moth/puzzles.py

#!/usr/bin/python3

import argparse
from collections import defaultdict, namedtuple
import glob
import hashlib
from importlib.machinery import SourceFileLoader
import mistune
import os
import random
import tempfile

messageChars = b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'

def djb2hash(buf):
    h = 5381
    for c in buf:
        h = ((h * 33) + c) & 0xffffffff
    return h

# We use a named tuple rather than a full class, because any random name generation has
# to be done with Puzzle's random number generator, and it's cleaner to not pass that around.
PuzzleFile = namedtuple('PuzzleFile', ['path', 'handle', 'name', 'visible'])
PuzzleFile.__doc__ = """A file associated with a puzzle.
    path: The path to the original input file. May be None (when this is created from a file handle
          and there is no original input.
    handle: A File-like object set to read the file from. You should be able to read straight
            from it without having to seek to the beginning of the file.
    name: The name of the output file.
    visible: A boolean indicating whether this file should visible to the user. If False,
             the file is still expected to be accessible, but it's path must be known
             (or figured out) to retrieve it."""


class Puzzle:

    KNOWN_KEYS = [
        'answer',
        'author',
        'file',
        'hidden',
        'name'
        'resource',
        'summary'
    ]
    REQUIRED_KEYS = [
        'author',
        'answer',
    ]
    SINGULAR_KEYS = [
        'name'
    ]

    # Get a big list of clean words for our answer file.
    ANSWER_WORDS = [w.strip() for w in open(os.path.join(os.path.dirname(__file__),
                                                         'answer_words.txt'))]

    def __init__(self, category_seed, path=None, points=None):
        """A MOTH Puzzle.
        :param category_seed: A byte string to use as a seed for random numbers for this puzzle.
                              It is combined with the puzzle points.
        :param path: An optional path to a puzzle directory. The point value for the puzzle is taken
                     from the puzzle directories name (it must be an integer greater than zero).
                     Within this directory, we expect:
            (optional) A puzzle.moth file in RFC2822 format. The puzzle will get its attributes
                       from the headers, and the body will be the puzzle description in
                       Markdown format.
            (optional) A puzzle.py file. This is expected to have a callable called make
                       that takes a single positional argument (this puzzle object).
                       This callable can then do whatever it needs to with this object.
        :param points: The point value of the puzzle. Mutually exclusive with path.
            If neither of the above are given, the point value for the puzzle will have to
            be set at instantiation.

        For puzzle attributes, this class acts like a dictionary that in most cases assigns
        always returns a list. Certain keys, however behave differently:
          - Keys in Puzzle.SINGULAR_KEYS can only have one value, and writing to these overwrites
            that value.
          - The keys 'hidden', 'file', and 'resource' all create a new PuzzleFile object that
            gets added under the 'files' key.
          - The 'answer' also adds a new hash under the the 'hash' key.
        """

        super().__init__()

        if (points is None and path is None) or (points is not None and path is not None):
            raise ValueError("Either points or path must be set, but not both.")

        self._dict = defaultdict(lambda: [])
        if os.path.isdir(path):
            self._puzzle_dir = path
        else:
            self._puzzle_dir = None
        self.message = bytes(random.choice(messageChars) for i in range(20))
        self.body = ''

        # A list of temporary files we've created that will need to be deleted.
        self._temp_files = []
        if path is not None:
            if not os.path.isdir(path):
                raise ValueError("No such directory: {}".format(path))

            pathname = os.path.split(path)[-1]
            try:
                self.points = int(pathname)
            except ValueError:
                raise ValueError("Directory name must be a point value: {}".format(path))
        elif points is not None:
            self.points = points

        self._seed = category_seed * self.points
        self.rand = random.Random(self._seed)

        if path is not None:
            files = os.listdir(path)

            if 'puzzle.moth' in files:
                self._read_config(open(os.path.join(path, 'puzzle.moth')))

            if 'puzzle.py' in files:
                # Good Lord this is dangerous as fuck.
                loader = SourceFileLoader('puzzle_mod', os.path.join(path, 'puzzle.py'))
                puzzle_mod = loader.load_module()
                if hasattr(puzzle_mod, 'make'):
                    self.body = '# `puzzle.body` was not set by the `make` function'
                    puzzle_mod.make(self)
                else:
                    self.body = '# `puzzle.py` does not define a `make` function'

    def cleanup(self):
        """Cleanup any outstanding temporary files."""
        for path in self._temp_files:
            if os.path.exists(path):
                try:
                    os.unlink(path)
                except OSError:
                    pass

    def _read_config(self, stream):
        """Read a configuration file (ISO 2822)"""
        body = []
        header = True
        for line in stream:
            if header:
                line = line.strip()
                if not line.strip():
                    header = False
                    continue
                key, val = line.split(':', 1)
                val = val.strip()
                self[key] = val
            else:
                body.append(line)
        self.body = ''.join(body)

    def random_hash(self):
        """Create a random hash from our number generator suitable for use as a filename."""
        return hashlib.sha1(str(self.rand.random()).encode('ascii')).digest()

    def _puzzle_file(self, path, name, visible=True):
        """Make a puzzle file instance for the given file. To add files as you would in the config
        file (to 'file', 'hidden', or 'resource', simply assign to that keyword in the object:
          puzzle['file'] = 'some_file.txt'
          puzzle['hidden'] = 'some_hidden_file.txt'
          puzzle['resource'] = 'some_file_in_the_category_resource_directory_omg_long_name.txt'
        :param path: The path to the file
        :param name: The name of the file. If set to None, the published file will have
                     a random hash as a name and have visible set to False.
        :return:
        """

