Answer the inbox from the panel, with templates

A reply starts from a template filled in the language the person wrote in,
is sent by the application when it has a mailer that delivers or handed to
the replier's mail program otherwise, and is recorded on the submission.
The same is available through the API.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/Models/Application.php

@@ -12,6 +12,7 @@ use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Support\Facades\Config;
 
@@ -59,6 +60,14 @@ class Application extends Model
     /**
      * @return BelongsTo<User, $this>
      */
+    /**
+     * @return HasMany<ApplicationReply, $this>
+     */
+    public function replies(): HasMany
+    {
+        return $this->hasMany(ApplicationReply::class)->latest('id');
+    }
+
     public function handler(): BelongsTo
     {
         return $this->belongsTo(User::class, 'handled_by');

app/Models/ApplicationReply.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/**
+ * An answer given to a submission, kept so the next person to open it knows
+ * what was already said.
+ */
+#[Fillable(['user_id', 'user_name', 'subject', 'body', 'channel'])]
+class ApplicationReply extends Model
+{
+    public const UPDATED_AT = null;
+
+    public const MAIL = 'mail';
+
+    public const MAILTO = 'mailto';
+
+    /**
+     * @return BelongsTo<Application, $this>
+     */
+    public function application(): BelongsTo
+    {
+        return $this->belongsTo(Application::class);
+    }
+}

app/Models/ReplyTemplate.php

@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use App\Enums\ApplicationKind;
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Spatie\Translatable\HasTranslations;
+
+/**
+ * An answer the inbox gives often enough to write once: "thanks, we'll be in
+ * touch", "this call is filled", "here is how we work".
+ *
+ * Written in every language, because the answer goes out in the one the
+ * person wrote in. `{name}`, `{subject}` and `{sender}` are filled in.
+ */
+#[Fillable(['name', 'kind', 'subject', 'body', 'position'])]
+class ReplyTemplate extends Model
+{
+    use HasFactory, HasTranslations;
+
+    public const PLACEHOLDERS = ['{name}', '{subject}', '{sender}'];
+
+    /**
+     * @var array<int, string>
+     */
+    public array $translatable = ['subject', 'body'];
+
+    protected function casts(): array
+    {
+        return ['position' => 'integer'];
+    }
+
+    /**
+     * @param  Builder<$this>  $query
+     * @return Builder<$this>
+     */
+    public function scopeFor(Builder $query, ApplicationKind $kind): Builder
+    {
+        return $query
+            ->where(fn (Builder $q) => $q->whereNull('kind')->orWhere('kind', $kind->value))
+            ->orderBy('position')
+            ->orderBy('name');
+    }
+
+    /**
+     * Subject and body for one submission, in its language.
+     *
+     * @return array{subject: string, body: string}
+     */
+    public function renderFor(Application $application, ?User $sender = null): array
+    {
+        $values = [$application->name, $application->subject(), $sender?->name ?? (string) config('app.name')];
+
+        return [
+            'subject' => str_replace(self::PLACEHOLDERS, $values, (string) $this->getTranslation('subject', $application->locale)),
+            'body' => str_replace(self::PLACEHOLDERS, $values, (string) $this->getTranslation('body', $application->locale)),
+        ];
+    }
+}