Open a profile's followers and following from its counts

app/Devnull/Client.php

@@ -4,6 +4,7 @@
 
 use App\Devnull\Data\Commit;
 use App\Devnull\Data\CommitThread;
+use App\Devnull\Data\Connection;
 use App\Devnull\Data\CurrentUser;
 use App\Devnull\Data\Notification;
 use App\Devnull\Data\Page;
@@ -220,6 +221,25 @@ public function userCommits(string $username, string $tab = 'commits', ?string $
         return Page::fromArray($this->get('users/'.rawurlencode($username).'/commits', $query), Commit::fromArray(...));
     }
 
+    /**
+     * The people following someone, or with 'following' the people they
+     * follow, newest follow first as the web lists them, 30 a page.
+     *
+     * @return Page<Connection>
+     */
+    public function connections(string $username, string $type, ?string $cursor = null): Page
+    {
+        return Page::fromArray($this->get(self::connectionsPath($username, $type), ['cursor' => $cursor]), Connection::fromArray(...));
+    }
+
+    /**
+     * Where someone's followers are, or with 'following' the people they follow.
+     */
+    public static function connectionsPath(string $username, string $type): string
+    {
+        return 'users/'.rawurlencode($username).'/'.($type === 'following' ? 'following' : 'followers');
+    }
+
     public function follow(string $username): void
     {
         $this->send('POST', 'users/'.rawurlencode($username).'/follow');

app/Devnull/Data/Connection.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace App\Devnull\Data;
+
+/**
+ * Someone in a profile's followers or following, as the web lists them, with
+ * whether you follow them and whether they follow you.
+ */
+final readonly class Connection
+{
+    /**
+     * Their user id, so a fresh page can be laid over the list (see FreshPage).
+     */
+    public string $id;
+
+    public function __construct(
+        public User $user,
+        public bool $isFollowed = false,
+        public bool $followsYou = false,
+    ) {
+        $this->id = $user->id;
+    }
+
+    /**
+     * Reads one of `GET /users/{username}/followers` or `/following`: the user,
+     * with `is_followed` and `follows_you` beside their profile.
+     *
+     * @param  array<string, mixed>  $data
+     */
+    public static function fromArray(array $data): self
+    {
+        return new self(
+            user: User::fromArray($data),
+            isFollowed: ($data['is_followed'] ?? false) === true,
+            followsYou: ($data['follows_you'] ?? false) === true,
+        );
+    }
+
+    public function withFollowed(bool $isFollowed): self
+    {
+        return new self($this->user, $isFollowed, $this->followsYou);
+    }
+}

app/Devnull/ResponseCache.php

@@ -43,6 +43,16 @@ final class ResponseCache
         '#^users/[^/]+$#',
         '#^users/[^/]+/commits$#',
         '#^saved$#',
+        '#^users/[^/]+/(followers|following)$#',
+    ];
+
+    /**
+     * The kept answers that list people with whether you follow each one.
+     */
+    private const array FollowedPeople = [
+        '#^users/[^/]+/(followers|following)$#',
+        '#^notifications$#',
+        '#^notifications/[^/]+/group$#',
     ];
 
     /**
@@ -344,21 +354,40 @@ public function commitDeleted(string $id): void
     }
 
     /**
-     * You followed or unfollowed someone: their profile and your following count change.
+     * You followed or unfollowed someone: their profile and your following
+     * count change, and every list of people kept with whether you follow them.
+     * Without their profile kept, the screen's word is taken that it changed.
      */
     public function followChanged(string $username, bool $following): void
     {
-        $changed = false;
+        $kept = $this->get("users/{$username}");
+        $changed = $kept === null || ($kept['is_following'] ?? false) !== $following;
 
-        $this->patch("users/{$username}", [], function (array $json) use ($following, &$changed): array {
-            $changed = ($json['is_following'] ?? false) !== $following;
-
-            return $changed ? [...self::count($json, 'followers_count', $following ? 1 : -1), 'is_following' => $following] : $json;
-        });
+        if ($changed && $kept !== null) {
+            $this->patch("users/{$username}", [], fn (array $json): array => [...self::count($json, 'followers_count', $following ? 1 : -1), 'is_following' => $following]);
+        }
 
         if ($changed && ($me = $this->username()) !== null) {
             $this->patch("users/{$me}", [], fn (array $json): array => self::count($json, 'following_count', $following ? 1 : -1));
         }
+
+        $this->patchFollowedPeople(rawurldecode($username), $following);
+    }
+
+    /**
+     * Marks someone followed, or not, wherever a kept list of people says whether you follow them.
+     */
+    private function patchFollowedPeople(string $username, bool $following): void
+    {
+        $userId = $this->userId();
+
+        foreach ($userId === null ? [] : $this->index($userId) as $meta) {
+            if (! self::listsFollowedPeople($meta['path'])) {
+                continue;
+            }
+
+            $this->patch($meta['path'], $meta['query'], fn (array $json): array => self::changeFollowed($json, $username, $following));
+        }
     }
 
     /**
@@ -662,6 +691,39 @@ private static function changeUser(mixed $node, string $id, array $profile): mix
         return $node;
     }
 
+    private static function listsFollowedPeople(string $path): bool
+    {
+        foreach (self::FollowedPeople as $pattern) {
+            if (preg_match($pattern, $path) === 1) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Gives every copy of the user with this username, anywhere in $node, that says whether you follow them, the new answer.
+     */
+    private static function changeFollowed(mixed $node, string $username, bool $following): mixed
+    {
+        if (! is_array($node)) {
+            return $node;
+        }
+
+        if (($node['username'] ?? null) === $username && array_key_exists('is_followed', $node)) {
+            $node['is_followed'] = $following;
+        }
+
+        foreach ($node as $key => $child) {
+            if (is_array($child)) {
+                $node[$key] = self::changeFollowed($child, $username, $following);
+            }
+        }
+
+        return $node;
+    }
+
     /**
      * devnull marks notifications read as it sends them, and you've seen them
      * by the time they're shown again, so they're kept as read, and without