import random
import optparse


def main():
    """ Reads through README.md for question/answer pairs and adds them to a list to randomly select from and quiz yourself. 
        - supports skipping quesitons with no documented answer with the -s flag
    """
    parser = optparse.OptionParser()
    parser.add_option("-s", "--skip", action="store_true",help="skips questions without an answer.", default=False)
    options, args = parser.parse_args()
    
    with open('README.md', 'r') as f:
        text = f.read()
        
    questions = []
    
    while True:
        question_start = text.find('<summary>') + 9
        question_end = text.find('</summary>')
        answer_end = text.find('</b></details>')
        
        if answer_end == -1:
            break
        
        question = text[question_start: question_end].replace('<br>', '').replace('<b>', '')
        answer = text[question_end + 17: answer_end]
        questions.append((question, answer))
        text = text[answer_end + 1:]
        
    num_questions = len(questions)
    
    while True:
        try:
            question, answer = questions[random.randint(0, num_questions)]
            
            if options.skip and not answer.strip():
                continue
            
            if input(f'Q: {question} ...Show answer? "y" for yes: ').lower() == 'y':
                print('A: ', answer)
        
        except KeyboardInterrupt:
            break
        
    print("\nGoodbye! See you next time.")
                

if __name__ == '__main__':
    main()