document.addEventListener('DOMContentLoaded', () => {
    loadStats();
    loadReportedNotes();
    loadUsers();
    loadBannedIps();
    initCollapsibles();
    initSearch();
});

let selectedUserId = null;
let selectedNotepadId = null;
let allUsers = [];

async function loadStats() {
    const container = document.getElementById('admin-stats');
    const reportedBadge = document.getElementById('reported-badge');
    try {
        const res = await fetch('/admin/stats');
        if (res.status === 403) {
            window.location.href = '/login.html';
            return;
        }
        const stats = await res.json();
        
        container.innerHTML = `
            <div class="stat-card">
                <h3>${stats.user_count}</h3>
                <p>Users</p>
                <small>${stats.banned_user_count} banned</small>
            </div>
            <div class="stat-card">
                <h3>${stats.notepad_count}</h3>
                <p>Notepads</p>
                <small>${stats.public_notepad_count} Public · ${stats.private_notepad_count} Encrypted</small>
            </div>
            <div class="stat-card">
                <h3>${stats.note_count}</h3>
                <p>Total Notes</p>
                <small>${stats.public_note_count} Public · ${stats.encrypted_note_count} Encrypted</small>
            </div>
            <div class="stat-card">
                <h3 style="color:${stats.reported_note_count > 0 ? '#ef4444' : '#10b981'};">${stats.reported_note_count}</h3>
                <p>Reported Notes</p>
                <small>${stats.reported_note_count > 0 ? 'Requires attention' : 'All clear'}</small>
            </div>
        `;

        if (reportedBadge) {
            reportedBadge.textContent = stats.reported_note_count;
            reportedBadge.style.display = stats.reported_note_count > 0 ? 'inline-block' : 'none';
        }
    } catch (err) {
        console.error('Error loading stats:', err);
    }
}

async function loadReportedNotes() {
    const listDiv = document.getElementById('reported-list');
    listDiv.innerHTML = '<p>Loading reported notes...</p>';

    try {
        const res = await fetch('/admin/reported_notes');
        if (!res.ok) throw new Error('Failed to load reported notes');
        const notes = await res.json();

        listDiv.innerHTML = '';
        if (notes.length === 0) {
            listDiv.innerHTML = '<p class="empty-text">No notes reported. Public content is clean.</p>';
            return;
        }

        notes.forEach(note => {
            const item = document.createElement('div');
            item.className = 'user-item';

            const info = document.createElement('div');
            info.className = 'item-info';
            info.innerHTML = `
                <div>
                    <strong>🚩 ${escapeHtml(note.title)}</strong>
                    <span class="badge badge-public">Pad: ${escapeHtml(note.notepad_name)}</span>
                </div>
                <div style="font-size:0.88rem; color:#475569; margin:4px 0;">
                    ${escapeHtml(note.content)}
                </div>
                <div style="font-size:0.75rem; color:#94a3b8;">
                    Reported Note #${note.id} · Author: ${escapeHtml(note.author_email || 'Unknown')} · ${new Date(note.created_at).toLocaleString()}
                </div>
            `;

            const actions = document.createElement('div');
            actions.className = 'item-actions';

            const restoreBtn = document.createElement('button');
            restoreBtn.className = 'admin-button btn-success';
            restoreBtn.textContent = '✓ Restore Note';
            restoreBtn.onclick = async () => {
                if (confirm('Restore this note? It will become visible on the public map again.')) {
                    await restoreNote(note.id);
                }
            };

            const deleteBtn = document.createElement('button');
            deleteBtn.className = 'admin-button btn-danger';
            deleteBtn.textContent = '🗑️ Delete Note';
            deleteBtn.onclick = async () => {
                if (confirm('Permanently delete this reported note?')) {
                    await deleteNote(note.id);
                    loadReportedNotes();
                    loadStats();
                }
            };

            actions.appendChild(restoreBtn);
            actions.appendChild(deleteBtn);

