Customer Rating and review changes

backend/app/api/routers/elec.py

@@ -141,23 +141,50 @@ def product(product_id: int) -> dict:
 def _overall_rating(sources: List[dict]) -> Optional[dict]:
     """The product's rating across the platforms that state one: the mean
     weighted by each platform's rating count (a platform that states no count
-    weighs as 1). None when no platform states a rating - never a guess."""
+    weighs as 1). None when no platform states a rating - never a guess.
+
+    One reading per platform: a site with a page per colour repeats the same
+    model rating on each, and adding those up would multiply its count."""
     if not sources:
         return None
     weight = lambda s: max(int(s["review_count"] or 0), 1)  # noqa: E731
+    per_site: Dict[str, dict] = {}
+    for s in sources:
+        if s["site"] not in per_site or weight(s) > weight(per_site[s["site"]]):
+            per_site[s["site"]] = s
+    sources = list(per_site.values())
     total = sum(weight(s) for s in sources)
     value = sum(Decimal(s["rating"]) * weight(s) for s in sources) / total
     counts = [s["review_count"] for s in sources if s["review_count"]]
     return {
         "value": round(float(value), 1),
         "count": sum(counts) if counts else None,
+        "breakdown": _breakdown(sources),
         "sources": [
-            {"site": s["site"], "rating": float(s["rating"]), "review_count": s["review_count"], "source_url": s["source_url"]}
+            {"site": s["site"], "rating": float(s["rating"]), "review_count": s["review_count"],
+             "breakdown": s.get("rating_breakdown"), "source_url": s["source_url"]}
             for s in sources
         ],
     }
 
 
+def _breakdown(sources: List[dict]) -> Optional[List[dict]]:
+    """5→1 star counts summed over the platforms that PUBLISH a breakdown.
+    None when none does - never estimated from the few review texts held."""
+    totals = {str(n): 0 for n in range(1, 6)}
+    stated = False
+    for s in sources:
+        for star, n in (s.get("rating_breakdown") or {}).items():
+            if star in totals and isinstance(n, int) and n > 0:
+                totals[star] += n
+                stated = True
+    if not stated:
+        return None
+    total = sum(totals.values())
+    return [{"stars": int(k), "count": totals[k], "percent": round(100 * totals[k] / total)}
+            for k in ("5", "4", "3", "2", "1")]
+
+
 @router.get("/products/{product_id}/price-history")
 def price_history(product_id: int) -> List[dict]:
     with connect() as conn: