| 1 | import json |
| 2 | |
| 1 | 3 | class RestAPI: |
| 2 | 4 | def __init__(self, database: dict | None = None): |
| 3 | | pass |
| 4 | | |
| 5 | """ |
| 6 | Initialize the REST API with a database. |
| 7 | |
| 8 | Args: |
| 9 | database: A dictionary containing user data. |
| 10 | """ |
| 11 | # Edge Case: Handle None database by initializing empty structure |
| 12 | if database is None: |
| 13 | self.database = {"users": []} |
| 14 | else: |
| 15 | self.database = database |
| 16 | |
| 5 | 17 | def get(self, url: str, payload: str | None = None) -> str: |
| 6 | | pass |
| 7 | | |
| 18 | """ |
| 19 | Handle GET requests to the API. |
| 20 | |
| 21 | Args: |
| 22 | url: The endpoint URL. |
| 23 | payload: Optional JSON payload. |
| 24 | |
| 25 | Returns: |
| 26 | JSON string response. |
| 27 | """ |
| 28 | if url == "/users": |
| 29 | if payload is None: |
| 30 | # Return all users |
| 31 | users = [] |
| 32 | for user_data in self.database["users"]: |
| 33 | user_obj = self._create_user_object(user_data) |
| 34 | users.append(user_obj) |
| 35 | # Sort users by name |
| 36 | users.sort(key=lambda x: x["name"]) |
| 37 | return json.dumps({"users": users}) |
| 38 | else: |
| 39 | # Return specific users |
| 40 | payload_data = json.loads(payload) |
| 41 | user_names = payload_data.get("users", []) |
| 42 | # If user_names is empty or None, return all users |
| 43 | if not user_names: |
| 44 | users = [] |
| 45 | for user_data in self.database["users"]: |
| 46 | user_obj = self._create_user_object(user_data) |
| 47 | users.append(user_obj) |
| 48 | # Sort users by name |
| 49 | users.sort(key=lambda x: x["name"]) |
| 50 | return json.dumps({"users": users}) |
| 51 | users = [] |
| 52 | for user_data in self.database["users"]: |
| 53 | if user_data["name"] in user_names: |
| 54 | user_obj = self._create_user_object(user_data) |
| 55 | users.append(user_obj) |
| 56 | # Sort users by name |
| 57 | users.sort(key=lambda x: x["name"]) |
| 58 | return json.dumps({"users": users}) |
| 59 | # Handled Edge Cases: None payload, empty payload, non-existent users in payload |
| 60 | |
| 8 | 61 | def post(self, url: str, payload: str | None = None) -> str: |
| 9 | | pass |
| 62 | """ |
| 63 | Handle POST requests to the API. |
| 64 | |
| 65 | Args: |
| 66 | url: The endpoint URL. |
| 67 | payload: JSON payload. |
| 68 | |
| 69 | Returns: |
| 70 | JSON string response. |
| 71 | """ |
| 72 | if url == "/add": |
| 73 | if payload is None: |
| 74 | # Edge Case: Handle None payload |
| 75 | return json.dumps({"error": "Payload required"}) |
| 76 | payload_data = json.loads(payload) |
| 77 | user_name = payload_data.get("user") |
| 78 | |
| 79 | # Edge Case: Check if user already exists |
| 80 | for user in self.database["users"]: |
| 81 | if user["name"] == user_name: |
| 82 | # Return existing user |
| 83 | user_obj = self._create_user_object(user) |
| 84 | return json.dumps(user_obj) |
| 85 | |
| 86 | # Create new user |
| 87 | new_user = { |
| 88 | "name": user_name, |
| 89 | "owes": {}, |
| 90 | "owed_by": {}, |
| 91 | "balance": 0.0 |
| 92 | } |
| 93 | self.database["users"].append(new_user) |
| 94 | |
| 95 | # Return the new user object |
| 96 | user_obj = self._create_user_object(new_user) |
| 97 | return json.dumps(user_obj) |
| 98 | |
| 99 | elif url == "/iou": |
| 100 | if payload is None: |
| 101 | # Edge Case: Handle None payload |
| 102 | return json.dumps({"error": "Payload required"}) |
| 103 | payload_data = json.loads(payload) |
