migrate site id to varchar instead of int

backend/apps/farms/models.py

@@ -1,14 +1,42 @@
 from datetime import date
+import secrets
 
 from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils import timezone
+from django.utils.text import slugify
 
 from apps.accounts.models import User
 
 
+def site_name_slug(site_name: str) -> str:
+    """Slug portion of a site id (no numeric suffix)."""
+    code = slugify(str(site_name or "").strip())[:55]
+    if not code:
+        raise ValidationError({"site_name": "Nama site tidak valid untuk dijadikan id."})
+    return code
+
+
+def site_id_from_name(site_name: str, *, numeric_suffix: int | None = None) -> str:
+    """Site PK: `{name-slug}-{4-digit number}`, matching farm dashboard identity."""
+    base = site_name_slug(site_name)
+    if numeric_suffix is None:
+        numeric_suffix = secrets.randbelow(10_000)
+    return f"{base}-{numeric_suffix:04d}"
+
+
+def allocate_site_id(site_name: str) -> str:
+    """Pick an unused site_id for HQ-only creates (seeds / manual)."""
+    for _ in range(32):
+        candidate = site_id_from_name(site_name)
+        if not Site.objects.filter(pk=candidate).exists():
+            return candidate
+    raise ValidationError({"site_name": "Gagal membuat id site unik — coba lagi."})
+
+
 class Site(models.Model):
-    site_id = models.BigAutoField(primary_key=True)
+    # Same shape as farm dashboard Site.site_id; when linked, equals ActiveSite.source_site_id.
+    site_id = models.SlugField(primary_key=True, max_length=64)
     site_name = models.CharField(max_length=30)
     user = models.ForeignKey(User, on_delete=models.CASCADE, related_name="sites")
     # Linked when GM/GM Admin adds the site dashboard to their Pengaturan view list.
@@ -29,6 +57,11 @@ class Site(models.Model):
     def __str__(self) -> str:
         return self.site_name
 
+    def save(self, *args, **kwargs):
+        if not self.site_id:
+            self.site_id = allocate_site_id(self.site_name)
+        super().save(*args, **kwargs)
+
 
 class Kandang(models.Model):
     kandang_id = models.BigAutoField(primary_key=True)