import { useEffect, useRef, useState } from 'react';
import { Link, useLocation } from 'react-router-dom';
import { gsap } from 'gsap';
import './PillNav.css';

export interface PillNavItem {
  label: string;
  href?: string;
  ariaLabel?: string;
  onClick?: () => void;
}

interface PillNavProps {
  logo?: string;
  logoText?: string;
  logoAlt?: string;
  items: PillNavItem[];
  activeHref?: string;
  className?: string;
  ease?: string;
  baseColor?: string;
  pillColor?: string;
  hoveredPillTextColor?: string;
  pillTextColor?: string;
  onMobileMenuClick?: () => void;
  initialLoadAnimation?: boolean;
}

const PillNav = ({
  logo,
  logoText,
  logoAlt = 'Logo',
  items,
  activeHref,
  className = '',
  ease = 'power3.easeOut',
  baseColor = '#0d0720',
  pillColor = '#1e0f3a',
  hoveredPillTextColor = '#e9d5ff',
  pillTextColor,
  onMobileMenuClick,
  initialLoadAnimation = true,
}: PillNavProps) => {
  const resolvedPillTextColor = pillTextColor ?? '#c084fc';
  const [isMobileMenuOpen, setIsMobileMenuOpen] = useState(false);

  const circleRefs = useRef<(HTMLSpanElement | null)[]>([]);
  const tlRefs = useRef<gsap.core.Timeline[]>([]);
  const activeTweenRefs = useRef<gsap.core.Tween[]>([]);
  const logoImgRef = useRef<HTMLImageElement>(null);
  const logoTweenRef = useRef<gsap.core.Tween | null>(null);
  const hamburgerRef = useRef<HTMLButtonElement>(null);
  const mobileMenuRef = useRef<HTMLDivElement>(null);
  const navItemsRef = useRef<HTMLDivElement>(null);
  const logoRef = useRef<HTMLAnchorElement | null>(null);

  useEffect(() => {
    const layout = () => {
      circleRefs.current.forEach((circle, index) => {
        if (!circle?.parentElement) return;
        const pill = circle.parentElement;
        const rect = pill.getBoundingClientRect();
        const { width: w, height: h } = rect;
        const R = ((w * w) / 4 + h * h) / (2 * h);
        const D = Math.ceil(2 * R) + 2;
        const delta = Math.ceil(R - Math.sqrt(Math.max(0, R * R - (w * w) / 4))) + 1;
        const originY = D - delta;

        circle.style.width = `${D}px`;
        circle.style.height = `${D}px`;
        circle.style.bottom = `-${delta}px`;

        gsap.set(circle, { xPercent: -50, scale: 0, transformOrigin: `50% ${originY}px` });

        const label = pill.querySelector('.pill-label');
        const white = pill.querySelector('.pill-label-hover');
        if (label) gsap.set(label, { y: 0 });
        if (white) gsap.set(white, { y: h + 12, opacity: 0 });

        tlRefs.current[index]?.kill();
        const tl = gsap.timeline({ paused: true });
        tl.to(circle, { scale: 1.2, xPercent: -50, duration: 2, ease, overwrite: 'auto' }, 0);
        if (label) tl.to(label, { y: -(h + 8), duration: 2, ease, overwrite: 'auto' }, 0);
        if (white) {
          gsap.set(white, { y: Math.ceil(h + 100), opacity: 0 });
          tl.to(white, { y: 0, opacity: 1, duration: 2, ease, overwrite: 'auto' }, 0);
        }
        tlRefs.current[index] = tl;
      });
    };

    layout();
    window.addEventListener('resize', layout);
    document.fonts?.ready?.then(layout).catch(() => {});

    const menu = mobileMenuRef.current;
    if (menu) gsap.set(menu, { visibility: 'hidden', opacity: 0, scaleY: 1 });

    if (initialLoadAnimation) {
      const logoEl = logoRef.current;
      const navItems = navItemsRef.current;
      if (logoEl) { gsap.set(logoEl, { scale: 0 }); gsap.to(logoEl, { scale: 1, duration: 0.6, ease }); }
      if (navItems) { gsap.set(navItems, { width: 0, overflow: 'hidden' }); gsap.to(navItems, { width: 'auto', duration: 0.6, ease }); }
    }

    return () => window.removeEventListener('resize', layout);
  }, [items, ease, initialLoadAnimation]);

  const handleEnter = (i: number) => {
    const tl = tlRefs.current[i];
    if (!tl) return;
    activeTweenRefs.current[i]?.kill();
    activeTweenRefs.current[i] = tl.tweenTo(tl.duration(), { duration: 0.3, ease, overwrite: 'auto' }) as gsap.core.Tween;
  };

  const handleLeave = (i: number) => {
    const tl = tlRefs.current[i];
    if (!tl) return;
    activeTweenRefs.current[i]?.kill();
    activeTweenRefs.current[i] = tl.tweenTo(0, { duration: 0.2, ease, overwrite: 'auto' }) as gsap.core.Tween;
  };

  const handleLogoEnter = () => {
    const img = logoImgRef.current;
    if (!img) return;
    logoTweenRef.current?.kill();
    gsap.set(img, { rotate: 0 });
    logoTweenRef.current = gsap.to(img, { rotate: 360, duration: 0.4, ease, overwrite: 'auto' });
  };

