make badge great again

validata_core/__init__.py

 import logging
+from collections import Counter
 from datetime import datetime, timezone
 
 import frictionless
@@ -19,6 +20,54 @@ def extract_required_field_names(schema: frictionless.schema.Schema):
     return field_names
 
 
+def compute_badge_metrics(report, config) -> dict:
+    """Compute badge metrics from report statistics and badge configuration."""
+
+    def build_badge(structure_status, body_status=None, error_ratio=None):
+        """Badge info creation"""
+        if structure_status == 'KO':
+            return {
+                "structure": 'KO'
+            }
+        return {
+            "structure": structure_status,
+            "body": body_status,
+            "error-ratio": error_ratio
+        }
+
+    table_report = report["tables"][0]
+    table_stats = table_report["stats"]
+
+    # Compute number of cells
+    cell_total_number = table_stats['fields'] * table_stats['rows']
+
+    # No errors
+    if table_stats["errors"] == 0 and len(table_report["structure_warnings"]) == 0:
+        return build_badge('OK', 'OK', 0.0)
+
+    # Structure part
+    structure_status = None
+    structure_errors_count = len([err for err in table_report["errors"] if '#head' in err.tags or '#structure' in err.tags])
+    if structure_errors_count == 0:
+        structure_status = 'OK' if len(table_report["structure_warnings"]) == 0 else 'WARN'
+    else:
+        return build_badge('KO')
+
+    # body part
+    value_errors = [err for err in table_report["errors"] if "#body" in err.tags]
+    if len(value_errors) == 0:
+        return build_badge(structure_status, 'OK', 0.0)
+
+    # Computes error ratio
+    weight_dict = config['body']['errors-weight']
+    err_code_counter = Counter([err.code for err in value_errors])
+    ratio = sum([nb * weight_dict.get(err_code, 1.0) for err_code, nb in err_code_counter.items()]) \
+        / cell_total_number
+    body_status = 'WARN' if ratio < config['body']['acceptability-threshold'] else 'KO'
+
+    return build_badge(structure_status, body_status, ratio)
+
+
 def validate(source, schema, **options):
     """Validate a `source` using a `schema`."""