| 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 | |
| 8 | # Convert list of user dicts to a more usable format |
| 9 | self.user_data = {} |
| 10 | for user in self.users: |
| 11 | self.user_data[user['name']] = { |
| 12 | 'owes': user.get('owes', {}), |
| 13 | 'owed_by': user.get('owed_by', {}), |
| 14 | 'balance': user.get('balance', 0.0) |
| 15 | } |
| 16 | |
| 5 | 17 | def get(self, url: str, payload: str | None = None) -> str: |
| 6 | | pass |
| 7 | | |
| 18 | # Edge Case: Handle invalid URL |
| 19 | if url != '/users': |
| 20 | return json.dumps({"error": "Invalid URL"}) |
| 21 | |
| 22 | # Edge Case: Handle invalid payload format |
| 23 | if payload is not None: |
| 24 | try: |
| 25 | payload_data = json.loads(payload) |
| 26 | except json.JSONDecodeError: |
| 27 | return json.dumps({"error": "Invalid payload format"}) |
| 28 | else: |
| 29 | payload_data = None |
| 30 | |
| 31 | # If no payload, return all users |
| 32 | if payload_data is None: |
| 33 | result_users = [] |
| 34 | for name in sorted(self.user_data.keys()): |
| 35 | user_info = self.user_data[name] |
| 36 | balance = sum(user_info['owed_by'].values()) - sum(user_info['owes'].values()) |
| 37 | result_users.append({ |
| 38 | 'name': name, |
| 39 | 'owes': user_info['owes'], |
| 40 | 'owed_by': user_info['owed_by'], |
| 41 | 'balance': round(balance, 2) |
| 42 | }) |
| 43 | return json.dumps({'users': result_users}) |
| 44 | |
| 45 | # If payload with specific users |
| 46 | # Edge Case: Handle missing 'users' key in payload |
| 47 | if 'users' not in payload_data: |
| 48 | return json.dumps({"error": "Missing users key in payload"}) |
| 49 | |
| 50 | requested_users = payload_data['users'] |
| 51 | result_users = [] |
| 52 | |
| 53 | # Edge Case: Handle non-existent users in request |
| 54 | for name in sorted(requested_users): |
| 55 | if name in self.user_data: |
| 56 | user_info = self.user_data[name] |
| 57 | balance = sum(user_info['owed_by'].values()) - sum(user_info['owes'].values()) |
| 58 | result_users.append({ |
| 59 | 'name': name, |
| 60 | 'owes': user_info['owes'], |
| 61 | 'owed_by': user_info['owed_by'], |
| 62 | 'balance': round(balance, 2) |
| 63 | }) |
| 64 | |
| 65 | return json.dumps({'users': result_users}) |
| 66 | # Handled Edge Cases: Invalid URL, invalid payload format, missing 'users' key in payload, non-existent users in request |
| 67 | |
| 8 | 68 | def post(self, url: str, payload: str | None = None) -> str: |
| 9 | | pass |
| 69 | # Edge Case: Handle invalid URL |
| 70 | if url not in ['/add', '/iou']: |
| 71 | return json.dumps({"error": "Invalid URL"}) |
| 72 | |
| 73 | # Edge Case: Handle missing payload |
| 74 | if payload is None: |
| 75 | return json.dumps({"error": "Missing payload"}) |
| 76 | |
| 77 | # Edge Case: Handle invalid payload format |
| 78 | try: |
| 79 | payload_data = json.loads(payload) |
| 80 | except json.JSONDecodeError: |
| 81 | return json.dumps({"error": "Invalid payload format"}) |
| 82 | |
| 83 | if url == '/add': |
| 84 | # Edge Case: Handle missing 'user' key in payload |
| 85 | if 'user' not in payload_data: |
| 86 | return json.dumps({"error": "Missing user key in payload"}) |
| 87 | |
| 88 | user_name = payload_data['user'] |
| 89 | |
| 90 | # Edge Case: Handle duplicate user creation |
| 91 | if user_name in self.user_data: |
| 92 | return json.dumps({"error": "User already exists"}) |
| 93 | |
| 94 | # Create new user |
| 95 | self.user_data[user_name] = { |
| 96 | 'owes': {}, |
| 97 | 'owed_by': {}, |
| 98 | 'balance': 0.0 |
| 99 | } |
| 100 | |
| 101 | new_user = { |
| 102 | 'name': user_name, |
| 103 | 'owes': {}, |
| 104 | 'owed_by': {}, |
| 105 | 'balance': 0.0 |
| 106 | } |
| 107 | |
| 108 | return json.dumps(new_user) |
| 109 | # Handled Edge Cases: Invalid URL, missing payload, invalid payload format, missing 'user' key in payload, duplicate user creation |
| 110 | |
| 111 | elif url == '/iou': |
| 112 | # Edge Case: Handle missing required keys in payload |