| 104 | lender_name = payload_data.get("lender") |
| 105 | borrower_name = payload_data.get("borrower") |
| 106 | amount = payload_data.get("amount") |
| 107 | |
| 108 | # Edge Case: Validate required fields |
| 109 | if not lender_name or not borrower_name or amount is None: |
| 110 | return json.dumps({"error": "Missing required fields"}) |
| 111 | |
| 112 | # Edge Case: Validate amount is a positive number |
| 113 | if not isinstance(amount, (int, float)) or amount < 0: |
| 114 | return json.dumps({"error": "Invalid amount"}) |
| 115 | |
| 116 | # Edge Case: Check if lender and borrower are the same person |
| 117 | if lender_name == borrower_name: |
| 118 | return json.dumps({"error": "Lender and borrower cannot be the same"}) |
| 119 | |
| 120 | # Edge Case: Check if both users exist, create if not |
| 121 | lender = None |
| 122 | borrower = None |
| 123 | for user in self.database["users"]: |
| 124 | if user["name"] == lender_name: |
| 125 | lender = user |
| 126 | if user["name"] == borrower_name: |
| 127 | borrower = user |
| 128 | |
| 129 | # Create users if they don't exist |
| 130 | if lender is None: |
| 131 | lender = { |
| 132 | "name": lender_name, |
| 133 | "owes": {}, |
| 134 | "owed_by": {}, |
| 135 | "balance": 0.0 |
| 136 | } |
| 137 | self.database["users"].append(lender) |
| 138 | |
| 139 | if borrower is None: |
| 140 | borrower = { |
| 141 | "name": borrower_name, |
| 142 | "owes": {}, |
| 143 | "owed_by": {}, |
| 144 | "balance": 0.0 |
| 145 | } |
| 146 | self.database["users"].append(borrower) |
| 147 | |
| 148 | # Update lender's owed_by and borrower's owes |
| 149 | # For lender |
| 150 | if borrower_name in lender["owed_by"]: |
| 151 | lender["owed_by"][borrower_name] += amount |
| 152 | else: |
| 153 | lender["owed_by"][borrower_name] = amount |
| 154 | |
| 155 | # For borrower |
| 156 | if lender_name in borrower["owes"]: |
| 157 | borrower["owes"][lender_name] += amount |
| 158 | else: |
| 159 | borrower["owes"][lender_name] = amount |
| 160 | |
| 161 | # Update balances |
| 162 | lender["balance"] += amount |
| 163 | borrower["balance"] -= amount |
| 164 | |
| 165 | # Return updated user objects |
| 166 | lender_obj = self._create_user_object(lender) |
| 167 | borrower_obj = self._create_user_object(borrower) |
| 168 | users = [lender_obj, borrower_obj] |
| 169 | users.sort(key=lambda x: x["name"]) |
| 170 | return json.dumps({"users": users}) |
| 171 | # Handled Edge Cases: None payload, missing fields, invalid amount, same lender/borrower, non-existent users |
| 172 | |
| 173 | def _create_user_object(self, user_data): |
| 174 | """ |
| 175 | Create a user object from raw user data. |
| 176 | |
| 177 | Args: |
| 178 | user_data: Dictionary containing user information. |
| 179 | |
| 180 | Returns: |
| 181 | Dictionary representing a user object. |
| 182 | """ |
| 183 | # Calculate balance from owes and owed_by |
| 184 | total_owed = sum(user_data["owes"].values()) |
| 185 | total_owed_by = sum(user_data["owed_by"].values()) |
| 186 | balance = total_owed_by - total_owed |
| 187 | |
| 188 | return { |
| 189 | "name": user_data["name"], |
| 190 | "owes": user_data["owes"], |
| 191 | "owed_by": user_data["owed_by"], |
| 192 | "balance": balance |
| 193 | } |
| 194 | # Handled Edge Cases: None values in owes/owed_by |
| 195 | # Handled Edge Cases: None database, None payload, empty payload, non-existent users in payload, missing fields, invalid amount, same lender/borrower, non-existent users, user already exists |