feat: Add about page

html/about/index.php

@@ -0,0 +1,8 @@
+<?php
+
+$title = "MobMash - About";
+$content = function () {
+    require __DIR__ . '/../../view/pages/about.php';
+};
+
+require_once __DIR__ . '/../../view/layout.php';

html/styles/main.css

@@ -15,6 +15,8 @@ nav {
     border-bottom: 1px solid black;
     margin: 0;
     display: block;
+    position: fixed;
+    top: 0;
 }
 
 nav ul {
@@ -69,12 +71,71 @@ nav a:hover, nav .active a {
     color: black;
 }
 
+#content {
+    padding-top: 50px;
+}
+
+.text-container {
+    width: 70vw;
+    margin-left: auto;
+    margin-right: auto;
+}
+
 h1 {
     text-align: center;
     font-size: 40px;
     margin: 60px;
 }
 
+.text-container p, .text-container a, .text-container li {
+    font-family: "Arial", sans-serif;
+    line-height: 20px;
+}
+
+.text-container a, .text-container a:visited {
+    text-decoration: none;
+    color: black;
+    position: relative;
+    transition: color 0.3s;
+    padding-left: 6px;
+    padding-top: 2px;
+    padding-right: 6px;
+    padding-bottom: 2px;
+}
+
+.text-container a::after {
+    content: '';
+    position: absolute;
+    top: 0;
+    right: 0;
+    left: 0;
+    bottom: 0;
+    background-color: black;
+    z-index: -2;
+}
+
+.text-container a::before {
+    content: '';
+    position: absolute;
+    top: 0;
+    right: 0;
+    width: 100%;
+    bottom: 0;
+    background-color: lightgrey;
+    transition: width 0.3s;
+    z-index: -1;
+}
+
+.text-container a:hover {
+    color: white;
+}
+
+.text-container a:hover::before {
+    width: 0;
+}
+
+
+
 .choice {
     position: relative;
 }

view/layout.php

@@ -33,10 +33,12 @@
                 <?php makeNavigationLink("Privacy", "/privacy"); ?>
             </ul>
         </nav>
-        <?php
-            if (isset($content)) {
-                $content();
-            }
-        ?>
+        <div id="content">
+            <?php
+                if (isset($content)) {
+                    $content();
+                }
+            ?>
+        </div>
     </body>
 </html>

view/pages/about.php

@@ -0,0 +1,104 @@
+<h1>About</h1>
+
+<div class="text-container">
+
+    <h2>The Story</h2>
+
+    <p>
+        Back when I was in school I watched <a href="https://en.wikipedia.org/wiki/The_Social_Network">
+        The Social Network movie</a>. I was fascinates by the scene in which Zuckerberg implemented Facemash in an
+        eventing. So, I was kinda curious if I could manage that too. I didn't. I took me 3 days to implement a very
+        <a href="https://github.com/overflowerror/promash">simple version</a>. (Writing this now, I also found out
+        that it took Zuckerberg
+        <a href="https://www.thecrimson.com/article/2003/11/19/facemash-creator-survives-ad-board-the/">a week</a>
+        - not just an evening. Welp.) Instead of students, my version used pictures of my professors, that I scraped
+        from my school's website - which, in retrospect, was morally a bit problematic.
+    </p>
+    <p>
+        Recently, I found the old source code again, and I was thinking: Maybe I can rewrite it. Let's not use humans
+        this time, and instead use something nerdy: Minecraft mobs. And while we are at it, let's also do it properly
+        - the previous version really was quite bad from a technical perspective.
+    </p>
+
+    <h2>Implementation</h2>
+
+    <p>
+        The basic idea is to give the users the choice between mobs. The better one is selected and its internal
+        rating increases. The algorithm used is the <a href="https://en.wikipedia.org/wiki/Elo_rating_system">Elo
+        rating system</a>. I won't go into details here, but the basic idea is the following: It works by assigning
+        each candidate a number, and calculate the winning probabilities for each match. This winning probability
+        then determines how many points are gained/lost by each candidate.
+    </p>
+    <p>
+        We can also use this rating to calculate the idea pairing. Mobs that have a similar rating might be more
+        engaging to compare than mobs where it's obvious which one is better.
+    </p>
+    <p>
+        The challenge here is twofold: First, we need to be able to asynchronously calculate and write the ratings to
+        the database. This could theoretically be solved by utilizing transactions. The other problem is, that I want
+        to be able to delete entries from the database in case I detect spam or "cheating". So, we need a list of all
+        changes, so we can undo them if necessary - which would also mean we need to recompute all ratings.
+    </p>
+    <p>
+        The way I chose to solve those problems, is by doing the calculations in on-the-fly in the database. The
+        only thing we need to store, is the match-ups including the winner and the date for sorting. The rating
+        calculation is then done by starting from a base rating for each mob (1500 in this case) and applying each
+        match to the ratings in sequence using a recursive query. (Initially, I tried to keep each rating as its
+        own row. However, I was not able to make it work. Not sure if that's a limitation of PostgreSQL or if I'm
+        just not smart enough. ^^ Either way, the current solution uses <code>jsonb</code> objects for the rating
+        state - which also turned out to be much faster than having each rating as its own object.)
+    </p>
+    <p>
+        This approach works quite well and can handle a few thousands of votes with no issues. However, since we
+        need to iterate over all matches every time we want to calculate the next pairing, it doesn't scale well
+        beyond that. My solution for this was to introduce a caching table, that contains a recent snapshot of
+        the ratings. The recursive calculation than seeds itself with the cache instead of starting from the
+        beginning. This cache can be generated regularly (maybe once a day) to keep the responses snappy.
+    </p>
+    <p>
+        The flip side of using this cache is, of course, that in case I need to delete some matches, I also need
+        to delete the corresponding cache entries. It's not a huge deal, but certainly something to be aware of.
+    </p>
+    <p>
+        If you want to learn more, check out the source code over on
+        <a href="https://github.com/overflowerror/mobmash.click">Github</a>. Pull Requests are welcome!
+    </p>
+
+    <h2>Credits & Tech Stack</h2>
+
+    <h3>Minecraft Related Content</h3>
+
+    <p>
+        Minecraft content and materials are trademarks and copyrights of <a href="https://www.minecraft.net/">Mojang Studios</a>.
+    </p>
+
+    <h3>Fonts</h3>
+
+    <ul>
+        <li><a href="https://www.fontspace.com/minecraft-font-f28180">Minecraft Font by JDGraphics</a> (Public Domain)</li>
+        <li><a href="http://fontawesome.io">Font Awesome v4.7.0</a> (OFL-1.1 & MIT)</li>
+    </ul>
+
+    <h3>Frontend Frameworks</h3>
+
+    <ul>
+        <li><a href="https://htmx.org/">HTMX</a> (0-Clause BSD)</li>
+        <li><a href="https://www.chartjs.org/">Chart.js</a> (MIT)</li>
+    </ul>
+
+
+    <h3>Backend Technologies</h3>
+
+    <ul>
+        <li><a href="https://www.php.net/">PHP</a></li>
+        <li><a href="https://www.postgresql.org/">PostgreSQL</a></li>
+    </ul>
+
+    <h2>Special Thanks</h2>
+
+    <p>
+        I'd like to thank the <a href="https://minecraft.wiki/">Minecraft Wiki</a> for letting me let use their API to
+        automatically update the mobs in the vote. The pictures for the mobs are also provided by them.
+    </p>
+
+</div>