| 113 | required_keys = ['lender', 'borrower', 'amount'] |
| 114 | for key in required_keys: |
| 115 | if key not in payload_data: |
| 116 | return json.dumps({"error": f"Missing {key} key in payload"}) |
| 117 | |
| 118 | lender = payload_data['lender'] |
| 119 | borrower = payload_data['borrower'] |
| 120 | amount = payload_data['amount'] |
| 121 | |
| 122 | # Edge Case: Handle non-numeric amount |
| 123 | if not isinstance(amount, (int, float)): |
| 124 | return json.dumps({"error": "Amount must be a number"}) |
| 125 | |
| 126 | # Edge Case: Handle negative amount |
| 127 | if amount < 0: |
| 128 | return json.dumps({"error": "Amount cannot be negative"}) |
| 129 | |
| 130 | # Edge Case: Handle same lender and borrower |
| 131 | if lender == borrower: |
| 132 | return json.dumps({"error": "Lender and borrower cannot be the same"}) |
| 133 | |
| 134 | # Edge Case: Handle non-existent lender or borrower |
| 135 | if lender not in self.user_data: |
| 136 | return json.dumps({"error": "Lender does not exist"}) |
| 137 | if borrower not in self.user_data: |
| 138 | return json.dumps({"error": "Borrower does not exist"}) |
| 139 | |
| 140 | # Update IOU information |
| 141 | # Handle lender side |
| 142 | if borrower in self.user_data[lender]['owes']: |
| 143 | # Lender owes borrower money, so this IOU reduces that debt |
| 144 | self.user_data[lender]['owes'][borrower] -= amount |
| 145 | if self.user_data[lender]['owes'][borrower] <= 0: |
| 146 | # Debt is fully paid or overpaid |
| 147 | remaining_amount = -self.user_data[lender]['owes'][borrower] |
| 148 | del self.user_data[lender]['owes'][borrower] |
| 149 | if remaining_amount > 0: |
| 150 | # Lender is now owed money |
| 151 | self.user_data[lender]['owed_by'][borrower] = remaining_amount |
| 152 | else: |
| 153 | # Lender doesn't owe borrower, so borrower owes lender |
| 154 | if borrower in self.user_data[lender]['owed_by']: |
| 155 | self.user_data[lender]['owed_by'][borrower] += amount |
| 156 | else: |
| 157 | self.user_data[lender]['owed_by'][borrower] = amount |
| 158 | |
| 159 | # Handle borrower side |
| 160 | if lender in self.user_data[borrower]['owed_by']: |
| 161 | # Borrower is owed money by lender, so this IOU reduces that |
| 162 | self.user_data[borrower]['owed_by'][lender] -= amount |
| 163 | if self.user_data[borrower]['owed_by'][lender] <= 0: |
| 164 | # Credit is fully used or overused |
| 165 | remaining_amount = -self.user_data[borrower]['owed_by'][lender] |
| 166 | del self.user_data[borrower]['owed_by'][lender] |
| 167 | if remaining_amount > 0: |
| 168 | # Borrower now owes money |
| 169 | self.user_data[borrower]['owes'][lender] = remaining_amount |
| 170 | else: |
| 171 | # Borrower is not owed money by lender, so borrower owes lender |
| 172 | if lender in self.user_data[borrower]['owes']: |
| 173 | self.user_data[borrower]['owes'][lender] += amount |
| 174 | else: |
| 175 | self.user_data[borrower]['owes'][lender] = amount |
| 176 | |
| 177 | # Prepare response with updated user information |
| 178 | updated_users = [] |
| 179 | for name in sorted([lender, borrower]): |
| 180 | user_info = self.user_data[name] |
| 181 | balance = sum(user_info['owed_by'].values()) - sum(user_info['owes'].values()) |
| 182 | updated_users.append({ |
| 183 | 'name': name, |
| 184 | 'owes': user_info['owes'], |
| 185 | 'owed_by': user_info['owed_by'], |
| 186 | 'balance': round(balance, 2) |
| 187 | }) |
| 188 | |
| 189 | return json.dumps({'users': updated_users}) |
| 190 | # Handled Edge Cases: Invalid URL, missing payload, invalid payload format, missing required keys in payload, non-numeric amount, negative amount, same lender and borrower, non-existent lender or borrower |
| 191 | # Handled Edge Cases: Invalid URL, missing payload, invalid payload format, missing required keys in payload, non-numeric amount, negative amount, same lender and borrower, non-existent lender or borrower, missing 'user' key in payload, duplicate user creation, missing 'users' key in payload, non-existent users in request |