admin.js

// Initialize Firebase
const firebaseConfig = {
    apiKey: "AIzaSyBRlsk-knQs-AMlaTFxlneBMTwlSfwyFaQ",
    authDomain: "dsmnru-data.firebaseapp.com",
    projectId: "dsmnru-data",
    storageBucket: "dsmnru-data.firebasestorage.app",
    messagingSenderId: "62250453477",
    appId: "1:62250453477:web:087c07403e4fead220470c",
    measurementId: "G-VL6V3T96YX"
};

firebase.initializeApp(firebaseConfig);

const auth = firebase.auth();
const db = firebase.firestore();
const storage = firebase.storage();
let allData = { pyqs: [], users: [], pendingUploads: [], contributors: [] };
const ADMIN_EMAIL = 'kush210431@gmail.com';

function isAdminUser(user) {
    return !!user && user.email === ADMIN_EMAIL;
}

document.addEventListener('DOMContentLoaded', function() {
    setupSectionCollapseBehavior();

    // Auth state listener
    auth.onAuthStateChanged(user => {
        if (user) {
            if (!isAdminUser(user)) {
                auth.signOut();
                document.getElementById('loginError').textContent = 'You do not have admin access.';
                document.getElementById('loginError').style.display = 'block';
                document.getElementById('loginSection').style.display = 'block';
                document.getElementById('adminSection').style.display = 'none';
                return;
            }
            // User is signed in
            document.getElementById('loginSection').style.display = 'none';
            document.getElementById('adminSection').style.display = 'block';
            loadData();
        } else {
            // User is signed out
            resetLazyLoadState();
            document.getElementById('loginSection').style.display = 'block';
            document.getElementById('adminSection').style.display = 'none';
        }
    });

    // Login form
    document.getElementById('loginForm').addEventListener('submit', function(e) {
        e.preventDefault();
        const email = document.getElementById('email').value;
        const password = document.getElementById('password').value;
        const errorDiv = document.getElementById('loginError');

        auth.signInWithEmailAndPassword(email, password)
            .then(() => {
                errorDiv.style.display = 'none';
            })
            .catch(error => {
                errorDiv.textContent = error.message;
                errorDiv.style.display = 'block';
            });
    });

    // Logout
    document.getElementById('logoutBtn').addEventListener('click', function() {
        auth.signOut();
    });

    // Generate sitemap button
    const genBtn = document.getElementById('generateSitemapBtn');
    if (genBtn) {
        genBtn.addEventListener('click', function() {
            if (!auth.currentUser) {
                alert('You must be signed in to generate the sitemap.');
                return;
            }
            generateSitemap();
        });
    }

    // Add PYQ form
    document.getElementById('addPyqForm').addEventListener('submit', async function(e) {
        e.preventDefault();
        const course = document.getElementById('pyqCourse').value.trim();
        const semester = document.getElementById('pyqSemester').value.trim();
        const subject = document.getElementById('pyqSubject').value.trim();
        const session = document.getElementById('pyqSession').value.trim();
        const file = document.getElementById('pyqFile').value;

        if (!course || !semester || !subject || !session || !file) {
            alert('Please fill in course, semester, subject, session, and file URL.');
            return;
        }

        let currentSubject = subject;
        let title = buildPyqTitle(course, semester, currentSubject, session);
        let duplicateExists = await pyqTitleExists(title);

        if (duplicateExists === null) {
            return;
        }

        while (duplicateExists) {
            const shouldRename = confirm(
                `A PYQ with this title already exists:\n\n${title}\n\nDo you want to provide another subject name?`
            );

            if (!shouldRename) {
                return;
            }

            const alternativeSubject = prompt('Enter another subject name for this PYQ:', currentSubject);
            if (alternativeSubject === null) {
                return;
            }

            currentSubject = alternativeSubject.trim();
            if (!currentSubject) {
                alert('Subject name cannot be empty.');
                continue;
            }

            title = buildPyqTitle(course, semester, currentSubject, session);

            duplicateExists = await pyqTitleExists(title);
            if (duplicateExists === null) {
                return;
            }
        }

        addItem('pyqs', { title, file, course, semester, subject: currentSubject, session });
        this.reset();
    });

