from typing import Optional

from flet.controls.base_control import control
from flet.controls.control_event import ControlEventHandler
from flet.controls.layout_control import LayoutControl
from flet.controls.types import (
    ColorValue,
    Number,
)

__all__ = ["CupertinoSlider"]


@control("CupertinoSlider")
class CupertinoSlider(LayoutControl):
    """
    An iOS-type slider.

    It provides a visual indication of adjustable content, as well as the current
    setting in the total range of content.

    Use a slider when you want people to set defined values (such as volume or
    brightness), or when people would benefit from instant feedback on the effect of
    setting changes.

    Raises:
        AssertionError: If [`min`][(c).] is greater than or equal to [`max`][(c).].
        AssertionError: If [`min`][(c).] is greater than or equal to [`value`][(c).].
        AssertionError: If [`max`][(c).] is less than or equal to [`value`][(c).].
    """

    value: Optional[Number] = None
    """
    The currently selected value for this slider.

    The slider's thumb is drawn at a position that corresponds to this value.
    """

    min: Number = 0.0
    """
    The minimum value the user can select.

    Note:
        - Must be less than or equal to [`max`][flet.CupertinoSlider.max].
        - If the [`max`][flet.CupertinoSlider.max] is equal to the `min`,
            then the slider is disabled.
    """

    max: Number = 1.0
    """
    The maximum value the user can select.

    Note:
        - Must be greater than or equal to [`min`][flet.CupertinoSlider.min].
        - If the [`min`][flet.CupertinoSlider.min] is equal to the `max`,
            then the slider is disabled.
    """

    divisions: Optional[int] = None
    """
    The number of discrete divisions.

    If `None`, the slider is continuous.
    """

    active_color: Optional[ColorValue] = None
    """
    The color to use for the portion of the
    slider track that is active.

    The "active" side of the slider is the side between the thumb and the minimum
    value.
    """

    thumb_color: Optional[ColorValue] = None
    """
    The color of the thumb.
    """

    on_change: Optional[ControlEventHandler["CupertinoSlider"]] = None
    """
    Called when the state of this slider changed.
    """

    on_change_start: Optional[ControlEventHandler["CupertinoSlider"]] = None
    """
    Called when the user starts selecting a new value for this slider.
    """

    on_change_end: Optional[ControlEventHandler["CupertinoSlider"]] = None
    """
    Called when the user is done selecting a new value for this slider.
    """

    on_focus: Optional[ControlEventHandler["CupertinoSlider"]] = None
    """
    Called when this slider has received focus.
    """

    on_blur: Optional[ControlEventHandler["CupertinoSlider"]] = None
    """
    Called when this slider has lost focus.
    """

    def before_update(self):
        super().before_update()
        self.value = self.value if self.value is not None else self.min
        assert self.min <= self.max, (
            f"min ({self.min}) must be less than or equal to max ({self.max})"
        )
        assert self.value is None or (self.value >= self.min), (
            f"value ({self.value}) must be greater than or equal to min ({self.min})"
        )
        assert self.value is None or (self.value <= self.max), (
            f"value ({self.value}) must be less than or equal to max ({self.max})"
        )