# payments/management/commands/fix_duplicate_wallet_usage_today.py from decimal import Decimal from datetime import date, datetime from django.core.management.base import BaseCommand, CommandError from django.db import transaction from django.db.models import F from accounts.models import User from payments.models import ViralPeWallet, ViralPeWalletUsage def signed_amount(usage: ViralPeWalletUsage) -> Decimal: """credit -> +amount, debit -> -amount""" amt = Decimal(usage.amount_used) return amt if usage.transaction_type == "credit" else (amt * Decimal("-1")) class Command(BaseCommand): help = ( "Detects duplicate wallet usage entries for a user on a given date (ignoring time), " "and deletes exactly one latest record while reversing its impact on the wallet, " "only if wallet won't go negative. Default date=today. Dry-run by default." ) def add_arguments(self, parser): parser.add_argument( "--mobile", required=True, help="User mobile number to check (e.g., 9000000001)", ) parser.add_argument( "--date", dest="on_date", default=None, help="Date in YYYY-MM-DD; defaults to today.", ) parser.add_argument( "--apply", action="store_true", help="Actually perform the deletion + wallet reversal. Omit for dry-run.", ) def handle(self, *args, **opts): mobile = opts["mobile"] on_date_str = opts.get("on_date") or date.today().isoformat() apply = opts["apply"] # parse date try: target_date = datetime.strptime(on_date_str, "%Y-%m-%d").date() except ValueError: raise CommandError("Invalid --date. Use YYYY-MM-DD") # fetch user try: user = User.objects.get(mobile_number=mobile) except User.DoesNotExist: raise CommandError(f"User with mobile {mobile} not found.") usages = ( ViralPeWalletUsage.objects .filter(user=user, used_on__date=target_date) .order_by("used_on", "id") ) self.stdout.write(f"User: {user.id} / {mobile}") self.stdout.write(f"Date: {target_date.isoformat()}") self.stdout.write(f"Found {usages.count()} usage record(s) on this date.\n") for u in usages: self.stdout.write( f" - usage#{u.id} [{u.transaction_type}] amt={u.amount_used} " f"purpose={u.purpose_code or ''} order_id={u.order_id or ''} " f"used_on={u.used_on.strftime('%H:%M:%S')} (signed={signed_amount(u)})" ) if usages.count() < 2: self.stdout.write("\nNo duplicates by date (ignoring time). Nothing to do.") return # Strategy: delete exactly ONE record (the latest) and reverse its impact. candidate = usages.last() s = signed_amount(candidate) # Current wallet wallet = ViralPeWallet.objects.filter(user=user).first() current_balance = wallet.balance if wallet else Decimal("0.00") # Reverse delta: deleting the usage means NEGATING its signed impact reverse_delta = (s * Decimal("-1")) projected_balance = current_balance + reverse_delta self.stdout.write("\nCandidate to delete (latest on the date):") self.stdout.write( f" -> usage#{candidate.id} [{candidate.transaction_type}] " f"amt={candidate.amount_used} (signed={s})" ) self.stdout.write(f"Current wallet balance: {current_balance}") self.stdout.write(f"Reverse delta on delete: {reverse_delta} " f"(wallet would become {projected_balance})") if projected_balance < 0: self.stdout.write( "\nSKIP: Deleting this record would make wallet negative. " "Marking for different manual action." ) return if not apply: self.stdout.write("\nDRY RUN: Would delete the candidate and set balance to " f"{projected_balance}. (Use --apply to execute.)") return # APPLY: Do it atomically and double-check concurrently try: with transaction.atomic(): # lock wallet row wallet, _ = ViralPeWallet.objects.select_for_update().get_or_create(user=user) fresh_balance = wallet.balance # recompute with fresh balance (safety under concurrency) new_projected = fresh_balance + reverse_delta if new_projected < 0: raise CommandError( f"Concurrent change detected: cannot delete usage#{candidate.id} " f"as wallet would go negative (now {fresh_balance} -> {new_projected})." ) # adjust wallet, then delete wallet.balance = F("balance") + reverse_delta wallet.save(update_fields=["balance"]) candidate.delete() # read back wallet.refresh_from_db(fields=["balance"]) self.stdout.write( f"\nAPPLIED: Deleted usage#{candidate.id}. " f"New wallet balance: {wallet.balance}" ) except Exception as e: raise CommandError(f"Failed to apply changes: {e}") # Usage # Dry run (no changes, just prints what it would do): # python manage.py fix_duplicate_wallet_usage_today --mobile 9000000007 # Pick a specific date: # python manage.py fix_duplicate_wallet_usage_today --mobile 9000000007 --date 2025-10-24 # Apply the fix (actually delete + adjust wallet): # python manage.py fix_duplicate_wallet_usage_today --mobile 9000000007 --apply # from decimal import Decimal # from datetime import date # from django.db import transaction # from django.db.models import F # from accounts.models import User # from payments.models import ViralPeWallet, ViralPeWalletUsage # def signed_amount(u): # amt = Decimal(u.amount_used) # return amt if u.transaction_type == "credit" else (amt * Decimal("-1")) # def fix_duplicate_today(mobile: str, apply=False, on_date=None): # d = on_date or date.today() # try: # user = User.objects.get(mobile_number=mobile) # except User.DoesNotExist: # print(f"User with mobile {mobile} not found.") # return # qs = ViralPeWalletUsage.objects.filter(user=user, used_on__date=d).order_by("used_on", "id") # print(f"User: {user.id} / {mobile} Date: {d} Count: {qs.count()}") # for u in qs: # print(f" - usage#{u.id} [{u.transaction_type}] amt={u.amount_used} used_on={u.used_on} signed={signed_amount(u)}") # if qs.count() < 2: # print("No duplicates by date. Nothing to do.") # return # cand = qs.last() # s = signed_amount(cand) # wallet = ViralPeWallet.objects.filter(user=user).first() # bal = wallet.balance if wallet else Decimal("0.00") # reverse_delta = (s * Decimal("-1")) # projected = bal + reverse_delta # print(f"\nCandidate: usage#{cand.id} [{cand.transaction_type}] amt={cand.amount_used} signed={s}") # print(f"Current balance: {bal} | Reverse delta: {reverse_delta} | Projected: {projected}") # if projected < 0: # print("SKIP: Deleting would make wallet negative. Take manual action.") # return # if not apply: # print("DRY RUN: Would delete this record and set balance to", projected) # return # try: # with transaction.atomic(): # w, _ = ViralPeWallet.objects.select_for_update().get_or_create(user=user) # fresh = w.balance # new_projected = fresh + reverse_delta # if new_projected < 0: # print("Concurrent change: now would go negative; abort.") # return # w.balance = F("balance") + reverse_delta # w.save(update_fields=["balance"]) # cand.delete() # w.refresh_from_db(fields=["balance"]) # print(f"APPLIED: Deleted usage#{cand.id}. New balance: {w.balance}") # except Exception as e: # print("ERROR:", e) # # Example: # # fix_duplicate_today("9000000007", apply=False) # dry run # # fix_duplicate_today("9000000007", apply=True) # apply