"use client";

import { useState, useEffect, useCallback, useRef } from "react";
import { useRouter } from "next/navigation";

function isInputFocused(): boolean {
  const el = document.activeElement;
  if (!el) return false;
  const tag = el.tagName.toLowerCase();
  if (tag === "input" || tag === "textarea" || tag === "select") return true;
  if ((el as HTMLElement).isContentEditable) return true;
  return false;
}

interface UseKeyboardNavOptions {
  itemCount: number;
  onSelect: (index: number) => void;
  enabled?: boolean;
}

export function useKeyboardNav({
  itemCount,
  onSelect,
  enabled = true,
}: UseKeyboardNavOptions) {
  const [selectedIndex, setSelectedIndex] = useState(-1);
  const router = useRouter();
  const gPressedRef = useRef(false);
  const gTimerRef = useRef<ReturnType<typeof setTimeout>>(undefined);

  const resetSelection = useCallback(() => {
    setSelectedIndex(-1);
  }, []);

  useEffect(() => {
    if (!enabled) return;

    function handleKeyDown(e: KeyboardEvent) {
      if (isInputFocused()) return;

      if (gPressedRef.current) {
        gPressedRef.current = false;
        clearTimeout(gTimerRef.current);

        if (e.key === "h") {
          e.preventDefault();
          router.push("/dashboard");
          return;
        }
        if (e.key === "s") {
          e.preventDefault();
          router.push("/dashboard/settings");
          return;
        }
        if (e.key === "k") {
          e.preventDefault();
          router.push("/dashboard/keys");
          return;
        }
        if (e.key === "d") {
          e.preventDefault();
          router.push("/dashboard/decisions");
          return;
        }
        return;
      }

      if (e.key === "g" && !e.metaKey && !e.ctrlKey && !e.altKey) {
        gPressedRef.current = true;
        gTimerRef.current = setTimeout(() => {
          gPressedRef.current = false;
        }, 500);
        return;
      }

      if (e.key === "j" && !e.metaKey && !e.ctrlKey) {
        e.preventDefault();
        setSelectedIndex((prev) => {
          const next = prev + 1;
          return next >= itemCount ? itemCount - 1 : next;
        });
        return;
      }

      if (e.key === "k" && !e.metaKey && !e.ctrlKey) {
        e.preventDefault();
        setSelectedIndex((prev) => {
          const next = prev - 1;
          return next < 0 ? 0 : next;
        });
        return;
      }

      if (e.key === "Enter" && selectedIndex >= 0) {
        e.preventDefault();
        onSelect(selectedIndex);
        return;
      }

      if (e.key === "Escape") {
        setSelectedIndex(-1);
        return;
      }
    }

    document.addEventListener("keydown", handleKeyDown);
    return () => {
      document.removeEventListener("keydown", handleKeyDown);
      clearTimeout(gTimerRef.current);
    };
  }, [enabled, itemCount, selectedIndex, onSelect, router]);

  useEffect(() => {
    if (selectedIndex < 0) return;

    const row = document.querySelector(`[data-keyboard-index="${selectedIndex}"]`);
    if (row) {
      row.scrollIntoView({ block: "nearest", behavior: "smooth" });
    }
  }, [selectedIndex]);

  return { selectedIndex, setSelectedIndex, resetSelection };
}