/**
 * Admin Shift Volunteers Module
 * Handles volunteer management modals and shift email functionality
 */

// Volunteer management state
let currentShiftData = null;
let allUsers = [];

// Load all users for the dropdown
async function loadAllUsers() {
    try {
        const response = await fetch('/api/users');
        const data = await response.json();
        
        if (data.success) {
            allUsers = data.users;
            populateUserSelect();
        } else {
            console.error('Failed to load users:', data.error);
        }
    } catch (error) {
        console.error('Error loading users:', error);
    }
}

// Populate user select dropdown
function populateUserSelect() {
    const select = document.getElementById('user-select');
    if (!select) return;
    
    // Clear existing options except the first one
    select.innerHTML = '<option value="">Select a user...</option>';
    
    allUsers.forEach(user => {
        const option = document.createElement('option');
        option.value = user.email || user.Email;
        option.textContent = `${user.name || user.Name || ''} (${user.email || user.Email})`;
        select.appendChild(option);
    });
}

// Show the shift user management modal
async function showShiftUserModal(shiftId, shiftData) {
    currentShiftData = { ...shiftData, ID: shiftId };
    
    // Update modal title and info
    const modalTitle = document.getElementById('modal-shift-title');
    const modalDetails = document.getElementById('modal-shift-details');
    
    if (modalTitle) modalTitle.textContent = shiftData.Title;
    
    if (modalDetails) {
        const shiftDate = window.adminCore.createLocalDate(shiftData.Date);
        modalDetails.textContent = 
            `${shiftDate.toLocaleDateString()} | ${shiftData['Start Time']} - ${shiftData['End Time']} | ${shiftData.Location || 'TBD'}`;
    }
    
    // Load users if not already loaded
    if (allUsers.length === 0) {
        await loadAllUsers();
    }
    
    // Display current volunteers
    displayCurrentVolunteers(shiftData.signups || []);
    
    // Show modal
    const modal = document.getElementById('shift-user-modal');
    if (modal) {
        modal.style.display = 'flex';
    }
}

// Display current volunteers in the modal
function displayCurrentVolunteers(volunteers) {
    const container = document.getElementById('current-volunteers-list');
    
    if (!container) return;
    
    if (!volunteers || volunteers.length === 0) {
        container.innerHTML = '<div class="no-volunteers">No volunteers signed up yet.</div>';
        return;
    }
    
    container.innerHTML = volunteers.map(volunteer => `
        <div class="volunteer-item">
            <div class="volunteer-info">
                <div class="volunteer-name">${window.adminCore.escapeHtml(volunteer['User Name'] || volunteer['User Email'] || 'Unknown')}</div>
                <div class="volunteer-email">${window.adminCore.escapeHtml(volunteer['User Email'])}</div>
            </div>
            <div class="volunteer-actions">
                <button class="btn btn-danger btn-sm remove-volunteer-btn" 
                        data-volunteer-id="${volunteer.ID || volunteer.id}" 
                        data-volunteer-email="${volunteer['User Email']}">
                    Remove
                </button>
            </div>
        </div>
    `).join('');
    
    // Add event listeners for remove buttons
    setupVolunteerActionListeners();
}

// Setup event listeners for volunteer actions
function setupVolunteerActionListeners() {
    const container = document.getElementById('current-volunteers-list');
    
    if (container) {
        container.addEventListener('click', function(e) {
            if (e.target.classList.contains('remove-volunteer-btn')) {
                const volunteerId = e.target.getAttribute('data-volunteer-id');
                const volunteerEmail = e.target.getAttribute('data-volunteer-email');
                removeVolunteerFromShift(volunteerId, volunteerEmail);
            }
        });
    }
}

// Add user to shift
async function addUserToShift() {
    const userSelect = document.getElementById('user-select');
    const userEmail = userSelect?.value;
    
    if (!userEmail) {
        window.adminCore.showStatus('Please select a user to add', 'error');
        return;
    }
    
    if (!currentShiftData || !currentShiftData.ID) {
        window.adminCore.showStatus('No shift selected or invalid shift data', 'error');
        console.error('Invalid currentShiftData:', currentShiftData);
        return;
    }
    
    try {
        const response = await fetch(`/api/shifts/admin/${currentShiftData.ID}/add-user`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({ userEmail })
        });
        
        const data = await response.json();
        
        if (data.success) {
            window.adminCore.showStatus('User successfully added to shift', 'success');
            if (userSelect) userSelect.value = ''; // Clear selection
            