    // Edit form
    document.getElementById('editForm').addEventListener('submit', function(e) {
        e.preventDefault();
        const type = document.getElementById('editType').value;
        const index = parseInt(document.getElementById('editIndex').value);
        const title = document.getElementById('editTitle').value;
        const file = document.getElementById('editFile').value;
        const course = document.getElementById('editCourse').value;
        const semester = document.getElementById('editSemester').value;
        editItem(type, index, { title, file, course, semester });
        bootstrap.Modal.getInstance(document.getElementById('editModal')).hide();
    });
});

function setupSectionCollapseBehavior() {
    const adminSection = document.getElementById('adminSection');
    if (!adminSection || !window.bootstrap || !window.bootstrap.Collapse) {
        return;
    }

    const collapses = Array.from(adminSection.querySelectorAll('.section-card .collapse'));
    collapses.forEach(currentCollapse => {
        currentCollapse.addEventListener('show.bs.collapse', function() {
            collapses.forEach(otherCollapse => {
                if (otherCollapse === currentCollapse || !otherCollapse.classList.contains('show')) {
                    return;
                }

                window.bootstrap.Collapse.getOrCreateInstance(otherCollapse, { toggle: false }).hide();
            });
        });
    });
}

function loadData() {
    // Auto-load pending uploads and registered users so counts and panels show immediately.
    loadPendingOnDemand();
    loadUsersOnDemand();
}

function resetLazyLoadState() {
    pyqsLoaded = false;
    pendingLoaded = false;
    usersLoaded = false;
    contributorsLoaded = false;
}

function generateSitemap() {
    // Build sitemap XML from allData
    try {
        const baseUrl = 'https://dsmnru-pyq.netlify.app/';
        const urls = [];

        // Add homepage
        urls.push({ loc: baseUrl, priority: 1.0, changefreq: 'daily' });

        // Add index.html explicitly
        urls.push({ loc: baseUrl + 'index.html', priority: 0.9, changefreq: 'daily' });

        // Add each PYQ file URL if present
        allData.pyqs.forEach(item => {
            if (item.file) urls.push({ loc: item.file, priority: 0.8, changefreq: 'monthly' });
        });

        const xmlParts = ['<?xml version="1.0" encoding="UTF-8"?>', '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">'];
        urls.forEach(u => {
            xmlParts.push('  <url>');
            xmlParts.push(`    <loc>${escapeXml(u.loc)}</loc>`);
            if (u.changefreq) xmlParts.push(`    <changefreq>${u.changefreq}</changefreq>`);
            if (u.priority !== undefined) xmlParts.push(`    <priority>${u.priority.toFixed(2)}</priority>`);
            xmlParts.push('  </url>');
        });
        xmlParts.push('</urlset>');
        const sitemapXml = xmlParts.join('\n');

        // Download as file instead of uploading to Firebase
        const blob = new Blob([sitemapXml], { type: 'application/xml' });
        const url = URL.createObjectURL(blob);
        const link = document.createElement('a');
        link.href = url;
        link.download = 'sitemap.xml';
        document.body.appendChild(link);
        link.click();
        document.body.removeChild(link);
        URL.revokeObjectURL(url);

        updateSitemapStatus('done', 'sitemap.xml');
        alert(`✓ Sitemap generated successfully!\n\nGenerated ${urls.length} URLs:\n- Homepage\n- ${allData.pyqs.length} PYQ items\n\nFile downloaded as sitemap.xml`);
    } catch (err) {
        console.error('Error generating sitemap:', err);
        updateSitemapStatus('error');
        alert('Error generating sitemap: ' + err.message);
    }
}

function escapeXml(unsafe) {
    return (unsafe || '').replace(/[<>&'\"]/g, function(c) {
        switch (c) {
            case '<': return '&lt;';
            case '>': return '&gt;';
            case '&': return '&amp;';
            case "'": return '&apos;';
            case '"': return '&quot;';
        }
    });
}

