# Copyright (C) 2005-2011 Aaron Bentley <abentley@panoramicfeedback.com>
#                         Chris Ball <cjb@laptop.org>
#                         Gianluca Montecchi <gian@grys.it>
#                         W. Trevor King <wking@drexel.edu>
#
# This file is part of Bugs Everywhere.
#
# Bugs Everywhere is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, either version 2 of the License, or (at your
# option) any later version.
#
# Bugs Everywhere 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
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Bugs Everywhere.  If not, see <http://www.gnu.org/licenses/>.

"""Serializing and deserializing dictionaries of parameters.

The serialized "mapfiles" should be clear, flat-text strings, and allow
easy merging of independent/conflicting changes.
"""

import errno
import os.path
import types
import yaml

import libbe
if libbe.TESTING == True:
    import doctest


class IllegalKey(Exception):
    def __init__(self, key):
        Exception.__init__(self, 'Illegal key "%s"' % key)
        self.key = key

class IllegalValue(Exception):
    def __init__(self, value):
        Exception.__init__(self, 'Illegal value "%s"' % value)
        self.value = value

class InvalidMapfileContents(Exception):
    def __init__(self, contents):
        Exception.__init__(self, 'Invalid YAML contents')
        self.contents = contents

def generate(map):
    """Generate a YAML mapfile content string.

    Examples
    --------

    >>> generate({'q':'p'})
    'q: p\\n\\n'
    >>> generate({'q':u'Fran\u00e7ais'})
    'q: Fran\\xc3\\xa7ais\\n\\n'
    >>> generate({'q':u'hello'})
    'q: hello\\n\\n'
    >>> generate({'q=':'p'})
    Traceback (most recent call last):
    IllegalKey: Illegal key "q="
    >>> generate({'q:':'p'})
    Traceback (most recent call last):
    IllegalKey: Illegal key "q:"
    >>> generate({'q\\n':'p'})
    Traceback (most recent call last):
    IllegalKey: Illegal key "q\\n"
    >>> generate({'':'p'})
    Traceback (most recent call last):
    IllegalKey: Illegal key ""
    >>> generate({'>q':'p'})
    Traceback (most recent call last):
    IllegalKey: Illegal key ">q"
    >>> generate({'q':'p\\n'})
    Traceback (most recent call last):
    IllegalValue: Illegal value "p\\n"

    See Also
    --------
    parse : inverse
    """
    keys = map.keys()
    keys.sort()
    for key in keys:
        try:
            assert not key.startswith('>')
            assert('\n' not in key)
            assert('=' not in key)
            assert(':' not in key)
            assert(len(key) > 0)
        except AssertionError:
            raise IllegalKey(unicode(key).encode('unicode_escape'))
        if '\n' in map[key]:
            raise IllegalValue(unicode(map[key]).encode('unicode_escape'))

    lines = []
    for key in keys:
        lines.append(yaml.safe_dump({key: map[key]},
                                    default_flow_style=False,
                                    allow_unicode=True))
        lines.append('')
    return '\n'.join(lines)

def parse(contents):
    """Parse a YAML mapfile string.

    Examples
    --------

    >>> parse('q: p\\n\\n')['q']
    'p'
    >>> parse('q: \\'p\\'\\n\\n')['q']
    'p'
    >>> contents = generate({'a':'b', 'c':'d', 'e':'f'})
    >>> dict = parse(contents)
    >>> dict['a']
    'b'
    >>> dict['c']
    'd'
    >>> dict['e']
    'f'
    >>> contents = generate({'q':u'Fran\u00e7ais'})
    >>> dict = parse(contents)
    >>> dict['q']
    u'Fran\\xe7ais'
    >>> dict = parse('a!')
    Traceback (most recent call last):
      ...
    InvalidMapfileContents: Invalid YAML contents

    See Also
    --------
    generate : inverse

    """
    c = yaml.load(contents)
    if type(c) == types.StringType:
        raise InvalidMapfileContents(
            'Unable to parse YAML (BE format missmatch?):\n\n%s' % contents)
    return c or {}

if libbe.TESTING == True:
    suite = doctest.DocTestSuite()