From 533dac94b42e3b2d3242e6d12468a048cbe944dd Mon Sep 17 00:00:00 2001
From: Dmitry Trubin <1437843+dtruebin@users.noreply.github.com>
Date: Wed, 7 Jan 2026 01:13:19 +0100
Subject: [PATCH] refactor(SFR): try Chain of Responsibility pattern

---
 .../strava-feed-refined.user.js               | 159 +++++++++++++-----
 1 file changed, 116 insertions(+), 43 deletions(-)

diff --git a/strava-feed-refined/strava-feed-refined.user.js b/strava-feed-refined/strava-feed-refined.user.js
index 66917f6..ab11ceb 100644
--- a/strava-feed-refined/strava-feed-refined.user.js
+++ b/strava-feed-refined/strava-feed-refined.user.js
@@ -64,13 +64,13 @@
       this._cache = {};
     }
 
-    // Marks this item as processed
+    /** Marks this item as processed. */
     markAsProcessed() {
       this.el.dataset.processed = "true";
     }
 
-    // Hides this item and logs the description of what is being hidden
     /**
+     * Hides this item (also marking as processed) and logs the description of what is being hidden.
      * @param {string} description
      */
     hide(description) {
@@ -132,64 +132,137 @@
     }
   }
 
-  // === Main function ===
-  function hideUnwantedEntries(root = document) {
-    root.querySelectorAll(`div[role="button"]:not([data-processed]):has(${SELECTORS.feedEntry})`)
-      .forEach((div) => {
-        const item = new FeedItem(/** @type {HTMLElement} */ (div));
+  class Handler {
+    /** @param {Handler} handler */
+    setNext(handler) {
+      this.nextHandler = handler;
+      return handler;
+    }
 
-        if (item.isChallenge) {
-          item.hide(`challenge progress: ${item.challengeInfo}`);
-          return;
-        }
+    // ToDo Consider redesign: in subclasses, each `hide` or `markAsProcessed` should be followed by
+    // ToDo `return;` to stop processing further down the chain - boilerplate & error-prone.
+    /** @param {FeedItem} feedItem */
+    handle(feedItem) {
+      this.nextHandler?.handle(feedItem);
+    }
+  }
 
-        if (!item.isActivity) {
-          item.markAsProcessed();
-          return;
-        }
+  class ChallengeHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      if (item.isChallenge) {
+        item.hide(`challenge progress: ${item.challengeInfo}`);
+        return;
+      }
+      super.handle(item);
+    }
+  }
 
-        if (item.isFromFavoriteAthlete) {
-          if (!document.URL.includes("/athletes/")) {
-            console.log(`skipping further processing of ${item.athleteName}'s ⭐ activity: ${item.activityName}`);
-          }
-          item.markAsProcessed();
-          return;
-        }
+  class ValidActivityHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      if (!item.isActivity) {
+        item.markAsProcessed();
+        return;
+      }
+      super.handle(item);
+    }
+  }
 
-        for (const tag of item.tags) {
-          if (CONFIG.unwantedTags.has(tag)) {
-            if ((tag === "Commute" || tag === "Регулярный маршрут") && item.hasPhoto) {
-              console.log(`not hiding commute activity with photo(s): ${item.activityName}`);
-              item.markAsProcessed();
-              return;
-            }
-            item.hide(`activity by tag "${tag}": ${item.activityName}`);
-            return;
-          }
+  class FavoriteAthleteWhitelistHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      if (item.isFromFavoriteAthlete) {
+        if (!document.URL.includes("/athletes/")) {
+          console.log(`skipping further processing of ${item.athleteName}'s ⭐ activity: ${item.activityName}`);
         }
+        item.markAsProcessed();
+        return;
+      }
+      super.handle(item);
+    }
+  }
 
-        for (const tag of item.partnerTags) {
-          if (CONFIG.unwantedPartnerTags.has(tag)) {
-            item.hide(`activity by partner tag "${tag}": ${item.activityName}`);
+  class TagHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      for (const tag of item.tags) {
+        if (CONFIG.unwantedTags.has(tag)) {
+          if ((tag === "Commute" || tag === "Регулярный маршрут") && item.hasPhoto) {
+            console.log(`not hiding commute activity with photo(s): ${item.activityName}`);
+            item.markAsProcessed();
             return;
           }
-        }
-
-        if (CONFIG.unwantedDevices.has(item.deviceName)) {
-          item.hide(`activity by device "${item.deviceName}": ${item.activityName}`);
+          item.hide(`activity by tag "${tag}": ${item.activityName}`);
           return;
         }
+      }
+      super.handle(item);
+    }
+  }
 
-        if (CONFIG.unwantedNames.some(name => item.activityName.toLowerCase().includes(name))) {
-          item.hide(`activity by name: ${item.activityName}`);
+  class PartnerTagHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      for (const tag of item.partnerTags) {
+        if (CONFIG.unwantedPartnerTags.has(tag)) {
+          item.hide(`activity by partner tag "${tag}": ${item.activityName}`);
           return;
         }
+      }
+      super.handle(item);
+    }
+  }
 
-        item.markAsProcessed();
+  class DeviceHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      if (CONFIG.unwantedDevices.has(item.deviceName)) {
+        item.hide(`activity by device "${item.deviceName}": ${item.activityName}`);
+        return;
+      }
+      super.handle(item);
+    }
+  }
+
+  class ActivityNameHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      if (CONFIG.unwantedNames.some(name => item.activityName.toLowerCase().includes(name))) {
+        item.hide(`activity by name: ${item.activityName}`);
+        return;
+      }
+      super.handle(item);
+    }
+  }
+
+  class FallbackHandler extends Handler {
+    /** @param {FeedItem} item */
+    handle(item) {
+      item.markAsProcessed();
+    }
+  }
+
+  const rootHandler = new ChallengeHandler();
+  rootHandler
+    .setNext(new ValidActivityHandler())
+    .setNext(new FavoriteAthleteWhitelistHandler())
+    .setNext(new TagHandler())
+    .setNext(new PartnerTagHandler())
+    .setNext(new DeviceHandler())
+    .setNext(new ActivityNameHandler())
+    .setNext(new FallbackHandler());
+
+  // === Main function ===
+  function processFeed(root = document) {
+    root.querySelectorAll(`div[role="button"]:not([data-processed]):has(${SELECTORS.feedEntry})`)
+      .forEach((div) => {
+        const item = new FeedItem(/** @type {HTMLElement} */(div));
+        rootHandler.handle(item);
       });
   }
 
-  const observer = new MutationObserver(() => hideUnwantedEntries());
+  const observer = new MutationObserver(() => processFeed());
   observer.observe(document.body, {
     childList: true,
     subtree: true,