function updateSitemapStatus(state, url) {
    const container = document.getElementById('sitemapStatus');
    const msg = document.getElementById('sitemapMessage');
    const link = document.getElementById('sitemapUrl');
    if (!container || !msg || !link) return;
    if (state === 'ready') {
        container.style.display = 'none';
    } else if (state === 'uploading') {
        container.style.display = 'block';
        msg.textContent = 'Generating sitemap and uploading...';
        link.style.display = 'none';
    } else if (state === 'done') {
        container.style.display = 'block';
        msg.textContent = 'Sitemap uploaded. Public URL:';
        link.href = url;
        link.textContent = url;
        link.style.display = 'block';
    } else if (state === 'error') {
        container.style.display = 'block';
        msg.textContent = 'Error generating sitemap. See console.';
        link.style.display = 'none';
    }
}

function renderLists() {
    renderPyqs();
    renderUsers();
    updateDashboardStats();
}

function updateDashboardStats() {
    const setCount = (id, value) => {
        const element = document.getElementById(id);
        if (element) {
            element.textContent = value;
        }
    };

    setCount('pyqsCount', allData.pyqs.length);
    setCount('pyqsHeaderCount', allData.pyqs.length);
    setCount('usersCount', allData.users.length);
    setCount('usersHeaderCount', allData.users.length);
    setCount('pendingCount', allData.pendingUploads.length);
    setCount('pendingHeaderCount', allData.pendingUploads.length);
    setCount('contributorsCount', allData.contributors.length);
    setCount('contributorsHeaderCount', allData.contributors.length);
}

function escapeHtml(value) {
    return (value || '')
        .toString()
        .replace(/&/g, '&amp;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;')
        .replace(/"/g, '&quot;')
        .replace(/'/g, '&#39;');
}

function copyToClipboard(text) {
    const value = (text || '').toString();
    if (!value) {
        alert('Nothing to copy.');
        return;
    }

    if (navigator.clipboard && navigator.clipboard.writeText) {
        navigator.clipboard.writeText(value)
            .then(() => alert('Copied to clipboard.'))
            .catch(() => fallbackCopy(value));
        return;
    }

    fallbackCopy(value);
}

function fallbackCopy(value) {
    const tempInput = document.createElement('input');
    tempInput.value = value;
    document.body.appendChild(tempInput);
    tempInput.select();
    document.execCommand('copy');
    document.body.removeChild(tempInput);
    alert('Copied to clipboard.');
}

function renderPyqs() {
    const list = document.getElementById('pyqsList');
    if (!list) return;

    if (!allData.pyqs.length) {
        list.innerHTML = '<div class="resource-empty">No PYQs added yet.</div>';
        updateDashboardStats();
        return;
    }

    list.innerHTML = allData.pyqs.map((pyq, index) => `
        <article class="resource-card">
            <div class="resource-top">
                <div>
                    <div class="resource-kicker">PYQ ${index + 1}</div>
                    <h5 class="resource-title">${escapeHtml(pyq.title)}</h5>
                    <div class="resource-meta">
                        ${pyq.course ? `<span class="resource-pill">${escapeHtml(pyq.course)}</span>` : ''}
                        ${pyq.semester ? `<span class="resource-pill">${escapeHtml(pyq.semester)} semester</span>` : ''}
                        ${pyq.session ? `<span class="resource-pill">${escapeHtml(pyq.session)} session</span>` : ''}
                    </div>
                </div>
                <div class="resource-actions">
                    <button class="btn btn-sm btn-outline-light" onclick='copyToClipboard(${JSON.stringify(pyq.file || '')})'>Copy URL</button>
                    <button class="btn btn-sm btn-outline-primary" onclick="editPyq(${index})">Edit</button>
                    <button class="btn btn-sm btn-outline-danger" onclick="deleteItem('pyqs', ${index})">Delete</button>
                </div>
            </div>
            <div class="resource-detail">${escapeHtml(pyq.file)}</div>
        </article>
    `).join('');

    updateDashboardStats();
}

function renderUsers() {
    const list = document.getElementById('usersList');
    if (!list) return;

    if (!allData.users.length) {
        list.innerHTML = '<div class="resource-empty">No registered users found.</div>';
        updateDashboardStats();
        return;
    }

