import string
import cmarkgfm
import argparse
import sqlite3
import sys
import os

parser = argparse.ArgumentParser(
    prog='CLRS practice exam generator',
    description='Generates practice exams from your clrs.db')

parser.add_argument('--db', default="clrs.db", dest='db_path', help='Path of the database to query')
parser.add_argument('--output', dest='output_path', help='Path (including file name) of the resulting HTML document', default="exam.html")
parser.add_argument('--template', dest='template_path', help='Path (including file name) of the HTML template', default="./template.html")
parser.add_argument('query', help='SQLite query string to select the desired problems')

class ModifiedTemplate(string.Template):
    delimiter = '%$%'

markdownOptions = (
    cmarkgfm.cmark.Options.CMARK_OPT_UNSAFE |
    cmarkgfm.cmark.Options.CMARK_OPT_GITHUB_PRE_LANG
)

def main(args):
    con = sqlite3.connect(args.db_path)
    con.row_factory = sqlite3.Row
    cur = con.cursor()

    practice_exam = ""
    template_string = "%$%content"

    if args.template_path is not None:
        with open(args.template_path, "r") as template_file:
            template_string = template_file.read()

    template = ModifiedTemplate(template_string)

    cur.execute(args.query)
    problems = cur.fetchall()

    for problem in problems:
        chapter = problem["chapter"]
        section = problem["section"]
        problem_number = problem["problem_number"]
        question = problem["question"]
        answer = problem["answer"]
        starred = problem["starred"]

        practice_exam = practice_exam + f"""
## {chapter}.{section}-{problem_number} {"*" if starred else ""}

{question}

<details>
    <summary>Solution</summary>
    {cmarkgfm.markdown_to_html(answer, markdownOptions)}
</details>
        """

    with open(args.output_path, "w") as output_file:
        output_file.write(template.substitute(content=cmarkgfm.markdown_to_html(practice_exam, markdownOptions)))

    return 0

if __name__ == '__main__':
    args = parser.parse_args()
    sys.exit(main(args))