import random
import sys
import datetime


class StudentManagementSystem:
    def __init__(self):
        self.students = []
        self.courses = []
        self.passed_courses = []

    def add_student(self):
        first_name = input("Enter the first name of the student: ")
        last_name = input("Enter the last name of the student: ")
        major = input("Select student's major (CE, EE, ET, ME, SE): ")

        if not self.is_valid_name(first_name) or not self.is_valid_name(last_name):
            print("Names should contain only letters and start with capital letters.")
            return

        current_year = datetime.datetime.now().year
        student_id = random.randint(10000, 99999)

        email = f"{first_name.lower()}.{last_name.lower()}@lut.fi"
        student_data = (student_id, first_name, last_name, current_year, major, email)
        self.students.append(student_data)

        with open("students.txt", "a") as f:
            f.write(','.join(map(str, student_data)) + 'n')

        print("Student added successfully!")

    def search_items(self, file_path, search_term, item_type):
        if len(search_term) < 3:
            print("Search term should contain at least 3 characters.")
            return

        with open(file_path, "r") as f:
            items = f.readlines()

        matching_items = [item for item in items if search_term in item]
        if matching_items:
            print(f"Matching {item_type}s:")
            for item in matching_items:
                item_info = item.strip().split(",")
                print(f"ID: {item_info[0]}, {item_type.capitalize()}: {item_info[1]}")
        else:
            print(f"No matching {item_type}s found.")

    def search_student(self):
        search_term = input("Give at least 3 characters of the student's first or last name: ")
        self.search_items("students.txt", search_term, "student")

    def search_course(self):
        search_term = input("Give at least 3 characters of the course name or teacher's name: ")
        self.search_items("courses.txt", search_term, "course")

    def is_valid_name(self, name):
        return name.isalpha() and name.istitle()

    def add_course_completion(self):
        course_id = input("Give the course ID: ")
        student_id = input("Give the student ID: ")

        grade = input("Give the grade (1-5): ")
        if not grade.isdigit() or not (1 <= int(grade) <= 5):
            print("Grade is not a correct grade.")
            return

        date_str = input("Enter a date (DD/MM/YYYY): ")
        try:
            date = datetime.datetime.strptime(date_str, "%d/%m/%Y")
            today = datetime.datetime.now()

            if date > today:
                print("Input date is later than today. Try again!")
                return

            if (today - date).days > 30:
                print("Input date is older than 30 days. Contact 'opinto'.")
                return
        except ValueError:
            print("Invalid date format. Use DD/MM/YYYY. Try again!")
            return

        with open("passed.txt", "r") as f:
            passed_courses = f.readlines()

        for i, line in enumerate(passed_courses):
            if line.startswith(course_id + "," + student_id):
                old_grade = int(line.strip().split(",")[-1])
                if int(grade) <= old_grade:
                    print(f"Student has passed this course earlier with grade {old_grade}")
                    return
                passed_courses[i] = f"{course_id},{student_id},{date_str},{grade}n"
                with open("passed.txt", "w") as f:
                    f.writelines(passed_courses)
                print("Record updated!")
                return

        with open("passed.txt", "a") as f:
            f.write(f"{course_id},{student_id},{date_str},{grade}n")
        print("Record added!")

    def show_student_record(self):
        student_id = input("Enter the student ID: ")

        with open("students.txt", "r") as f:
            students = f.readlines()

        student_info = [s.strip().split(",") for s in students if student_id in s][0]

        with open("passed.txt", "r") as f:
            passed_courses = f.readlines()

        with open("courses.txt", "r") as f:
            courses_info = f.readlines()

        student_courses = []
        total_credits = 0
        total_grade = 0

        for line in passed_courses:
            if line.startswith(student_id):
                course_id, date_str, grade = line.strip().split(",")[:3]
                total_grade += int(grade)
                date = datetime.datetime.strptime(date_str, "%d/%m/%Y")
                course_info = [c.strip().split(",") for c in courses_info if course_id in c][0]
                course_name, credits, teachers = course_info[1], course_info[2], course_info[3]
                student_courses.append((course_id, course_name, credits, date_str, teachers, grade))
                total_credits += int(credits)

        if student_info:
            print("Student ID:", student_id)
            print("Name:", student_info[1], student_info[2])
            print("Starting year:", student_info[3])
            print("Major:", student_info[4])
            print("Email:", student_info[5])

            if student_courses:
                print("Passed courses:")
                for course in student_courses:
                    course_id, course_name, credits, date_str, teachers, grade = course
                    print(f"Course ID: {course_id}, Name: {course_name}, Credits: {credits}, Date: {date_str}, Teacher(s): {teachers}, Grade: {grade}")

                average_grade = total_grade / len(student_courses)
                print(f"Total credits: {total_credits}, Average grade: {average_grade:.1f}")
            else:
                print("No passed courses.")
        else:
            print("Student not found.")

    def main_menu(self):
            print("You may select one of the following:n1) Add studentn2) Search studentn3) Search coursen4) Add course completionn5) Show student's recordn0) Exit")
            choice = input("What is your selection? ")

            if choice == "1":
                self.add_student()
            elif choice == "2":
                self.search_student()
            elif choice == "3":
                self.search_course()
            elif choice == "4":
                self.add_course_completion()
            elif choice == "5":
                self.show_student_record()
            elif choice == "0":
                print("Exiting the program.")
                sys.exit()
            else:
                print("Invalid input. Please select a valid option.")


if __name__ == "__main__":
    system = StudentManagementSystem&#40;&#41;
    while 1:
        system.main_menu()