    list.innerHTML = allData.users.map((user, index) => {
        const createdAt = user.createdAt ? new Date(user.createdAt.toDate()).toLocaleString() : 'Unknown';
        return `
        <article class="resource-card">
            <div class="resource-top">
                <div class="d-flex align-items-start gap-3">
                    <div class="contributor-avatar-small">${escapeHtml((user.name || user.signupName || 'U').slice(0, 2).toUpperCase())}</div>
                    <div>
                        <div class="resource-kicker">Registered user ${index + 1}</div>
                        <h5 class="resource-title">${escapeHtml(user.name || user.signupName || 'Unnamed User')}</h5>
                        <div class="resource-meta">
                            <span class="resource-pill">${escapeHtml(user.role || 'user')}</span>
                            <span class="resource-pill">${escapeHtml(user.course || user.signupCourse || 'N/A')}</span>
                        </div>
                    </div>
                </div>
                <div class="resource-actions">
                    <button class="btn btn-sm btn-outline-primary" onclick="editUser('${user.uid}')"><i class="fas fa-edit me-1"></i>Edit</button>
                    <button class="btn btn-sm btn-outline-danger" onclick="deleteUser('${user.uid}', '${(user.name || user.signupName || 'user').replace(/'/g, "\\'")}')"><i class="fas fa-trash me-1"></i>Delete</button>
                </div>
            </div>
            <div class="resource-detail">
                <div>Email: ${escapeHtml(user.email || user.signupEmail || 'No email')}</div>
                <div>Phone: ${escapeHtml(user.phone || 'N/A')}</div>
                <div>Created: ${escapeHtml(createdAt)}</div>
                <div>UID: ${escapeHtml(user.uid || 'N/A')}</div>
            </div>
        </article>
    `;
    }).join('');

    updateDashboardStats();
}

function addItem(type, item) {
    // Add document to Firestore collection
    db.collection(type).add(item)
        .then(docRef => {
            allData[type].push({ id: docRef.id, ...item });
            renderLists();
            alert('Item added successfully!');
        })
        .catch(error => {
            console.error('Error adding item:', error);
            alert('Error adding item. Please try again.');
        });
}

function editItem(type, index, item) {
    const existing = allData[type][index];
    if (!existing || !existing.id) {
        alert('Unable to find item id to update.');
        return;
    }
    db.collection(type).doc(existing.id).set(item, { merge: true })
        .then(() => {
            allData[type][index] = { id: existing.id, ...item };
            renderLists();
            alert('Item updated successfully!');
        })
        .catch(error => {
            console.error('Error updating item:', error);
            alert('Error updating item. Please try again.');
        });
}

function deleteItem(type, index) {
    if (confirm('Are you sure you want to delete this item?')) {
        const existing = allData[type][index];
        if (!existing || !existing.id) {
            alert('Unable to find item id to delete.');
            return;
        }
        db.collection(type).doc(existing.id).delete()
            .then(() => {
                allData[type].splice(index, 1);
                renderLists();
                alert('Item deleted successfully!');
            })
            .catch(error => {
                console.error('Error deleting item:', error);
                alert('Error deleting item. Please try again.');
            });
    }
}

function saveData() {
    // Deprecated for Firestore-based flows. Keep for compatibility but warn.
    console.warn('saveData() called - this project now uses Firestore. Use addItem/editItem/deleteItem instead.');
}

function buildPyqTitle(course, semester, subject, session) {
    return `${normalizePyqText(course)} ${normalizePyqText(semester)} Sem ${normalizePyqText(subject)} {${normalizePyqText(session)}}`;
}

function normalizePyqText(value) {
    return (value || '').toString().replace(/\s+/g, ' ').trim();
}

function pyqTitleExists(title) {
    return db.collection('pyqs').where('title', '==', title).get()
        .then(snapshot => !snapshot.empty)
        .catch(error => {
            console.error('Error checking for duplicate PYQ title:', error);
            alert('Unable to validate duplicate PYQ titles right now. Please try again.');
            return null;
        });
}

