Add docs about running PayPal balancing

Author: olasitarska

howto/foundation-budget.md

@@ -16,3 +16,16 @@
 11. Manually update "Item" and "Category" columns.
 12. Balance of CAFBank (in Balance sheet) should check out with the Balance on the actual account.
 
+## PayPal
+
+13. Go to [Download history](https://history.paypal.com/cgi-bin/webscr?cmd=_history-download)
+14. Select date range since latest update to now
+15. File Types for Download: Comma Delimited - All activity
+16. Hit "Download history"
+17. Run [`paypal..py` script](../scripts/paypal.py) like this: `python paypal.py path_to_exported_csv.csv`
+18. Upload newly generated CSV to Budget spreadsheet, ad as new sheet
+19. Copy data from new sheet and paste it to "Items" sheet in Budget ad the end. 
+20. Sort Items sheet by day, Z-A. 
+21. Manually update "Item" and "Category" columns.
+22. Balance of PayPal (in Balance sheet) should check out with the Balance on the actual account.
+

scripts/paypal.py

@@ -0,0 +1,62 @@
+import csv
+import sys
+import datetime
+
+
+def read_statement(filename):
+    source_data = []
+    with open('source.csv', 'rb') as sourcefile:
+        reader = csv.DictReader(sourcefile)
+        for row in reader: 
+            source_data.append(row)
+    return source_data
+
+def normalize_source(source_data):
+    normalized_data = []
+
+    # Remove transactions without reference ID -- we don't want currency conversion transactions
+    for row in source_data:
+        if row[' Reference Txn ID'] == '':
+            normalized_data.append(row)
+
+    transactions = {row[' Transaction ID']: row for row in normalized_data}
+    
+    # Replace USD values with GBP values if transaction currency was converted
+    for row in source_data:
+        if row[' Currency'] == 'USD' and row[' Reference Txn ID'] != '':
+            id = row[' Reference Txn ID']
+            if id in transactions:
+                transactions[id][' Fee'] = row[' Fee']
+                transactions[id][' Gross'] = row[' Gross']
+                transactions[id][' Net'] = row[' Net']
+                transactions[id][' Currency'] = row[' Currency']
+
+    return transactions.values()
+
+def write_csv(data):
+    fieldnames = ['Description on bank statement', 'Item', 'Category', 'Date', 'Money in USD', 'Money in GBP', 'Money out USD', 'Money out GBP', 'Account', 'Is refunded?']
+    output_filename = 'paypal_{}.csv'.format(datetime.datetime.now().strftime('%Y%m%d'))
+    
+    with open(output_filename, 'w') as csvfile:
+        writer = csv.writer(csvfile)
+        writer.writerow(fieldnames)
+
+        for row in data:
+            name = '{} / {}'.format(row[' Name'], row[' Transaction ID'])
+            if row[' Currency'] == 'GBP' and '-' in row[' Net']:
+                writer.writerow([name, '', '', row['Date'], '', '', '', row[' Net'].replace('-', ''), 'PayPal', '-'])
+            elif row[' Currency'] == 'GBP' and not '-' in row[' Net']:
+                writer.writerow([name, '', '', row['Date'], '', row[' Net'], '', '', 'PayPal', '-'])
+            elif row[' Currency'] == 'USD' and '-' in row[' Net']:
+                writer.writerow([name, '', '', row['Date'], '', row[' Net'].replace('-', ''), '', '', 'PayPal', '-'])
+            elif row[' Currency'] == 'USD' and not '-' in row[' Net']:
+                writer.writerow([name, '', '', row['Date'], row[' Net'], '', '', '', 'PayPal', '-'])
+            print 'Transaction {} on {} processed'.format(name, row['Date'])
+    
+    print 'CSV saved to {}'.format(output_filename)
+
+
+if __name__ == "__main__":
+    source_data = read_statement(sys.argv[1])
+    normalized_data = normalize_source(source_data)
+    write_csv(normalized_data)