'''
Created on Jan 16, 2014

@author: sean
'''
from __future__ import absolute_import, division, print_function

from functools import partial
import json
import logging
import os
import sys

import jinja2

from .conda_interface import PY3
from .environ import get_dict as get_environ
from .metadata import select_lines, ns_cfg
from .source import WORK_DIR

log = logging.getLogger(__file__)


class UndefinedNeverFail(jinja2.Undefined):
    """
    A class for Undefined jinja variables.
    This is even less strict than the default jinja2.Undefined class,
    because it permits things like {{ MY_UNDEFINED_VAR[:2] }} and
    {{ MY_UNDEFINED_VAR|int }}. This can mask lots of errors in jinja templates, so it
    should only be used for a first-pass parse, when you plan on running a 'strict'
    second pass later.
    """
    all_undefined_names = []

    def __init__(self, hint=None, obj=jinja2.runtime.missing, name=None,
                 exc=jinja2.exceptions.UndefinedError):
        UndefinedNeverFail.all_undefined_names.append(name)
        jinja2.Undefined.__init__(self, hint, obj, name, exc)

    __add__ = __radd__ = __mul__ = __rmul__ = __div__ = __rdiv__ = \
    __truediv__ = __rtruediv__ = __floordiv__ = __rfloordiv__ = \
    __mod__ = __rmod__ = __pos__ = __neg__ = __call__ = \
    __getitem__ = __lt__ = __le__ = __gt__ = __ge__ = \
    __complex__ = __pow__ = __rpow__ = \
        lambda self, *args, **kwargs: UndefinedNeverFail(hint=self._undefined_hint,
                                                         obj=self._undefined_obj,
                                                         name=self._undefined_name,
                                                         exc=self._undefined_exception)

    __str__ = __repr__ = \
        lambda *args, **kwargs: u''

    __int__ = lambda _: 0
    __float__ = lambda _: 0.0

    def __getattr__(self, k):
        try:
            return object.__getattr__(self, k)
        except AttributeError:
            return UndefinedNeverFail(hint=self._undefined_hint,
                                      obj=self._undefined_obj,
                                      name=self._undefined_name + '.' + k,
                                      exc=self._undefined_exception)


class FilteredLoader(jinja2.BaseLoader):
    """
    A pass-through for the given loader, except that the loaded source is
    filtered according to any metadata selectors in the source text.
    """

    def __init__(self, unfiltered_loader):
        self._unfiltered_loader = unfiltered_loader
        self.list_templates = unfiltered_loader.list_templates

    def get_source(self, environment, template):
        contents, filename, uptodate = self._unfiltered_loader.get_source(environment,
                                                                          template)
        return select_lines(contents, ns_cfg()), filename, uptodate


def load_setup_py_data(setup_file='setup.py', from_recipe_dir=False, recipe_dir=None,
                    unload_modules=None, fail_on_error=False):
    
    _setuptools_data = {}

    def setup(**kw):
        _setuptools_data.update(kw)

    import setuptools
    import distutils.core
 
    try:
    	import numpy.distutils.core
    except ImportError:
        do_numpy = False
    else:
        do_numpy = True

    cd_to_work = False

    if from_recipe_dir and recipe_dir:
        setup_file = os.path.abspath(os.path.join(recipe_dir, setup_file))
    elif os.path.exists(WORK_DIR):
        cd_to_work = True
        cwd = os.getcwd()
        os.chdir(WORK_DIR)
        if not os.path.isabs(setup_file):
            setup_file = os.path.join(WORK_DIR, setup_file)
        # this is very important - or else if versioneer or otherwise is in the start folder,
        # things will pick up the wrong versioneer/whatever!
        sys.path.insert(0, WORK_DIR)
    else:
        log.debug("Did not find setup.py file in manually specified location, and source "
                  "not downloaded yet.")
        return {}

    # Patch setuptools, distutils
    setuptools_setup = setuptools.setup
    distutils_setup = distutils.core.setup
    setuptools.setup = distutils.core.setup = setup

    if do_numpy:
        numpy_setup = numpy.distutils.core.setup
        numpy.distutils.core.setup = setup
    
    ns = {
        '__name__': '__main__',
        '__doc__': None,
        '__file__': setup_file,
    }
    try:
        code = compile(open(setup_file).read(), setup_file, 'exec', dont_inherit=1)
        exec(code, ns, ns)
        distutils.core.setup = distutils_setup
        setuptools.setup = setuptools_setup
        if do_numpy:
            numpy.distutils.core.setup = numpy_setup
    # this happens if setup.py is used in load_setup_py_data, but source is not yet downloaded
    except:
        raise
    finally:
        if cd_to_work:
            os.chdir(cwd)
    del sys.path[0]

    return _setuptools_data


def load_setuptools(setup_file='setup.py', from_recipe_dir=False, recipe_dir=None,
                    unload_modules=None, fail_on_error=False):
    log.warn("Deprecation notice: the load_setuptools function has been renamed to "
             "load_setup_py_data.  load_setuptools will be removed in a future release.")
    return load_setup_py_data(setup_file=setup_file, from_recipe_dir=from_recipe_dir,
                              recipe_dir=recipe_dir, unload_modules=unload_modules,
                              fail_on_error=fail_on_error)


def load_npm():
    # json module expects bytes in Python 2 and str in Python 3.
    mode_dict = {'mode': 'r', 'encoding': 'utf-8'} if PY3 else {'mode': 'rb'}
    with open('package.json', **mode_dict) as pkg:
        return json.load(pkg)


def context_processor(initial_metadata, recipe_dir):
    """
    Return a dictionary to use as context for jinja templates.

    initial_metadata: Augment the context with values from this MetaData object.
                      Used to bootstrap metadata contents via multiple parsing passes.
    """
    ctx = get_environ(m=initial_metadata)
    environ = dict(os.environ)
    environ.update(get_environ(m=initial_metadata))

    ctx.update(
        load_setup_py_data=partial(load_setup_py_data, recipe_dir=recipe_dir),
        # maintain old alias for backwards compatibility:
        load_setuptools=partial(load_setuptools, recipe_dir=recipe_dir),
        load_npm=load_npm,
        environ=environ)
    return ctx