  const toggleMobileMenu = () => {
    const newState = !isMobileMenuOpen;
    setIsMobileMenuOpen(newState);
    const hamburger = hamburgerRef.current;
    const menu = mobileMenuRef.current;

    if (hamburger) {
      const lines = hamburger.querySelectorAll('.hamburger-line');
      if (newState) {
        gsap.to(lines[0], { rotation: 45, y: 3, duration: 0.3, ease });
        gsap.to(lines[1], { rotation: -45, y: -3, duration: 0.3, ease });
      } else {
        gsap.to(lines[0], { rotation: 0, y: 0, duration: 0.3, ease });
        gsap.to(lines[1], { rotation: 0, y: 0, duration: 0.3, ease });
      }
    }

    if (menu) {
      if (newState) {
        gsap.set(menu, { visibility: 'visible' });
        gsap.fromTo(menu, { opacity: 0, y: 10 }, { opacity: 1, y: 0, duration: 0.3, ease });
      } else {
        gsap.to(menu, { opacity: 0, y: 10, duration: 0.2, ease, onComplete: () => gsap.set(menu, { visibility: 'hidden' }) });
      }
    }
    onMobileMenuClick?.();
  };

  const cssVars = {
    ['--base']: baseColor,
    ['--pill-bg']: pillColor,
    ['--hover-text']: hoveredPillTextColor,
    ['--pill-text']: resolvedPillTextColor,
  } as React.CSSProperties;

  const location = useLocation();
  const currentHref = activeHref ?? location.pathname;

  const renderPill = (item: PillNavItem, i: number) => {
    const isActive = item.href ? currentHref === item.href : false;
    const pillClass = `pill${isActive ? ' is-active' : ''}`;
    const inner = (
      <>
        <span className="hover-circle" aria-hidden="true" ref={el => { circleRefs.current[i] = el; }} />
        <span className="label-stack">
          <span className="pill-label">{item.label}</span>
          <span className="pill-label-hover" aria-hidden="true">{item.label}</span>
        </span>
      </>
    );

    if (item.onClick) {
      return (
        <button role="menuitem" className={pillClass}
          aria-label={item.ariaLabel || item.label}
          onMouseEnter={() => handleEnter(i)} onMouseLeave={() => handleLeave(i)}
          onClick={item.onClick}>
          {inner}
        </button>
      );
    }

    const isInternal = item.href && !item.href.startsWith('http') && !item.href.startsWith('mailto');
    if (isInternal) {
      return (
        <Link role="menuitem" to={item.href!} className={pillClass}
          aria-label={item.ariaLabel || item.label}
          onMouseEnter={() => handleEnter(i)} onMouseLeave={() => handleLeave(i)}>
          {inner}
        </Link>
      );
    }

    return (
      <a role="menuitem" href={item.href || '#'} className={pillClass}
        aria-label={item.ariaLabel || item.label}
        onMouseEnter={() => handleEnter(i)} onMouseLeave={() => handleLeave(i)}>
        {inner}
      </a>
    );
  };

  return (
    <div className="pill-nav-container">
      <nav className={`pill-nav ${className}`} aria-label="Primary" style={cssVars}>
        {/* Logo / brand */}
        <a
          className="pill-logo"
          href="#"
          aria-label="Home"
          onMouseEnter={handleLogoEnter}
          ref={logoRef}
          style={{ background: baseColor, color: resolvedPillTextColor }}
        >
          {logo
            ? <img src={logo} alt={logoAlt} ref={logoImgRef} />
            : <span style={{ fontWeight: 800, fontSize: 14, letterSpacing: '0.05em', color: '#c084fc' }}>{logoText ?? 'AUTHRIX'}</span>
          }
        </a>

        {/* Desktop nav items */}
        <div className="pill-nav-items desktop-only" ref={navItemsRef}>
          <ul className="pill-list" role="menubar">
            {items.map((item, i) => (
              <li key={i} role="none">{renderPill(item, i)}</li>
            ))}
          </ul>
        </div>

        {/* Mobile hamburger */}
        <button
          className="mobile-menu-button mobile-only"
          onClick={toggleMobileMenu}
          aria-label="Toggle menu"
          ref={hamburgerRef}
        >
          <span className="hamburger-line" />
          <span className="hamburger-line" />
        </button>
      </nav>

      {/* Mobile popover */}
      <div className="mobile-menu-popover mobile-only" ref={mobileMenuRef} style={cssVars}>
        <ul className="mobile-menu-list">
          {items.map((item, i) => (
            <li key={i}>
              {item.onClick
                ? <button className={`mobile-menu-link${currentHref === item.href ? ' is-active' : ''}`} onClick={() => { item.onClick?.(); setIsMobileMenuOpen(false); }}>{item.label}</button>
                : item.href && !item.href.startsWith('http')
                  ? <Link to={item.href} className={`mobile-menu-link${currentHref === item.href ? ' is-active' : ''}`} onClick={() => setIsMobileMenuOpen(false)}>{item.label}</Link>
                  : <a href={item.href || '#'} className={`mobile-menu-link${currentHref === item.href ? ' is-active' : ''}`} onClick={() => setIsMobileMenuOpen(false)}>{item.label}</a>
              }
            </li>
          ))}
        </ul>
      </div>
    </div>
  );
};

export default PillNav;