Merge pull request #52 from pennlabs/anthony/backend-geocoords

Add coords to sublet model

Author: alisx255

backend/market/migrations/0005_sublet_true_latitude_sublet_true_longitude.py

@@ -0,0 +1,23 @@
+# Generated by Django 5.0.2 on 2026-02-13 23:08
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("market", "0004_rename_address_sublet_street_address_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="sublet",
+            name="latitude",
+            field=models.FloatField(blank=True, null=True),
+        ),
+        migrations.AddField(
+            model_name="sublet",
+            name="longitude",
+            field=models.FloatField(blank=True, null=True),
+        ),
+    ]

backend/market/models.py

@@ -1,3 +1,6 @@
+import hashlib
+import math
+
 from django.contrib.auth.models import AbstractUser
 from django.core.exceptions import ValidationError
 from django.core.validators import MinValueValidator
@@ -42,7 +45,6 @@ class Meta:
     def __str__(self):
         return f"Offer for {self.listing} made by {self.user}"
 
-
 class Category(models.Model):
     name = models.CharField(max_length=100, unique=True)
 
@@ -130,12 +132,42 @@ class Sublet(Listing):
     baths = models.PositiveIntegerField()
     start_date = models.DateField()
     end_date = models.DateField()
+    latitude = models.FloatField(null=True, blank=True)
+    longitude = models.FloatField(null=True, blank=True)
 
     def clean(self):
         super().clean()
         if self.start_date and self.end_date and self.start_date >= self.end_date:
             raise ValidationError({"end_date": "End date must be after start date"})
 
+    def _calculate_approximate_location(self, latitude, longitude):
+        if latitude is None or longitude is None:
+            return None, None
+
+        lat_str = f"{float(latitude):.9f}"
+        lon_str = f"{float(longitude):.9f}"
+        seed = hashlib.md5(f"{lat_str}{lon_str}".encode()).hexdigest()
+
+        offset_factor = int(seed[:8], 16) / 0xFFFFFFFF
+
+        offset_distance = 0.0005 + (offset_factor * 0.0013)
+        angle = offset_factor * 2 * math.pi
+
+        lat_offset = offset_distance * math.sin(angle)
+        lon_offset = offset_distance * math.cos(angle)
+
+        approx_lat = float(latitude) + lat_offset
+        approx_lon = float(longitude) + lon_offset
+        return approx_lat, approx_lon
+
+    @property
+    def approximate_location(self):
+        if self.latitude is not None and self.longitude is not None:
+            approximate_location = self._calculate_approximate_location(
+                self.latitude, self.longitude)
+            return approximate_location
+        return None, None
+
     def save(self, *args, **kwargs):
         self.full_clean()
         super().save(*args, **kwargs)

backend/market/serializers.py

@@ -1,3 +1,4 @@
+
 from django.contrib.auth import get_user_model
 from django.core.exceptions import ValidationError as ModelValidationError
 from profanity_check import predict
@@ -98,10 +99,23 @@ def get_condition(self, obj):
 
 
 class SubletDataSerializer(ModelSerializer):
+    latitude = SerializerMethodField()
+    longitude = SerializerMethodField()
+
     class Meta:
         model = Sublet
-        fields = ["street_address", "beds", "baths", "start_date", "end_date"]
+        fields = ["street_address", "beds", "baths", "start_date", "end_date",
+            "latitude", "longitude"]
 
+    def get_latitude(self, obj):
+        if obj.approximate_location is not None:
+            return float(obj.approximate_location[0])
+        return None
+
+    def get_longitude(self, obj):
+        if obj.approximate_location is not None:
+            return float(obj.approximate_location[1])
+        return None
 
 # Unified serializer for all listing types (Items and Sublets); used for CRUD operations
 class ListingSerializer(ListingTypeMixin, ModelSerializer):
@@ -265,12 +279,23 @@ def _create_item(self, validated_data, additional_data):
     def _create_sublet(self, validated_data, additional_data):
         tags = validated_data.pop("tags", None)
 
+        latitude = additional_data.get("latitude")
+        longitude = additional_data.get("longitude")
+
+
+        if latitude is not None:
+            latitude = float(latitude)
+        if longitude is not None:
+            longitude = float(longitude)
+
         sublet = Sublet.objects.create(
             street_address=additional_data.get("street_address"),
             beds=additional_data.get("beds"),
             baths=additional_data.get("baths"),
             start_date=additional_data.get("start_date"),
             end_date=additional_data.get("end_date"),
+            latitude=latitude,
+            longitude=longitude,
             **validated_data,
         )
 
@@ -323,10 +348,16 @@ def _update_item(self, instance, additional_data):
 
     def _update_sublet(self, instance, additional_data):
         sublet = instance.sublet
-        sublet_fields = ["street_address", "beds", "baths", "start_date", "end_date"]
-        for field in sublet_fields:
+        str_fields = ["street_address", "beds", "baths", "start_date", "end_date"]
+        float_fields = ["latitude", "longitude"]
+        for field in str_fields:
             if field in additional_data:
                 setattr(sublet, field, additional_data[field])
+
+        for field in float_fields:
+            if field in additional_data:
+                value = additional_data[field]
+                setattr(sublet, field, float(value) if value is not None else None)
         sublet.full_clean()
         sublet.save()