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

let selectedUserId = null;
let selectedNotepadId = null;
let allUsers = []; // Store users for client-side searching

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 style="padding:10px;">No users found.</p>';
        return;
    }

    users.forEach(user => {
        const userDiv = document.createElement('div');
        userDiv.className = 'user-item';
        
        // Handle "Unowned" user display specifically or generic
        const ipDisplay = user.id === 0 ? '' : `<br> <small>IP: ${escapeHtml(user.last_ip || 'Unknown')}</small>`;
        
        const infoDiv = document.createElement('div');
        infoDiv.innerHTML = `<strong>${escapeHtml(user.email)}</strong> (${escapeHtml(user.first_name)} ${escapeHtml(user.last_name)}) ${ipDisplay}`;
        
        const actionsDiv = document.createElement('div');

        // Ban IP Button (only for real users with IPs)
        if (user.last_ip && user.id !== 0) {
            const banIpBtn = document.createElement('button');
            banIpBtn.className = 'admin-button';
            banIpBtn.textContent = 'Ban IP';
            banIpBtn.onclick = (e) => {
                e.stopPropagation();
                banUserIp(user.id);
            };
            actionsDiv.appendChild(banIpBtn);
        }

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

        userDiv.addEventListener('click', () => {
            selectedUserId = user.id;
            loadNotepads(user.id);
            expandSection('notepad-list');
        });
        userListDiv.appendChild(userDiv);
    });
}

function initSearch() {
    const searchInput = document.getElementById('user-search');
    searchInput.addEventListener('input', (e) => {
        const term = e.target.value.toLowerCase();
        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))
        );
        renderUsers(filtered);
    });
}

async function loadNotepads(userId) {
    const notepadListDiv = document.getElementById('notepad-list');
    notepadListDiv.innerHTML = '<p>Loading notepads...</p>';

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

        notepadListDiv.innerHTML = '';
        notepads.forEach(notepad => {
            const notepadDiv = document.createElement('div');
            notepadDiv.className = 'user-item';
            
            const infoDiv = document.createElement('div');
            infoDiv.innerHTML = `<strong>${escapeHtml(notepad.name)}</strong> (Public: ${notepad.is_public})`;
            
            const deleteBtn = document.createElement('button');
            deleteBtn.className = 'admin-button';
            deleteBtn.textContent = 'Delete Pad';
            deleteBtn.onclick = async (e) => {
                e.stopPropagation();
                if(confirm('Delete this entire notepad and all its notes?')) {
                    await deleteNotepad(notepad.id);
                    loadNotepads(userId);
                }
            };

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

            notepadDiv.addEventListener('click', () => {
                selectedNotepadId = notepad.id;
                loadNotes(notepad.id);
                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) {
    const noteListDiv = document.getElementById('note-list');
    noteListDiv.innerHTML = '<p>Loading notes...</p>';

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

        noteListDiv.innerHTML = '';
        notes.forEach(note => {
            const noteDiv = document.createElement('div');
            noteDiv.className = 'user-item';
            
            const infoDiv = document.createElement('div');
            infoDiv.innerHTML = `<strong>${escapeHtml(note.title)}</strong>: ${escapeHtml(note.content)}`;
            noteDiv.appendChild(infoDiv);

            // Add delete button for each note
            const deleteButton = document.createElement('button');
            deleteButton.className = 'admin-button';
            deleteButton.textContent = 'Delete Note';
            deleteButton.addEventListener('click', async (e) => {
                e.stopPropagation(); // Prevent selecting the note
                if (confirm('Are you sure you want to delete this note?')) {
                    await deleteNote(note.id);
                    loadNotes(notepadId); // Refresh notes after deletion
                }
            });
            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.');
        } else {
            alert('Failed to delete notepad.');
        }
    } catch (err) {
        console.error(err);
    }
}

async function banUserIp(userId) {
    if(!confirm("Are you sure you want to ban this IP address? This will block all future access 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);
    } catch (err) {
        console.error(err);
        alert("Error banning IP");
    }
}

async function loadStats() {
    const container = document.getElementById('admin-stats');
    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>${stats.user_count}</h3><p>Users</p></div>
            <div class="stat-card"><h3>${stats.notepad_count}</h3><p>Notepads</p></div>
            <div class="stat-card"><h3>${stats.note_count}</h3><p>Notes</p></div>
        `;
    } catch (err) {
        console.error(err);
        container.innerHTML = '';
    }
}

function initCollapsibles() {
    const headers = document.querySelectorAll('.section-title');
    headers.forEach(header => {
        header.addEventListener('click', () => {
            const content = header.nextElementSibling;
            content.classList.toggle('collapsed');
        });
    });
}

function expandSection(id) {
    const el = document.getElementById(id);
    if(el) el.classList.remove('collapsed');
}

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;");
}