Add the Topic Log Enhancements miscellaneous feature.

source/content-scripts/features/exports.ts

@@ -10,6 +10,7 @@ export * from "./miscellaneous/group-list-subscribe-button.js";
 export * from "./miscellaneous/hide-own-username.js";
 export * from "./miscellaneous/show-topic-author.js";
 export * from "./miscellaneous/topic-info-ignore.js";
+export * from "./miscellaneous/topic-log-enhancements.js";
 export * from "./miscellaneous/unignore-all-button.js";
 export * from "./theme-switcher.js";
 export * from "./themed-logo.js";

source/content-scripts/features/miscellaneous/topic-log-enhancements.tsx

@@ -0,0 +1,315 @@
+import fastDiff from "fast-diff";
+import {type JSX, render} from "preact";
+import {capitalize, log, querySelector} from "../../../utilities/exports.js";
+
+export function runTopicLogEnhancementsFeature(): void {
+  const count = applyEnhancements();
+  if (count > 0) {
+    log(`Topic Log Enhancements: Applied to ${count} topic log entries.`);
+  }
+}
+
+function applyEnhancements(): number {
+  // Get the topic log listing if there is one.
+  const listing =
+    document.querySelector<HTMLOListElement>(
+      ".topic-log-listing:not([data-trx-topic-log-enhancements])",
+    ) ?? undefined;
+  if (listing === undefined) {
+    return 0;
+  }
+
+  // Open the topic log `<details>` element.
+  querySelector<HTMLDetailsElement>("details.topic-log").open = true;
+
+  const entries = listing.querySelectorAll<HTMLLIElement>(".topic-log-entry");
+  const enhancements: JSX.Element[] = [];
+
+  for (const entry of Array.from(entries)) {
+    const editor = entry.querySelector(".link-user")?.textContent ?? undefined;
+
+    // Grab the text of the topic log entry.
+    let text = entry.textContent ?? undefined;
+    if (text === undefined) {
+      log(
+        "Undefined topic log entry text encountered, this should be unreachable.",
+        true,
+      );
+      continue;
+    }
+
+    // Remove any excess whitespace.
+    text = text.replace(/\s+/g, " ").trim();
+
+    // Remove the editor's name too as we already have that.
+    text = text.slice(text.indexOf(" ") + 1);
+
+    // Grab the timestamp and remove it from the text.
+    const timestampIndex = text.lastIndexOf("(");
+    const timestamp = text.slice(timestampIndex);
+    text = text.slice(0, timestampIndex - 1);
+
+    // Account for the original poster making edits.
+    const editedByAuthor = text.startsWith("(OP) ");
+    if (editedByAuthor) {
+      text = text.slice("(OP) ".length);
+    }
+
+    // Account for deleted and removed topics or users not having their names
+    // shown.
+    if (text.startsWith("user ")) {
+      text = text.slice("user ".length);
+    }
+
+    // Create the enhanced entry and remove the original one.
+    enhancements.push(
+      <TopicLogEnhancement
+        editedByAuthor={editedByAuthor}
+        editor={editor}
+        text={text}
+        timestamp={timestamp}
+      />,
+    );
+    entry.remove();
+  }
+
+  listing.dataset.trxTopicLogEnhancements = "true";
+  render(enhancements, listing);
+  return enhancements.length;
+}
+
+/** Properties for the {@linkcode TopicLogEnhancement} component. */
+type TopicLogEnhancementProps = {
+  /** Whether the original topic author made the changes. */
+  editedByAuthor: boolean;
+
+  /**
+   * The username of the person making the change, can be undefined if no user
+   * link was in the entry.
+   */
+  editor: string | undefined;
+
+  /** The text body of the entry. */
+  text: string;
+
+  /** The timestamp of when the edit was made. */
+  timestamp: string;
+};
+
+/** The topic log entry enhancement component. */
+function TopicLogEnhancement(props: TopicLogEnhancementProps): JSX.Element {
+  const {editedByAuthor, editor, text, timestamp} = props;
+
+  const editorLink = editor ? (
+    <a class="link-user" href={`/user/${editor}`}>
+      {editor}
+    </a>
+  ) : (
+    "Unknown user"
+  );
+
+  const originalPosterSpan = editedByAuthor ? (
+    <>
+      (<abbr title="Original Poster (of the topic)">OP</abbr>)
+    </>
+  ) : undefined;
+
+  const transformedText = transformText(text);
+
+  return (
+    <li class="topic-log-entry">
+      {editorLink} {originalPosterSpan} {transformedText.title} {timestamp}{" "}
+      <br /> {transformedText.body}
+    </li>
+  );
+}
+
+/** The result of the {@linkcode transformText} function. */
+type TransformedText = {
+  /** The main body of the topic log entry. */
+  body: JSX.Element | string;
+
+  /** The title of the entry to be placed between the username and timestamp. */
+  title: string;
+};
+
+/** Transform the topic log entry text into its respective enhanced version. */
+function transformText(text: string): TransformedText {
+  // Check for tag additions and removals.
+  if (text.startsWith("added tag") || text.startsWith("removed tag")) {
+    const sections = text.includes("' and removed tag")
+      ? // If the entry has both added and removed tags in the same line, split
+        // them in the middle so we can more easily match them. The extra colon
