# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of astroid.
#
# astroid is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 2.1 of the License, or (at your
# option) any later version.
#
# astroid is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
# for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with astroid. If not, see <http://www.gnu.org/licenses/>.
"""astroid manager: avoid multiple astroid build of a same module when
possible by providing a class responsible to get astroid representation
from various source and using a cache of built modules)
"""
from __future__ import print_function

__docformat__ = "restructuredtext en"

import collections
import imp
import os
from os.path import dirname, join, isdir, exists
from warnings import warn
import zipimport

from logilab.common.configuration import OptionsProviderMixIn

from astroid.exceptions import AstroidBuildingException
from astroid import modutils


def astroid_wrapper(func, modname):
    """wrapper to give to AstroidManager.project_from_files"""
    print('parsing %s...' % modname)
    try:
        return func(modname)
    except AstroidBuildingException as exc:
        print(exc)
    except Exception as exc:
        import traceback
        traceback.print_exc()

def _silent_no_wrap(func, modname):
    """silent wrapper that doesn't do anything; can be used for tests"""
    return func(modname)

def safe_repr(obj):
    try:
        return repr(obj)
    except:
        return '???'



class AstroidManager(OptionsProviderMixIn):
    """the astroid manager, responsible to build astroid from files
     or modules.

    Use the Borg pattern.
    """

    name = 'astroid loader'
    options = (("ignore",
                {'type' : "csv", 'metavar' : "<file>",
                 'dest' : "black_list", "default" : ('CVS',),
                 'help' : "add <file> (may be a directory) to the black list\
. It should be a base name, not a path. You may set this option multiple times\
."}),
               ("project",
                {'default': "No Name", 'type' : 'string', 'short': 'p',
                 'metavar' : '<project name>',
                 'help' : 'set the project name.'}),
              )
    brain = {}
    def __init__(self):
        self.__dict__ = AstroidManager.brain
        if not self.__dict__:
            OptionsProviderMixIn.__init__(self)
            self.load_defaults()
            # NOTE: cache entries are added by the [re]builder
            self.astroid_cache = {}
            self._mod_file_cache = {}
            self.transforms = collections.defaultdict(list)
            self._failed_import_hooks = []
            self.always_load_extensions = False
            self.extension_package_whitelist = set()

    def ast_from_file(self, filepath, modname=None, fallback=True, source=False):
        """given a module name, return the astroid object"""
        try:
            filepath = modutils.get_source_file(filepath, include_no_ext=True)
            source = True
        except modutils.NoSourceFile:
            pass
        if modname is None:
            try:
                modname = '.'.join(modutils.modpath_from_file(filepath))
            except ImportError:
                modname = filepath
        if modname in self.astroid_cache and self.astroid_cache[modname].file == filepath:
            return self.astroid_cache[modname]
        if source:
            from astroid.builder import AstroidBuilder
            return AstroidBuilder(self).file_build(filepath, modname)
        elif fallback and modname:
            return self.ast_from_module_name(modname)
        raise AstroidBuildingException('unable to get astroid for file %s' %
                                       filepath)

    def _build_stub_module(self, modname):
        from astroid.builder import AstroidBuilder
        return AstroidBuilder(self).string_build('', modname)

    def _can_load_extension(self, modname):
        if self.always_load_extensions:
            return True
        if modutils.is_standard_module(modname):
            return True
        parts = modname.split('.')
        return any(
            '.'.join(parts[:x]) in self.extension_package_whitelist
            for x in range(1, len(parts) + 1))

