SplitWise machine-coding implementation in python

Author: raghav1010

S/splitwise/CalculationService.py

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+from CalculationServiceImp import CalcultaionServiceImpl
+
+
+class CalculationService(CalcultaionServiceImpl):
+
+    def percentageSplit(self, paidby, amount, debtusers, contributions):
+        billCopy = list()
+        for i in range(len(debtusers)):
+            c = (contributions[i] * amount) / 100
+            paidby.getDebts()[debtusers[i]] = paidby.getDebts().get(debtusers[i], 0) + c
+            billCopy.append((paidby, debtusers[i], c))
+        return billCopy
+
+    def equalSplit(self, paidby, amount, debtusers, contributions):
+        billCopy = list()
+        for i in range(len(debtusers)):
+            c = (amount) / len(debtusers)
+            paidby.getDebts()[debtusers[i]] = paidby.getDebts().get(debtusers[i], 0) + c
+            billCopy.append((paidby, debtusers[i], c))
+        return billCopy
+
+    def exactSplit(self, paidby, amount, debtusers, contributions):
+        billCopy = list()
+        for i in range(len(debtusers)):
+            c = contributions[i]
+            paidby.getDebts()[debtusers[i]] = paidby.getDebts().get(debtusers[i], 0) + c
+            billCopy.append((paidby, debtusers[i]))
+        return billCopy

S/splitwise/CalculationServiceImp.py

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+import abc
+class CalcultaionServiceImpl(metaclass = abc.ABCMeta):
+
+    @abc.abstractmethod
+    def percentageSplit(paidby,amount,debtusers,contributions):
+        pass 
+
+    @abc.abstractmethod
+    def equalSplit(paidby,amount,debtusers,contributions):
+        pass 
+
+    @abc.abstractmethod
+    def exactSplit(paidby,amount,debtusers,contributions):
+        pass 
+
+
+    

S/splitwise/Expense.py

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+from CalculationService import CalculationService
+
+
+class Expense:
+
+    __paidBy = None 
+    __amount = None 
+    __divisions = None 
+    __debtUsers = None 
+    __strategy = None 
+    __contributions = None
+    __bill = None 
+    calculation = CalculationService()
+
+    def __init__(self,paiby,amount,divisions, debtUsers,strategy,contributions):
+        self.__paidBy = paiby
+        self.__amount = amount 
+        self.__divisions = divisions
+        self.__debtUsers = debtUsers
+        self.__strategy = strategy
+        self.__contributions = contributions
+        self.__bill = list()
+        
+    
+    def getBill(self):
+
+        if self.__strategy=="PERCENT":
+            self.__bill = self.calculation.percentageSplit(self.__paidBy,self.__amount,self.__debtUsers,self.__contributions)
+        elif self.__strategy=="EXACT":
+            self.__bill = self.calculation.exactSplit(self.__paidBy,self.__amount,self.__debtUsers,self.__contributions)
+        elif self.__strategy=="EQUAL":
+            self.__bill = self.calculation.equalSplit(self.__paidBy,self.__amount,self.__debtUsers,self.__contributions)
+        return self.__bill 
+    
+    def getPaidBy(self):
+        return self.__paidBy
+    
+    def getDeptUsers(self):
+        return self.__debtUsers

S/splitwise/ExpenseController.py

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+from Expense import Expense
+
+
+class ExpenseController:
+    __expense= None
+    __settledBill = None
+    def __init__(self,paiby,amount,divisions, debtUsers,strategy,contributions):
+        self.__settledBill= list()
+        self.__expense = Expense(paiby,amount,divisions, debtUsers,strategy,contributions)
+        self.__settleBill()
+        
+    
+    def __settleBill(self):
+        bill = self.__expense.getBill()
+        
+        for b in bill:
+            gu,du = b[0],b[1]
+            if (du.getDebts().get(gu,0)>gu.getDebts().get(du,0)):
+                du.getDebts()[gu] = du.getDebts().get(gu,0) - gu.getDebts().get(du,0)
+                gu.getDebts()[du] = 0
+                updateString = gu.getName() + " pays " + str(du.getDebts()[gu]) + "to " + du.getName()
+                self.__settledBill.append(updateString)
+            elif (du.getDebts().get(gu,0)<gu.getDebts().get(du,0)):
+                gu.getDebts()[du] = gu.getDebts().get(du,0) - du.getDebts().get(gu,0) 
+                du.getDebts()[gu] = 0
+                updateString = du.getName() + " pays " + str(gu.getDebts()[du]) + "to " + gu.getName()
+                self.__settledBill.append(updateString)
+            else:
+                gu.getDebts()[du] = gu.getDebts().get(du,0) - du.getDebts().get(gu,0) 
+                du.getDebts()[gu] = 0
+        
+    def getSettledBill(self):
+        return self.__settledBill
+                

S/splitwise/README.md

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+- To run the implementation:
+    ```
+    python3 SplitwiseDriver.py
+    ```
+    **Output**:
+    ```
+    u2 pays 620.0to u1
+    u3 pays 1130.0to u1
+    u1 pays 230.0to u4
+    ```
+    
+    **NOTE**: Customise around the default input values set in the SplitwiseDriver.py to test out different results.