            item.appendChild(info);
            item.appendChild(actions);
            listDiv.appendChild(item);
        });
    } catch (err) {
        console.error(err);
        listDiv.innerHTML = '<p style="color:red;">Error loading reported notes.</p>';
    }
}

async function restoreNote(noteId) {
    try {
        const res = await fetch(`/admin/notes/${noteId}/restore`, { method: 'POST' });
        const data = await res.json();
        alert(data.message || 'Note restored');
        loadReportedNotes();
        loadStats();
    } catch (err) {
        console.error(err);
        alert('Error restoring note');
    }
}

async function loadUsers() {
    const userListDiv = document.getElementById('user-list');
    userListDiv.innerHTML = '<p>Loading users...</p>';

    try {
        const res = await fetch('/admin/users');
        if (res.status === 403) {
            window.location.href = '/login.html';
            return;
        }
        allUsers = await res.json();
        renderUsers(allUsers);
    } catch (err) {
        console.error(err);
        userListDiv.innerHTML = '<p style="color:red;">Error loading users.</p>';
    }
}

function renderUsers(users) {
    const userListDiv = document.getElementById('user-list');
    userListDiv.innerHTML = '';
    
    if (users.length === 0) {
        userListDiv.innerHTML = '<p class="empty-text">No users found.</p>';
        return;
    }

    users.forEach(user => {
        const userDiv = document.createElement('div');
        userDiv.className = 'user-item';
        if (selectedUserId === user.id) userDiv.classList.add('selected');

        const infoDiv = document.createElement('div');
        infoDiv.className = 'item-info';

        const adminBadge = user.is_admin ? '<span class="badge badge-admin">Admin</span>' : '';
        const bannedBadge = user.is_banned ? '<span class="badge badge-banned">Banned</span>' : '';
        const ipDisplay = user.id === 0 ? '' : `<br><small style="color:#64748b;">IP: ${escapeHtml(user.last_ip || 'No IP recorded')}</small>`;
        
        infoDiv.innerHTML = `<strong>${escapeHtml(user.email)}</strong> ${escapeHtml(user.first_name ? `(${user.first_name} ${user.last_name})` : '')} ${adminBadge}${bannedBadge}${ipDisplay}`;
        
        const actionsDiv = document.createElement('div');
        actionsDiv.className = 'item-actions';

        if (user.id !== 0) {
            // Ban / Unban User
            const banUserBtn = document.createElement('button');
            banUserBtn.className = `admin-button ${user.is_banned ? 'btn-success' : 'btn-warning'}`;
            banUserBtn.textContent = user.is_banned ? 'Unban Account' : 'Ban Account';
            banUserBtn.onclick = async (e) => {
                e.stopPropagation();
                const action = user.is_banned ? 'unban' : 'ban';
                if (confirm(`Are you sure you want to ${action} user ${user.email}?`)) {
                    await toggleUserBan(user.id, user.is_banned);
                }
            };
            actionsDiv.appendChild(banUserBtn);

            // Ban IP Button
            if (user.last_ip) {
                const banIpBtn = document.createElement('button');
                banIpBtn.className = 'admin-button btn-secondary';
                banIpBtn.textContent = 'Ban IP';
                banIpBtn.onclick = (e) => {
                    e.stopPropagation();
                    banUserIp(user.id);
                };
                actionsDiv.appendChild(banIpBtn);
            }

            // Toggle Admin Button
            const toggleAdminBtn = document.createElement('button');
            toggleAdminBtn.className = 'admin-button btn-primary';
            toggleAdminBtn.textContent = user.is_admin ? 'Demote Admin' : 'Make Admin';
            toggleAdminBtn.onclick = async (e) => {
                e.stopPropagation();
                if (confirm(`${user.is_admin ? 'Demote' : 'Promote'} ${user.email} to Admin?`)) {
                    await toggleAdmin(user.id);
                }
            };
            actionsDiv.appendChild(toggleAdminBtn);

