import random
from math import gcd, lcm
import xml.etree.ElementTree as ET
from collections import Counter

# Konstanten
# Anzahl der zu generierenden Fragen.
NUM_QUESTIONS = 1
# Algebraische Struktur der Aufgaben
STRUCTURE = "-(+)"

# TODO
# Platzhalter hinzufügen

# Anzahl der benötigten Brüche
NUM_FRACTIONS = 1 + STRUCTURE.count("+") + STRUCTURE.count("+") + STRUCTURE.count("*") + STRUCTURE.count("/")
# Größter Zähler
MAX_NUMERATOR = 20
# Größter Nenner
MAX_DENOMINATOR = 20
# Größter erlaubter gemeinsamer Nenner
MAX_COMMON_DENOMINATOR = 100
# Dateiname für Ausgabe
FILENAME = 'formulas_new_quiz.xml'





def create_formula_question(n):
    numerators = []
    denominators = []
    for i in range(NUM_FRACTIONS):
        n = random.randint(1, MAX_NUMERATOR)
        d = random.randint(2, MAX_DENOMINATOR)
        numerators.append(n)
        denominators.append(d)

    # Sicherstellen, dass die Nenner unterschiedlich sind
    same_denominators = [k for k,v in Counter(denominators).items() if v>1]
    while len(same_denominators) > 1:
        new_denom = random.randint(2, MAX_DENOMINATOR)
        denominators.replace(same_denominators[0], new_denom)
        same_denominators = [k for k,v in Counter(denominators).items() if v>1]
    # [DEBUG]
    print(numerators)
    print(denominators)
    # [DEBUG]
    *denoms_integers, = denominators
    common_denominator = lcm(*denoms_integers)

    fractions = []
    for i in range(NUM_FRACTIONS):
        fraction = {"n": numerators[i], "d": denominators[i]}
        fractions.append(fraction)
    # [DEBUG]
    print(fractions)
    # [DEBUG]

    cd = common_denominator
    expanded_numerators = [frac["n"] * cd // frac["d"] for frac in fractions]

    expanded_fractions = []
    for i in range(NUM_FRACTIONS):
        fraction = {"n": expanded_numerators[i], "d": cd}
        expanded_fractions.append(fraction)
    # [DEBUG]
    print(expanded_fractions)
    # [DEBUG]

    eval_string = f"{expanded_numerators[0]}"
    cnt_next_fraction = 1
    for c in STRUCTURE:
        if c == "(" or c ==")":
            eval_string += c
        elif c == "+" or c == "-" or c == "*" or c == "/":
            eval_string += c
            eval_string += f"{expanded_numerators[cnt_next_fraction]}"
            cnt_next_fraction += 1

    # [DEBUG]
    print(eval_string)
    # [DEBUG]
    result_numerator = eval(eval_string)

    question = ET.Element('question', attrib={'type': 'formulas'})

    return question


def generate_questions(num_questions):
    """
    Generiert eine Liste von Aufgaben.

    Args:
        num_questions (int): Die Anzahl der zu generierenden Fragen.

    Returns:
        list: Eine Liste von Frage-Elementen.
    """
    questions = []
    for i in range(num_questions):
        # Hier können Sie die Funktionsdefinition für die Erzeugung einer Aufgabe hinzufügen
        questions.append(create_formula_question(i))

    return questions

def create_quiz(questions):
    """
    Erstellt das gesamte Quiz-Element.

    Args:
        questions (list): Eine Liste von Frage-Elementen.

    Returns:
        Element: Das gesamte Quiz -Element.
    """
    quiz = ET.Element('quiz')
    for q in questions:
        quiz.append(q)
    return quiz

def save_to_file(xml_element, filename):
    """
    Speichert das XML-Dokument in eine Datei.

    Args:
        xml_element (Element): Das XML-Element, zu speichern.
        filename (str): Der Name der Zieldatei.

    Returns:
        None
    """
    tree = ET.ElementTree(xml_element)
    with open(filename, 'wb') as f:
        tree.write(f, encoding='utf_8', xml_declaration=True)

    return

def replace_vars2(xml_file):
    # XML-Datei lesen
    with open(xml_file, 'r') as f:
        text = f.read()

    text = text.replace("&","&")
    text = text.replace("&lt;","<")
    text = text.replace("&gt;",">")

    with open(xml_file, 'w') as f:
        f.write(text)


# Hauptprogramm
if __name__ == "__main__":

    questions = generate_questions(NUM_QUESTIONS)
    quiz = create_quiz(questions)

    save_to_file(quiz, FILENAME)
    replace_vars2(FILENAME)

    print("Moodle-XMLDatei erfolgreich erstellt.")