[REF] Refactor phenotypic/BIDS subjects check and add more intermedia…

…te stdout for `bagel bids` (#227)

* add utility for getting subject list from BIDS directory names

* add test for get_bids_subjects_simple()

* refactor initial subject IDs check and add more intermediate messages for BIDS command

* print provided inputs before initial bagel bids checks

* print first message from bagel bids even earlier

bagel/bids_utils.py

@@ -11,6 +11,19 @@ def map_term_to_namespace(term: str, namespace: dict) -> str:
     return namespace.get(term, False)
 
 
+def get_bids_subjects_simple(bids_dir: Path) -> list:
+    """Returns list of subject IDs (in format of sub-<SUBJECT>) for a BIDS directory inferred from the names of non-empty subdirectories."""
+    bids_subject_list = []
+    for path in bids_dir.iterdir():
+        if (
+            path.name.startswith("sub-")
+            and path.is_dir()
+            and any(path.iterdir())
+        ):
+            bids_subject_list.append(path.name)
+    return bids_subject_list
+
+
 def check_unique_bids_subjects(pheno_subjects: list, bids_subjects: list):
     """Raises informative error if subject IDs exist that are found only in the BIDS directory."""
     unique_bids_subjects = set(bids_subjects).difference(pheno_subjects)

bagel/cli.py

@@ -201,13 +201,17 @@ def bids(
     # Check if output file already exists
     check_overwrite(output, overwrite)
 
-    jsonld = load_json(jsonld_path)
-    layout = BIDSLayout(bids_dir, validate=True)
+    space = 32
+    print(
+        "Running initial checks of inputs...\n"
+        f"   {'Phenotypic .jsonld to augment:' : <{space}} {jsonld_path}\n"
+        f"   {'BIDS dataset directory:' : <{space}} {bids_dir}"
+    )
 
+    jsonld = load_json(jsonld_path)
     # Strip and store context to be added back later, since it's not part of
     # (and can't be easily added) to the existing data model
     context = {"@context": jsonld.pop("@context")}
-
     try:
         pheno_dataset = models.Dataset.parse_obj(jsonld)
     except ValidationError as err:
@@ -217,21 +221,21 @@ def bids(
         pheno_subject.hasLabel: pheno_subject
         for pheno_subject in getattr(pheno_dataset, "hasSamples")
     }
-    bids_subject_list = ["sub-" + sub_id for sub_id in layout.get_subjects()]
 
+    # TODO: Revert to using Layout.get_subjects() to get BIDS subjects once pybids performance is improved
     butil.check_unique_bids_subjects(
         pheno_subjects=pheno_subject_dict.keys(),
-        bids_subjects=bids_subject_list,
+        bids_subjects=butil.get_bids_subjects_simple(bids_dir),
     )
+    print("Initial checks of inputs passed.\n")
+
+    print("Parsing and validating BIDS dataset. This may take a while...")
+    layout = BIDSLayout(bids_dir, validate=True)
+    print("BIDS parsing completed.\n")
 
-    # Display validated input paths to user
-    space = 32
     print(
-        "Parsing BIDS metadata to be merged with phenotypic annotations:\n"
-        f"   {'Phenotypic .jsonld to augment:' : <{space}} {jsonld_path}\n"
-        f"   {'BIDS dataset directory:' : <{space}} {bids_dir}\n"
+        "Merging subject-level BIDS metadata with the phenotypic annotations...\n"
     )
-
     for bids_sub_id in layout.get_subjects():
         pheno_subject = pheno_subject_dict.get(f"sub-{bids_sub_id}")
         session_list = []

bagel/tests/test_utility.py

@@ -336,6 +336,22 @@ def test_generate_context(get_test_context, model, attributes):
         assert attribute in get_test_context["@context"]
 
 
+@pytest.mark.parametrize(
+    "bids_dir",
+    ["synthetic", "ds000248"],
+)
+def test_get_bids_subjects_simple(bids_path, bids_dir):
+    """Test that get_bids_subjects_simple() correctly extracts subject IDs from a BIDS directory."""
+    bids_subject_list = butil.get_bids_subjects_simple(bids_path / bids_dir)
+    expected_subjects = [
+        f"sub-{sub_id}"
+        for sub_id in BIDSLayout(
+            bids_path / bids_dir, validate=True
+        ).get_subjects()
+    ]
+    assert sorted(bids_subject_list) == sorted(expected_subjects)
+
+
 @pytest.mark.parametrize(
     "bids_list, expectation",
     [