+        // in the split string is so we don't accidentally split on an " and "
+        // in a tag.
+        text.split("' and ")
+      : [text];
+
+    // Match the added tags using the first section, as it always comes first.
+    const {added} =
+      /^added tags? (?<added>.+)$/g.exec(sections[0])?.groups ?? {};
+
+    // Match the removed tags using the second section first and if that
+    // doesn't exist, try using the first section.
+    const {removed} =
+      /^removed tags? (?<removed>.+)$/g.exec(sections[1] ?? sections[0])
+        ?.groups ?? {};
+
+    // Collect all the diff spans into one array.
+    const spans: JSX.Element[] = [];
+
+    // Get the topic's group path by removing the ID and slug from the pathname.
+    // So for example "/~group/id36/title_slug" becomes "/~group".
+    const groupPath = window.location.pathname.slice(
+      0,
+      window.location.pathname.indexOf("/", 1),
+    );
+
+    if (removed !== undefined) {
+      const tags = removed.replace(/'/g, "").split(", ");
+      spans.push(
+        ...tags.map((tag) => (
+          <>
+            <span class="trx-topic-log-diff-from">
+              <a href={`${groupPath}?tag=${tag}`}>{tag}</a>
+            </span>
+            <br />
+          </>
+        )),
+      );
+    }
+
+    if (added !== undefined) {
+      const tags = added.replace(/'/g, "").split(", ");
+      spans.push(
+        ...tags.map((tag) => (
+          <>
+            <span class="trx-topic-log-diff-to">
+              <a href={`${groupPath}?tag=${tag}`}>{tag}</a>
+            </span>
+            <br />
+          </>
+        )),
+      );
+    }
+
+    return {
+      body: <>{spans}</>,
+      title: "edited the tags",
+    };
+  }
+
+  // Check for link changes.
+  if (text.startsWith("changed link from")) {
+    // The Tildes link topic schema only allows HTTP or HTTPS links so we can
+    // take advantage of that to match them more easily.
+    const {from, to} = /(?<from>http.+) to (?<to>http.+)$/g.exec(text)!.groups!;
+    return {
+      body: <DiffSpans from={from} to={to} />,
+      title: "edited the link",
+    };
+  }
+
+  // Check for title changes.
+  if (text.startsWith("changed title from")) {
+    const {from, to} = /"(?<from>.+)" to "(?<to>.+)"$/g.exec(text)!.groups!;
+    return {
+      body: <DiffSpans from={from} to={to} />,
+      title: "edited the title",
+    };
+  }
+
+  // Check for both the locking and unlocking of topics.
+  if (text.includes("locked comments")) {
+    const locked = text.startsWith("locked");
+    return {
+      body: locked
+        ? "New comments can not be posted."
+        : "New comments can be posted again.",
+      title: `${locked ? "" : "un"}locked the topic`,
+    };
+  }
+
+  // Check for the topic group being changed.
+  if (text.startsWith("moved from")) {
+    const {from, to} = /(?<from>~.+) to (?<to>~.+)/g.exec(text)!.groups!;
+    return {
+      body: (
+        <>
+          From{" "}
+          <a class="link-group" href={`/${from}`}>
+            {from}
+          </a>{" "}
+          to{" "}
+          <a class="link-group" href={`/${to}`}>
+            {to}
+          </a>
+        </>
+      ),
+      title: "moved the topic",
+    };
+  }
+
+  // Check for topic removals and un-removals.
+  if (text.includes("removed")) {
+    const removed = text.startsWith("removed");
+    return {
+      body: removed
+        ? "The topic was removed by a site administrator."
+        : "The topic has been made available again.",
+      title: `${removed ? "" : "un-"}removed the topic`,
+    };
+  }
+
+  // Log any unhandled topic log entries and return the text as the body so the
+  // entry still shows up in a decent enough way.
+  log(`Unhandled topic log entry: ${text}`, true);
+  return {body: capitalize(text), title: ""};
+}
+
+/** Properties for the {@linkcode DiffSpans} component. */
+type DiffSpansProps = {
+  /** The original text string. */
+  from: string;
+
+  /** The resulting text string to compare against the original with. */
+  to: string;
+};
+
+/**
+ * Calculate the diff between to strings using `fast-diff` and render the
+ * results as two `<span>`s.
+ */
+function DiffSpans({from, to}: DiffSpansProps): JSX.Element {
+  const fromParts: Array<JSX.Element | string> = [];
+  const toParts: typeof fromParts = [];
+
+  for (const [action, change] of fastDiff(from, to)) {
+    // eslint-disable-next-line default-case
+    switch (action) {
+      case fastDiff.EQUAL: {
+        fromParts.push(change);
+        toParts.push(change);
+        break;
+      }
+
+      case fastDiff.INSERT: {
+        toParts.push(<span class="trx-topic-log-diff-insert">{change}</span>);
+        break;
+      }
+
+      case fastDiff.DELETE: {
+        fromParts.push(<span class="trx-topic-log-diff-delete">{change}</span>);
+        break;
+      }
+    }
+  }
+
+  return (
+    <>
+      <span class="trx-topic-log-diff-from">{fromParts}</span>
+      <br />
+      <span class="trx-topic-log-diff-to">{toParts}</span>
+    </>
+  );
+}