// Global functions for onclick
window.editPyq = function(index) {
    const pyq = allData.pyqs[index];
    document.getElementById('editType').value = 'pyqs';
    document.getElementById('editIndex').value = index;
    document.getElementById('editTitle').value = pyq.title;
    document.getElementById('editFile').value = pyq.file;
    document.getElementById('editCourseDiv').style.display = 'none';
    document.getElementById('editSemesterDiv').style.display = 'none';
    new bootstrap.Modal(document.getElementById('editModal')).show();
};

window.deleteItem = deleteItem;
window.editUser = function(uid) {
    const user = allData.users.find(item => item.uid === uid);
    if (!user) {
        alert('User not found.');
        return;
    }

    document.getElementById('userEditUid').value = user.uid || '';
    document.getElementById('userEditName').value = user.name || user.signupName || '';
    document.getElementById('userEditEmail').value = user.email || user.signupEmail || '';
    document.getElementById('userEditCourse').value = user.course || user.signupCourse || '';
    document.getElementById('userEditPhone').value = user.phone || '';
    document.getElementById('userEditRole').value = user.role || 'user';
    document.getElementById('userEditCreatedAt').value = user.createdAt ? new Date(user.createdAt.toDate()).toLocaleString() : 'Unknown';

    const modal = new bootstrap.Modal(document.getElementById('userEditModal'));
    modal.show();
};

window.deleteUser = function(uid, name) {
    if (confirm(`Are you sure you want to delete ${name}?`)) {
        db.collection('users').doc(uid).delete()
            .then(() => {
                allData.users = allData.users.filter(item => item.uid !== uid);
                renderUsers();
                alert('User record deleted successfully!');
            })
            .catch(error => {
                console.error('Error deleting user:', error);
                alert('Error deleting user: ' + error.message);
            });
    }
};

    document.addEventListener('DOMContentLoaded', function() {
        const userEditForm = document.getElementById('userEditForm');
        if (!userEditForm) return;

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

            const uid = document.getElementById('userEditUid').value;
            const name = document.getElementById('userEditName').value.trim();
            const email = document.getElementById('userEditEmail').value.trim();
            const course = document.getElementById('userEditCourse').value.trim();
            const phone = document.getElementById('userEditPhone').value.trim();
            const role = document.getElementById('userEditRole').value.trim();

            if (!uid || !name || !email || !course || !phone || !role) {
                alert('All user fields are required.');
                return;
            }

            const updatedUser = {
                uid,
                name,
                email,
                course,
                phone,
                role,
                signupName: name,
                signupEmail: email,
                signupCourse: course
            };

            db.collection('users').doc(uid).set(updatedUser, { merge: true })
                .then(() => {
                    const index = allData.users.findIndex(item => item.uid === uid);
                    if (index !== -1) {
                        allData.users[index] = { ...allData.users[index], ...updatedUser };
                    }
                    renderUsers();
                    bootstrap.Modal.getInstance(document.getElementById('userEditModal')).hide();
                    alert('User updated successfully!');
                })
                .catch(error => {
                    console.error('Error updating user:', error);
                    alert('Error updating user: ' + error.message);
                });
        });
    });
// Pending Uploads Management
function loadPendingUploads() {
    db.collection('pendingUploads').where('status', '==', 'pending').get()
        .then(snapshot => {
            allData.pendingUploads = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
            const pendingCount = allData.pendingUploads.length;
            updateDashboardStats();
            
            if (pendingCount === 0) {
                document.getElementById('pendingUploadsList').innerHTML = '';
                document.getElementById('noPendingMessage').style.display = 'block';
            } else {
                document.getElementById('noPendingMessage').style.display = 'none';
                renderPendingUploads(allData.pendingUploads);
            }
        })
        .catch(error => {
            console.error('Error loading pending uploads:', error);
        });
}

function renderPendingUploads(pendingDocs) {
    const list = document.getElementById('pendingUploadsList');
    if (!list) return;

    if (!pendingDocs.length) {
        list.innerHTML = '<div class="resource-empty">No pending uploads found.</div>';
        updateDashboardStats();
        return;
    }

