/* ==================== 玄潮科技 - Main JavaScript ==================== */

(function () {
    'use strict';

    /* ----- DOM Ready ----- */
    document.addEventListener('DOMContentLoaded', function () {
        initMobileMenu();
        initSmoothScroll();
        initHeaderScroll();
        initActiveNav();
        initRevealAnimations();
        initCounters();
        initBackToTop();
        initContactForm();
        initFooterYear();
    });

    /* ==================== Mobile Menu ==================== */
    function initMobileMenu() {
        var btn = document.getElementById('mobile-menu-btn');
        var menu = document.getElementById('mobile-menu');
        if (!btn || !menu) return;

        btn.addEventListener('click', function () {
            menu.classList.toggle('hidden');
            var icon = btn.querySelector('i');
            if (menu.classList.contains('hidden')) {
                icon.className = 'fas fa-bars text-xl';
            } else {
                icon.className = 'fas fa-xmark text-xl';
            }
        });

        // Close mobile menu when a link is clicked
        var links = menu.querySelectorAll('.mobile-nav-link');
        links.forEach(function (link) {
            link.addEventListener('click', function () {
                menu.classList.add('hidden');
                btn.querySelector('i').className = 'fas fa-bars text-xl';
            });
        });
    }

    /* ==================== Smooth Scroll ==================== */
    function initSmoothScroll() {
        var links = document.querySelectorAll('a[href^="#"]');
        links.forEach(function (link) {
            link.addEventListener('click', function (e) {
                var href = link.getAttribute('href');
                if (href === '#' || href === '') return;
                var target = document.querySelector(href);
                if (!target) return;
                e.preventDefault();
                var headerHeight = document.getElementById('header').offsetHeight;
                var targetPos = target.getBoundingClientRect().top + window.pageYOffset - headerHeight + 1;
                window.scrollTo({
                    top: targetPos,
                    behavior: 'smooth'
                });
            });
        });
    }

    /* ==================== Header Scroll Effect ==================== */
    function initHeaderScroll() {
        var header = document.getElementById('header');
        if (!header) return;
        window.addEventListener('scroll', function () {
            if (window.scrollY > 10) {
                header.classList.add('scrolled');
            } else {
                header.classList.remove('scrolled');
            }
        });
    }

    /* ==================== Active Nav Highlighting ==================== */
    function initActiveNav() {
        var sections = document.querySelectorAll('section[id]');
        var navLinks = document.querySelectorAll('.nav-link');
        if (!sections.length || !navLinks.length) return;

        var observer = new IntersectionObserver(function (entries) {
            entries.forEach(function (entry) {
                if (entry.isIntersecting) {
                    var id = entry.target.getAttribute('id');
                    navLinks.forEach(function (link) {
                        if (link.getAttribute('href') === '#' + id) {
                            link.classList.add('active');
                            link.classList.remove('text-gray-600');
                        } else {
                            link.classList.remove('active');
                            link.classList.add('text-gray-600');
                        }
                    });
                }
            });
        }, {
            rootMargin: '-40% 0px -55% 0px'
        });

        sections.forEach(function (section) {
            observer.observe(section);
        });
    }

    /* ==================== Reveal Animations ==================== */
    function initRevealAnimations() {
        var elements = document.querySelectorAll('.reveal-up, .reveal-left, .reveal-right');
        if (!elements.length) return;

        // Set animation delay from inline style
        elements.forEach(function (el) {
            var styleDelay = el.style.animationDelay;
            if (styleDelay) {
                el.style.setProperty('--reveal-delay', styleDelay);
            }
        });

        var observer = new IntersectionObserver(function (entries) {
            entries.forEach(function (entry) {
                if (entry.isIntersecting) {
                    entry.target.classList.add('revealed');
                    observer.unobserve(entry.target);
                }
            });
        }, {
            threshold: 0.15,
            rootMargin: '0px 0px -50px 0px'
        });

        elements.forEach(function (el) {
            observer.observe(el);
        });
    }

