"""
Global configuration objects.

Joe Presbrey  <presbrey@mit.edu>
"""

from ConfigParser import ConfigParser, NoSectionError, NoOptionError
import os

_ENV_BASE='_SQL_MIT_EDU'

class Section(object):
    """Configuration section namespace."""
    def __init__(self, d):
        self.items = d

    def __getattr__(self, k):
        v = self.items.get(k, None)
        try:
            if str(int(v)) == str(v): v = int(v)
        except TypeError: pass
        except ValueError: pass
        try:
            if str(v).lower() == 'true': v = True
            if str(v).lower() == 'false': v = False
        except TypeError: pass
        except ValueError: pass
        return v

    def __iter__(self):
        return iter(self.items)

    def __str__(self):
        return str(self.items)

class Config(object):
    """Base configuration namespace."""
    def __init__(self, filename, *args, **kwargs):
        self._cp = ConfigParser(*args, **kwargs)
        self.read(filename)
        self._none = Section({})
    
    def _samefile(self, f1, f2):
        try:
            return os.path.samefile(f1, f2)
        except OSError, e:
            return False
    
    def read(self, filename):
        config_path = [os.path.join(x, filename) for x in [
            os.path.dirname(__file__),
            '/etc']]
        if _ENV_BASE in os.environ:
            config_path.insert(1, os.path.join(os.environ[_ENV_BASE], 'etc', filename))
        def append(path):
            r = os.path.join(path, filename)
            if not r in config_path:
                config_path.append(r)
        if 'HOME' in os.environ:
            append(os.environ['HOME'])
        if 'PWD' in os.environ:
            append(os.environ['PWD'])
        self._cp.read(config_path)
        self._sections = dict(map(lambda x: (x, Section(dict(self._cp.items(x)))),
                                  self._cp.sections()))
    
    def get(self, *av, **kw):
        try: return self._cp.get(*av, **kw)
        except NoSectionError: return None
        except NoOptionError: return None
    
    def __getattr__(self, k):
        return self._sections.get(k, self._none)
    
    def __str__(self):
        d = {}
        for x in self._cp.sections():
            d[x] = dict(self._cp.items(x))
        return str(d)

if __name__ == '__main__':
    import mitsql
    print mitsql.config