            // Delete User Button
            const deleteUserBtn = document.createElement('button');
            deleteUserBtn.className = 'admin-button btn-danger';
            deleteUserBtn.textContent = 'Delete User';
            deleteUserBtn.onclick = async (e) => {
                e.stopPropagation();
                if (confirm(`Permanently delete user ${user.email} and all their notepads/notes? This cannot be undone.`)) {
                    await deleteUser(user.id);
                }
            };
            actionsDiv.appendChild(deleteUserBtn);
        }

        userDiv.appendChild(infoDiv);
        userDiv.appendChild(actionsDiv);

        userDiv.addEventListener('click', () => {
            selectedUserId = user.id;
            document.querySelectorAll('#user-list .user-item').forEach(el => el.classList.remove('selected'));
            userDiv.classList.add('selected');
            loadNotepads(user.id, user.email);
            expandSection('notepad-list');
        });

        userListDiv.appendChild(userDiv);
    });
}

async function toggleUserBan(userId, isCurrentlyBanned) {
    try {
        const endpoint = isCurrentlyBanned ? `/admin/users/${userId}/unban` : `/admin/users/${userId}/ban`;
        const res = await fetch(endpoint, { method: 'POST' });
        const data = await res.json();
        alert(data.message || 'User status updated');
        loadUsers();
        loadStats();
    } catch (err) {
        console.error(err);
        alert('Error updating user ban status');
    }
}

async function toggleAdmin(userId) {
    try {
        const res = await fetch(`/admin/users/${userId}/toggle_admin`, { method: 'POST' });
        const data = await res.json();
        if (res.ok) {
            alert(data.message);
            loadUsers();
        } else {
            alert(data.error || 'Failed to update admin status');
        }
    } catch (err) {
        console.error(err);
        alert('Error updating admin status');
    }
}

async function deleteUser(userId) {
    try {
        const res = await fetch(`/admin/users/${userId}`, { method: 'DELETE' });
        const data = await res.json();
        alert(data.message || 'User deleted');
        selectedUserId = null;
        loadUsers();
        loadStats();
        document.getElementById('notepad-list').innerHTML = '<p class="empty-text">Select a user above to see their notepads.</p>';
        document.getElementById('note-list').innerHTML = '<p class="empty-text">Select a notepad to see its notes.</p>';
    } catch (err) {
        console.error(err);
        alert('Error deleting user');
    }
}

async function loadBannedIps() {
    const listDiv = document.getElementById('banned-ip-list');
    try {
        const res = await fetch('/admin/banned_ips');
        const ips = await res.json();

        listDiv.innerHTML = '';
        if (ips.length === 0) {
            listDiv.innerHTML = '<p class="empty-text">No IP addresses currently banned.</p>';
            return;
        }

        ips.forEach(item => {
            const row = document.createElement('div');
            row.className = 'user-item';

            const info = document.createElement('div');
            info.className = 'item-info';
            info.innerHTML = `<strong>🚫 ${escapeHtml(item.ip_address)}</strong> <span style="font-size:0.8rem; color:#94a3b8;">· Banned ${new Date(item.created_at).toLocaleString()}</span>`;

            const unbanBtn = document.createElement('button');
            unbanBtn.className = 'admin-button btn-success';
            unbanBtn.textContent = 'Unban IP';
            unbanBtn.onclick = async () => {
                if (confirm(`Unban IP address ${item.ip_address}?`)) {
                    await unbanIp(item.id);
                }
            };

            row.appendChild(info);
            row.appendChild(unbanBtn);
            listDiv.appendChild(row);
        });
    } catch (err) {
        console.error(err);
        listDiv.innerHTML = '<p style="color:red;">Error loading banned IPs.</p>';
    }
}

async function unbanIp(ipId) {
    try {
        const res = await fetch(`/admin/banned_ips/${ipId}`, { method: 'DELETE' });
        const data = await res.json();
        alert(data.message || 'IP unbanned');
        loadBannedIps();
    } catch (err) {
        console.error(err);
        alert('Error unbanning IP');
    }
}

