"""Configuration options for datasets


Especially, the locations of data files.
"""

import os, sys, logging
def _logger():  return logging.getLogger('pylearn.datasets.config')
def debug(*msg): _logger().debug(' '.join(str(m) for m in msg))
def info(*msg): _logger().info(' '.join(str(m) for m in msg))
def warn(*msg): _logger().warn(' '.join(str(m) for m in msg))
def warning(*msg): _logger().warning(' '.join(str(m) for m in msg))
def error(*msg): _logger().error(' '.join(str(m) for m in msg))


def env_get(key, default, key2 = None):
    if key2 and os.getenv(key) is None:
        key=key2
    if os.getenv(key) is None:
        if env_get.first_warning:
            warning("Environment variable", key, 'is not set. Using default of', default)
            env_get.first_warning = False
        return default
    else:
        return os.getenv(key)
env_get.first_warning = True

def data_root():
    """Deprecated, use data_roots() or get_filepath_in_roots()
    
    It id deprecated as it don't allow to use more then 1 path.
    """
    roots = env_get('PYLEARN_DATA_ROOT', os.getenv('HOME')+'/data', 'DBPATH')
    return roots.split(':')[0]

def data_roots():
    """Return a list of path that are in the PYLEARN_DATA_ROOT env variable."""
    if hasattr(data_roots, 'rval'):
        return data_roots.rval
    roots = os.getenv('PYLEARN_DATA_ROOT')
    if roots is None:
        roots = data_root()
    else:
        roots = roots.split(':')
    roots2 = []
    #remove directory that don't exist
    for root in roots:
        if os.path.exists(root):
            roots2.append(root)
    data_roots.rval = roots2
    return roots2


def get_filepath_in_roots(name):
    """Return the full path of name that exist under a directory
    in the PYLEARN_DATA_ROOT env variable.
    """
    for root in data_roots():
        path = os.path.join(root,name)
        if os.path.exists(path):
            return path