"""Class implementation for line cap interface.
"""

from typing import Dict
from typing import Union

from apysc._display.line_caps import LineCaps
from apysc._html.debug_mode import add_debug_info_setting
from apysc._type.revert_interface import RevertInterface
from apysc._type.string import String
from apysc._type.variable_name_interface import VariableNameInterface
from apysc._validation import arg_validation_decos


class LineCapInterface(VariableNameInterface, RevertInterface):

    _line_cap: String

    def _initialize_line_cap_if_not_initialized(self) -> None:
        """
        Initialize the _line_cap attribute if this
        interface does not initialize it yet.
        """
        if hasattr(self, '_line_cap'):
            return
        self._line_cap = String(LineCaps.BUTT.value)

    @property
    @add_debug_info_setting(
        module_name=__name__, class_name='LineCapInterface')
    def line_cap(self) -> Union[String, LineCaps]:
        """
        Get this instance's line cap style setting.

        Returns
        -------
        line_cap : String
            Line cap style setting.

        Examples
        --------
        >>> import apysc as ap
        >>> stage: ap.Stage = ap.Stage()
        >>> sprite: ap.Sprite = ap.Sprite()
        >>> sprite.graphics.line_style(color='#fff', thickness=10)
        >>> line: ap.Line = sprite.graphics.draw_line(
        ...     x_start=50, y_start=50, x_end=150, y_end=50)
        >>> line.line_cap = ap.LineCaps.ROUND
        >>> line.line_cap
        String('round')
        """
        self._initialize_line_cap_if_not_initialized()
        return self._line_cap._copy()

    @line_cap.setter
    @arg_validation_decos.is_line_cap(
        arg_position_index=1, optional=False)
    def line_cap(self, value: Union[String, LineCaps]) -> None:
        """
        Set line cap style setting.

        Parameters
        ----------
        value : String or LineCaps
            Line cap style setting to set.
        """
        from apysc._html.debug_mode import DebugInfo
        with DebugInfo(
                callable_='line_cap', args=[value], kwargs={},
                module_name=__name__,
                class_name=LineCapInterface.__name__):
            self._update_line_cap_and_skip_appending_exp(value=value)
            self._append_line_cap_update_expression()

    @add_debug_info_setting(
        module_name=__name__, class_name='LineCapInterface')
    def _append_line_cap_update_expression(self) -> None:
        """
        Append line cap updating expression.
        """
        import apysc as ap
        from apysc._type import value_util
        cap_name: str = value_util.get_value_str_for_expression(
            value=self._line_cap)
        expression: str = (
            f'{self.variable_name}.attr({{"stroke-linecap": {cap_name}}});'
        )
        ap.append_js_expression(expression=expression)

    def _update_line_cap_and_skip_appending_exp(
            self, *, value: Union[String, LineCaps]) -> None:
        """
        Update line cap and skip appending expression.

        Parameters
        ----------
        value : String or LineCaps
            Line cap style setting to set.
        """
        if isinstance(value, String):
            self._line_cap = value._copy()
        else:
            self._line_cap = String(value.value)

    _line_cap_snapshots: Dict[str, str]

    def _make_snapshot(self, *, snapshot_name: str) -> None:
        """
        Make value's snapshot.

        Parameters
        ----------
        snapshot_name : str
            Target snapshot name.
        """
        self._initialize_line_cap_if_not_initialized()
        self._set_single_snapshot_val_to_dict(
            dict_name='_line_cap_snapshots',
            value=self._line_cap._value, snapshot_name=snapshot_name)

    def _revert(self, *, snapshot_name: str) -> None:
        """
        Revert value if snapshot exists.

        Parameters
        ----------
        snapshot_name : str
            Target snapshot name.
        """
        if not self._snapshot_exists(snapshot_name=snapshot_name):
            return
        self._line_cap._value = self._line_cap_snapshots[snapshot_name]
