import { useCallback, useEffect, useRef } from 'react';
import {
  adjustAdjacentGridFr,
  FLOATING_WIDGET_CELL_MIN_H,
  FLOATING_WIDGET_CELL_MIN_W,
  FLOATING_WIDGET_GRID_GAP,
} from '../types/floatingWidget';
import { isPrimaryPointerButton } from '../utils/pointerDrag';

type SplitAxis = 'col' | 'row';

interface Options {
  onColFrChange: (next: number[]) => void;
  onRowFrChange: (next: number[]) => void;
  getColFr: () => number[];
  getRowFr: () => number[];
  getBodySize: () => { width: number; height: number };
  onSplitEnd?: () => void;
}

export function useFloatingWidgetGridSplit({
  onColFrChange,
  onRowFrChange,
  getColFr,
  getRowFr,
  getBodySize,
  onSplitEnd,
}: Options) {
  const activeDragRef = useRef<(() => void) | null>(null);

  useEffect(() => () => {
    activeDragRef.current?.();
    document.body.style.cursor = '';
    document.body.style.userSelect = '';
  }, []);

  const startSplit = useCallback((
    e: React.PointerEvent,
    axis: SplitAxis,
    index: number,
  ) => {
    if (!isPrimaryPointerButton(e)) return;
    e.preventDefault();
    e.stopPropagation();

    const handle = e.currentTarget as HTMLElement;
    try {
      handle.setPointerCapture(e.pointerId);
    } catch {
      /* ignore */
    }
    handle.classList.add('fw-grid-splitter--active');

    const startX = e.clientX;
    const startY = e.clientY;
    const startColFr = [...getColFr()];
    const startRowFr = [...getRowFr()];

    document.body.style.cursor = axis === 'col' ? 'col-resize' : 'row-resize';
    document.body.style.userSelect = 'none';

    activeDragRef.current?.();

    const onMove = (ev: PointerEvent) => {
      const size = getBodySize();
      if (axis === 'col') {
        if (size.width <= 0) return;
        const delta = ev.clientX - startX;
        onColFrChange(adjustAdjacentGridFr(
          startColFr,
          index,
          delta,
          size.width,
          FLOATING_WIDGET_GRID_GAP,
          FLOATING_WIDGET_CELL_MIN_W,
        ));
        return;
      }
      if (size.height <= 0) return;
      const delta = ev.clientY - startY;
      onRowFrChange(adjustAdjacentGridFr(
        startRowFr,
        index,
        delta,
        size.height,
        FLOATING_WIDGET_GRID_GAP,
        FLOATING_WIDGET_CELL_MIN_H,
      ));
    };

    const onUp = (ev: PointerEvent) => {
      handle.classList.remove('fw-grid-splitter--active');
      document.body.style.cursor = '';
      document.body.style.userSelect = '';
      try {
        if (handle.hasPointerCapture(ev.pointerId)) {
          handle.releasePointerCapture(ev.pointerId);
        }
      } catch {
        /* ignore */
      }
      document.removeEventListener('pointermove', onMove, true);
      document.removeEventListener('pointerup', onUp, true);
      document.removeEventListener('pointercancel', onUp, true);
      activeDragRef.current = null;
      onSplitEnd?.();
    };

    document.addEventListener('pointermove', onMove, { capture: true });
    document.addEventListener('pointerup', onUp, { capture: true });
    document.addEventListener('pointercancel', onUp, { capture: true });

    activeDragRef.current = () => {
      document.removeEventListener('pointermove', onMove, true);
      document.removeEventListener('pointerup', onUp, true);
      document.removeEventListener('pointercancel', onUp, true);
    };
  }, [getBodySize, getColFr, getRowFr, onColFrChange, onRowFrChange, onSplitEnd]);

  const onColSplitPointerDown = useCallback(
    (index: number) => (e: React.PointerEvent) => startSplit(e, 'col', index),
    [startSplit],
  );

  const onRowSplitPointerDown = useCallback(
    (index: number) => (e: React.PointerEvent) => startSplit(e, 'row', index),
    [startSplit],
  );

  return { onColSplitPointerDown, onRowSplitPointerDown };
}