# CodeQ: an online programming tutor.
# Copyright (C) 2015 UL FRI
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

import threading

from db.models import Problem
import server
import server.user_session

__all__ = ['RobotSession']

class RobotSession(server.LanguageSession):
    """Abstracts a Robot session.
    Only public methods are available to the outside world due to the use of multiprocessing managers.
    Therefore prefix any private methods with an underscore (_).
    No properties are accessible; use getters and setters instead.
    Values are passed by value instead of by reference (deep copy!).
    """
    def __init__(self, output_cb=None):
        self._access_lock = threading.Lock()
        self._sent_hints = []

    def destroy(self):
        pass

    def __del__(self):
        pass

    def hint(self, sid, problem_id, program):
        session = server.user_session.get_session_by_id(sid)
        p = Problem.get(id=problem_id)

        language_module = server.problems.load_language(p.language, 'common')
        problem_module = server.problems.load_problem(p.language, p.group, p.identifier, 'common')

        # experiment support for allowing none/automatic/manual/all hints
        # descriptor: {'id': 'hints', 'group': 'none|automatic|manual|all'}
        allowed_hints = 'all'
        for experiment in session.get_experiments():
            if experiment.get('id') == 'hints':
                allowed_hints = experiment.get('group')
                break

        hints = []
        # manually defined problem-specific hints
        if not hints and hasattr(problem_module, 'hint') and \
                allowed_hints in ('all', 'manual'):
            hints = problem_module.hint(program)

        # generic language hints (style etc.)
        if not hints and hasattr(language_module, 'hint'):
            hints = language_module.hint(program)

        if not hints:
            hints = [{'id': 'no_hint'}]

        self._instantiate_and_save_hints(language_module, problem_module, hints)
        return hints

    def test(self, sid, problem_id, program):
        p = Problem.get(id=problem_id)
        language_module = server.problems.load_language(p.language, 'common')
        problem_module = server.problems.load_problem(p.language, p.group, p.identifier, 'common')

        try:
            passed, hints = problem_module.test(program)
            if passed:
                session = server.user_session.get_session_by_id(sid)
                session.update_solution(problem_id, solution=program, done=True)
        except AttributeError as ex:
            hints = [{'id': 'system_error', 'args': {'message': 'test function does not exist'}}]

        self._instantiate_and_save_hints(language_module, problem_module, hints)
        return hints

    # Add hint parameters (such as message index) based on hint class. Append
    # the finalized hints to the list of sent hints.
    def _instantiate_and_save_hints(self, language_mod, problem_mod, hints):
        with self._access_lock:
            for hint in hints:
                for mod in [language_mod, problem_mod]:
                    if hasattr(mod, 'hint_type') and hint['id'] in mod.hint_type:
                        hint_type = mod.hint_type[hint['id']]
                        hint_type.instantiate(hint, self._sent_hints)
            self._sent_hints.extend(hints)

server.language_session_handlers['robot'] = lambda user_session, problem_id, language_identifier, group_identifier, problem_identifier: RobotSession()