feat: add backbone_code to Tower for road routing waypoints

Towers can now be explicitly assigned to a backbone by setting
backbone_code. This field is included in create/update DTOs and
the response. The backbone OSRM routing merges these tower waypoints
with Closure waypoints, sorted by distance from OTB-start.

Run once on DB: ALTER TABLE towers ADD COLUMN backbone_code VARCHAR(255);

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

model/dto/req/tower_dto.go

@@ -8,7 +8,8 @@ type TowerDTO struct {
     TowerCode     string     `json:"tower_code" validate:"required"`
     Longitude     float64    `json:"longitude" validate:"required"`
     Latitude      float64    `json:"latitude" validate:"required"`
-    ExternalTower *bool      `json:"external_tower,omitempty"` // Make nullable
+    ExternalTower *bool      `json:"external_tower,omitempty"`
+    BackboneCode  *string    `json:"backbone_code,omitempty"`
 }
 
 type UpdateTowerDTO struct {
@@ -17,8 +18,9 @@ type UpdateTowerDTO struct {
     TowerCode     *string    `json:"tower_code,omitempty"`
     Longitude     *float64   `json:"longitude,omitempty" validate:"omitempty,longitude"`
     Latitude      *float64   `json:"latitude,omitempty" validate:"omitempty,latitude"`
-    ExternalTower *bool      `json:"external_tower,omitempty"` // Make nullable
+    ExternalTower *bool      `json:"external_tower,omitempty"`
     ImageURL      *string    `json:"image_url,omitempty"`
+    BackboneCode  *string    `json:"backbone_code,omitempty"`
 }
 
 // Add to model/dto/req/tower_dto.go

model/dto/res/tower_res.go

@@ -14,7 +14,8 @@ type TowerResponse struct {
     Address      string     `json:"address"`
     ImageURL     string     `json:"image_url"`
     ImageURLs    []string   `json:"image_urls"` // Store multiple images as JSONB
-    ExternalTower *bool     `json:"external_tower"` // Make nullable
+    ExternalTower *bool     `json:"external_tower"`
+    BackboneCode  *string   `json:"backbone_code,omitempty"`
     CreatedAt    time.Time  `json:"created_at"`
     UpdatedAt    time.Time  `json:"updated_at"`
 }

model/entity/tower.go

@@ -15,6 +15,7 @@ type Tower struct {
     ImageURL      string     `json:"image_url"`           // Keep for backward compatibility
     ImageURLs     StringSlice `json:"image_urls" gorm:"type:jsonb"` // Multiple images
     ExternalTower *bool      `json:"external_tower,omitempty"`
+    BackboneCode  *string    `json:"backbone_code,omitempty" gorm:"column:backbone_code"`
     CreatedAt     time.Time  `json:"created_at"`
     UpdatedAt     time.Time  `json:"updated_at"`
     

usecase/tower_usecase.go

@@ -79,9 +79,10 @@ func (u *towerUsecase) PostWithMultipleImages(tower req.TowerDTO, imageFiles []*
         TowerCode:     tower.TowerCode,
         Longitude:     tower.Longitude,
         Latitude:      tower.Latitude,
-        ImageURL:      primaryImageURL,          // Primary image
-        ImageURLs:     entity.StringSlice(imageURLs), // All images
+        ImageURL:      primaryImageURL,
+        ImageURLs:     entity.StringSlice(imageURLs),
         ExternalTower: tower.ExternalTower,
+        BackboneCode:  tower.BackboneCode,
         CreatedAt:     time.Now(),
         UpdatedAt:     time.Now(),
     }
@@ -115,6 +116,9 @@ func (u *towerUsecase) UpdateTowerWithMultipleImages(id uuid.UUID, tower req.Upd
     if tower.ImageURL != nil {
         updates["ImageURL"] = *tower.ImageURL
     }
+    if tower.BackboneCode != nil {
+        updates["BackboneCode"] = *tower.BackboneCode
+    }
 
     // Handle multiple image uploads
     if len(imageFiles) > 0 {
@@ -197,12 +201,13 @@ func (u *towerUsecase) Post(tower req.TowerDTO, imageFile *multipart.FileHeader)
 
     newTower := entity.Tower{
         ID:            uuid.New(),
-        DeviceID:     tower.DeviceID,      // Now nullable
+        DeviceID:      tower.DeviceID,
         TowerCode:     tower.TowerCode,
         Longitude:     tower.Longitude,
         Latitude:      tower.Latitude,
         ImageURL:      imageURL,
-        ExternalTower: tower.ExternalTower, // Now nullable
+        ExternalTower: tower.ExternalTower,
+        BackboneCode:  tower.BackboneCode,
         CreatedAt:     time.Now(),
         UpdatedAt:     time.Now(),
     }

utils/helper/towerHelperRes.go

@@ -37,7 +37,8 @@ func ConvertToTowerResponses(towers []entity.Tower, geocoder service.GeocodingSe
             Address:      address,
             ImageURL:     tower.ImageURL,
             ImageURLs:    allImageURLs,      // All images
-            ExternalTower: tower.ExternalTower, // Now nullable
+            ExternalTower: tower.ExternalTower,
+            BackboneCode:  tower.BackboneCode,
             CreatedAt:    tower.CreatedAt,
             UpdatedAt:    tower.UpdatedAt,
         }
@@ -62,19 +63,19 @@ func ConvertToTowerIDResponses(tower entity.Tower, geocoder service.GeocodingSer
     if tower.Device.DeviceCode != "" {
         deviceCode = &tower.Device.DeviceCode
     }
-    // Get all image URLs
     allImageURLs := tower.GetAllImageURLs()
 
     towerResp := res.TowerResponse{
         ID:            tower.ID,
-        DeviceCode:   deviceCode,         // Now nullable
+        DeviceCode:    deviceCode,
         TowerCode:     &tower.TowerCode,
         Longitude:     tower.Longitude,
         Latitude:      tower.Latitude,
         Address:       address,
         ImageURL:      tower.ImageURL,
-        ImageURLs:    allImageURLs,      // All images
-        ExternalTower: tower.ExternalTower, // Now nullable
+        ImageURLs:     allImageURLs,
+        ExternalTower: tower.ExternalTower,
+        BackboneCode:  tower.BackboneCode,
         CreatedAt:     tower.CreatedAt,
         UpdatedAt:     tower.UpdatedAt,
     }