from typing import Any, Callable, Optional, cast

from typing_extensions import Self

from ...binding import BindableProperty, bind, bind_from, bind_to
from ...element import Element


class ContentElement(Element):
    CONTENT_PROP = 'innerHTML'
    content = BindableProperty(
        on_change=lambda sender, content: cast(Self, sender)._handle_content_change(content))  # pylint: disable=protected-access

    def __init__(self, *, content: str, **kwargs: Any) -> None:
        super().__init__(**kwargs)
        self.content = content
        self._handle_content_change(content)

    def bind_content_to(self,
                        target_object: Any,
                        target_name: str = 'content',
                        forward: Optional[Callable[[Any], Any]] = None,
                        ) -> Self:
        """Bind the content of this element to the target object's target_name property.

        The binding works one way only, from this element to the target.
        The update happens immediately and whenever a value changes.

        :param target_object: The object to bind to.
        :param target_name: The name of the property to bind to.
        :param forward: A function to apply to the value before applying it to the target (default: identity).
        """
        bind_to(self, 'content', target_object, target_name, forward)
        return self

    def bind_content_from(self,
                          target_object: Any,
                          target_name: str = 'content',
                          backward: Optional[Callable[[Any], Any]] = None,
                          ) -> Self:
        """Bind the content of this element from the target object's target_name property.

        The binding works one way only, from the target to this element.
        The update happens immediately and whenever a value changes.

        :param target_object: The object to bind from.
        :param target_name: The name of the property to bind from.
        :param backward: A function to apply to the value before applying it to this element (default: identity).
        """
        bind_from(self, 'content', target_object, target_name, backward)
        return self

    def bind_content(self,
                     target_object: Any,
                     target_name: str = 'content', *,
                     forward: Optional[Callable[[Any], Any]] = None,
                     backward: Optional[Callable[[Any], Any]] = None,
                     ) -> Self:
        """Bind the content of this element to the target object's target_name property.

        The binding works both ways, from this element to the target and from the target to this element.
        The update happens immediately and whenever a value changes.
        The backward binding takes precedence for the initial synchronization.

        :param target_object: The object to bind to.
        :param target_name: The name of the property to bind to.
        :param forward: A function to apply to the value before applying it to the target (default: identity).
        :param backward: A function to apply to the value before applying it to this element (default: identity).
        """
        bind(self, 'content', target_object, target_name, forward=forward, backward=backward)
        return self

    def set_content(self, content: str) -> None:
        """Set the content of this element.

        :param content: The new content.
        """
        self.content = content

    def _handle_content_change(self, content: str) -> None:
        """Called when the content of this element changes.

        :param content: The new content.
        """
        if self.CONTENT_PROP == 'innerHTML' and '</script>' in content:
            raise ValueError('HTML elements must not contain <script> tags. Use ui.add_body_html() instead.')
        self._props[self.CONTENT_PROP] = content
        self.update()