#! /usr/bin/env python

import sys
import pypandoc
from mako.template import Template


class Struct(object):
    def __init__(self, entries):
        for name, val in entries.iteritems():
            self.__dict__[name] = dict_to_struct(val)

    def __repr__(self):
        return repr(self.__dict__)


def dict_to_struct(data):
    if isinstance(data, list):
        return [dict_to_struct(d) for d in data]
    elif isinstance(data, dict):
        return Struct(data)
    else:
        return data


QUESTIONS_ONLY_TEMPLATE = Template(r"""
% for i, q in enumerate(questions):
    ${q}
% endfor
""", strict_undefined=True)


TEMPLATE = Template(r"""
\documentclass[11pt]{article}

\usepackage{akteach}
\usepackage{examtron}
\pagestyle{empty}

\usepackage{titlesec}
\titleformat{\section}
  {\normalfont\sffamily\large\bfseries}
  {Problem \thesection. }{0em}{}

\begin{document}

\akteachheader{Numerical Methods (CS 357)}%
{Worksheet}

% for i, q in enumerate(questions):
    ${q}
% endfor
\end{document}
""", strict_undefined=True)


def convert_page(page):
    if page.type in ["TextQuestion", "FileUploadQuestion"]:
        prompt = pypandoc.convert(
            page.prompt, 'latex',
            format='markdown') + "\n\\vspace*{2cm}"
        return (prompt)
    elif page.type == "ChoiceQuestion":
        prompt = pypandoc.convert(
            page.prompt, 'latex',
            format='markdown')

        choices = [
            "\item "
            +
            pypandoc.convert(
                ch.replace("~CORRECT~", r"\correct "), 'latex',
                format='markdown')
            for ch in page.choices]

        return (
            "{}\n"
            r"\begin{{examtronchoices}}"
            "\n"
            "{}\n"
            r"\end{{examtronchoices}}"
            "\n"
            .format(
                prompt,
                "\n".join(choices))
            )


def main():
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument("-1", "--one", action="store_true")
    parser.add_argument("-q", "--questions-only", action="store_true")
    parser.add_argument("input", default="-", nargs="?")
    parser.add_argument("output", default="-", nargs="?")

    args = parser.parse_args()

    from yaml import load
    if args.input == "-":
        data = sys.stdin.read()
    else:
        with open(args.input, "r") as inf:
            data = inf.read()

    data = dict_to_struct(load(data))

    questions = []

    if not args.one:
        flow_desc = data
        for grp in flow_desc.groups:
            for page in grp.pages:
                print page.id
                questions.append(convert_page(page))
        template = TEMPLATE
        if args.questions_only:
            template = QUESTIONS_ONLY_TEMPLATE

        data = template.render(questions=questions)
    else:
        data = convert_page(data)

    if args.output == "-":
        sys.stdout.write(data)
    else:
        with open(args.output, "w") as outf:
            outf.write(data)


if __name__ == "__main__":
    main()