script.js

// --- Data Configuration ---
const chapters = [
    {
        id: 13, name: "ALIPUR",
        video: "https://drive.google.com/file/d/15ep3wbj92XNFoB-3WMk5Ayro6j8xr1AW/preview",
        pdf: "https://drive.google.com/file/d/1Kr2o33yzxIX0nrdIMc4azZz5SqT8gLdf/preview",
        dl: "https://drive.google.com/uc?export=download&id=1Kr2o33yzxIX0nrdIMc4azZz5SqT8gLdf"
    },
    {
        id: 14, name: "MEMARI VM",
        video: "https://drive.google.com/file/d/1xcZ6MBx0SkR0icYNzYQSR432Uoll71-t/preview",
        pdf: "https://drive.google.com/file/d/15A2BGbE94hBC-RjNb9bf8iYdOFVLpPYe/preview",
        dl: "https://drive.google.com/uc?export=download&id=15A2BGbE94hBC-RjNb9bf8iYdOFVLpPYe"
    },
    {
        id: 15, name: "BANKURA CHRISTIAN",
        video: "https://drive.google.com/file/d/1dGwmXW24N5R8v4ciuHSaDOI9048sAoxX/preview",
        pdf: "https://drive.google.com/file/d/1Niw7qutrHlftvmY9LIQZ4yXZnF7UQBH-/preview",
        dl: "https://drive.google.com/uc?export=download&id=1Niw7qutrHlftvmY9LIQZ4yXZnF7UQBH-"
    },
    {
        id: 16, name: "JALPAIGURI",
        video: "https://drive.google.com/file/d/1z8X3qdERSuwViD59k1R38D_Z_IxUSgqy/preview",
        pdf: "https://drive.google.com/file/d/1Pfxd58Ci-kinsIg7km_U698uEs-O3eeF/preview",
        dl: "https://drive.google.com/uc?export=download&id=1Pfxd58Ci-kinsIg7km_U698uEs-O3eeF"
    },
    {
        id: 17, name: "NIMPITH",
        video: "https://drive.google.com/file/d/1Alx9Tz2wlpd8tAyoIj5OvQQzKwERWfzq/preview",
        pdf: "https://drive.google.com/file/d/1t_nnJxBTKk2JPuwQt7fi7ZjDXjBEV4Y5/preview",
        dl: "https://drive.google.com/uc?export=download&id=1t_nnJxBTKk2JPuwQt7fi7ZjDXjBEV4Y5"
    },
    {
        id: 18, name: "SILIGURI",
        video: "https://drive.google.com/file/d/1bYHO6alTyoEuYBQyKHO0guQmKRsmgrSv/preview",
        pdf: "https://drive.google.com/file/d/1tml81LYmxWlpdIuvVnxeSqQrJ8zjyDP6/preview",
        dl: "https://drive.google.com/uc?export=download&id=1tml81LYmxWlpdIuvVnxeSqQrJ8zjyDP6"
    }
];

// --- Initialization ---
document.addEventListener('DOMContentLoaded', () => {
    initStars(); // Load saved stars
    renderChapterList();
    handleRouting(); // Check current URL
});

window.addEventListener('hashchange', handleRouting);

// --- Routing (The Fix for Back Button) ---
function handleRouting() {
    const hash = window.location.hash;
    
    // Hide all views first
    document.querySelectorAll('.page-view').forEach(v => v.classList.add('hidden'));
    document.getElementById('nav-title').innerText = "Home";
    closeAllDropdowns();

    if (!hash || hash === '#home') {
        document.getElementById('view-home').classList.remove('hidden');
        document.getElementById('nav-title').innerText = "Chapter List";
    } 
    else if (hash.startsWith('#chapter/')) {
        const id = parseInt(hash.split('/')[1]);
        showChapterDetail(id);
    }
    else if (hash.startsWith('#player/')) {
        // format: #player/video/13 or #player/pdf/13
        const parts = hash.split('/');
        const type = parts[1];
        const id = parseInt(parts[2]);
        showPlayer(type, id);
    }
}

