document.addEventListener('DOMContentLoaded', function () {
    // 네비게이션 메뉴 로직
    const navItems = document.querySelectorAll('.nav-item');
    const subMenus = document.querySelectorAll('.nav-sub-menu .sub-menu-inner');
    const navSubMenu = document.getElementById('nav-sub-menu');
    let leaveTimeout;

    if (navItems.length > 0 && subMenus.length > 0 && navSubMenu) {
        navItems.forEach(item => {
            item.addEventListener('mouseenter', function () {
                clearTimeout(leaveTimeout);
                const menu = this.getAttribute('data-menu');

                // 모든 서브메뉴 숨기기 및 활성 클래스 제거
                subMenus.forEach(submenu => {
                    submenu.style.display = 'none';
                });
                navItems.forEach(navItem => {
                    navItem.classList.remove('active');
                });

                // 해당 서브메뉴 보이기 및 활성 클래스 추가
                const targetSubMenu = document.querySelector(`.sub-menu-inner[data-menu="${menu}"]`);
                if (targetSubMenu) {
                    targetSubMenu.style.display = 'block';
                    this.classList.add('active');
                    navSubMenu.classList.add('active');
                }
            });
        });

        navSubMenu.addEventListener('mouseleave', function () {
            this.classList.remove('active');
            navItems.forEach(item => item.classList.remove('active'));
        });

        navSubMenu.addEventListener('mouseenter', function () {
            clearTimeout(leaveTimeout);
        });

        document.querySelector('.top-area').addEventListener('mouseleave', function () {
            navSubMenu.classList.remove('active');
            navItems.forEach(item => item.classList.remove('active'));
        });
    }

    // 전체메뉴 오버레이 로직
    const menuToggle = document.getElementById('menuToggle');
    const menuClose = document.getElementById('menuClose');
    const fullMenuOverlay = document.getElementById('fullMenuOverlay');

    if (menuToggle && menuClose && fullMenuOverlay) {
        menuToggle.addEventListener('click', () => {
            fullMenuOverlay.classList.add('active');
        });

        menuClose.addEventListener('click', () => {
            fullMenuOverlay.classList.remove('active');
        });
    }


    // 아래는 메인페이지 전용 영상 슬라이더 로직
    const videos = document.querySelectorAll('.main-bg');
    if (videos.length > 0) {
        // 영상이 있으면(메인페이지)만 영상 관련 코드 실행
        const mainVisualPaging = document.querySelector('.main-visual-paging');
        const mainVisualTitle = document.querySelector('.main-visual-title');
        const progressFills = [
            document.getElementById('progress-1'),
            document.getElementById('progress-2'),
            document.getElementById('progress-3')
        ];
        let currentVideoIndex = 0;
        let isTransitioning = false;
        let autoplayAttempted = false;

        // Progress fill elements check removed

        const koreanSlogans = [
            {
                eng: "AI Technology",
                line1: "AI 모델/데이터 기반, 시계열 및 영상 데이터 특화",
                line2: "멀티모달 AI와 MLOps 솔루션으로",
                line3: "미래를 엽니다."
            },
            {
                eng: "Digital Twin Technology",
                line1: "현실과 가상을 완벽하게 연결하는",
                line2: "디지털 트윈 기술로 새로운",
                line3: "미래를 만들어갑니다."
            },
            {
                eng: "Big Data Analytics",
                line1: "빅데이터 분석으로 인사이트를 발견하고",
                line2: "데이터 기반의 혁신적인",
                line3: "솔루션을 제공합니다."
            }
        ];

        function attemptAutoplay() {
            if (autoplayAttempted) return;
            autoplayAttempted = true;
            videos.forEach((video, index) => {
                video.muted = true;
                video.playsInline = true;
                video.loop = false;
                video.autoplay = true;
                video.style.display = 'none';
                video.pause();
                video.currentTime = 0;
            });
            const firstVideo = videos[0];
            firstVideo.style.display = 'block';
            const playAttempts = [
                () => firstVideo.play(),
                () => new Promise(resolve => {
                    firstVideo.play().then(resolve).catch(() => {
                        document.body.click();
                        setTimeout(() => firstVideo.play().then(resolve), 100);
                    });
                }),
                () => new Promise(resolve => {
                    setTimeout(() => firstVideo.play().then(resolve), 1000);
                })
            ];
            let attemptIndex = 0;
            const tryNextAttempt = () => {
                if (attemptIndex < playAttempts.length) {
                    playAttempts[attemptIndex]()
                        .then(() => {
                            startVideoSequence();
                        })
                        .catch(error => {
                            attemptIndex++;
                            tryNextAttempt();
                        });
                } else {
                    showPlayButton();
                }
            };
            tryNextAttempt();
        }

        function showPlayButton() {
            const playButton = document.createElement('button');
            playButton.textContent = 'Play';
            playButton.style.cssText = `
                position: absolute;
                top: 50%;
                left: 50%;
                transform: translate(-50%, -50%);
                z-index: 1000;
                background: rgba(0, 0, 0, 0.8);
                color: white;
                border: none;
                padding: 20px 40px;
                border-radius: 8px;
                cursor: pointer;
                font-size: 18px;
                font-weight: bold;
                box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
            `;
            playButton.addEventListener('click', () => {
                playButton.remove();
                startVideoSequence();
            });
            document.querySelector('.main-image').appendChild(playButton);
        }

        function initializeVideos() {
            videos.forEach((video, index) => {
                video.muted = true;
                video.playsInline = true;
                video.loop = false;
                video.style.display = 'none';
                video.pause();
                video.currentTime = 0;
                video.addEventListener('ended', function () {
                    if (index === currentVideoIndex) {
                        nextVideo();
                    }
                });
                video.addEventListener('play', function () {
                    // Video started playing
                });
                video.addEventListener('error', function (e) {
                    // Video error occurred
                });
            });
        }

