Updated Useful import scripts (markdown)

Useful-import-scripts.md

@@ -108,4 +108,36 @@ with open("openScale_garmin_connect_import.csv", "wb") as outfile, open(sys.argv
             bmi(float(row["weight"])),
             row["fat"]
             ])
+```
+
+## Garmin format --> openScale CSV file
+
+by antonmosich see https://github.com/oliexdev/openScale/issues/879
+
+```python
+#!/usr/bin/python
+
+import csv
+import json
+import datetime
+import argparse
+
+OPENSCALE_HEADER = '"biceps","bone","caliper1","caliper2","caliper3","calories","chest","comment","dateTime","fat","hip","lbm","muscle","neck","thigh","visceralFat","waist","water","weight"'
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument("input")
+    parser.add_argument("output")
+    args = parser.parse_args()
+    with open(args.input, 'r') as input_file:
+        input_json = json.load(input_file)
+    filtered = [entry for entry in input_json if "weight" in entry]
+    with open(args.output, 'w') as output_file:
+        writer = csv.DictWriter(output_file, OPENSCALE_HEADER.replace('"', '').split(','))
+        output_file.write(f'{OPENSCALE_HEADER}\n')
+
+        for entry in filtered:
+            timestamp = datetime.datetime.fromisoformat(entry['weight']['timestampGMT'].ljust(23,'0'))
+            weight = entry['weight']['weight'] / 1000
+            writer.writerow({'dateTime': timestamp, 'weight': weight})
 ```