    def ast_from_module_name(self, modname, context_file=None):
        """given a module name, return the astroid object"""
        if modname in self.astroid_cache:
            return self.astroid_cache[modname]
        if modname == '__main__':
            return self._build_stub_module(modname)
        old_cwd = os.getcwd()
        if context_file:
            os.chdir(dirname(context_file))
        try:
            filepath, mp_type = self.file_from_module_name(modname, context_file)
            if mp_type == modutils.PY_ZIPMODULE:
                module = self.zip_import_data(filepath)
                if module is not None:
                    return module
            elif mp_type in (imp.C_BUILTIN, imp.C_EXTENSION):
                if mp_type == imp.C_EXTENSION and not self._can_load_extension(modname): 
                    return self._build_stub_module(modname)
                try:
                    module = modutils.load_module_from_name(modname)
                except Exception as ex:
                    msg = 'Unable to load module %s (%s)' % (modname, ex)
                    raise AstroidBuildingException(msg)
                return self.ast_from_module(module, modname)
            elif mp_type == imp.PY_COMPILED:
                raise AstroidBuildingException("Unable to load compiled module %s" % (modname,))
            if filepath is None:
                raise AstroidBuildingException("Unable to load module %s" % (modname,))
            return self.ast_from_file(filepath, modname, fallback=False)
        except AstroidBuildingException as e:
            for hook in self._failed_import_hooks:
                try:
                    return hook(modname)
                except AstroidBuildingException:
                    pass
            raise e
        finally:
            os.chdir(old_cwd)

    def zip_import_data(self, filepath):
        if zipimport is None:
            return None
        from astroid.builder import AstroidBuilder
        builder = AstroidBuilder(self)
        for ext in ('.zip', '.egg'):
            try:
                eggpath, resource = filepath.rsplit(ext + os.path.sep, 1)
            except ValueError:
                continue
            try:
                importer = zipimport.zipimporter(eggpath + ext)
                zmodname = resource.replace(os.path.sep, '.')
                if importer.is_package(resource):
                    zmodname = zmodname + '.__init__'
                module = builder.string_build(importer.get_source(resource),
                                              zmodname, filepath)
                return module
            except:
                continue
        return None

    def file_from_module_name(self, modname, contextfile):
        try:
            value = self._mod_file_cache[(modname, contextfile)]
        except KeyError:
            try:
                value = modutils.file_info_from_modpath(
                    modname.split('.'), context_file=contextfile)
            except ImportError as ex:
                msg = 'Unable to load module %s (%s)' % (modname, ex)
                value = AstroidBuildingException(msg)
            self._mod_file_cache[(modname, contextfile)] = value
        if isinstance(value, AstroidBuildingException):
            raise value
        return value

    def ast_from_module(self, module, modname=None):
        """given an imported module, return the astroid object"""
        modname = modname or module.__name__
        if modname in self.astroid_cache:
            return self.astroid_cache[modname]
        try:
            # some builtin modules don't have __file__ attribute
            filepath = module.__file__
            if modutils.is_python_source(filepath):
                return self.ast_from_file(filepath, modname)
        except AttributeError:
            pass
        from astroid.builder import AstroidBuilder
        return AstroidBuilder(self).module_build(module, modname)

    def ast_from_class(self, klass, modname=None):
        """get astroid for the given class"""
        if modname is None:
            try:
                modname = klass.__module__
            except AttributeError:
                raise AstroidBuildingException(
                    'Unable to get module for class %s' % safe_repr(klass))
        modastroid = self.ast_from_module_name(modname)
        return modastroid.getattr(klass.__name__)[0] # XXX


    def infer_ast_from_something(self, obj, context=None):
        """infer astroid for the given class"""
        if hasattr(obj, '__class__') and not isinstance(obj, type):
            klass = obj.__class__
        else:
            klass = obj
        try:
            modname = klass.__module__
        except AttributeError:
            raise AstroidBuildingException(
                'Unable to get module for %s' % safe_repr(klass))
        except Exception as ex:
            raise AstroidBuildingException(
                'Unexpected error while retrieving module for %s: %s'
                % (safe_repr(klass), ex))
        try:
            name = klass.__name__
        except AttributeError:
            raise AstroidBuildingException(
                'Unable to get name for %s' % safe_repr(klass))
        except Exception as ex:
            raise AstroidBuildingException(
                'Unexpected error while retrieving name for %s: %s'
                % (safe_repr(klass), ex))
        # take care, on living object __module__ is regularly wrong :(
        modastroid = self.ast_from_module_name(modname)
        if klass is obj:
            for  infered in modastroid.igetattr(name, context):
                yield infered
        else:
            for infered in modastroid.igetattr(name, context):
                yield infered.instanciate_class()

