.status ?? 'draft';
+    const row = this.posts.create({
+      id: uuid(),
+      title: payload.title.trim(),
+      bodyMd: payload.bodyMd ?? '',
+      status,
+      publishedAt: status === 'published' ? new Date().toISOString() : null,
+    });
+    await this.posts.save(row);
+    return this.toView(row);
+  }
+
+  async update(id: string, payload: UpdatePostPayload): Promise<AdminBlogPost> {
+    const row = await this.posts.findOne({ where: { id } });
+    if (!row) throw ApiError.notFound('Post not found');
+
+    if (payload.title !== undefined) row.title = payload.title.trim();
+    if (payload.bodyMd !== undefined) row.bodyMd = payload.bodyMd;
+
+    if (payload.status !== undefined) {
+      if (payload.status === 'published') {
+        row.status = 'published';
+        // Only stamp publishedAt if this post has never been published before;
+        // preserve the original publishedAt for re-publications.
+        if (!row.publishedAt) {
+          row.publishedAt = new Date().toISOString();
+        }
+      } else if (payload.status === 'draft') {
+        row.status = 'draft';
+        // preserve publishedAt so a later re-publish keeps the original publication timestamp.
+      }
+    }
+
+    await this.posts.save(row);
+    return this.toView(row);
+  }
+
+  async remove(id: string): Promise<void> {
+    const row = await this.posts.findOne({ where: { id } });
+    if (!row) throw ApiError.notFound('Post not found');
+    await this.posts.delete({ id });
+  }
+
+  private toView(r: BlogPostEntity): AdminBlogPost {
+    return {
+      id: r.id,
+      title: r.title,
+      bodyMd: r.bodyMd ?? '',
+      status: r.status,
+      createdAt: r.createdAt,
+      updatedAt: r.updatedAt,
+      publishedAt: r.publishedAt ?? null,
+    };
+  }
+}