"""
THIS CODE HAS BEEN TESTED AND IS FULLY OPERATIONAL.

Problem Statement: To create ADT that implement the "set" concept.
a. Add (newElement) -> Place a value into the set
b. Remove (element) -> Remove the value
c. Contains (element) -> Return true if element is in collection
d. Size () -> Return number of values in collection
Iterator () -> Return an iterator used to loop over collection
e. Intersection of two sets
f. Union of two sets
g. Difference between two sets
h. Subset 

Code from DataStructuresAndAlgorithms (SPPU - Second Year - Computer Engineering - Content) repository on KSKA Git: https://git.kska.io/sppu-se-comp-content/DataStructuresAndAlgorithms/
"""

# BEGINNING OF CODE
class sets:
    """Implementation using list"""
    def __init__(self) -> None:
            self.data = []

    def get_iter(self) -> iter:
        return iter(self.data)

    def add(self, elmt: any) -> None:
        if (elmt not in self.data):
            self.data.append(elmt)

    def remove(self, elmt: any) -> bool:
        if (elmt in self.data):
            self.data.remove(elmt)
            return True
        else:
            return False

    def contains(self, elmt: any) -> bool:
        return (elmt in self.data)

    def size(self) -> int:
        l = 0
        iter1 = self.get_iter()
        for elmt in iter1:
            l += 1
        return l

    def intersection(self, input_set: any) -> list:
        ans = []
        set1 = list(input_set)
        for elmt in set1:
            if (elmt in self.data):
                ans.append(elmt)
        return ans

    def union(self, input_set: any) -> list:
        ans = self.data.copy()
        set1 = list(input_set)
        for elmt in set1:
            if (elmt not in self.data):
                ans.append(elmt)
        return ans

    def difference(self, input_set: any) -> list:
        ans = self.data.copy()
        set1 = list(input_set)
        for elmt in set1:
            if elmt in ans:
                ans.remove(elmt)
        return ans

    def subset(self, input_set: any) -> bool:
        for e in input_set:
            if e not in self.data:
                return False
        return True

    def display(self) -> None:
        str_set = str(self.data)
        print(str_set.replace('[', '{').replace(']', '}'))


def input_set() -> set:
    ans = set()
    n = int(input("Total elements in set are:\t"))
    for i in range(n):
        ans.add(int(input(f"Enter element {i+1}:\t")))
    return ans


def print_set(lst: list) -> None:
    str_set = str(lst)
    print(str_set.replace('[', '{').replace(']', '}'))


def menu():
    print("----- MAIN MENU -----")
    print("0 -> Display main menu")
    print("1 -> Add new element")
    print("2 -> Remove an element")
    print("3 -> Search for an element")
    print("4 -> Display size of set")
    print("5 -> Intersection of sets")
    print("6 -> Union of sets")
    print("7 -> Difference of sets")
    print("8 -> Check if subset of a set")
    print("9 -> Display set")
    print("10 -> Exit")


def main() -> None:
    s1 = sets()
    choice = 1
    menu()
    while (choice != 10):
        choice = int(input("Choose an option (0-10):\t"))
        match (choice):
            case (1):
                n = int(input("Number to add:\t"))
                s1.add(n)
                print("Element added sucessfully.")
            case (2):
                n = int(input("Number to remove:\t"))
                if (s1.remove(n)):
                    print("Element removed sucessfully.")
                else:
                    print("Element not present in set.")
            case (3):
                n = int(input("Number to search:\t"))
                if (s1.contains(n)):
                    print("Element is present in the set.")
                else:
                    print("Element does not exist in the set.")
            case (4):
                print("Size of the set is: ", s1.size())
            case (5):
                s = input_set()
                print("Intersection of sets is: ", end="")
                print_set(s1.intersection(s))
            case (6):
                s = input_set()
                print("Union of sets is: ", end="")
                print_set(s1.union(s))
            case (7):
                s = input_set()
                print("Difference of sets is: ", end="")
                print_set(s1.difference(s))
            case (8):
                s = input_set()
                if (s1.subset(s)):
                    print("Set is s subset.")
                else:
                    print("Set is NOT a subset.")
            case (9):
                s1.display()
            case (10):
                print("\n## END OF CODE\n")
            case (0):
                menu()
            case default:
                print("Please choose a valid option (0-10)")

if __name__ == "__main__":
    main()
# END OF CODE