source/content-scripts/setup.tsx

@@ -28,6 +28,7 @@ import {
   runThemedLogoFeature,
   runShowTopicAuthorFeature,
   runTopicInfoIgnore,
+  runTopicLogEnhancementsFeature,
   runUnignoreAllButtonFeature,
   runUsernameColorsFeature,
   runThemeSwitcherFeature,
@@ -229,6 +230,10 @@ async function initialize() {
       runTopicInfoIgnore();
     }
 
+    if (miscEnabled.value.has(MiscellaneousFeature.TopicLogEnhancements)) {
+      runTopicLogEnhancementsFeature();
+    }
+
     if (
       miscEnabled.value.has(MiscellaneousFeature.UnignoreAllButton) &&
       isLoggedIn

source/options/components/miscellaneous.tsx

@@ -56,6 +56,15 @@ function FeatureDescription({
     );
   }
 
+  if (feature === MiscellaneousFeature.TopicLogEnhancements) {
+    return (
+      <p class="description">
+        Enhance the topic log entries by adding text diffs, links and layout
+        adjustments. Also automatically expands the topic log.
+      </p>
+    );
+  }
+
   if (feature === MiscellaneousFeature.UnignoreAllButton) {
     return (
       <p class="description">

source/scss/content-scripts.scss

@@ -7,6 +7,7 @@
 @import "scripts/markdown-toolbar";
 @import "scripts/show-topic-author";
 @import "scripts/topic-info-ignore";
+@import "scripts/topic-log-enhancements";
 @import "scripts/user-labels";
 @import "scripts/username-colors";
 

source/scss/scripts/_topic-log-enhancements.scss

@@ -0,0 +1,53 @@
+[data-trx-topic-log-enhancements] {
+  --entry-spacing: 4px;
+
+  display: flex;
+  flex-direction: column;
+  gap: var(--entry-spacing);
+
+  .topic-log-entry {
+    border-left: 1px solid var(--border-color);
+    margin: 0;
+    margin-top: var(--entry-spacing);
+    padding-left: var(--entry-spacing);
+  }
+
+  .trx-topic-log-diff {
+    &-from,
+    &-to {
+      &::before {
+        align-items: center;
+        display: inline-flex;
+        font-family: monospace;
+        font-size: large;
+        font-weight: bold;
+        justify-content: center;
+        margin-right: var(--entry-spacing);
+      }
+    }
+
+    &-from::before {
+      color: var(--error-color);
+      content: "-";
+    }
+
+    &-to::before {
+      color: var(--success-color);
+      content: "+";
+    }
+
+    &-delete,
+    &-insert {
+      font-weight: bold;
+      text-decoration: underline;
+    }
+
+    &-delete {
+      color: var(--error-color);
+    }
+
+    &-insert {
+      color: var(--success-color);
+    }
+  }
+}

source/storage/enums.ts

@@ -26,6 +26,7 @@ export enum MiscellaneousFeature {
   HideOwnUsername = "hide-own-username",
   ShowTopicAuthor = "show-topic-author",
   TopicInfoIgnore = "topic-info-ignore",
+  TopicLogEnhancements = "topic-log-enhancements",
   UnignoreAllButton = "unignore-all-button",
 }