| 1 | import json |
| 2 | |
| 1 | 3 | class RestAPI: |
| 2 | 4 | def __init__(self, database: dict | None = None): |
| 3 | | pass |
| 4 | | |
| 5 | # Edge Case: Handle None database by initializing empty users dict |
| 6 | self.users = database.get('users', []) if database else [] |
| 7 | |
| 5 | 8 | def get(self, url: str, payload: str | None = None) -> str: |
| 6 | | pass |
| 7 | | |
| 9 | if url == '/users': |
| 10 | if payload is None: |
| 11 | # Return all users |
| 12 | return json.dumps({"users": [self._format_user(user) for user in self.users]}) |
| 13 | else: |
| 14 | # Return specific users |
| 15 | data = json.loads(payload) |
| 16 | user_names = data.get('users', []) |
| 17 | # Edge Case: Handle when users list is empty in payload |
| 18 | if not user_names: |
| 19 | return json.dumps({"users": []}) |
| 20 | |
| 21 | result_users = [] |
| 22 | for user in self.users: |
| 23 | if user['name'] in user_names: |
| 24 | result_users.append(self._format_user(user)) |
| 25 | |
| 26 | # Sort by name |
| 27 | result_users.sort(key=lambda x: x['name']) |
| 28 | return json.dumps({"users": result_users}) |
| 29 | |
| 8 | 30 | def post(self, url: str, payload: str | None = None) -> str: |
| 9 | | pass |
| 31 | if url == '/add': |
| 32 | if payload is None: |
| 33 | # Edge Case: Handle missing payload for add user |
| 34 | return json.dumps({"error": "Payload required"}) |
| 35 | |
| 36 | data = json.loads(payload) |
| 37 | user_name = data.get('user') |
| 38 | |
| 39 | # Edge Case: Handle missing user name in payload |
| 40 | if not user_name: |
| 41 | return json.dumps({"error": "User name required"}) |
| 42 | |
| 43 | # Edge Case: Handle duplicate user creation |
| 44 | for user in self.users: |
| 45 | if user['name'] == user_name: |
| 46 | return json.dumps({"error": "User already exists"}) |
| 47 | |
| 48 | new_user = { |
| 49 | "name": user_name, |
| 50 | "owes": {}, |
| 51 | "owed_by": {}, |
| 52 | "balance": 0.0 |
| 53 | } |
| 54 | self.users.append(new_user) |
| 55 | return json.dumps(self._format_user(new_user)) |
| 56 | |
| 57 | elif url == '/iou': |
| 58 | if payload is None: |
| 59 | # Edge Case: Handle missing payload for IOU |
| 60 | return json.dumps({"error": "Payload required"}) |
| 61 | |
| 62 | data = json.loads(payload) |
| 63 | lender_name = data.get('lender') |
| 64 | borrower_name = data.get('borrower') |
| 65 | amount = data.get('amount') |
| 66 | |
| 67 | # Edge Case: Handle missing required fields in IOU payload |
| 68 | if not lender_name or not borrower_name or amount is None: |
| 69 | return json.dumps({"error": "Missing required fields"}) |
| 70 | |
| 71 | # Edge Case: Handle non-numeric amount |
| 72 | try: |
| 73 | amount = float(amount) |
| 74 | except (ValueError, TypeError): |
| 75 | return json.dumps({"error": "Invalid amount"}) |
| 76 | |
| 77 | # Edge Case: Handle negative amount |
| 78 | if amount < 0: |
| 79 | return json.dumps({"error": "Amount must be positive"}) |
| 80 | |
| 81 | # Edge Case: Handle lender and borrower being the same person |
| 82 | if lender_name == borrower_name: |
| 83 | return json.dumps({"error": "Cannot create IOU between same user"}) |
| 84 | |
| 85 | lender = None |
| 86 | borrower = None |
| 87 | |
| 88 | # Find lender and borrower |
| 89 | for user in self.users: |
| 90 | if user['name'] == lender_name: |
| 91 | lender = user |
| 92 | elif user['name'] == borrower_name: |
| 93 | borrower = user |
| 94 | |
| 95 | # Edge Case: Handle lender or borrower not existing |
| 96 | if not lender or not borrower: |
| 97 | return json.dumps({"error": "User not found"}) |
| 98 | |
| 99 | # Update owes and owed_by |
| 100 | # Update lender's owed_by |
| 101 | if borrower_name in lender['owed_by']: |
| 102 | lender['owed_by'][borrower_name] += amount |
| 103 | else: |
| 104 | lender['owed_by'][borrower_name] = amount |
| 105 | |
| 106 | # Update borrower's owes |
| 107 | if lender_name in borrower['owes']: |
| 108 | borrower['owes'][lender_name] += amount |
| 109 | else: |
| 110 | borrower['owes'][lender_name] = amount |
| 111 | |
| 112 | # Update balances |
| 113 | lender['balance'] += amount |
| 114 | borrower['balance'] -= amount |
| 115 | |
| 116 | # Return updated users |
| 117 | result_users = [self._format_user(lender), self._format_user(borrower)] |
| 118 | result_users.sort(key=lambda x: x['name']) |
| 119 | return json.dumps({"users": result_users}) |
| 120 | |
| 121 | def _format_user(self, user): |
| 122 | # Calculate balance from owes and owed_by |
| 123 | total_owed = sum(user['owes'].values()) |
| 124 | total_owed_by = sum(user['owed_by'].values()) |
| 125 | balance = total_owed_by - total_owed |
| 126 | |
| 127 | return { |
| 128 | "name": user['name'], |
| 129 | "owes": user['owes'], |
| 130 | "owed_by": user['owed_by'], |
| 131 | "balance": balance |
| 132 | } |
| 133 | |
| 134 | # Handled Edge Cases: None database, missing payload, empty users list in payload, missing user name, duplicate user creation, missing IOU fields, non-numeric amount, negative amount, same lender/borrower, user not found |