async function banUserIp(userId) {
    if(!confirm("Are you sure you want to ban this IP address? This will block registration and login from this IP.")) return;
    try {
        const res = await fetch(`/admin/users/${userId}/ban_ip`, { method: 'POST' });
        const data = await res.json();
        alert(data.message || data.error);
        loadBannedIps();
    } catch (err) {
        console.error(err);
        alert("Error banning IP");
    }
}

async function loadNotepads(userId, userEmail) {
    const notepadListDiv = document.getElementById('notepad-list');
    const headerTitle = document.getElementById('notepads-header-title');
    if (headerTitle) {
        headerTitle.textContent = `📁 Notepads for: ${userEmail}`;
    }
    notepadListDiv.innerHTML = '<p>Loading notepads...</p>';

    try {
        const res = await fetch(`/admin/users/${userId}/notepads`);
        const notepads = await res.json();

        notepadListDiv.innerHTML = '';
        if (notepads.length === 0) {
            notepadListDiv.innerHTML = '<p class="empty-text">No notepads found for this user.</p>';
            return;
        }

        notepads.forEach(notepad => {
            const notepadDiv = document.createElement('div');
            notepadDiv.className = 'user-item';
            if (selectedNotepadId === notepad.id) notepadDiv.classList.add('selected');
            
            const badge = notepad.is_public ? 
                '<span class="badge badge-public">🌐 Public</span>' : 
                '<span class="badge badge-encrypted">🔒 Zero-Knowledge Encrypted</span>';

            const infoDiv = document.createElement('div');
            infoDiv.className = 'item-info';
            infoDiv.innerHTML = `<strong>${escapeHtml(notepad.name)}</strong> ${badge} <br><small style="color:#64748b;">Pad ID: #${notepad.id} · Notes: ${notepad.note_count || 0}</small>`;
            
            const deleteBtn = document.createElement('button');
            deleteBtn.className = 'admin-button btn-danger';
            deleteBtn.textContent = 'Delete Pad';
            deleteBtn.onclick = async (e) => {
                e.stopPropagation();
                if(confirm(`Delete entire notepad "${notepad.name}" and all its notes?`)) {
                    await deleteNotepad(notepad.id);
                    loadNotepads(userId, userEmail);
                    loadStats();
                }
            };

            notepadDiv.appendChild(infoDiv);
            notepadDiv.appendChild(deleteBtn);

            notepadDiv.addEventListener('click', () => {
                selectedNotepadId = notepad.id;
                document.querySelectorAll('#notepad-list .user-item').forEach(el => el.classList.remove('selected'));
                notepadDiv.classList.add('selected');
                loadNotes(notepad.id, notepad.name, notepad.is_public);
                expandSection('note-list');
            });
            notepadListDiv.appendChild(notepadDiv);
        });
    } catch (err) {
        console.error(err);
        notepadListDiv.innerHTML = '<p style="color:red;">Error loading notepads.</p>';
    }
}

async function loadNotes(notepadId, notepadName, isPublic) {
    const noteListDiv = document.getElementById('note-list');
    const headerTitle = document.getElementById('notes-header-title');
    if (headerTitle) {
        headerTitle.textContent = `📝 Notes in: ${notepadName}`;
    }
    noteListDiv.innerHTML = '<p>Loading notes...</p>';

    try {
        const res = await fetch(`/admin/notepads/${notepadId}/notes`);
        const notes = await res.json();

        noteListDiv.innerHTML = '';
        if (notes.length === 0) {
            noteListDiv.innerHTML = '<p class="empty-text">This notepad is empty.</p>';
            return;
        }

        notes.forEach(note => {
            const noteDiv = document.createElement('div');
            noteDiv.className = 'user-item';
            
            const infoDiv = document.createElement('div');
            infoDiv.className = 'item-info';

