add notes/remark and refactor round-trip

app-modules/booking/src/Models/Booking.php

@@ -3,6 +3,7 @@
 namespace Modules\Booking\Models;
 
 use App\Models\User;
+use Illuminate\Database\Eloquent\Casts\Attribute;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
@@ -43,10 +44,14 @@ class Booking extends Model
         'user_id',
         'openid',
         'ev_route_id',
+        'linked_booking_id',
+        'is_return_leg',
         'departure_time_slot_id',
         'travel_date',
         'passenger_name',
         'passenger_phone',
+        'notes',
+        'remark',
         'pickup_address',
         'pickup_lat',
         'pickup_lng',
@@ -55,8 +60,6 @@ class Booking extends Model
         'dropoff_lng',
         'price',
         'status',
-        'is_round_trip',
-        'return_travel_date',
         'created_by_channel',
         'driver_name',
         'driver_phone',
@@ -77,8 +80,7 @@ class Booking extends Model
             'dropoff_lng' => 'decimal:7',
             'price' => 'decimal:2',
             'status' => BookingStatus::class,
-            'is_round_trip' => 'boolean',
-            'return_travel_date' => 'date',
+            'is_return_leg' => 'boolean',
             'created_by_channel' => BookingChannel::class,
         ];
     }
@@ -93,6 +95,16 @@ class Booking extends Model
         return $this->belongsTo(EvRoute::class, 'ev_route_id');
     }
 
+    /**
+     * The other leg of a round trip (outbound <-> return), linked
+     * bidirectionally by CreateBookingAction. Null for a plain one-way
+     * booking — see the `isRoundTrip()` accessor (domain.md §2b).
+     */
+    public function linkedBooking(): BelongsTo
+    {
+        return $this->belongsTo(Booking::class, 'linked_booking_id');
+    }
+
     public function timeSlot(): BelongsTo
     {
         return $this->belongsTo(DepartureTimeSlot::class, 'departure_time_slot_id');
@@ -107,4 +119,17 @@ class Booking extends Model
     {
         return $this->hasMany(Payment::class);
     }
+
+    /**
+     * True when this booking has a linked leg — i.e. it's one half of a
+     * round trip. Computed, not stored: presence of `linked_booking_id` is
+     * the single source of truth, so it can't drift out of sync the way a
+     * separate flag column could (domain.md §2b).
+     */
+    public function isRoundTrip(): Attribute
+    {
+        return Attribute::make(
+            get: fn (): bool => $this->linked_booking_id !== null,
+        );
+    }
 }