from dataclasses import dataclass, field, fields
from typing import Any, Callable, Dict, Iterator, List, Optional

from xsdata.exceptions import SchemaValueError
from xsdata.formats.dataclass.models.elements import XmlType
from xsdata.models.enums import DataType, FormType, Namespace, NamespaceType
from xsdata.utils import text
from xsdata.utils.constants import return_true


@dataclass
class ElementBase:
    """
    Base xsd schema model.

    :param index: Occurrence position inside the definition
    :param ns_map: Namespace prefix-URI map
    """

    index: int = field(
        default_factory=int,
        init=False,
        metadata={"type": "Ignore"},
    )
    ns_map: Dict[str, str] = field(
        default_factory=dict,
        init=False,
        metadata={"type": "Ignore"},
    )

    @property
    def class_name(self) -> str:
        """Return the schema element class name."""
        return self.__class__.__name__

    @property
    def default_type(self) -> str:
        """Return the default type if the given element has not specific
        type."""
        return DataType.STRING.prefixed(self.xs_prefix)

    @property
    def default_value(self) -> Any:
        """Return the default or the fixed attribute value."""
        default = getattr(self, "default", None)
        if default is None and hasattr(self, "fixed"):
            default = getattr(self, "fixed", None)

        return default

    @property
    def display_help(self) -> Optional[str]:
        """Return the display help for this element."""
        return None

    @property
    def bases(self) -> Iterator[str]:
        """Return an iterator of all the base types."""
        yield from ()

    @property
    def has_children(self) -> bool:
        """Return whether or not this element has any children."""
        return next(self.children(), None) is not None

    @property
    def has_form(self) -> bool:
        """Return whether or not this element has the form attribute."""
        return hasattr(self, "form")

    @property
    def is_abstract(self) -> bool:
        """Return whether or not this element is defined as abstract."""
        return getattr(self, "abstract", False)

    @property
    def is_property(self) -> bool:
        """Return whether this element is qualified to be a class property."""
        return False

    @property
    def is_fixed(self) -> bool:
        """Return whether or not this element has a fixed value."""
        return getattr(self, "fixed", None) is not None

    @property
    def is_mixed(self) -> bool:
        """Return whether or not this element accepts mixed content value."""
        return False

    @property
    def is_nillable(self) -> bool:
        """Return whether or not this element is accepts empty empty values."""
        return getattr(self, "nillable", False)

    @property
    def is_qualified(self) -> bool:
        """Return whether or not this element name needs to be referenced with
        the target namespace."""
        if self.has_form:
            if getattr(self, "form", FormType.UNQUALIFIED) == FormType.QUALIFIED:
                return True

            if self.is_ref:
                return True

        return False

    @property
    def is_ref(self) -> bool:
        """Return whether or not this element is a reference to another
        element."""
        return getattr(self, "ref", None) is not None

    @property
    def is_wildcard(self) -> bool:
        """Return whether or not this element is a wildcard
        element/attribute."""
        return False

    @property
    def prefix(self) -> Optional[str]:
        """Return the namespace prefix for this element's type."""
        ref = getattr(self, "ref", None)
        return None if ref is None else text.prefix(ref)

    @property
    def raw_namespace(self) -> Optional[str]:
        """Return if present the target namespace attribute value."""
        return getattr(self, "target_namespace", None)

    @property
    def real_name(self) -> str:
        """
        Return the real name for this element by looking by looking either to
        the name or ref attribute value.

        :raises SchemaValueError: when instance has no name/ref
            attribute.
        """
        name = getattr(self, "name", None) or getattr(self, "ref", None)
        if name:
            return text.suffix(name)

        raise SchemaValueError(f"Schema class `{self.class_name}` unknown real name.")

    @property
    def attr_types(self) -> Iterator[str]:
        """Return the attribute types for this element."""
        yield from ()

    @property
    def substitutions(self) -> List[str]:
        """Return the substitution groups of this element."""
        return []

    @property
    def xs_prefix(self) -> Optional[str]:
        """Return the xml schema uri prefix."""
        for prefix, uri in self.ns_map.items():
            if uri == Namespace.XS.uri:
                return prefix

        return None

    def get_restrictions(self) -> Dict[str, Any]:
        """Return the restrictions dictionary of this element."""
        return {}

    def children(self, condition: Callable = return_true) -> Iterator["ElementBase"]:
        """Iterate over all the ElementBase children of this element that match
        the given condition if any."""
        for f in fields(self):
            value = getattr(self, f.name)
            if isinstance(value, list) and value and isinstance(value[0], ElementBase):
                yield from (val for val in value if condition(val))
            elif isinstance(value, ElementBase) and condition(value):
                yield value


def text_node(**kwargs: Any) -> Any:
    """Shortcut method for text node fields."""
    metadata = extract_metadata(kwargs, type=XmlType.TEXT)
    add_default_value(kwargs, optional=False)

    return field(metadata=metadata, **kwargs)


def attribute(optional: bool = True, **kwargs: Any) -> Any:
    """Shortcut method for attribute fields."""
    metadata = extract_metadata(kwargs, type=XmlType.ATTRIBUTE)
    add_default_value(kwargs, optional=optional)

    return field(metadata=metadata, **kwargs)


def element(optional: bool = True, **kwargs: Any) -> Any:
    """Shortcut method for element fields."""
    metadata = extract_metadata(kwargs, type=XmlType.ELEMENT)
    add_default_value(kwargs, optional=optional)

    return field(metadata=metadata, **kwargs)


def add_default_value(params: Dict, optional: bool):
    """Add default value to the params if it's missing and its marked as
    optional."""

    if optional and not ("default" in params or "default_factory" in params):
        params["default"] = None


def array_element(**kwargs: Any) -> Any:
    """Shortcut method for list element fields."""
    metadata = extract_metadata(kwargs, type=XmlType.ELEMENT)
    return field(metadata=metadata, default_factory=list, **kwargs)


def array_any_element(**kwargs: Any) -> Any:
    """Shortcut method for list wildcard fields."""
    metadata = extract_metadata(
        kwargs, type=XmlType.WILDCARD, namespace=NamespaceType.ANY_NS
    )
    return field(metadata=metadata, default_factory=list, **kwargs)


def extract_metadata(params: Dict, **kwargs: Any) -> Dict:
    """Extract not standard dataclass field parameters to a new metadata
    dictionary and merge with any provided keyword arguments."""
    metadata = {
        key: params.pop(key) for key in list(params.keys()) if key not in FIELD_PARAMS
    }
    metadata.update(kwargs)
    return metadata


FIELD_PARAMS = (
    "default",
    "default_factory",
    "init",
    "repr",
    "hash",
    "compare",
)