from typing import Optional
from nicegui import ui


class AutoScrollArea(ui.scroll_area):
    """A scroll area that automatically scrolls to bottom when new content is added

    Features:
    - Auto-scrolls to bottom when at bottom and new content arrives
    - Stops auto-scroll when user scrolls up manually
    - Resumes auto-scroll when user scrolls back to bottom
    """

    _auto_scroll_enabled: bool = True
    _auto_scroll_timer: Optional[ui.timer] = None

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # Set up scroll monitoring
        # self._handle_scroll
        self.on_scroll(self._handle_scroll_event)
        self.on('wheel', self._handle_wheel, ['deltaY'])

        # Create timer for auto-scrolling
        self._auto_scroll_timer = ui.timer(0.1, lambda: self.scroll_to(percent=1))
        self._auto_scroll_timer.activate()

    def _scroll_event_test(self, e):
        print(e.vertical_percentage)

    def _handle_scroll_event(self, event_data):
        """Handle scroll events to detect when user is at bottom"""

        if not self._auto_scroll_timer:
            print('no timer instantiated.')
            return

        # If scrolled to bottom (100%), enable auto-scroll
        if event_data.vertical_percentage > 0.99:  # Using 0.99 for some tolerance
            if not self._auto_scroll_timer.active:
                self._auto_scroll_timer.activate()

    def _handle_wheel(self, event_data):
        """Handle mouse wheel events to detect manual scrolling"""
        delta_y = event_data.args['deltaY']
        if not self._auto_scroll_timer:
            print('no timer instantiated.')
            return
        # If scrolling up (negative delta), disable auto-scroll
        if delta_y < 0:
            if self._auto_scroll_timer.active:
                self._auto_scroll_timer.deactivate()

    def enable_auto_scroll(self):
        """Manually enable auto-scrolling"""
        if self._auto_scroll_timer:
            if not self._auto_scroll_timer.active:
                self._auto_scroll_timer.activate()

    def disable_auto_scroll(self):
        """Manually disable auto-scrolling"""

        if self._auto_scroll_timer:
            if self._auto_scroll_timer.active:
                self._auto_scroll_timer.deactivate()

    def cleanup(self):
        """Clean up timer when component is destroyed"""
        if self._auto_scroll_timer:
            self._auto_scroll_timer.deactivate()
            self._auto_scroll_timer = None