            if (note.is_encrypted) {
                const preview = note.content ? (note.content.length > 50 ? note.content.substring(0, 50) + '...' : note.content) : '';
                infoDiv.innerHTML = `
                    <div><strong>🔒 [Encrypted Private Note #${note.id}]</strong> <span class="badge badge-encrypted">E2EE Protected</span></div>
                    <div style="font-family:monospace; color:#64748b; font-size:0.8rem; margin:4px 0;">Zero-Knowledge Ciphertext: ${escapeHtml(preview)}</div>
                    <small style="color:#94a3b8;">Created: ${new Date(note.created_at).toLocaleString()} · Lat/Lng at Rest: Redacted [0, 0]</small>
                `;
            } else {
                infoDiv.innerHTML = `
                    <div><strong>🌐 ${escapeHtml(note.title)}</strong> <span class="badge badge-public">Public Note #${note.id}</span></div>
                    <div style="font-size:0.88rem; color:#334155; margin:4px 0;">${escapeHtml(note.content)}</div>
                    <small style="color:#94a3b8;">Location: (${note.lat}, ${note.lng}) · Created: ${new Date(note.created_at).toLocaleString()}</small>
                `;
            }
            noteDiv.appendChild(infoDiv);

            const deleteButton = document.createElement('button');
            deleteButton.className = 'admin-button btn-danger';
            deleteButton.textContent = 'Delete Note';
            deleteButton.addEventListener('click', async (e) => {
                e.stopPropagation();
                if (confirm('Permanently delete this note?')) {
                    await deleteNote(note.id);
                    loadNotes(notepadId, notepadName, isPublic);
                    loadStats();
                }
            });
            noteDiv.appendChild(deleteButton);

            noteListDiv.appendChild(noteDiv);
        });
    } catch (err) {
        console.error(err);
        noteListDiv.innerHTML = '<p style="color:red;">Error loading notes.</p>';
    }
}

async function deleteNote(noteId) {
    try {
        const res = await fetch(`/admin/notes/${noteId}`, { method: 'DELETE' });
        if (res.ok) {
            alert('Note deleted successfully.');
        } else {
            alert('Failed to delete note.');
        }
    } catch (err) {
        console.error(err);
        alert('Error deleting note.');
    }
}

async function deleteNotepad(notepadId) {
    try {
        const res = await fetch(`/admin/notepads/${notepadId}`, { method: 'DELETE' });
        if (res.ok) {
            alert('Notepad deleted.');
            document.getElementById('note-list').innerHTML = '<p class="empty-text">Select a notepad to see its notes.</p>';
        } else {
            alert('Failed to delete notepad.');
        }
    } catch (err) {
        console.error(err);
    }
}

function initSearch() {
    const searchInput = document.getElementById('user-search');
    if (!searchInput) return;
    searchInput.addEventListener('input', (e) => {
        const term = e.target.value.toLowerCase().trim();
        const filtered = allUsers.filter(user => 
            (user.email && user.email.toLowerCase().includes(term)) ||
            (user.first_name && user.first_name.toLowerCase().includes(term)) ||
            (user.last_name && user.last_name.toLowerCase().includes(term)) ||
            (user.last_ip && user.last_ip.toLowerCase().includes(term))
        );
        renderUsers(filtered);
    });
}

function initCollapsibles() {
    const headers = document.querySelectorAll('.section-title');
    headers.forEach(header => {
        header.addEventListener('click', () => {
            const section = header.parentElement;
            const content = section.querySelector('.section-content');
            if (content) {
                content.classList.toggle('collapsed');
                const icon = header.querySelector('.toggle-icon');
                if (icon) {
                    icon.textContent = content.classList.contains('collapsed') ? '▶' : '▼';
                }
            }
        });
    });
}

function expandSection(id) {
    const el = document.getElementById(id);
    if (el) {
        el.classList.remove('collapsed');
        const header = el.parentElement.querySelector('.section-title .toggle-icon');
        if (header) header.textContent = '▼';
    }
}

function escapeHtml(text) {
    if (text === null || text === undefined) return '';
    return String(text)
        .replace(/&/g, "&amp;")
        .replace(/</g, "&lt;")
        .replace(/>/g, "&gt;")
        .replace(/"/g, "&quot;")
        .replace(/'/g, "&#039;");
}