Merged API and Databank into Main branch

database/helpers/utils/post_utils.ts

@@ -0,0 +1,128 @@
+/// <reference lib="deno.ns" />
+
+/**
+ * @author Esad Mustafoski
+ * @description This file is responsible for creating Functions to easily access the Database, Specifically for Posts
+ * @file postUtil.ts
+ */
+
+// +++ IMPORTS ------------------------------------------------------ //
+import { DB } from "https://deno.land/x/sqlite@v3.9.1/mod.ts";
+import { Post } from "../interfaces.ts";
+import { mapPostRow, queryDatabase } from "./mod.ts";
+
+async function getPostsFromDB(db: DB, user_uuid?: string): Promise<Post[]> {
+  const query = user_uuid
+    ? `SELECT * FROM posts WHERE user_id = ?`
+    : `SELECT * FROM posts`;
+  const params = user_uuid ? [user_uuid] : [];
+  return await queryDatabase<Post>(db, query, params, mapPostRow);
+}
+
+async function getPostById(db: DB, postId: string): Promise<Post | null> {
+  const query = `SELECT * FROM posts WHERE posts_uuid = ?`;
+  const posts = await queryDatabase<Post>(db, query, [postId], mapPostRow);
+  return posts.length > 0 ? posts[0] : null;
+}
+
+async function createPost(
+  db: DB,
+  userId: string,
+  createdAt: string,
+  postText: string,
+  postType: string,
+): Promise<string> {
+  const query = `
+    INSERT INTO posts (user_id, created_at, post_text, post_type, likes, comments)
+    VALUES (?, ?, ?, ?, 0, 0)
+  `;
+
+  db.query(query, [userId, createdAt, postText, postType]);
+  return db.lastInsertRowId.toString();
+}
+
+async function updatePost(
+  db: DB,
+  postId: string,
+  postText?: string,
+  postType?: string,
+): Promise<void> {
+  let query = `UPDATE posts SET `;
+  const params: any[] = [];
+
+  if (postText) {
+    query += `post_text = ?`;
+    params.push(postText);
+
+    if (postType) {
+      query += `, post_type = ?`;
+      params.push(postType);
+    }
+  } else if (postType) {
+    query += `post_type = ?`;
+    params.push(postType);
+  }
+
+  query += ` WHERE posts_uuid = ?`;
+  params.push(postId);
+
+  db.query(query, params);
+}
+
+// This function deletes the comments on the post first, then
+// deletes the post to avoid errors
+async function deletePost(db: DB, postId: string): Promise<void> {
+  const deleteCommentsQuery = `DELETE FROM comments WHERE post_id = ?`;
+  db.query(deleteCommentsQuery, [postId]);
+
+  const deletePostQuery = `DELETE FROM posts WHERE posts_uuid = ?`;
+  db.query(deletePostQuery, [postId]);
+}
+
+// This is simplified and doesn't work as it would in a real application
+// or website like twitter, this only exists as a test
+async function likePost(db: DB, postId: string, userId: string): Promise<void> {
+  const query = `UPDATE posts SET likes = likes + 1 WHERE posts_uuid = ?`;
+  db.query(query, [postId]);
+}
+
+/**
+ * @param posts_to_filter The Posts in an array to filter
+ * @param post_types The types of Posts to filter for
+ * @returns Array of Posts
+ */
+// Filter functions merged to one
+function filterPosts(posts_to_filter: Post[], post_types: string[]): Post[] {
+  if (post_types.length === 0) {
+    return posts_to_filter;
+  }
+
+  // Set is a type that we can specify the values to
+  // example: const set = new Set<number>();
+  // set.add(1); Will work
+  // set.add("2"); Will not work, it will error because
+  // it is a string.
+  const includedPostIds = new Set<number>();
+  const result: Post[] = [];
+
+  for (const type of post_types) {
+    for (const post of posts_to_filter) {
+      if (!includedPostIds.has(post.posts_uuid) && post.post_type === type) {
+        result.push(post);
+        includedPostIds.add(post.posts_uuid);
+      }
+    }
+  }
+
+  return result;
+}
+
+export {
+  getPostsFromDB,
+  getPostById,
+  createPost,
+  updatePost,
+  deletePost,
+  likePost,
+  filterPosts,
+};