from abc import ABC, abstractmethod
from typing import Any, List

from .utils import IS_ANDROID
from .view import ViewBase

# ========================================
# Base class
# ========================================


class ScrollViewBase(ABC):
    @abstractmethod
    def __init__(self) -> None:
        super().__init__()
        self.views: List[Any] = []

    @abstractmethod
    def add_view(self, view) -> None:
        pass


if IS_ANDROID:
    # ========================================
    # Android class
    # https://developer.android.com/reference/android/widget/ScrollView
    # ========================================

    from java import jclass

    class ScrollView(ScrollViewBase, ViewBase):
        def __init__(self, context) -> None:
            super().__init__()
            self.native_class = jclass("android.widget.ScrollView")
            self.native_instance = self.native_class(context)

        def add_view(self, view):
            self.views.append(view)
            # In Android, ScrollView can host only one direct child
            if len(self.views) == 1:
                self.native_instance.addView(view.native_instance)
            else:
                raise Exception("ScrollView can host only one direct child")

else:
    # ========================================
    # iOS class
    # https://developer.apple.com/documentation/uikit/uiscrollview
    # ========================================

    from rubicon.objc import ObjCClass

    class ScrollView(ScrollViewBase, ViewBase):
        def __init__(self) -> None:
            super().__init__()
            self.native_class = ObjCClass("UIScrollView")
            self.native_instance = self.native_class.alloc().initWithFrame_(((0, 0), (0, 0)))

        def add_view(self, view):
            self.views.append(view)
            # Ensure view is a subview of scrollview
            if view.native_instance not in self.native_instance.subviews:
                self.native_instance.addSubview_(view.native_instance)