        # Make sure it actually exists.
        if not os.path.exists(path):
            raise ValueError("Included file {} does not exist.")

        file = open(path, 'rb')

        return PuzzleFile(path=path, handle=file, name=name, visible=visible)

    def make_temp_file(self, name=None, mode='rw+b', visible=True):
        """Get a file object for adding dynamically generated data to the puzzle. When you're
        done with this file, flush it, but don't close it.
        :param name: The name of the file for links within the puzzle. If this is None, a name
                     will be generated for you.
        :param mode: The mode under which
        :param visible: Whether or not the file will be visible to the user.
        :return: A file object for writing
        """

        if name is None:
            name = self.random_hash()

        file = tempfile.NamedTemporaryFile(mode=mode, delete=False)
        file_read = open(file.name, 'rb')

        self._dict['files'][name] = PuzzleFile(path=file.name, handle=file_read,
                                               name=name, visible=visible)

        return file

    def make_handle_file(self, handle, name, visible=True):
        """Add a file to the puzzle from a file handle.
        :param handle: A file object or equivalent.
        :param name: The name of the file in the final puzzle.
        :param visible: Whether or not it's visible.
        :return: None
        """

    def __setitem__(self, key, value):
        """Set a value for this puzzle, as if it were set in the config file. Most values default
        being added to a list. Files (regardless of type) go in a dict under ['files']. Keys
        in Puzzle.SINGULAR_KEYS are single values that get overwritten with subsequent assignments.
        Only keys in Puzzle.KNOWN_KEYS are accepted.
        :param key:
        :param value:
        :return:
        """

        key = key.lower()

        if key in ('file', 'resource', 'hidden') and self._puzzle_dir is None:
            raise KeyError("Cannot set a puzzle file for single file puzzles.")

        if key == 'answer':
            # Handle adding answers to the puzzle
            self._dict['hash'].append(djb2hash(value.encode('utf8')))
            self._dict['answer'].append(value)
        elif key == 'file':
            # Handle adding files to the puzzle
            path = os.path.join(self._puzzle_dir, 'files', value)
            self._dict['files'][value] = self._puzzle_file(path, value)
        elif key == 'resource':
            # Handle adding category files to the puzzle
            path = os.path.join(self._puzzle_dir, '../res', value)
            self._dict['files'].append(self._puzzle_file(path, value))
        elif key == 'hidden':
            # Handle adding secret, 'hidden' files to the puzzle.
            path = os.path.join(self._puzzle_dir, 'files', value)
            name = self.random_hash()
            self._dict['files'].append(self._puzzle_file(path, name, visible=False))
        elif key in self.SINGULAR_KEYS:
            # These keys can only have one value
            self._dict[key] = value
        elif key in self.KNOWN_KEYS:
            self._dict[key].append(value)
        else:
            raise KeyError("Invalid Attribute: {}".format(key))

    def __getitem__(self, item):
        return self._dict[item.lower()]

    def make_answer(self, word_count, sep=' '):
        """Generate and return a new answer. It's automatically added to the puzzle answer list.
        :param int word_count: The number of words to include in the answer.
        :param str|bytes sep: The word separator.
        :returns: The answer string
        """

        answer = sep.join(self.rand.sample(self.ANSWER_WORDS, word_count))
        self['answer'] = answer

        return answer

    def htmlify(self):
        """Format and return the markdown for the puzzle body."""
        return mistune.markdown(self.body)

    def publish(self):
        obj = {
            'author': self['author'],
            'hashes': self['hashes'],
            'body': self.htmlify(),
        }
        return obj

    def secrets(self):
        obj = {
            'answers': self['answers'],
            'summary': self['summary'],
        }
        return obj

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Build a puzzle category')
    parser.add_argument('puzzledir', nargs='+', help='Directory of puzzle source')
    args = parser.parse_args()

    for puzzledir in args.puzzledir:
        puzzles = {}
        secrets = {}
        for puzzlePath in glob.glob(os.path.join(puzzledir, "*.moth")):
            filename = os.path.basename(puzzlePath)
            points, ext = os.path.splitext(filename)
            points = int(points)
            puzzle = Puzzle(puzzlePath, "test")
            puzzles[points] = puzzle

        for points in sorted(puzzles):
            puzzle = puzzles[points]
            print(puzzle.secrets())


class Category:
    def __init__(self, path, seed):
        self.path = path
        self.seed = seed
        self.pointvals = []
        for fpath in glob.glob(os.path.join(path, "[0-9]*")):
            pn = os.path.basename(fpath)
            points = int(pn)
            self.pointvals.append(points)
        self.pointvals.sort()

    def puzzle(self, points):
        path = os.path.join(self.path, str(points))
        return Puzzle(path, self.seed)

    def puzzles(self):
        for points in self.pointvals:
            yield self.puzzle(points)