    /* ==================== Counter Animation ==================== */
    function initCounters() {
        var counters = document.querySelectorAll('.counter');
        if (!counters.length) return;

        var observer = new IntersectionObserver(function (entries) {
            entries.forEach(function (entry) {
                if (entry.isIntersecting) {
                    animateCounter(entry.target);
                    observer.unobserve(entry.target);
                }
            });
        }, {
            threshold: 0.5
        });

        counters.forEach(function (counter) {
            observer.observe(counter);
        });
    }

    function animateCounter(el) {
        var target = parseInt(el.getAttribute('data-target'), 10);
        var duration = 2000;
        var startTime = null;

        function step(timestamp) {
            if (!startTime) startTime = timestamp;
            var progress = Math.min((timestamp - startTime) / duration, 1);
            // Ease out cubic
            var eased = 1 - Math.pow(1 - progress, 3);
            var current = Math.floor(eased * target);
            el.textContent = current;
            if (progress < 1) {
                requestAnimationFrame(step);
            } else {
                el.textContent = target;
            }
        }

        requestAnimationFrame(step);
    }

    /* ==================== Back to Top ==================== */
    function initBackToTop() {
        var btn = document.getElementById('back-to-top');
        if (!btn) return;

        window.addEventListener('scroll', function () {
            if (window.scrollY > 500) {
                btn.classList.add('visible');
                btn.classList.remove('opacity-0', 'invisible');
            } else {
                btn.classList.remove('visible');
                btn.classList.add('opacity-0', 'invisible');
            }
        });

        btn.addEventListener('click', function () {
            window.scrollTo({
                top: 0,
                behavior: 'smooth'
            });
        });
    }

    /* ==================== Contact Form ==================== */
    function initContactForm() {
        var form = document.getElementById('contact-form');
        if (!form) return;

        var successMsg = document.getElementById('form-success');

        form.addEventListener('submit', function (e) {
            e.preventDefault();

            // Clear previous errors
            var errorMessages = form.querySelectorAll('.error-msg');
            errorMessages.forEach(function (msg) { msg.classList.add('hidden'); });
            var inputs = form.querySelectorAll('.form-input');
            inputs.forEach(function (input) { input.classList.remove('error'); });

            var isValid = true;

            // Validate name
            var name = document.getElementById('name');
            if (!name.value.trim()) {
                showError(name, 'name');
                isValid = false;
            }

            // Validate phone (Chinese phone: 11 digits starting with 1, or landline)
            var phone = document.getElementById('phone');
            var phoneVal = phone.value.trim();
            if (!phoneVal || !/^[\d\s\-+()]{7,20}$/.test(phoneVal)) {
                showError(phone, 'phone');
                isValid = false;
            }

            // Validate email
            var email = document.getElementById('email');
            var emailVal = email.value.trim();
            if (!emailVal || !/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(emailVal)) {
                showError(email, 'email');
                isValid = false;
            }

            // Validate company
            var company = document.getElementById('company');
            if (!company.value.trim()) {
                showError(company, 'company');
                isValid = false;
            }

            // Validate message
            var message = document.getElementById('message');
            if (!message.value.trim()) {
                showError(message, 'message');
                isValid = false;
            }

            if (isValid) {
                // === Submit logic ===
                // 此处可对接后端API，示例：
                // fetch('/api/contact', { method: 'POST', body: new FormData(form) })
                //     .then(res => res.json())
                //     .then(data => { ... })
                //     .catch(err => { ... });

                // 模拟提交成功
                form.style.display = 'none';
                successMsg.classList.remove('hidden');

                // 5秒后恢复表单
                setTimeout(function () {
                    form.reset();
                    form.style.display = '';
                    successMsg.classList.add('hidden');
                }, 5000);
            }
        });

        function showError(input, fieldId) {
            input.classList.add('error');
            var errorMsg = input.parentElement.querySelector('.error-msg');
            if (errorMsg) {
                errorMsg.classList.remove('hidden');
            }
        }

        // Clear error on input
        var allInputs = form.querySelectorAll('.form-input');
        allInputs.forEach(function (input) {
            input.addEventListener('input', function () {
                input.classList.remove('error');
                var errorMsg = input.parentElement.querySelector('.error-msg');
                if (errorMsg) errorMsg.classList.add('hidden');
            });
        });
    }

    /* ==================== Footer Year ==================== */
    function initFooterYear() {
        var yearEl = document.getElementById('current-year');
        if (yearEl) {
            yearEl.textContent = new Date().getFullYear();
        }
    }

})();