#!/usr/bin/env python
"""
Commandline tool for doing operations on Problems
"""
from __future__ import unicode_literals

import argparse
import logging
import sys
from path import path

from cStringIO import StringIO
from collections import defaultdict

from calc import UndefinedVariable
from capa_problem import LoncapaProblem
from mako.lookup import TemplateLookup

logging.basicConfig(format="%(levelname)s %(message)s")
log = logging.getLogger('capa.checker')


class DemoSystem(object):
    def __init__(self):
        self.lookup = TemplateLookup(directories=[path(__file__).dirname() / 'templates'])
        self.DEBUG = True

    def render_template(self, template_filename, dictionary, context=None):
        if context is None:
            context = {}

        context_dict = {}
        context_dict.update(dictionary)
        context_dict.update(context)
        return self.lookup.get_template(template_filename).render(**context_dict)

def main():
    parser = argparse.ArgumentParser(description='Check Problem Files')
    parser.add_argument("command", choices=['test', 'show']) # Watch? Render? Open?
    parser.add_argument("files", nargs="+", type=argparse.FileType('r'))
    parser.add_argument("--seed", required=False, type=int)
    parser.add_argument("--log-level", required=False, default="INFO",
                        choices=['info', 'debug', 'warn', 'error',
                                 'INFO', 'DEBUG', 'WARN', 'ERROR'])

    args = parser.parse_args()
    log.setLevel(args.log_level.upper())

    system = DemoSystem()

    for problem_file in args.files:
        log.info("Opening {0}".format(problem_file.name))

        try:
            problem = LoncapaProblem(problem_file, "fakeid", seed=args.seed, system=system)
        except Exception as ex:
            log.error("Could not parse file {0}".format(problem_file.name))
            log.exception(ex)
            continue

        if args.command == 'test':
            command_test(problem)
        elif args.command == 'show':
            command_show(problem)

        problem_file.close()

    # In case we want to do anything else here.

def command_show(problem):
    """Display the text for this problem"""
    print problem.get_html()
    

def command_test(problem):
    # We're going to trap stdout/stderr from the problems (yes, some print)    
    old_stdout, old_stderr = sys.stdout, sys.stderr
    try:
        sys.stdout = StringIO()
        sys.stderr = StringIO()

        check_that_suggested_answers_work(problem)
        check_that_blanks_fail(problem)

        log_captured_output(sys.stdout, 
                            "captured stdout from {0}".format(problem))
        log_captured_output(sys.stderr,
                            "captured stderr from {0}".format(problem))
    except Exception as e:
        log.exception(e)
    finally:
        sys.stdout, sys.stderr = old_stdout, old_stderr

def check_that_blanks_fail(problem):
    """Leaving it blank should never work. Neither should a space."""
    blank_answers = dict((answer_id, u"") 
                         for answer_id in problem.get_question_answers())
    grading_results = problem.grade_answers(blank_answers)
    try:
        assert(all(result == 'incorrect' for result in grading_results.values()))
    except AssertionError:
        log.error("Blank accepted as correct answer in {0} for {1}"
                  .format(problem,
                          [answer_id for answer_id, result
                           in sorted(grading_results.items())
                           if result != 'incorrect']))


def check_that_suggested_answers_work(problem):
    """Split this up so that we're only used for formula/numeric answers.

    Examples of where this fails:
    * Displayed answers use units but acceptable ones do not.
      - L1e0.xml
      - Presents itself as UndefinedVariable (when it tries to pass to calc)
    * "a or d" is what's displayed, but only "a" or "d" is accepted, not the 
      string "a or d".
      - L1-e00.xml
    """
    # These are actual answers we get from the responsetypes
    real_answers = problem.get_question_answers()

    # all_answers is real_answers + blanks for other answer_ids for which the
    # responsetypes can't provide us pre-canned answers (customresponse)
    all_answer_ids = problem.get_answer_ids()
    all_answers = dict((answer_id, real_answers.get(answer_id, ""))
                       for answer_id in all_answer_ids)

    log.debug("Real answers: {0}".format(real_answers))
    if real_answers:
        try:
            real_results = dict((answer_id, result) for answer_id, result 
                                in problem.grade_answers(all_answers).items()
                                if answer_id in real_answers)
            log.debug(real_results)
            assert(all(result == 'correct'
                       for answer_id, result in real_results.items()))
        except UndefinedVariable as uv_exc:
            log.error("The variable \"{0}\" specified in the ".format(uv_exc) + 
                      "solution isn't recognized (is it a units measure?).")
        except AssertionError:
            log.error("The following generated answers were not accepted for {0}:"
                      .format(problem))
            for question_id, result in sorted(real_results.items()):
                if result != 'correct':
                    log.error("  {0} = {1}".format(question_id, real_answers[question_id]))
        except Exception as ex:
            log.error("Uncaught error in {0}".format(problem))
            log.exception(ex)

def log_captured_output(output_stream, stream_name):
    output_stream.seek(0)
    output_text = output_stream.read()
    if output_text:
        log.info("##### Begin {0} #####\n".format(stream_name) + output_text)
        log.info("##### End {0} #####".format(stream_name))


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