import { useState, useEffect, useCallback, useMemo } from 'react';
import { motion, AnimatePresence } from 'framer-motion';
import { FiMenu, FiX, FiExternalLink, FiArrowUpRight } from 'react-icons/fi';
import { HiSparkles } from 'react-icons/hi';

export default function Navbar() {
  const [isOpen, setIsOpen] = useState(false);
  const [scrolled, setScrolled] = useState(false);

  // Memoized menu items for better performance
  const menuItems = useMemo(
    () => [
      { label: 'Features', href: '#features' },
      { label: 'Converters', href: '#converters' },
      { label: 'Social Media', href: '#social-media' },
      { label: 'About', href: '#about' },
    ],
    [],
  );

  // Optimized scroll handler with throttling
  const handleScroll = useCallback(() => {
    const scrollTop = window.scrollY;
    setScrolled(scrollTop > 20);
  }, []);

  useEffect(() => {
    let ticking = false;

    const throttledScroll = () => {
      if (!ticking) {
        requestAnimationFrame(() => {
          handleScroll();
          ticking = false;
        });
        ticking = true;
      }
    };

    window.addEventListener('scroll', throttledScroll, { passive: true });
    return () => window.removeEventListener('scroll', throttledScroll);
  }, [handleScroll]);

  // Close mobile menu when clicking outside
  useEffect(() => {
    const handleClickOutside = event => {
      if (isOpen && !event.target.closest('nav')) {
        setIsOpen(false);
      }
    };

    document.addEventListener('click', handleClickOutside);
    return () => document.removeEventListener('click', handleClickOutside);
  }, [isOpen]);

  // Enhanced smooth scroll with easing function
  const easeInOutCubic = (t) => {
    return t < 0.5 ? 4 * t * t * t : (t - 1) * (2 * t - 2) * (2 * t - 2) + 1;
  };

  const smoothScrollTo = useCallback((targetPosition, duration = 1200) => {
    const startPosition = window.pageYOffset;
    const distance = targetPosition - startPosition;
    let startTime = null;

    const animation = (currentTime) => {
      if (startTime === null) startTime = currentTime;
      const timeElapsed = currentTime - startTime;
      const progress = Math.min(timeElapsed / duration, 1);
      const ease = easeInOutCubic(progress);
      
      window.scrollTo(0, startPosition + distance * ease);
      
      if (timeElapsed < duration) {
        requestAnimationFrame(animation);
      }
    };

    requestAnimationFrame(animation);
  }, []);

  // Smooth scroll handler with improved offset calculation and animation
  const handleSmoothScroll = useCallback(
    href => {
      if (href.startsWith('#')) {
        const element = document.querySelector(href);
        if (element) {
          const offset = 80; // Account for fixed navbar height
          const elementPosition = element.getBoundingClientRect().top;
          const offsetPosition = elementPosition + window.pageYOffset - offset;

          smoothScrollTo(offsetPosition, 1200); // 1.2 second duration
          setIsOpen(false);
        }
      }
    },
    [smoothScrollTo, setIsOpen],
  );

  // Enhanced scroll to top with animation
  const scrollToTop = useCallback(() => {
    smoothScrollTo(0, 1000); // 1 second duration for scroll to top
  }, [smoothScrollTo]);

  return (
    <motion.nav
      className={`fixed top-0 left-0 right-0 z-50 transition-all duration-500 ease-out ${
        scrolled
          ? 'bg-[var(--background-secondary)]/95 backdrop-blur-xl border-b border-[var(--border)] shadow-lg'
          : 'bg-transparent'
      }`}
      initial={{ y: -100, opacity: 0 }}
      animate={{ y: 0, opacity: 1 }}
      transition={{ duration: 0.8, ease: [0.16, 1, 0.3, 1] }}
    >
      <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8">
        <div className="flex items-center justify-between h-14 sm:h-16">
          {/* Logo */}
          <motion.div
            className="flex items-center space-x-2 cursor-pointer group"
            whileHover={{ scale: 1.02 }}
            whileTap={{ scale: 0.98 }}
            transition={{ duration: 0.2 }}
            onClick={scrollToTop}
          >
            <div className="relative">
              <HiSparkles className="text-xl sm:text-2xl text-[var(--accent)] group-hover:text-[var(--accent-hover)] transition-colors duration-300" />
              <div className="absolute inset-0 bg-[var(--accent)] blur-lg opacity-20 group-hover:opacity-30 transition-opacity duration-300"></div>
            </div>
            <span className="text-lg sm:text-xl font-bold gradient-text">
              LumaKit
            </span>
          </motion.div>

