feat: embed follow badge for profiles matching activity graph

app/Actions/CreateUserBadge.php

@@ -0,0 +1,119 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Actions;
+
+use App\Enums\ActivityGraphTheme;
+use App\Models\User;
+
+/**
+ * Generates a compact SVG follow badge for a user's GitHub profile README.
+ *
+ * @phpstan-type Palette array{card: string, border: string, ink: string, muted: string, empty: string, lanes: list<string>}
+ */
+final readonly class CreateUserBadge
+{
+    private const int HEIGHT = 20;
+
+    /**
+     * The colors of `resources/css/app.css`.
+     *
+     * @var Palette
+     */
+    private const array LIGHT = [
+        'card' => '#ffffff',
+        'border' => '#e1e4e8',
+        'ink' => '#121417',
+        'muted' => '#5b616b',
+        'empty' => '#eef0f2',
+        'lanes' => ['#d9480f', '#2f9e44', '#9c36b5', '#0c8599', '#c2255c', '#b7791f'],
+    ];
+
+    /**
+     * @var Palette
+     */
+    private const array DARK = [
+        'card' => '#18181a',
+        'border' => '#2a2a2d',
+        'ink' => '#ececec',
+        'muted' => '#a1a1a6',
+        'empty' => '#232326',
+        'lanes' => ['#ff8a4c', '#51cf66', '#da77f2', '#3bc9db', '#f06595', '#fcc419'],
+    ];
+
+    /**
+     * Renders the compact SVG follow badge for the given user and theme.
+     */
+    public function handle(
+        User $user,
+        ActivityGraphTheme $theme = ActivityGraphTheme::Light,
+    ): string {
+        $message = $this->message($user);
+        $messageWidth = $this->textWidth($message);
+        $dotX = 77;
+        $messageX = 86;
+        $width = $messageX + $messageWidth + 10;
+
+        return view('svg.user-badge', [
+            'width' => $width,
+            'height' => self::HEIGHT,
+            'dotX' => $dotX,
+            'messageX' => $messageX,
+            'message' => $message,
+            'styles' => $this->styles($theme, $user->lane()),
+        ])->render();
+    }
+
+    /**
+     * Formats the follow message with the user's handle.
+     */
+    public function message(User $user): string
+    {
+        return "follow @{$user->handle}";
+    }
+
+    /**
+     * Calculates the estimated pixel width for the monospace message text.
+     */
+    public function textWidth(string $text): int
+    {
+        return (int) ceil(mb_strlen($text) * 6.6);
+    }
+
+    /**
+     * Generates CSS stylesheet rules for the given theme and user lane color.
+     */
+    private function styles(ActivityGraphTheme $theme, int|string $lane): string
+    {
+        return match ($theme) {
+            ActivityGraphTheme::Light => $this->palette(self::LIGHT, $lane),
+            ActivityGraphTheme::Dark => $this->palette(self::DARK, $lane),
+            ActivityGraphTheme::Auto => $this->palette(self::LIGHT, $lane).'@media (prefers-color-scheme: dark){'.$this->palette(self::DARK, $lane).'}',
+        };
+    }
+
+    /**
+     * Compiles CSS rules mapping palette values to card, ink, muted, lane, and empty classes.
+     *
+     * @param  Palette  $palette
+     */
+    private function palette(array $palette, int|string $lane): string
+    {
+        $color = is_string($lane) ? $lane : $palette['lanes'][$lane];
+
+        $rules = [
+            '.card' => "fill:{$palette['card']};stroke:{$palette['border']}",
+            '.ink' => "fill:{$palette['ink']}",
+            '.muted' => "fill:{$palette['muted']}",
+            '.lane' => "fill:{$color}",
+            '.l0' => "fill:{$palette['empty']}",
+        ];
+
+        return implode('', array_map(
+            fn (string $selector, string $declarations): string => "{$selector}{{$declarations}}",
+            array_keys($rules),
+            $rules,
+        ));
+    }
+}

app/Http/Controllers/UserBadgeController.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers;
+
+use App\Actions\CreateUserBadge;
+use App\Http\Requests\ShowUserBadgeRequest;
+use App\Models\User;
+use Illuminate\Http\Response;
+
+final readonly class UserBadgeController
+{
+    /**
+     * Serves the SVG follow badge for the user.
+     */
+    public function show(ShowUserBadgeRequest $request, User $user, CreateUserBadge $action): Response
+    {
+        return response($action->handle($user, $request->theme()), headers: [
+            'Content-Type' => 'image/svg+xml',
+        ]);
+    }
+}

app/Http/Controllers/UserProfileController.php

@@ -28,6 +28,7 @@ public function edit(#[CurrentUser] User $user, CommitTranslations $translations
             'automaticLane' => $user->automaticLane(),
             'githubSyncedAt' => $user->github_synced_at?->toIso8601String(),
             'activityGraphUrl' => route('user-activity-graph.show', $user),
+            'badgeUrl' => route('user-badge.svg', $user),
             'profileUrl' => route('user.show', $user),
         ]);
     }

app/Http/Requests/ShowUserBadgeRequest.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Requests;
+
+use App\Enums\ActivityGraphTheme;
+use Illuminate\Foundation\Http\FormRequest;
+
+final class ShowUserBadgeRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * The badge is embedded where nobody reads validation errors, so nothing is rejected and defaults are used.
+     *
+     * @return array<string, array<int, string>>
+     */
+    public function rules(): array
+    {
+        return [];
+    }
+
+    /**
+     * Resolves the requested theme from query parameters, defaulting to light mode.
+     */
+    public function theme(): ActivityGraphTheme
+    {
+        $theme = $this->query('theme');
+
+        return (is_string($theme) ? ActivityGraphTheme::tryFrom($theme) : null) ?? ActivityGraphTheme::Light;
+    }
+}