'use client';

import { Suspense, useState, useEffect, useCallback } from 'react';
import { StaticLink } from '@/components/ui/static-link';
import Image from 'next/image';
import { usePathname } from 'next/navigation';
import { Menu, X } from 'lucide-react';
import { AnimatePresence, motion } from 'framer-motion';
import { Button } from '@/components/ui/button';
import { COMPANY_INFO, NAVIGATION, type NavigationItem } from '@/lib/constants';
import { useFocusTrap } from '@/hooks/use-focus-trap';

function HeaderContent() {
  const [isOpen, setIsOpen] = useState(false);
  const [isScrolled, setIsScrolled] = useState(false);
  const [headerTheme, setHeaderTheme] = useState<'light' | 'dark'>('light');
  const pathname = usePathname();
  const focusTrapRef = useFocusTrap<HTMLDivElement>(isOpen);

  // 监听 data-header-theme 属性变化（产品落地页控制导航栏颜色）
  useEffect(() => {
    const handleThemeChange = () => {
      const theme = document.documentElement.getAttribute('data-header-theme');
      setHeaderTheme(theme === 'dark' ? 'dark' : 'light');
    };

    handleThemeChange();

    const observer = new MutationObserver(handleThemeChange);
    observer.observe(document.documentElement, {
      attributes: true,
      attributeFilter: ['data-header-theme'],
    });

    return () => observer.disconnect();
  }, []);

  useEffect(() => {
    const handleScroll = () => {
      setIsScrolled(window.scrollY > 20);
    };

    const handleGlobalKeyDown = (e: KeyboardEvent) => {
      if (e.key === 'Escape' && isOpen) {
        setIsOpen(false);
      }
    };

    window.addEventListener('scroll', handleScroll, { passive: true });
    window.addEventListener('keydown', handleGlobalKeyDown);

    return () => {
      window.removeEventListener('scroll', handleScroll);
      window.removeEventListener('keydown', handleGlobalKeyDown);
    };
  }, [isOpen]);

  const handleKeyDown = useCallback((e: React.KeyboardEvent) => {
    if (e.key === 'Enter' || e.key === ' ') {
      e.preventDefault();
      setIsOpen(!isOpen);
    }
    if (e.key === 'Escape' && isOpen) {
      setIsOpen(false);
    }
  }, [isOpen]);

  const handleNavClick = useCallback((href: string) => {
    // Close mobile menu, then navigate (StaticLink delegates navigation to onClick when present)
    setIsOpen(false);
    window.location.href = href;
  }, []);

  const isActive = useCallback((item: NavigationItem) => {
    if (item.id === 'contact') {
      return pathname === '/contact';
    }
    
    if (item.id === 'home') {
      return pathname === '/';
    }
    
    return pathname === `/${item.id}`;
  }, [pathname]);

  const navigationItems = NAVIGATION;

  return (
    <>
      <header 
        className={`
          fixed top-0 left-0 right-0 z-50
          transition-all duration-300 ease-out
          ${headerTheme === 'dark'
            ? isScrolled
              ? 'bg-[#0A0A0A]/90 backdrop-blur-xl border-b border-[#1A1A1A]'
              : 'bg-transparent'
            : isScrolled
              ? 'bg-white/95 backdrop-blur-xl border-b border-[#E2E8F0] shadow-sm'
              : 'bg-transparent'
          }
        `}
      >
        <div className="container-wide">
          <div className="flex items-center justify-between h-16">
            <StaticLink 
              href="/"
              className="flex items-center group"
              aria-label="返回首页"
            >
              <Image 
                src={headerTheme === 'dark' ? '/logo-white.svg' : '/logo.svg'} 
                alt={COMPANY_INFO.shortName}
                width={128}
                height={32}
                className="transition-transform duration-200 group-hover:scale-105"
                loading="eager"
                priority
              />
            </StaticLink>

            <nav className="hidden md:flex items-center gap-1" role="navigation" aria-label="主导航" data-testid="desktop-navigation">
              {navigationItems.map((item) => (
                <StaticLink
                  key={item.id}
                  href={item.href}
                  onClick={() => handleNavClick(item.href)}
                  className={`
                    relative px-3 py-1.5 text-sm font-medium
                    transition-all duration-300
                    ${headerTheme === 'dark'
                      ? isActive(item)
                        ? 'text-white'
                        : 'text-[#B0B0B0] hover:text-white'
                      : isActive(item)
                        ? 'text-[#1C1C1C]'
                        : 'text-[#3D3D3D] hover:text-[#1C1C1C]'
                    }
                  `}
                  aria-current={isActive(item) ? 'page' : undefined}
                >
                  {item.label}
                  <span 
                    className={`
                      absolute bottom-0 left-1/2 -translate-x-1/2 w-6 h-0.5 bg-[var(--color-brand-primary)] rounded-full
                      transition-all duration-200 ease-out
                      ${isActive(item) 
                        ? 'opacity-100 scale-x-100' 
                        : 'opacity-0 scale-x-0'
                      }
                    `}
                  />
                </StaticLink>
              ))}
            </nav>