// --- Render Home List ---
function renderChapterList() {
    const list = document.getElementById('chapter-list');
    list.innerHTML = '';
    
    chapters.forEach((chap) => {
        const isStarred = localStorage.getItem(`star_${chap.id}`) === 'true';
        
        const card = document.createElement('div');
        card.className = `chapter-card ${isStarred ? 'starred' : ''}`;
        card.id = `card-${chap.id}`;
        card.innerHTML = `
            <div class="card-left" onclick="location.hash='#chapter/${chap.id}'">
                <span class="chap-id">CHAPTER ${chap.id}</span>
                <div class="chap-name">${chap.name}</div>
            </div>
            <span class="material-icons star-indicator">star</span>
            <div class="menu-btn" onclick="toggleDropdown(event, ${chap.id})">
                <span class="material-icons">more_vert</span>
            </div>
            
            <div class="dropdown" id="dd-${chap.id}">
                <div class="dd-item" onclick="window.open('${chap.dl}', '_blank')">Download PDF</div>
                <div class="dd-item" onclick="toggleStar(${chap.id})">
                    ${isStarred ? 'Unstar' : 'Star Mark'}
                </div>
            </div>
        `;
        list.appendChild(card);
    });
}

// --- Detail View Logic ---
function showChapterDetail(id) {
    const chap = chapters.find(c => c.id === id);
    if (!chap) return;

    document.getElementById('view-chapter').classList.remove('hidden');
    document.getElementById('nav-title').innerText = `${chap.id}. ${chap.name}`;

    // Setup buttons
    document.getElementById('btn-open-pdf').onclick = () => {
        location.hash = `#player/pdf/${id}`;
    };
    document.getElementById('btn-open-video').onclick = () => {
        location.hash = `#player/video/${id}`;
    };
}

// --- Player Logic ---
function showPlayer(type, id) {
    const chap = chapters.find(c => c.id === id);
    const playerView = document.getElementById('view-player');
    const iframe = document.getElementById('main-frame');
    const title = document.getElementById('player-title');
    
    playerView.classList.remove('hidden');
    
    if (type === 'video') {
        title.innerText = "Video: " + chap.name;
        iframe.src = chap.video;
    } else {
        title.innerText = "Solution: " + chap.name;
        iframe.src = chap.pdf;
    }

    // Nav Buttons
    const currentIndex = chapters.findIndex(c => c.id === id);
    
    document.getElementById('prev-chap-btn').onclick = () => {
        if (currentIndex > 0) {
            location.hash = `#player/${type}/${chapters[currentIndex - 1].id}`;
        } else alert("First Chapter");
    };
    
    document.getElementById('next-chap-btn').onclick = () => {
        if (currentIndex < chapters.length - 1) {
            location.hash = `#player/${type}/${chapters[currentIndex + 1].id}`;
        } else alert("Last Chapter");
    };
}

// --- Features ---

// Star Feature
function initStars() {
    // Just ensures storage is ready, no explicit action needed
}

function toggleStar(id) {
    const key = `star_${id}`;
    const current = localStorage.getItem(key) === 'true';
    localStorage.setItem(key, !current);
    
    renderChapterList(); // Re-render to update UI
}

// Sidebar
function toggleSidebar() {
    document.getElementById('sidebar').classList.toggle('active');
    const overlay = document.getElementById('overlay');
    overlay.style.display = overlay.style.display === 'block' ? 'none' : 'block';
}

// Dropdowns
function toggleDropdown(e, id) {
    e.stopPropagation();
    closeAllDropdowns();
    document.getElementById(`dd-${id}`).classList.add('show');
}

function closeAllDropdowns() {
    document.querySelectorAll('.dropdown').forEach(el => el.classList.remove('show'));
}

window.onclick = function(event) {
    if (!event.target.closest('.menu-btn')) {
        closeAllDropdowns();
    }
};

// Landscape
function toggleLandscape() {
    document.getElementById('player-wrapper').classList.toggle('landscape');
}

// Info Modals
const infoContent = {
    info: { title: "App Info", body: "Version 2.0<br>Built for Class 11 Semester 2 Math." },
    about: { title: "About", body: "This tool helps students access Ray & Martin solutions quickly and efficiently without lag." },
    creator: { title: "Creator", body: "Created by: <b>Faltu Chele</b><br>Dedication to learning." }
};

function showModal(type) {
    toggleSidebar();
    const data = infoContent[type];
    document.getElementById('modal-title').innerHTML = data.title;
    document.getElementById('modal-body').innerHTML = data.body;
    document.getElementById('info-modal').classList.remove('hidden');
}

function closeModal() {
    document.getElementById('info-modal').classList.add('hidden');
}