Merge pull request #1942 from willhoh/isbn_search

Isbn check befor search

bookwyrm/views/search.py

@@ -24,6 +24,8 @@ class Search(View):
     def get(self, request):
         """that search bar up top"""
         query = request.GET.get("q")
+        # check if query is isbn
+        query = isbn_check(query)
         min_confidence = request.GET.get("min_confidence", 0)
         search_type = request.GET.get("type")
         search_remote = (
@@ -123,3 +125,35 @@ def list_search(query, viewer, *_):
         )
         .order_by("-similarity")
     ), None
+
+
+def isbn_check(query):
+    """isbn10 or isbn13 check, if so remove separators"""
+    if query:
+        su_num = re.sub(r"(?<=\d)\D(?=\d|[xX])", "", query)
+        if len(su_num) == 13 and su_num.isdecimal():
+            # Multiply every other digit by  3
+            # Add these numbers and the other digits
+            product = sum(int(ch) for ch in su_num[::2]) + sum(
+                int(ch) * 3 for ch in su_num[1::2]
+            )
+            if product % 10 == 0:
+                return su_num
+        elif (
+            len(su_num) == 10
+            and su_num[:-1].isdecimal()
+            and (su_num[-1].isdecimal() or su_num[-1].lower() == "x")
+        ):
+            product = 0
+            # Iterate through code_string
+            for i in range(9):
+                # for each character, multiply by a different decreasing number: 10 - x
+                product = product + int(su_num[i]) * (10 - i)
+            # Handle last character
+            if su_num[9].lower() == "x":
+                product += 10
+            else:
+                product += int(su_num[9])
+            if product % 11 == 0:
+                return su_num
+    return query