            // Refresh the shift data and reload volunteers with better error handling
            try {
                await refreshCurrentShiftData();
                console.log('Refreshed shift data after adding user');
            } catch (refreshError) {
                console.error('Error during refresh after adding user:', refreshError);
                // Still show success since the add operation worked
            }
        } else {
            window.adminCore.showStatus(data.error || 'Failed to add user to shift', 'error');
        }
    } catch (error) {
        console.error('Error adding user to shift:', error);
        window.adminCore.showStatus('Failed to add user to shift', 'error');
    }
}

// Remove volunteer from shift
async function removeVolunteerFromShift(volunteerId, volunteerEmail) {
    if (!confirm(`Are you sure you want to remove ${volunteerEmail} from this shift?`)) {
        return;
    }
    
    if (!currentShiftData || !currentShiftData.ID) {
        window.adminCore.showStatus('No shift selected or invalid shift data', 'error');
        console.error('Invalid currentShiftData:', currentShiftData);
        return;
    }
    
    try {
        const response = await fetch(`/api/shifts/admin/${currentShiftData.ID}/remove-user/${volunteerId}`, {
            method: 'DELETE'
        });
        
        const data = await response.json();
        
        if (data.success) {
            window.adminCore.showStatus('Volunteer successfully removed from shift', 'success');
            
            // Refresh the shift data and reload volunteers with better error handling
            try {
                await refreshCurrentShiftData();
                console.log('Refreshed shift data after removing volunteer');
            } catch (refreshError) {
                console.error('Error during refresh after removing volunteer:', refreshError);
                // Still show success since the remove operation worked
            }
        } else {
            window.adminCore.showStatus(data.error || 'Failed to remove volunteer from shift', 'error');
        }
    } catch (error) {
        console.error('Error removing volunteer from shift:', error);
        window.adminCore.showStatus('Failed to remove volunteer from shift', 'error');
    }
}

// Refresh current shift data
async function refreshCurrentShiftData() {
    if (!currentShiftData || !currentShiftData.ID) {
        console.warn('No current shift data or missing ID, skipping refresh');
        return;
    }
    
    try {
        console.log('Refreshing shift data for shift ID:', currentShiftData.ID);
        
        // Instead of reloading ALL admin shifts, just get this specific shift's signups
        // This prevents the expensive backend call and reduces the refresh cascade
        const response = await fetch(`/api/shifts/admin`);
        const data = await response.json();
        
        if (data.success && data.shifts && Array.isArray(data.shifts)) {
            const updatedShift = data.shifts.find(s => s && s.ID === currentShiftData.ID);
            if (updatedShift) {
                console.log('Found updated shift with', updatedShift.signups?.length || 0, 'volunteers');
                currentShiftData = updatedShift;
                displayCurrentVolunteers(updatedShift.signups || []);
                
                // Only update the specific shift in the main list, don't refresh everything
                updateShiftInList(updatedShift);
            } else {
                console.warn('Could not find updated shift with ID:', currentShiftData.ID);
            }
        } else {
            console.error('Failed to refresh shift data:', data.error || 'Invalid response format');
        }
    } catch (error) {
        console.error('Error refreshing shift data:', error);
    }
}

// Update a single shift in the list without full refresh
function updateShiftInList(updatedShift) {
    const shiftElement = document.querySelector(`[data-shift-id="${updatedShift.ID}"]`);
    if (shiftElement) {
        const shiftItem = shiftElement.closest('.shift-admin-item');
        if (shiftItem) {
            const signupCount = updatedShift.signups ? updatedShift.signups.length : 0;
            
            // Find the volunteer count paragraph (contains 👥)
            const volunteerCountElement = Array.from(shiftItem.querySelectorAll('p')).find(p => 
                p.textContent.includes('👥')
            );
            
            if (volunteerCountElement) {
                volunteerCountElement.textContent = `👥 ${signupCount}/${updatedShift['Max Volunteers']} volunteers`;
            }
            
