"""
Gchecky provides an abstraction layer between google checkout API and user code.

It wraps-up the clumsy Level 2 integration API into a human-friendly form.

All the interaction between Checkout API and user code is handled by
the library, which includes the following topics:
  - generating/validating/parsing XML messages for/from Google Checkout API
  - transforming the xml DOM trees into a human-friendly structures
    almost word-by-word following the official specification from google.
  - does the technical low-level tasks such as generating authentication
    token from user vendor_id and merchant_key etc.
  - parses Google Checkout API notification messages and runs
    the corresponding hook methods.

Intergration of the library consists of four phases:
  1. gather your account settings such as your vendor_id, merchant_key,
     your local currency symbol (ATM either 'USD' or 'GBP')
  2. create a unique instance of L{gchecky.ControllerLevel_2} class by
     subclassing it. Provide custom implementation to the abstract methods.
     Basically all you need is to define your reaction to various API
     notifications (see step 5 for details).
  3. set up a separate background thread for sending requests to
     U{Google Checkout API <http://code.google.com/apis/checkout/developer/index.html#order_processing_api>}.
  4. set up a web-handler at a publicly accessible url. Refer to the 
     U{Google Checkout Notification API
     <http://code.google.com/apis/checkout/developer/index.html#handling_notifications>}.
     But instead of processing incoming XML messages yourself, it should
     pass the incoming request text to your customized instance of
     L{gchecky.ControllerLevel_2} (to L{gchecky.ControllerLevel_2.recieve}).
  5. Provide your local order-processing system integration by overriding
     abstract methods of your custom instance of L{gchecky.ControllerLevel_2}
     (see steps 2 and 3).
     Basically you will need to store Orders in your custom order-processing
     system, update it state every time you receive a notification from
     Google Checkout Notification API (notifications correspond to abstract
     Controller.on_XXX methods). Plus in the step 3 you will need to scan your
     Order list and perform actions on those orders which are ready for the
     further processing (charging, refunding, delivering etc.) 

@author: etarassov
@version: $Revision $
@contact: gchecky at gmail
"""

import os.path
import re

VERSION = (0, 2, 1)

def version(version=VERSION):
    """
    Return version string.
    >>> version((0,1,1))
    '0.1.1'
    >>> version((0,1,0))
    '0.1.0'
    >>> version(VERSION) == version()
    True
    """
    return '.'.join([str(v) for v in version])

def human_version(version=VERSION):
    """
    Return human-friendly version string.
    >>> human_version((0,1,0))
    '0.1'
    >>> human_version(VERSION) == human_version()
    True
    """
    # For a release version do not include the minor revision number '.0'
    human_version = '.'.join([str(v) for v in version[:-1]])
    # For maintenance versions replace the minor number by SVN revision.
    if version[-1]:
        rev = None
        # Do as django does - try to manually parse svn/entries file:
        import gchecky
        entries_path = '%s/.svn/entries' % (gchecky.__path__[0])
        if os.path.exists(entries_path):
            entries = open(entries_path, 'r').read()
            # Versions >= 7 of the entries file are flat text.  The first line is
            # the version number. The next set of digits after 'dir' is the revision.
            if re.match('(\d+)', entries):
                rev_match = re.search('\d+\s+dir\s+(\d+)', entries)
                if rev_match:
                    rev = rev_match.groups()[0]
            # Older XML versions of the file specify revision as an attribute of
            # the first entries node.
            else:
                from xml.dom import minidom
                dom = minidom.parse(entries_path)
                rev = dom.getElementsByTagName('entry')[0].getAttribute('revision')
        if not rev:
            rev = 'unknown'
        human_version = '%s-%s-SVN%s' % (human_version, version[-1], rev)
    return human_version

if __name__ == "__main__":
    def run_doctests():
        import doctest
        doctest.testmod()
    run_doctests()