          {/* Desktop Menu */}
          <div className="hidden md:flex items-center space-x-6 lg:space-x-8">
            {menuItems.map((item, index) => (
              <motion.button
                key={index}
                onClick={() => handleSmoothScroll(item.href)}
                className="text-[var(--foreground-secondary)] hover:text-[var(--foreground)] transition-colors duration-300 text-sm font-medium relative group"
                whileHover={{ y: -1 }}
                transition={{ duration: 0.2 }}
              >
                {item.label}
                <span className="absolute bottom-0 left-0 w-0 h-0.5 bg-[var(--accent)] group-hover:w-full transition-all duration-300"></span>
              </motion.button>
            ))}
            <motion.a
              onClick={() => handleSmoothScroll("#features")}
              rel="noopener noreferrer"
              className="group relative flex items-center space-x-2 bg-[var(--accent)] hover:bg-[var(--accent-hover)] text-[var(--background)] px-4 py-2 rounded-xl transition-all duration-300 text-sm font-medium shadow-lg hover:shadow-xl overflow-hidden"
              whileHover={{ scale: 1.02, y: -1 }}
              whileTap={{ scale: 0.98 }}
              transition={{ duration: 0.2 }}
            >
              <div className="absolute inset-0 bg-gradient-to-r from-[var(--accent)] to-[var(--accent-hover)] opacity-0 group-hover:opacity-100 transition-opacity duration-300"></div>
              <FiExternalLink className="text-sm relative z-10" />
              <span className="relative z-10">Try LumaKit</span>
            </motion.a>
          </div>

          {/* Mobile Menu Button */}
          <motion.button
            className="md:hidden text-[var(--foreground-secondary)] hover:text-[var(--foreground)] transition-colors duration-300 p-2 rounded-lg hover:bg-[var(--background-secondary)]"
            onClick={() => setIsOpen(!isOpen)}
            whileTap={{ scale: 0.95 }}
            aria-label="Toggle menu"
          >
            <motion.div
              animate={isOpen ? 'open' : 'closed'}
              variants={{
                open: { rotate: 180 },
                closed: { rotate: 0 },
              }}
              transition={{ duration: 0.3 }}
            >
              {isOpen ? <FiX size={20} /> : <FiMenu size={20} />}
            </motion.div>
          </motion.button>
        </div>

        {/* Mobile Menu */}
        <AnimatePresence mode="wait">
          {isOpen && (
            <motion.div
              className="md:hidden absolute top-full left-0 right-0 bg-[var(--background-secondary)]/98 backdrop-blur-xl border-b border-[var(--border)] shadow-2xl"
              initial={{ opacity: 0, height: 0, y: -10 }}
              animate={{ opacity: 1, height: 'auto', y: 0 }}
              exit={{ opacity: 0, height: 0, y: -10 }}
              transition={{ duration: 0.4, ease: [0.16, 1, 0.3, 1] }}
            >
              <div className="px-4 py-6 space-y-4">
                {menuItems.map((item, index) => (
                  <motion.button
                    key={index}
                    onClick={() => handleSmoothScroll(item.href)}
                    className="block w-full text-left text-[var(--foreground-secondary)] hover:text-[var(--foreground)] transition-colors duration-300 text-base font-medium py-2 px-3 rounded-lg hover:bg-[var(--background-tertiary)]"
                    initial={{ opacity: 0, x: -20 }}
                    animate={{ opacity: 1, x: 0 }}
                    transition={{ delay: index * 0.1, duration: 0.3 }}
                  >
                    {item.label}
                  </motion.button>
                ))}
                <motion.a
                  href="https://huggingface.co/spaces/YoruAkio/LumaKit"
                  target="_blank"
                  rel="noopener noreferrer"
                  className="group relative flex items-center space-x-2 bg-[var(--accent)] hover:bg-[var(--accent-hover)] text-[var(--background)] px-4 py-3 rounded-xl transition-all duration-300 text-base font-medium w-fit shadow-lg overflow-hidden"
                  onClick={() => setIsOpen(false)}
                  initial={{ opacity: 0, x: -20 }}
                  animate={{ opacity: 1, x: 0 }}
                  transition={{ delay: 0.4, duration: 0.3 }}
                >
                  <div className="absolute inset-0 bg-gradient-to-r from-[var(--accent)] to-[var(--accent-hover)] opacity-0 group-hover:opacity-100 transition-opacity duration-300"></div>
                  <FiExternalLink className="text-sm relative z-10" />
                  <span className="relative z-10">Try LumaKit</span>
                  <FiArrowUpRight className="text-sm group-hover:translate-x-0.5 group-hover:-translate-y-0.5 transition-transform duration-200 relative z-10" />
                </motion.a>
              </div>
            </motion.div>
          )}
        </AnimatePresence>
      </div>
    </motion.nav>
  );
}