"""Astroid hooks for the Python 2 GObject introspection bindings.

Helps with understanding everything imported from 'gi.repository'
"""

import inspect
import itertools
import sys
import re

from astroid import MANAGER, AstroidBuildingException
from astroid.builder import AstroidBuilder


_inspected_modules = {}

_identifier_re = r'^[A-Za-z_]\w*$'

def _gi_build_stub(parent):
    """
    Inspect the passed module recursively and build stubs for functions,
    classes, etc.
    """
    classes = {}
    functions = {}
    constants = {}
    methods = {}
    for name in dir(parent):
        if name.startswith("__"):
            continue

        # Check if this is a valid name in python
        if not re.match(_identifier_re, name):
            continue

        try:
            obj = getattr(parent, name)
        except:
            continue

        if inspect.isclass(obj):
            classes[name] = obj
        elif (inspect.isfunction(obj) or
              inspect.isbuiltin(obj)):
            functions[name] = obj
        elif (inspect.ismethod(obj) or
              inspect.ismethoddescriptor(obj)):
            methods[name] = obj
        elif type(obj) in [int, str]:
            constants[name] = obj
        elif (str(obj).startswith("<flags") or
              str(obj).startswith("<enum ") or
              str(obj).startswith("<GType ") or
              inspect.isdatadescriptor(obj)):
            constants[name] = 0
        elif callable(obj):
            # Fall back to a function for anything callable
            functions[name] = obj
        else:
            # Assume everything else is some manner of constant
            constants[name] = 0

    ret = ""

    if constants:
        ret += "# %s contants\n\n" % parent.__name__
    for name in sorted(constants):
        if name[0].isdigit():
            # GDK has some busted constant names like
            # Gdk.EventType.2BUTTON_PRESS
            continue

        val = constants[name]

        strval = str(val)
        if type(val) is str:
            strval = '"%s"' % str(val).replace("\\", "\\\\")
        ret += "%s = %s\n" % (name, strval)

    if ret:
        ret += "\n\n"
    if functions:
        ret += "# %s functions\n\n" % parent.__name__
    for name in sorted(functions):
        func = functions[name]
        ret += "def %s(*args, **kwargs):\n" % name
        ret += "    pass\n"

    if ret:
        ret += "\n\n"
    if methods:
        ret += "# %s methods\n\n" % parent.__name__
    for name in sorted(methods):
        func = methods[name]
        ret += "def %s(self, *args, **kwargs):\n" % name
        ret += "    pass\n"

    if ret:
        ret += "\n\n"
    if classes:
        ret += "# %s classes\n\n" % parent.__name__
    for name in sorted(classes):
        ret += "class %s(object):\n" % name

        classret = _gi_build_stub(classes[name])
        if not classret:
            classret = "pass\n"

        for line in classret.splitlines():
            ret += "    " + line + "\n"
        ret += "\n"

    return ret

def _import_gi_module(modname):
    # we only consider gi.repository submodules
    if not modname.startswith('gi.repository.'):
        raise AstroidBuildingException()
    # build astroid representation unless we already tried so
    if modname not in _inspected_modules:
        modnames = [modname]
        optional_modnames = []

        # GLib and GObject may have some special case handling
        # in pygobject that we need to cope with. However at
        # least as of pygobject3-3.13.91 the _glib module doesn't
        # exist anymore, so if treat these modules as optional.
        if modname == 'gi.repository.GLib':
            optional_modnames.append('gi._glib')
        elif modname == 'gi.repository.GObject':
            optional_modnames.append('gi._gobject')

        try:
            modcode = ''
            for m in itertools.chain(modnames, optional_modnames):
                try:
                    __import__(m)
                    modcode += _gi_build_stub(sys.modules[m])
                except ImportError:
                    if m not in optional_modnames:
                        raise
        except ImportError:
            astng = _inspected_modules[modname] = None
        else:
            astng = AstroidBuilder(MANAGER).string_build(modcode, modname)
            _inspected_modules[modname] = astng
    else:
        astng = _inspected_modules[modname]
    if astng is None:
        raise AstroidBuildingException('Failed to import module %r' % modname)
    return astng


MANAGER.register_failed_import_hook(_import_gi_module)