            // Update the data attribute with new shift data
            const manageBtn = shiftItem.querySelector('.manage-volunteers-btn');
            if (manageBtn) {
                manageBtn.setAttribute('data-shift', JSON.stringify(updatedShift).replace(/'/g, "&#39;"));
            }
        }
    }
}

// Close modal
function closeShiftUserModal() {
    const modal = document.getElementById('shift-user-modal');
    if (modal) {
        modal.style.display = 'none';
    }
    currentShiftData = null;
    
    // Don't refresh the entire shifts list when closing modal
    // The shifts list should already be up to date from the individual updates
    console.log('Modal closed - shifts list should already be current');
}

// Email shift details to all volunteers
async function emailShiftDetails() {
    if (!currentShiftData) {
        window.adminCore.showStatus('No shift selected', 'error');
        return;
    }
    
    // Check if there are volunteers to email
    const volunteers = currentShiftData.signups || [];
    if (volunteers.length === 0) {
        window.adminCore.showStatus('No volunteers signed up for this shift', 'error');
        return;
    }
    
    // Confirm action
    const confirmMessage = `Send shift details email to ${volunteers.length} volunteer${volunteers.length !== 1 ? 's' : ''}?`;
    if (!confirm(confirmMessage)) {
        return;
    }

    // Initialize progress tracking for shift emails
    initializeShiftEmailProgress(volunteers.length);

    try {
        const response = await fetch(`/api/shifts/admin/${currentShiftData.ID}/email-details`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            }
        });
        
        const data = await response.json();
        
        if (data.success) {
            // Display detailed results
            updateShiftEmailProgress(data.results);
            window.adminCore.showStatus(data.message, 'success');
            console.log('Email results:', data.results);
        } else {
            showShiftEmailError(data.error || 'Failed to send emails');
            if (data.details) {
                console.error('Failed email details:', data.details);
            }
        }
    } catch (error) {
        console.error('Error sending shift details emails:', error);
        showShiftEmailError('Failed to send emails - Network error');
    }
}

// Initialize shift email progress display
function initializeShiftEmailProgress(totalCount) {
    const progressContainer = document.getElementById('shift-email-progress-container');
    const statusList = document.getElementById('shift-email-status-list');
    const pendingCountEl = document.getElementById('shift-pending-count');
    const successCountEl = document.getElementById('shift-success-count');
    const errorCountEl = document.getElementById('shift-error-count');
    const progressBar = document.getElementById('shift-email-progress-bar');
    const progressText = document.getElementById('shift-progress-text');
    const closeBtn = document.getElementById('close-shift-progress-btn');
    
    if (!progressContainer) return;
    
    // Show progress container
    progressContainer.classList.add('show');
    
    // Reset counters
    if (pendingCountEl) pendingCountEl.textContent = totalCount;
    if (successCountEl) successCountEl.textContent = '0';
    if (errorCountEl) errorCountEl.textContent = '0';
    
    // Reset progress bar
    if (progressBar) {
        progressBar.style.width = '0%';
        progressBar.classList.remove('complete', 'error');
    }
    if (progressText) progressText.textContent = '0%';
    
    // Clear status list
    if (statusList) statusList.innerHTML = '';
    
    // Hide close button initially
    if (closeBtn) closeBtn.style.display = 'none';
    
    // Add status items for each volunteer
    const volunteers = currentShiftData.signups || [];
    volunteers.forEach(volunteer => {
        if (statusList) {
            const statusItem = document.createElement('div');
            statusItem.className = 'email-status-item';
            statusItem.innerHTML = `
                <div class="email-status-recipient">${volunteer['User Name'] || volunteer['User Email']}</div>
                <div class="email-status-result pending">
                    <div class="progress-spinner"></div>
                    <span>Sending...</span>
                </div>
            `;
            statusList.appendChild(statusItem);
        }
    });
}

// Update shift email progress with results
function updateShiftEmailProgress(results) {
    const statusList = document.getElementById('shift-email-status-list');
    const pendingCountEl = document.getElementById('shift-pending-count');
    const successCountEl = document.getElementById('shift-success-count');
    const errorCountEl = document.getElementById('shift-error-count');
    const progressBar = document.getElementById('shift-email-progress-bar');
    const progressText = document.getElementById('shift-progress-text');
    const closeBtn = document.getElementById('close-shift-progress-btn');
    
    const successful = results.successful || [];
    const failed = results.failed || [];
    const total = results.total || (successful.length + failed.length);
    