    list.innerHTML = pendingDocs.map((doc, index) => {
        // doc is already a converted object with { id, ...data }
        const data = doc;
        const uploadDate = data.uploadedAt ? new Date(data.uploadedAt.toDate()).toLocaleString() : 'Unknown';
        return `
            <article class="resource-card">
                <div class="resource-top">
                    <div>
                        <div class="resource-kicker">Pending upload ${index + 1}</div>
                        <h5 class="resource-title">${escapeHtml(data.title)}</h5>
                        <div class="resource-meta">
                            <span class="resource-pill">${escapeHtml(data.course || 'N/A')}</span>
                            <span class="resource-pill">${escapeHtml(data.semester || 'N/A')}</span>
                        </div>
                    </div>
                    <div class="resource-actions">
                        <button class="btn btn-sm btn-outline-light" onclick='copyToClipboard(${JSON.stringify(data.downloadUrl || '')})'>Copy URL</button>
                        <button class="btn btn-sm btn-outline-info" onclick="downloadPendingFile('${data.downloadUrl}', '${data.fileName.replace(/'/g, "\\'")}')">
                            <i class="fas fa-download me-1"></i> Download
                        </button>
                        <button class="btn btn-sm btn-outline-danger" onclick="deletePendingUpload('${doc.id}')">
                            <i class="fas fa-trash me-1"></i> Delete
                        </button>
                    </div>
                </div>
                <div class="resource-detail">
                    <div>File: <code>${escapeHtml(data.fileName)}</code></div>
                    <div>Uploaded by: <strong>${escapeHtml(data.studentName || 'Anonymous')}</strong></div>
                    <div>${escapeHtml(uploadDate)}</div>
                </div>
            </article>
        `;
    }).join('');

    updateDashboardStats();
}

function downloadPendingFile(downloadUrl, fileName) {
    const a = document.createElement('a');
    a.href = downloadUrl;
    a.download = fileName;
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
}

function deletePendingUpload(docId) {
    if (confirm('Delete this pending upload from the list? The file on gofile.io will auto-delete after 30 days.')) {
        // Delete from Firestore only
        db.collection('pendingUploads').doc(docId).delete()
            .then(() => {
                alert('Upload removed from pending list!');
                loadPendingUploads();
            })
            .catch(error => {
                console.error('Error deleting upload:', error);
                alert('Error deleting upload: ' + error.message);
            });
    }
}

// Global function for onclick
window.downloadPendingFile = downloadPendingFile;
window.deletePendingUpload = deletePendingUpload;

// Lazy loading functions - only load data when section is expanded
let pyqsLoaded = false;
let syllabusLoaded = false;
let pendingLoaded = false;
let usersLoaded = false;

window.loadPyqsOnDemand = function() {
    if (pyqsLoaded) return;
    pyqsLoaded = true;
    
    db.collection('pyqs').get()
        .then(pyqSnap => {
            allData.pyqs = pyqSnap.docs.map(doc => ({ id: doc.id, ...doc.data() }));
            document.getElementById('pyqsCount').textContent = allData.pyqs.length;
            renderPyqs();
        })
        .catch(error => {
            console.error('Error loading PYQs:', error);
            document.getElementById('pyqsList').innerHTML = '<div class="alert alert-danger">Error loading PYQs</div>';
        });
};

window.loadPendingOnDemand = function() {
    if (pendingLoaded) return;
    pendingLoaded = true;
    loadPendingUploads();
};

window.loadUsersOnDemand = function() {
    if (usersLoaded) return;
    usersLoaded = true;

    db.collection('users').orderBy('createdAt', 'desc').get()
        .then(snapshot => {
            allData.users = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
            document.getElementById('usersCount').textContent = allData.users.length;
            renderUsers();
        })
        .catch(error => {
            console.error('Error loading users:', error);
            const list = document.getElementById('usersList');
            if (list) {
                list.innerHTML = '<div class="alert alert-danger">Error loading users</div>';
            }
        });
};
// Contributor Management Functions
let contributorsLoaded = false;

window.loadContributorsOnDemand = function() {
    if (contributorsLoaded) return;
    contributorsLoaded = true;
    loadContributors();
};

function loadContributors() {
    db.collection('contributors').orderBy('name').get()
        .then(snapshot => {
            const contributors = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
            allData.contributors = contributors;
            contributorsLoaded = true;
            renderContributors(contributors);
            updateDashboardStats();
        })
        .catch(error => {
            console.error('Error loading contributors:', error);
            document.getElementById('contributorsList').innerHTML = '<div class="alert alert-danger">Error loading contributors</div>';
        });
}

function renderContributors(contributors) {
    const list = document.getElementById('contributorsList');
    if (!list) return;