        function startVideoSequence() {
            currentVideoIndex = 0;
            playCurrentVideo();
        }

        function playCurrentVideo() {
            if (isTransitioning) return;
            isTransitioning = true;
            videos.forEach(video => {
                video.style.display = 'none';
                video.pause();
            });
            const currentVideo = videos[currentVideoIndex];
            currentVideo.style.display = 'block';
            if (mainVisualPaging) {
                mainVisualPaging.textContent = `${String(currentVideoIndex + 1).padStart(2, '0')}/03`;
            }
            updateSlogan(currentVideoIndex);
            resetProgressBars();
            const playPromise = currentVideo.play();
            if (playPromise !== undefined) {
                playPromise.then(() => {
                    startProgressBar(currentVideo, currentVideoIndex);
                    isTransitioning = false;
                }).catch(error => {
                    setTimeout(() => {
                        isTransitioning = false;
                        nextVideo();
                    }, 1000);
                });
            }
        }

        function nextVideo() {
            currentVideoIndex = (currentVideoIndex + 1) % videos.length;
            playCurrentVideo();
        }

        function updateSlogan(index) {
            if (!mainVisualTitle) return;
            const slogan = koreanSlogans[index];
            const engSloganElement = mainVisualTitle.querySelector('.eng-slogan');
            const koreanLines = mainVisualTitle.querySelectorAll('div:not(.eng-slogan)');
            if (engSloganElement) {
                engSloganElement.textContent = slogan.eng;
            }
            if (koreanLines.length >= 3) {
                koreanLines[0].textContent = slogan.line1;
                koreanLines[1].textContent = slogan.line2;
                koreanLines[2].textContent = slogan.line3;
            }
        }

        function resetProgressBars() {
            progressFills.forEach(fill => {
                if (fill) {
                    fill.style.width = '0%';
                }
            });
        }

        function startProgressBar(video, videoIndex) {
            const progressFill = progressFills[videoIndex];
            if (!progressFill) return;
            const updateProgress = () => {
                if (video.duration && !isNaN(video.duration) && video.duration > 0) {
                    const progress = (video.currentTime / video.duration) * 100;
                    progressFill.style.width = progress + '%';
                }
            };
            video.removeEventListener('timeupdate', updateProgress);
            video.addEventListener('timeupdate', updateProgress);
        }

        if (videos.length > 0) {
            initializeVideos();
            let loadedCount = 0;
            videos.forEach(video => {
                video.addEventListener('loadeddata', function () {
                    loadedCount++;
                    if (loadedCount === videos.length) {
                        attemptAutoplay();
                    }
                });
            });
            setTimeout(() => {
                if (loadedCount < videos.length) {
                    attemptAutoplay();
                }
            }, 5000);
        }

        const userInteractionEvents = ['click', 'touchstart', 'keydown', 'scroll'];
        userInteractionEvents.forEach(eventType => {
            document.addEventListener(eventType, function () {
                const currentVideo = videos[currentVideoIndex];
                if (currentVideo && currentVideo.paused && !autoplayAttempted) {
                    currentVideo.play().catch(error => {
                        // Failed to play video after user interaction
                    });
                }
            }, { once: true });
        });
    }

    // --- 아래부터는 모든 페이지에서 동작해야 하는 코드 ---

    const tabs = document.querySelectorAll('.headarea-tab');
    tabs.forEach(tab => {
        tab.addEventListener('click', function (e) {
            if (e.target.closest('a')) return;
            const link = this.querySelector('a');
            if (link && link.href) {
                window.location.href = link.href;
            }
        });
    });

    // 탭 네비게이션 드롭다운(.dropdown) 마우스 오버/아웃 이벤트
    if (document.querySelectorAll('.headarea-tab.dropdown').length > 0) {
        document.querySelectorAll('.headarea-tab.dropdown').forEach(tab => {
            tab.addEventListener('mouseenter', function () {
                this.classList.add('hover');
            });
            tab.addEventListener('mouseleave', function () {
                this.classList.remove('hover');
            });
        });
    }

    // 스크롤 이벤트 처리
    const topArea = document.querySelector('.top-area');
    if (topArea) {
        const handleScroll = () => {
            const scrollPosition = window.scrollY;
            if (scrollPosition >= 80) {
                topArea.classList.add('scrolled');
            } else {
                topArea.classList.remove('scrolled');
            }
        };

        window.addEventListener('scroll', handleScroll);
        // 초기 로드 시 스크롤 위치 확인
        handleScroll();
    }

    // 스크롤 방향에 따라 .top-area 보이기/숨기기
    let lastScrollY = window.scrollY;
    let ticking = false;
    function handleFloatingMenu() {
        const currentScrollY = window.scrollY;
        if (!topArea) return;
        if (currentScrollY < 10) {
            topArea.classList.add('show-on-scroll');
            topArea.classList.remove('hide-on-scroll');
        } else if (currentScrollY < lastScrollY) {
            // 위로 스크롤: 메뉴 보이기
            topArea.classList.add('show-on-scroll');
            topArea.classList.remove('hide-on-scroll');
        } else if (currentScrollY > lastScrollY) {
            // 아래로 스크롤: 메뉴 숨기기
            topArea.classList.remove('show-on-scroll');
            topArea.classList.add('hide-on-scroll');
        }
        lastScrollY = currentScrollY;
        ticking = false;
    }
    function onScroll() {
        if (!ticking) {
            window.requestAnimationFrame(handleFloatingMenu);
            ticking = true;
        }
    }
    window.addEventListener('scroll', onScroll);
    // 초기 상태
    if (topArea) topArea.classList.add('show-on-scroll');
});