import { useCallback, useEffect, useRef } from "react";
import { Platform, StatusBar, type GestureResponderEvent } from "react-native";
import * as Haptics from "expo-haptics";
import { isWeb as platformIsWeb } from "@/constants/platform";
import { decideLongPressMove } from "@/utils/sidebar-gesture-arbitration";
import type { useContextMenu } from "@/components/ui/context-menu";

export function useLongPressDragInteraction(input: {
  drag: () => void;
  menuController: ReturnType<typeof useContextMenu> | null;
}) {
  const didLongPressRef = useRef(false);
  const dragArmedRef = useRef(false);
  const dragActivatedRef = useRef(false);
  const didStartDragRef = useRef(false);
  const scrollIntentRef = useRef(false);
  const menuOpenedRef = useRef(false);
  const touchStartRef = useRef<{ x: number; y: number } | null>(null);
  const touchCurrentRef = useRef<{ x: number; y: number } | null>(null);
  const dragArmTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
  const contextMenuTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  const clearTimers = useCallback(() => {
    if (dragArmTimerRef.current) {
      clearTimeout(dragArmTimerRef.current);
      dragArmTimerRef.current = null;
    }
    if (contextMenuTimerRef.current) {
      clearTimeout(contextMenuTimerRef.current);
      contextMenuTimerRef.current = null;
    }
  }, []);

  const openContextMenuAtStartPoint = useCallback(() => {
    if (!input.menuController || !touchStartRef.current) {
      return;
    }
    const statusBarHeight = Platform.OS === "android" ? (StatusBar.currentHeight ?? 0) : 0;
    input.menuController.setAnchorRect({
      x: touchStartRef.current.x,
      y: touchStartRef.current.y + statusBarHeight,
      width: 0,
      height: 0,
    });
    input.menuController.setOpen(true);
    menuOpenedRef.current = true;
    didLongPressRef.current = true;
  }, [input.menuController]);

  const handleLongPress = useCallback(() => {
    // Manual timers own long-press behavior on mobile.
  }, []);

  useEffect(() => {
    return () => {
      clearTimers();
    };
  }, [clearTimers]);

  const armTimers = useCallback(() => {
    clearTimers();
    if (platformIsWeb) {
      return;
    }

    const DRAG_ARM_DELAY_MS = 180;
    const DRAG_ARM_STATIONARY_SLOP_PX = 4;
    const CONTEXT_MENU_DELAY_MS = 450;
    const CONTEXT_MENU_STATIONARY_SLOP_PX = 6;

    dragArmTimerRef.current = setTimeout(() => {
      if (scrollIntentRef.current || didStartDragRef.current || menuOpenedRef.current) {
        return;
      }
      const start = touchStartRef.current;
      const current = touchCurrentRef.current ?? start;
      if (!start || !current) {
        return;
      }
      const dx = current.x - start.x;
      const dy = current.y - start.y;
      const distance = Math.sqrt(dx * dx + dy * dy);
      if (distance > DRAG_ARM_STATIONARY_SLOP_PX) {
        return;
      }
      dragArmedRef.current = true;
      dragActivatedRef.current = true;
      didLongPressRef.current = true;
      void Haptics.selectionAsync().catch(() => {});
      input.drag();
    }, DRAG_ARM_DELAY_MS);

    if (!input.menuController) {
      return;
    }

    contextMenuTimerRef.current = setTimeout(() => {
      if (scrollIntentRef.current || didStartDragRef.current || menuOpenedRef.current) {
        return;
      }
      const start = touchStartRef.current;
      const current = touchCurrentRef.current ?? start;
      if (!start || !current) {
        return;
      }
      const dx = current.x - start.x;
      const dy = current.y - start.y;
      const distance = Math.sqrt(dx * dx + dy * dy);
      if (distance > CONTEXT_MENU_STATIONARY_SLOP_PX) {
        return;
      }
      void Haptics.selectionAsync().catch(() => {});
      openContextMenuAtStartPoint();
    }, CONTEXT_MENU_DELAY_MS);
  }, [clearTimers, input, openContextMenuAtStartPoint]);

  const handleDragIntent = useCallback(
    (_details: { dx: number; dy: number; distance: number }) => {
      if (!dragActivatedRef.current) {
        return;
      }
      didStartDragRef.current = true;
      didLongPressRef.current = true;
      clearTimers();
      void Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Medium).catch(() => {});
    },
    [clearTimers],
  );

  const handleScrollIntent = useCallback(
    (_details: { dx: number; dy: number; distance: number }) => {
      scrollIntentRef.current = true;
      didLongPressRef.current = true;
      clearTimers();
    },
    [clearTimers],
  );

  const handleSwipeIntent = useCallback(
    (_details: { dx: number; dy: number; distance: number }) => {
      didLongPressRef.current = true;
      clearTimers();
    },
    [clearTimers],
  );

  const handlePressIn = useCallback(
    (event: GestureResponderEvent) => {
      didLongPressRef.current = false;
      dragArmedRef.current = false;
      dragActivatedRef.current = false;
      didStartDragRef.current = false;
      scrollIntentRef.current = false;
      menuOpenedRef.current = false;
      touchStartRef.current = {
        x: event.nativeEvent.pageX,
        y: event.nativeEvent.pageY,
      };
      touchCurrentRef.current = {
        x: event.nativeEvent.pageX,
        y: event.nativeEvent.pageY,
      };
      armTimers();
    },
    [armTimers],
  );

  const handleTouchMove = useCallback(
    (event: GestureResponderEvent) => {
      const start = touchStartRef.current;
      if (!start || didStartDragRef.current || menuOpenedRef.current) {
        return;
      }

      const touch = event?.nativeEvent?.touches?.[0] ?? event?.nativeEvent;
      const x = touch?.pageX;
      const y = touch?.pageY;
      if (typeof x !== "number" || typeof y !== "number") {
        return;
      }

      const current = { x, y };
      touchCurrentRef.current = current;
      const dx = current.x - start.x;
      const dy = current.y - start.y;
      const distance = Math.sqrt(dx * dx + dy * dy);
      const decision = decideLongPressMove({
        dragArmed: dragArmedRef.current,
        didStartDrag: didStartDragRef.current,
        startPoint: start,
        currentPoint: current,
      });

      if (decision === "vertical_scroll") {
        handleScrollIntent({ dx, dy, distance });
        return;
      }

      if (decision === "horizontal_swipe" || decision === "cancel_long_press") {
        handleSwipeIntent({ dx, dy, distance });
        return;
      }

      if (decision === "start_drag") {
        handleDragIntent({ dx, dy, distance });
      }
    },
    [handleDragIntent, handleScrollIntent, handleSwipeIntent],
  );

  const handlePressOut = useCallback(() => {
    clearTimers();
    dragArmedRef.current = false;
    dragActivatedRef.current = false;
    touchStartRef.current = null;
    touchCurrentRef.current = null;
  }, [clearTimers]);

  return {
    didLongPressRef,
    handleLongPress,
    handlePressIn,
    handleTouchMove,
    handlePressOut,
  };
}