# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: nil -*-
# vi: set ft=python sts=4 ts=4 sw=4 et:
"""Miscellaneous utility functions
"""
from cPickle import dumps, loads
import inspect

from distutils.version import LooseVersion
import numpy as np
from textwrap import dedent

def getsource(function):
    """Returns the source code of a function"""
    src = dumps(dedent(inspect.getsource(function)))
    return src

def create_function_from_source(function_source):
    """Return a function object from a function source
    """
    ns = {}
    try:
        exec loads(function_source) in ns
    except Exception, msg:
        msg = str(msg) + '\nError executing function:\n %s\n'%function_source
        msg += '\n'.join( ["Functions in connection strings have to be standalone.",
                           "They cannot be declared either interactively or inside",
                           "another function or inline in the connect string. Any",
                           "imports should be done inside the function"
                           ])
        raise RuntimeError(msg)
    funcname = [name for name in ns.keys() if name != '__builtins__'][0]
    func = ns[funcname]
    return func

def find_indices(condition):
   "Return the indices where ravel(condition) is true"
   res, = np.nonzero(np.ravel(condition))
   return res

def is_container(item):
   """Checks if item is a container (list, tuple, dict, set)
   
   Parameters
   ----------
   item : object 
       object to check for .__iter__
      
   Returns
   -------
   output : Boolean
       True if container
       False if not (eg string)
   """
   if hasattr(item, '__iter__'):
      return True
   else:
      return False
      
def container_to_string(cont):
   """Convert a container to a command line string.
   
   Elements of the container are joined with a space between them,
   suitable for a command line parameter.

   If the container `cont` is only a sequence, like a string and not a
   container, it is returned unmodified.

   Parameters
   ----------
   cont : container
      A container object like a list, tuple, dict, or a set.

   Returns
   -------
   cont_str : string
       Container elements joined into a string.

   """
   if hasattr(cont, '__iter__'):
      return ' '.join(cont)
   else:
      return str(cont)


# Dependency checks.  Copied this from Nipy, with some modificiations
# (added app as a parameter).
def package_check(pkg_name, version=None, app=None, checker=LooseVersion,
                  exc_failed_import=ImportError,
                  exc_failed_check=RuntimeError):
    """Check that the minimal version of the required package is installed.

    Parameters
    ----------
    pkg_name : string
        Name of the required package.
    version : string, optional
        Minimal version number for required package.
    app : string, optional
        Application that is performing the check.  For instance, the
        name of the tutorial being executed that depends on specific
        packages.  Default is *Nipype*.
    checker : object, optional
        The class that will perform the version checking.  Default is
        distutils.version.LooseVersion.
    exc_failed_import : Exception, optional
        Class of the exception to be thrown if import failed.
    exc_failed_check : Exception, optional
        Class of the exception to be thrown if version check failed.

    Examples
    --------
    package_check('numpy', '1.3')
    package_check('networkx', '1.0', 'tutorial1')

    """

    if app:
        msg = '%s requires %s' % (app, pkg_name)
    else:
        msg = 'Nipype requires %s' % pkg_name
    if version:
      msg += ' with version >= %s' % (version,)
    try:
        mod = __import__(pkg_name)
    except ImportError:
        raise exc_failed_import(msg)
    if not version:
        return
    try:
        have_version = mod.__version__
    except AttributeError:
        raise exc_failed_check('Cannot find version for %s' % pkg_name)
    if checker(have_version) < checker(version):
        raise exc_failed_check(msg)

def str2bool(v):
    if isinstance(v, bool):
        return v
    lower = v.lower()
    if lower in ("yes", "true", "t", "1"):
        return True
    elif lower in ("no", "false", "n", "0"):
        return False
    else:
        raise ValueError("%s cannot be converted to bool"%v)
