feat(assets): add the ability to disassociate an uploaded asset from a well

api/asset.py

@@ -19,7 +19,7 @@
 
 from fastapi import APIRouter, Depends, Form, UploadFile, File
 from fastapi_pagination.ext.sqlalchemy import paginate
-from sqlalchemy import select
+from sqlalchemy import delete, select
 from sqlalchemy.exc import ProgrammingError
 from starlette.concurrency import run_in_threadpool
 from starlette.status import (
@@ -38,7 +38,13 @@
 )
 from db import Thing
 from db.asset import Asset, AssetThingAssociation
-from schemas.asset import AssetResponse, CreateAsset, UpdateAsset
+from schemas.asset import (
+    AssetAssociationResponse,
+    AssetAssociationUpdate,
+    AssetResponse,
+    CreateAsset,
+    UpdateAsset,
+)
 from services.audit_helper import audit_add
 from services.crud_helper import model_patcher, model_deleter
 from services.edit_notification_helper import (
@@ -481,6 +487,53 @@ async def get_asset(
 
 
 # PATCH ======================================================================
+@router.patch("/{asset_id}/association")
+async def update_asset_thing_association(
+    asset_id: int,
+    association_data: AssetAssociationUpdate,
+    session: session_dependency,
+    user: editor_dependency,
+) -> AssetAssociationResponse:
+    """
+    Move an asset to another Thing or remove its Thing association.
+
+    Passing a `thing_id` replaces any existing Thing links for the asset with
+    that one Thing. Passing `thing_id: null` leaves the Asset record in place
+    and removes all Thing links.
+    """
+    simple_get_by_id(session, Asset, asset_id)
+
+    thing_id = association_data.thing_id
+    thing = None
+    if thing_id is not None:
+        thing = session.get(Thing, thing_id)
+        if thing is None:
+            raise PydanticStyleException(
+                status_code=HTTP_409_CONFLICT,
+                detail=[
+                    {
+                        "loc": ["body", "thing_id"],
+                        "msg": f"Thing with ID {thing_id} not found.",
+                        "type": "value_error",
+                        "input": {"thing_id": thing_id},
+                    }
+                ],
+            )
+
+    association_delete = delete(AssetThingAssociation).where(
+        AssetThingAssociation.asset_id == asset_id
+    )
+    session.execute(association_delete)
+
+    if thing is not None:
+        assoc = AssetThingAssociation(asset_id=asset_id, thing_id=thing.id)
+        audit_add(user, assoc)
+        session.add(assoc)
+
+    session.commit()
+    return AssetAssociationResponse(asset_id=asset_id, thing_id=thing_id)
+
+
 @router.patch("/{asset_id}")
 async def update_asset(
     asset_id: int,

schemas/asset.py

@@ -38,6 +38,15 @@ class AssetResponse(BaseResponseModel, BaseAsset):
     signed_url: str | None = None
 
 
+class AssetAssociationUpdate(BaseModel):
+    thing_id: int | None = None
+
+
+class AssetAssociationResponse(BaseModel):
+    asset_id: int
+    thing_id: int | None = None
+
+
 # -------- UPDATE ----------
 class UpdateAsset(BaseUpdateModel):
     name: str | None = None

tests/test_asset.py

@@ -21,11 +21,13 @@
 from unittest.mock import MagicMock, patch
 
 import pytest
+from sqlalchemy import select
 
 from api.asset import get_storage_bucket
 from main import app
 from core.dependencies import viewer_function, admin_function, editor_function
-from db import Asset
+from db.engine import session_ctx
+from db import Asset, AssetThingAssociation, Thing
 from schemas import DT_FMT
 from services import gcs_helper
 from tests import (
@@ -334,6 +336,105 @@ def test_get_asset_by_id_404_not_found(asset):
 # PATCH tests ================================================================
 
 
+def test_patch_asset_association_moves_asset_to_another_thing(
+    asset_with_associated_thing, water_well_thing
+):
+    with session_ctx() as session:
+        other_thing = Thing(
+            name="Other Test Well",
+            thing_type="water well",
+            release_status="draft",
+        )
+        session.add(other_thing)
+        session.commit()
+        session.refresh(other_thing)
+        other_thing_id = other_thing.id
+
+    response = client.patch(
+        f"/asset/{asset_with_associated_thing.id}/association",
+        json={"thing_id": other_thing_id},
+    )
+
+    assert response.status_code == 200
+    data = response.json()
+    assert data == {
+        "asset_id": asset_with_associated_thing.id,
+        "thing_id": other_thing_id,
+    }
+
+    with session_ctx() as session:
+        asset_association_matches = (
+            AssetThingAssociation.asset_id == asset_with_associated_thing.id
+        )
+        thing_id_query = select(AssetThingAssociation.thing_id).where(
+            asset_association_matches
+        )
+        thing_ids = session.scalars(thing_id_query).all()
+        assert thing_ids == [other_thing_id]
+        assert water_well_thing.id not in thing_ids
+
+        session.delete(session.get(Thing, other_thing_id))
+        session.commit()
+
+
+def test_patch_asset_association_disassociates_asset(
+    asset_with_associated_thing,
+):
+    response = client.patch(
+        f"/asset/{asset_with_associated_thing.id}/association",
+        json={"thing_id": None},
+    )
+
+    assert response.status_code == 200
+    data = response.json()
+    assert data == {
+        "asset_id": asset_with_associated_thing.id,
+        "thing_id": None,
+    }
+
+    with session_ctx() as session:
+        asset = session.get(Asset, asset_with_associated_thing.id)
+        asset_association_matches = (
+            AssetThingAssociation.asset_id == asset_with_associated_thing.id
+        )
+        association = session.scalars(
+            select(AssetThingAssociation).where(asset_association_matches)
+        ).one_or_none()
+
+    assert asset is not None
+    assert association is None
+
+
+def test_patch_asset_association_bad_thing_id(asset_with_associated_thing):
+    bad_thing_id = 99999
+
+    response = client.patch(
+        f"/asset/{asset_with_associated_thing.id}/association",
+        json={"thing_id": bad_thing_id},
+    )
+
+    assert response.status_code == 409
+    data = response.json()
+    assert data["detail"][0]["loc"] == ["body", "thing_id"]
+    expected_message = f"Thing with ID {bad_thing_id} not found."
+    assert data["detail"][0]["msg"] == expected_message
+    assert data["detail"][0]["type"] == "value_error"
+    assert data["detail"][0]["input"] == {"thing_id": bad_thing_id}
+
+
+def test_patch_asset_association_bad_asset_id():
+    bad_asset_id = 99999
+
+    response = client.patch(
+        f"/asset/{bad_asset_id}/association",
+        json={"thing_id": None},
+    )
+
+    assert response.status_code == 404
+    data = response.json()
+    assert data["detail"] == f"Asset with ID {bad_asset_id} not found."
+
+
 def test_patch_asset(asset):
     payload = {
         "name": "patched name",