            <div className="hidden md:flex items-center gap-3">
              <Button 
                size="sm"
                variant={headerTheme === 'dark' ? 'outline' : 'default'}
                className={headerTheme === 'dark' ? 'border-white/30 text-white hover:bg-white/10 hover:text-white' : ''}
                asChild
              >
                <StaticLink href="/contact" data-testid="consult-button">立即咨询</StaticLink>
              </Button>
            </div>

            <button
              className={`
                md:hidden p-3 -mr-3 rounded-lg transition-all duration-200 active:scale-95
                ${headerTheme === 'dark'
                  ? 'text-white hover:bg-white/10'
                  : 'text-[#3D3D3D] hover:text-[#1C1C1C] hover:bg-[#F5F5F5]'
                }
              `}
              onClick={() => setIsOpen(!isOpen)}
              onKeyDown={handleKeyDown}
              aria-expanded={isOpen}
              aria-controls="mobile-menu"
              aria-label={isOpen ? '关闭菜单' : '打开菜单'}
              data-testid="mobile-menu-button"
              style={{ minWidth: '44px', minHeight: '44px' }}
            >
              {isOpen ? <X className="w-6 h-6" /> : <Menu className="w-6 h-6" />}
            </button>
          </div>
        </div>
      </header>

      <AnimatePresence mode="wait">
        {isOpen && (
          <motion.div 
            ref={focusTrapRef}
            initial={{ opacity: 0 }}
            animate={{ opacity: 1 }}
            exit={{ opacity: 0 }}
            transition={{ duration: 0.2 }}
            className="fixed inset-0 z-40 md:hidden"
          >
            <div 
              className="absolute inset-0 bg-black/30 backdrop-blur-sm"
              onClick={() => setIsOpen(false)}
              aria-hidden="true"
            />
            <motion.div 
              initial={{ x: '100%' }}
              animate={{ x: 0 }}
              exit={{ x: '100%' }}
              transition={{ type: "spring", stiffness: 300, damping: 30 }}
              className="absolute top-16 right-0 bottom-0 left-0 bg-white/98 backdrop-blur-xl shadow-2xl overflow-y-auto"
              id="mobile-menu"
              role="navigation"
              aria-label="移动端导航"
              data-testid="mobile-navigation"
            >
              <nav className="container-wide py-6">
                {navigationItems.map((item, index) => (
                  <motion.div
                    key={item.id}
                    initial={{ x: 20, opacity: 0 }}
                    animate={{ x: 0, opacity: 1 }}
                    transition={{ delay: index * 0.05 }}
                  >
                    <StaticLink
                      href={item.href}
                      onClick={() => handleNavClick(item.href)}
                      className={`
                        block px-4 py-4 text-base font-medium rounded-lg
                        transition-all duration-200
                        ${isActive(item)
                          ? 'text-[#1C1C1C] bg-[#F5F5F5] border-l-4 border-[var(--color-brand-primary)]'
                          : 'text-[#3D3D3D] hover:text-[#1C1C1C] hover:bg-[#F5F5F5]'
                        }
                      `}
                      style={{ minHeight: '48px', display: 'flex', alignItems: 'center' }}
                    >
                      {item.label}
                    </StaticLink>
                  </motion.div>
                ))}
                <div className="mt-6 px-4 pt-6 border-t border-[#E2E8F0]">
                  <Button 
                    className="w-full"
                    asChild
                    size="lg"
                  >
                    <StaticLink href="/contact" onClick={() => setIsOpen(false)}>
                      联系我们
                    </StaticLink>
                  </Button>
                </div>
              </nav>
            </motion.div>
          </motion.div>
        )}
      </AnimatePresence>
    </>
  );
}

function HeaderFallback() {
  return (
    <header className="fixed top-0 left-0 right-0 z-50 bg-transparent">
      <div className="container-wide">
        <div className="flex items-center justify-between h-16">
          <div className="h-8 w-8 bg-gray-200 animate-pulse rounded" />
          <nav className="hidden md:flex items-center gap-1">
            {[1, 2, 3, 4, 5].map((i) => (
              <div key={i} className="h-6 w-16 bg-gray-200 animate-pulse rounded mx-1" />
            ))}
          </nav>
          <div className="h-9 w-20 bg-gray-200 animate-pulse rounded" />
        </div>
      </div>
    </header>
  );
}

export function Header() {
  return (
    <Suspense fallback={<HeaderFallback />}>
      <HeaderContent />
    </Suspense>
  );
}