From f48713c4703fc6a1f13479225da1af8244cdab2e Mon Sep 17 00:00:00 2001
From: Oliver Booth <git@olivr.me>
Date: Sun, 24 Sep 2023 17:03:06 +0100
Subject: [PATCH] feat: add tag filtering (resolves WEB-1)

---
 .../Controllers/Blog/BlogApiController.cs     | 11 +++++++++
 src/ts/API.ts                                 |  5 ++++
 src/ts/app.ts                                 | 24 ++++++++++++++++++-
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/OliverBooth/Controllers/Blog/BlogApiController.cs b/OliverBooth/Controllers/Blog/BlogApiController.cs
index 792186f..c0f8704 100644
--- a/OliverBooth/Controllers/Blog/BlogApiController.cs
+++ b/OliverBooth/Controllers/Blog/BlogApiController.cs
@@ -41,6 +41,17 @@ public sealed class BlogApiController : ControllerBase
         return Ok(allPosts.Select(post => CreatePostObject(post)));
     }
 
+    [HttpGet("posts/tagged/{tag}/{page:int?}")]
+    public IActionResult GetTaggedBlogPosts(string tag, int page = 0)
+    {
+        const int itemsPerPage = 10;
+        tag = tag.Replace('-', ' ').ToLowerInvariant();
+
+        IReadOnlyList<IBlogPost> allPosts = _blogPostService.GetBlogPosts(page, itemsPerPage);
+        allPosts = allPosts.Where(post => post.Tags.Contains(tag)).ToList();
+        return Ok(allPosts.Select(post => CreatePostObject(post)));
+    }
+
     [HttpGet("author/{id:guid}")]
     public IActionResult GetAuthor(Guid id)
     {
diff --git a/src/ts/API.ts b/src/ts/API.ts
index f8b1aeb..a1e070d 100644
--- a/src/ts/API.ts
+++ b/src/ts/API.ts
@@ -20,6 +20,11 @@ class API {
         return response.map(obj => new BlogPost(obj));
     }
 
+    static async getBlogPostsByTag(tag: string, page: number): Promise<BlogPost[]> {
+        const response = await API.getResponse(`posts/tagged/${tag}/${page}`);
+        return response.map(obj => new BlogPost(obj));
+    }
+
     static async getAuthor(id: string): Promise<Author> {
         const response = await API.getResponse(`author/${id}`);
         return new Author(response);
diff --git a/src/ts/app.ts b/src/ts/app.ts
index d69f389..39ee1f5 100644
--- a/src/ts/app.ts
+++ b/src/ts/app.ts
@@ -2,6 +2,7 @@ import API from "./API";
 import UI from "./UI";
 import Input from "./Input";
 import Author from "./Author";
+import BlogPost from "./BlogPost";
 
 declare const Handlebars: any;
 declare const Prism: any;
@@ -27,6 +28,19 @@ declare const Prism: any;
         }
     });
 
+    function getQueryVariable(variable: string): string {
+        const query = window.location.search.substring(1);
+        const vars = query.split("&");
+        for (const element of vars) {
+            const pair = element.split("=");
+            if (pair[0] == variable) {
+                return pair[1];
+            }
+        }
+
+        return null;
+    }
+
     Input.registerShortcut(Input.KONAMI_CODE, () => {
         window.open("https://www.youtube.com/watch?v=dQw4w9WgXcQ", "_blank");
     });
@@ -46,7 +60,15 @@ declare const Prism: any;
         const template = Handlebars.compile(UI.blogPostTemplate.innerHTML);
         API.getBlogPostCount().then(async (count) => {
             for (let i = 0; i <= count / 10; i++) {
-                const posts = await API.getBlogPosts(i);
+                let posts: BlogPost[];
+
+                const tag = getQueryVariable("tag");
+                if (tag !== null) {
+                    posts = await API.getBlogPostsByTag(tag, i);
+                } else {
+                    posts = await API.getBlogPosts(i);
+                }
+
                 for (const post of posts) {
                     let author: Author;
                     if (authors[post.authorId]) {