    def project_from_files(self, files, func_wrapper=astroid_wrapper,
                           project_name=None, black_list=None):
        """return a Project from a list of files or modules"""
        # build the project representation
        project_name = project_name or self.config.project
        black_list = black_list or self.config.black_list
        project = Project(project_name)
        for something in files:
            if not exists(something):
                fpath = modutils.file_from_modpath(something.split('.'))
            elif isdir(something):
                fpath = join(something, '__init__.py')
            else:
                fpath = something
            astroid = func_wrapper(self.ast_from_file, fpath)
            if astroid is None:
                continue
            # XXX why is first file defining the project.path ?
            project.path = project.path or astroid.file
            project.add_module(astroid)
            base_name = astroid.name
            # recurse in package except if __init__ was explicitly given
            if astroid.package and something.find('__init__') == -1:
                # recurse on others packages / modules if this is a package
                for fpath in modutils.get_module_files(dirname(astroid.file),
                                                       black_list):
                    astroid = func_wrapper(self.ast_from_file, fpath)
                    if astroid is None or astroid.name == base_name:
                        continue
                    project.add_module(astroid)
        return project

    def register_transform(self, node_class, transform, predicate=None):
        """Register `transform(node)` function to be applied on the given
        Astroid's `node_class` if `predicate` is None or returns true
        when called with the node as argument.

        The transform function may return a value which is then used to
        substitute the original node in the tree.
        """
        self.transforms[node_class].append((transform, predicate))

    def unregister_transform(self, node_class, transform, predicate=None):
        """Unregister the given transform."""
        self.transforms[node_class].remove((transform, predicate))

    def register_failed_import_hook(self, hook):
        """"Registers a hook to resolve imports that cannot be found otherwise.

        `hook` must be a function that accepts a single argument `modname` which
        contains the name of the module or package that could not be imported.
        If `hook` can resolve the import, must return a node of type `astroid.Module`,
        otherwise, it must raise `AstroidBuildingException`.
        """
        self._failed_import_hooks.append(hook)

    def transform(self, node):
        """Call matching transforms for the given node if any and return the
        transformed node.
        """
        cls = node.__class__
        if cls not in self.transforms:
            # no transform registered for this class of node
            return node

        transforms = self.transforms[cls]
        orig_node = node  # copy the reference
        for transform_func, predicate in transforms:
            if predicate is None or predicate(node):
                ret = transform_func(node)
                # if the transformation function returns something, it's
                # expected to be a replacement for the node
                if ret is not None:
                    if node is not orig_node:
                        # node has already be modified by some previous
                        # transformation, warn about it
                        warn('node %s substituted multiple times' % node)
                    node = ret
        return node

    def cache_module(self, module):
        """Cache a module if no module with the same name is known yet."""
        self.astroid_cache.setdefault(module.name, module)

    def clear_cache(self):
        # XXX clear transforms
        self.astroid_cache.clear()
        # force bootstrap again, else we may ends up with cache inconsistency
        # between the manager and CONST_PROXY, making
        # unittest_lookup.LookupTC.test_builtin_lookup fail depending on the
        # test order
        from astroid.raw_building import astroid_bootstrapping
        astroid_bootstrapping()


class Project(object):
    """a project handle a set of modules / packages"""
    def __init__(self, name=''):
        self.name = name
        self.path = None
        self.modules = []
        self.locals = {}
        self.__getitem__ = self.locals.__getitem__
        self.__iter__ = self.locals.__iter__
        self.values = self.locals.values
        self.keys = self.locals.keys
        self.items = self.locals.items

    def add_module(self, node):
        self.locals[node.name] = node
        self.modules.append(node)

    def get_module(self, name):
        return self.locals[name]

    def get_children(self):
        return self.modules

    def __repr__(self):
        return '<Project %r at %s (%s modules)>' % (self.name, id(self),
                                                    len(self.modules))


