from astroid import MANAGER, AstroidImportError, inference_tip, nodes
from astroid.nodes import scoped_nodes

from pylint_django import utils

_STR_FIELDS = (
    "CharField",
    "SlugField",
    "URLField",
    "TextField",
    "EmailField",
    "CommaSeparatedIntegerField",
    "FilePathField",
    "GenericIPAddressField",
    "IPAddressField",
    "RegexField",
    "SlugField",
)
_INT_FIELDS = (
    "IntegerField",
    "SmallIntegerField",
    "BigIntegerField",
    "PositiveIntegerField",
    "PositiveSmallIntegerField",
)
_BOOL_FIELDS = ("BooleanField", "NullBooleanField")
_RANGE_FIELDS = (
    "RangeField",
    "IntegerRangeField",
    "BigIntegerRangeField",
    "FloatRangeField",
    "DateTimeRangeField",
    "DateRangeField",
)


def is_model_field(cls):
    return cls.qname().startswith("django.db.models.fields") or cls.qname().startswith("django.contrib.postgres.fields")


def is_form_field(cls):
    return cls.qname().startswith("django.forms.fields")


def is_model_or_form_field(cls):
    return is_model_field(cls) or is_form_field(cls)


def apply_type_shim(cls, _context=None):  # noqa

    if cls.name in _STR_FIELDS:
        base_nodes = scoped_nodes.builtin_lookup("str")
    elif cls.name in _INT_FIELDS:
        base_nodes = scoped_nodes.builtin_lookup("int")
    elif cls.name in _BOOL_FIELDS:
        base_nodes = scoped_nodes.builtin_lookup("bool")
    elif cls.name == "FloatField":
        base_nodes = scoped_nodes.builtin_lookup("float")
    elif cls.name == "DecimalField":
        try:
            base_nodes = MANAGER.ast_from_module_name("_decimal").lookup("Decimal")
        except AstroidImportError:
            base_nodes = MANAGER.ast_from_module_name("_pydecimal").lookup("Decimal")
    elif cls.name in ("SplitDateTimeField", "DateTimeField"):
        base_nodes = MANAGER.ast_from_module_name("datetime").lookup("datetime")
    elif cls.name == "TimeField":
        base_nodes = MANAGER.ast_from_module_name("datetime").lookup("time")
    elif cls.name == "DateField":
        base_nodes = MANAGER.ast_from_module_name("datetime").lookup("date")
    elif cls.name == "DurationField":
        base_nodes = MANAGER.ast_from_module_name("datetime").lookup("timedelta")
    elif cls.name == "UUIDField":
        base_nodes = MANAGER.ast_from_module_name("uuid").lookup("UUID")
    elif cls.name == "ManyToManyField":
        base_nodes = MANAGER.ast_from_module_name("django.db.models.query").lookup("QuerySet")
    elif cls.name in ("ImageField", "FileField"):
        base_nodes = MANAGER.ast_from_module_name("django.core.files.base").lookup("File")
    elif cls.name == "ArrayField":
        base_nodes = scoped_nodes.builtin_lookup("list")
    elif cls.name in ("HStoreField", "JSONField"):
        base_nodes = scoped_nodes.builtin_lookup("dict")
    elif cls.name in _RANGE_FIELDS:
        base_nodes = MANAGER.ast_from_module_name("psycopg2._range").lookup("Range")
    else:
        return iter([cls])

    # XXX: for some reason, with python3, this particular line triggers a
    # check in the StdlibChecker for deprecated methods; one of these nodes
    # is an ImportFrom which has no qname() method, causing the checker
    # to die...
    if utils.PY3:
        base_nodes = [_valid_base_node(n, _context) for n in base_nodes[1]]
        base_nodes = [n for n in base_nodes if n]
    else:
        base_nodes = list(base_nodes[1])

    return iter([cls] + base_nodes)


def _valid_base_node(node, context):
    """Attempts to convert `node` to a valid base node, returns None if it cannot."""
    if isinstance(node, nodes.AssignAttr):
        inferred = next(node.parent.value.infer(context), None)
        if inferred and isinstance(node, nodes.ClassDef):
            return inferred
        return None
    if isinstance(node, nodes.ImportFrom):
        return None
    return node


def add_transforms(manager):
    manager.register_transform(nodes.ClassDef, inference_tip(apply_type_shim), is_model_or_form_field)