S/splitwise/SplitwiseDriver.py

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+from ExpenseController import ExpenseController
+from UserController import UserController
+from User import User
+
+
+class SplitwiseDriver:
+
+    def printStatement(self, statements):
+        for s in statements:
+            print(s)
+
+    def main(self):
+        expenseList = list()
+        userList = list()
+
+        u1 = User("u1", 1)
+        userList.append(u1)
+        u2 = User("u2", 2)
+        userList.append(u2)
+        u3 = User("u3", 3)
+        userList.append(u3)
+        u4 = User("u4", 4)
+        userList.append(u4)
+        userManager = UserController(userList)
+
+        ex1 = ExpenseController(u1, 1000, 4, [u1, u2, u3, u4], "EQUAL", [])
+
+        # self.printStatement(userManager.getUserBill(u4))
+        # self.printStatement(userManager.getUserBill(u1))
+
+        ex2 = ExpenseController(u1, 1250, 2, [u2, u3], "EXACT", [370, 880])
+        # self.printStatement(ex2.getSettledBill())
+
+        ex3 = ExpenseController(u4, 1200, 4, [u1, u2, u3, u4], "PERCENT", [40, 20, 20, 20])
+        self.printStatement(userManager.getUserBill(u1))
+        # self.printStatement(ex3.getSettledBill())
+
+
+spl = SplitwiseDriver()
+spl.main()

S/splitwise/User.py

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+class User:
+    __name = None 
+    __dues = None 
+    __id = None
+
+    def __init__(self,name,id):
+        self.__id= id 
+        self.__name= name 
+        self.__dues= dict()
+
+    def getName(self):
+        return self.__name
+    
+    def getId(self):
+        return self.__id
+    
+    def getDebts(self):
+        return self.__dues
+    
+    

S/splitwise/UserController.py

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+class UserController:
+    __userList= None
+    __settledBill = None
+    def __init__(self,userList):
+        self.__settledBill= list()
+        self.__userList = userList
+        self.__settleBill()
+        
+    
+    def __settleBill(self):
+        for gu in self.__userList:
+            for du in self.__userList:
+                if (gu!=du):
+                    if (du.getDebts().get(gu,0)>gu.getDebts().get(du,0)):
+                        du.getDebts()[gu] = du.getDebts().get(gu,0) - gu.getDebts().get(du,0)
+                        gu.getDebts()[du] = 0
+                        updateString = gu.getName() + " pays " + str(du.getDebts()[gu]) + "to " + du.getName()
+                        self.__settledBill.append(updateString)
+                    elif (du.getDebts().get(gu,0)<gu.getDebts().get(du,0)):
+                        gu.getDebts()[du] = gu.getDebts().get(du,0) - du.getDebts().get(gu,0) 
+                        du.getDebts()[gu] = 0
+                        updateString = du.getName() + " pays " + str(gu.getDebts()[du]) + "to " + gu.getName()
+                        self.__settledBill.append(updateString)
+                    else:
+                        gu.getDebts()[du] = gu.getDebts().get(du,0) - du.getDebts().get(gu,0) 
+                        du.getDebts()[gu] = 0
+                
+    def getSettledBill(self):
+        return self.__settledBill
+    
+    def getUserBill(self,u):
+        self.getSettledBill()
+        userBill = list()
+        for gu in self.__userList:
+            if (gu!=u):
+                if (u.getDebts().get(gu,0)>gu.getDebts().get(u,0)):
+                    updateString = gu.getName() + " pays " + str(u.getDebts()[gu]) + "to " + u.getName()
+                    userBill.append(updateString)
+                elif (u.getDebts().get(gu,0)<gu.getDebts().get(u,0)):
+                    u.getDebts()[gu] = 0
+                    updateString = u.getName() + " pays " + str(gu.getDebts()[u]) + "to " + gu.getName()
+                    userBill.append(updateString)
+        if (len(userBill)==0):
+            userBill.append("No Bill ")
+        return userBill