    // Update counters
    if (successCountEl) successCountEl.textContent = successful.length;
    if (errorCountEl) errorCountEl.textContent = failed.length;
    if (pendingCountEl) pendingCountEl.textContent = '0';
    
    // Update progress bar
    const percentage = ((successful.length + failed.length) / total * 100).toFixed(1);
    if (progressBar) {
        progressBar.style.width = percentage + '%';
        progressText.textContent = percentage + '%';
        
        if (failed.length > 0) {
            progressBar.classList.add('error');
        } else {
            progressBar.classList.add('complete');
        }
    }
    
    // Update individual status items
    if (statusList) {
        const statusItems = statusList.children;
        
        // Update successful emails
        successful.forEach(result => {
            const statusItem = Array.from(statusItems).find(item => 
                item.querySelector('.email-status-recipient').textContent.includes(result.email) ||
                item.querySelector('.email-status-recipient').textContent.includes(result.name)
            );
            if (statusItem) {
                statusItem.querySelector('.email-status-result').innerHTML = `
                    <span class="email-status-result success">✓ Sent</span>
                `;
            }
        });
        
        // Update failed emails
        failed.forEach(result => {
            const statusItem = Array.from(statusItems).find(item => 
                item.querySelector('.email-status-recipient').textContent.includes(result.email) ||
                item.querySelector('.email-status-recipient').textContent.includes(result.name)
            );
            if (statusItem) {
                statusItem.querySelector('.email-status-result').innerHTML = `
                    <span class="email-status-result error" title="${result.error || 'Unknown error'}">✗ Failed</span>
                `;
            }
        });
    }
    
    // Show close button
    if (closeBtn) {
        closeBtn.style.display = 'block';
        closeBtn.onclick = () => {
            const progressContainer = document.getElementById('shift-email-progress-container');
            if (progressContainer) {
                progressContainer.classList.remove('show');
            }
        };
    }
}

// Show shift email error
function showShiftEmailError(message) {
    const progressContainer = document.getElementById('shift-email-progress-container');
    const progressBar = document.getElementById('shift-email-progress-bar');
    const progressText = document.getElementById('shift-progress-text');
    const closeBtn = document.getElementById('close-shift-progress-btn');
    
    // Show progress container if not visible
    if (progressContainer) {
        progressContainer.classList.add('show');
    }
    
    // Update progress bar to show error
    if (progressBar) {
        progressBar.style.width = '100%';
        progressBar.classList.add('error');
    }
    if (progressText) progressText.textContent = 'Error';
    
    // Show close button
    if (closeBtn) {
        closeBtn.style.display = 'block';
        closeBtn.onclick = () => {
            if (progressContainer) {
                progressContainer.classList.remove('show');
            }
        };
    }
    
    window.adminCore.showStatus(message, 'error');
}

// Setup volunteer modal event listeners
function setupVolunteerModalEventListeners() {
    const closeModalBtn = document.getElementById('close-user-modal');
    const addUserBtn = document.getElementById('add-user-btn');
    const emailShiftDetailsBtn = document.getElementById('email-shift-details-btn');
    const modal = document.getElementById('shift-user-modal');
    
    if (closeModalBtn) {
        closeModalBtn.addEventListener('click', closeShiftUserModal);
    }
    
    if (addUserBtn) {
        addUserBtn.addEventListener('click', addUserToShift);
    }
    
    if (emailShiftDetailsBtn) {
        emailShiftDetailsBtn.addEventListener('click', emailShiftDetails);
    }
    
    // Close modal when clicking outside
    if (modal) {
        modal.addEventListener('click', function(e) {
            if (e.target === modal) {
                closeShiftUserModal();
            }
        });
    }
}

// Export shift volunteer functions
window.adminShiftVolunteers = {
    showShiftUserModal,
    closeShiftUserModal,
    addUserToShift,
    removeVolunteerFromShift,
    emailShiftDetails,
    setupVolunteerModalEventListeners,
    loadAllUsers,
    getCurrentShiftData: () => currentShiftData,
    getAllUsers: () => allUsers
};