    if (!contributors.length) {
        list.innerHTML = '<div class="resource-empty">No contributors yet. Add one using the form above.</div>';
        updateDashboardStats();
        return;
    }

    list.innerHTML = contributors.map(contributor => `
        <article class="resource-card">
            <div class="resource-top">
                <div class="d-flex align-items-start gap-3">
                    <div class="contributor-avatar-small">${escapeHtml(contributor.avatar)}</div>
                    <div>
                        <div class="resource-kicker">Contributor</div>
                        <h5 class="resource-title">${escapeHtml(contributor.name)}</h5>
                        <div class="resource-meta">
                            <span class="resource-pill">${escapeHtml(contributor.role)}</span>
                        </div>
                    </div>
                </div>
                <div class="resource-actions">
                    <button class="btn btn-sm btn-outline-primary" onclick="editContributor('${contributor.id}', '${contributor.name}', '${contributor.avatar}', '${contributor.role}')">
                        <i class="fas fa-edit me-1"></i>Edit
                    </button>
                    <button class="btn btn-sm btn-outline-danger" onclick="deleteContributor('${contributor.id}', '${contributor.name}')">
                        <i class="fas fa-trash me-1"></i>Delete
                    </button>
                </div>
            </div>
        </article>
    `).join('');

    updateDashboardStats();
}

function getContributorInitials(name) {
    return name
        .trim()
        .split(/\s+/)
        .filter(part => part.length)
        .map(part => part[0].toUpperCase())
        .join('')
        .slice(0, 4);
}

const allowedContributorRoles = [
    'PYQs Provider',
    'Syllabus Provider',
    'PYQs + Syllabus Provider'
];

document.addEventListener('DOMContentLoaded', function() {
    // Contributor form submission
    const addContributorForm = document.getElementById('addContributorForm');
    if (addContributorForm) {
        const nameInput = document.getElementById('contributorName');
        const avatarInput = document.getElementById('contributorAvatar');
        const roleInput = document.getElementById('contributorRole');

        if (nameInput && avatarInput) {
            nameInput.addEventListener('input', function() {
                const initials = getContributorInitials(nameInput.value);
                avatarInput.value = initials;
            });
        }

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

            const name = nameInput.value.trim();
            const avatar = getContributorInitials(name);
            const role = roleInput.value;

            if (!name || !avatar || !role) {
                alert('Please fill all fields');
                return;
            }

            if (!allowedContributorRoles.includes(role)) {
                alert('Please select a valid role');
                return;
            }

            db.collection('contributors').add({
                name,
                avatar,
                role
            })
            .then(() => {
                addContributorForm.reset();
                loadContributors();
            })
            .catch(error => {
                console.error('Error adding contributor:', error);
                alert('Error adding contributor: ' + error.message);
            });
        });
        
        // Load contributors on page init
        loadContributors();
    }
});

window.editContributor = function(id, name, avatar, role) {
    const newName = prompt('Edit name:', name);
    if (newName === null) return;

    const newRole = prompt('Edit role (PYQs Provider / Syllabus Provider / PYQs + Syllabus Provider):', role);
    if (newRole === null) return;

    const trimmedName = newName.trim();
    const trimmedRole = newRole.trim();
    const newAvatar = getContributorInitials(trimmedName);

    if (!trimmedName || !newAvatar || !trimmedRole) {
        alert('All fields are required');
        return;
    }

    if (!allowedContributorRoles.includes(trimmedRole)) {
        alert('Please enter a valid role');
        return;
    }

    db.collection('contributors').doc(id).set({
        name: trimmedName,
        avatar: newAvatar,
        role: trimmedRole
    })
    .then(() => {
        loadContributors();
    })
    .catch(error => {
        console.error('Error updating contributor:', error);
        alert('Error updating contributor: ' + error.message);
    });
};

window.deleteContributor = function(id, name) {
    if (confirm(`Are you sure you want to delete ${name}?`)) {
        db.collection('contributors').doc(id).delete()
            .then(() => {
                loadContributors();
            })
            .catch(error => {
                console.error('Error deleting contributor:', error);
                alert('Error deleting contributor: ' + error.message);
            });
    }
};