// XSS prevention helper
function escapeHtml(text) {
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
}

// Get ticket ID from URL (handles both /ticket/123 and ?id=123 formats)
function getTicketIdFromUrl() {
    // Try new URL format first: /ticket/123456789
    const pathMatch = window.location.pathname.match(/\/ticket\/(\d+)/);
    if (pathMatch) {
        return pathMatch[1];
    }
    // Fall back to query param: ?id=123456789
    const params = new URLSearchParams(window.location.search);
    return params.get('id');
}

/**
 * Toggle visibility groups field based on visibility selection
 */
function toggleVisibilityGroupsEdit() {
    const visibility = document.getElementById('visibilitySelect')?.value;
    const groupsField = document.getElementById('visibilityGroupsField');
    if (groupsField) {
        groupsField.style.display = visibility === 'internal' ? 'block' : 'none';
    }
}

/**
 * Get selected visibility groups
 */
function getSelectedVisibilityGroups() {
    const checkboxes = document.querySelectorAll('.visibility-group-checkbox:checked');
    return Array.from(checkboxes).map(cb => cb.value);
}

function saveTicket() {
    const editables = document.querySelectorAll('.editable');
    const data = {};
    
    const ticketId = getTicketIdFromUrl();
    
    if (!ticketId) {
        console.error('Could not determine ticket ID');
        return;
    }
    
    editables.forEach(field => {
        if (field.dataset.field) {
            // For contenteditable divs, use textContent/innerText; for inputs/textareas, use value
            if (field.hasAttribute('contenteditable')) {
                data[field.dataset.field] = field.textContent.trim();
            } else {
                data[field.dataset.field] = field.value;
            }
        }
    });

    // Get visibility settings
    const visibilitySelect = document.getElementById('visibilitySelect');
    if (visibilitySelect) {
        data.visibility = visibilitySelect.value;
        if (data.visibility === 'internal') {
            data.visibility_groups = getSelectedVisibilityGroups();
        }
    }

    // Use the correct API path
    const apiUrl = '/api/update_ticket.php';

    fetch(apiUrl, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            ticket_id: ticketId,
            ...data
        })
    })
    .then(response => {
        if (!response.ok) {
            return response.text().then(text => {
                console.error('Server response:', text);
                throw new Error('Network response was not ok');
            });
        }
        return response.json();
    })
    .then(data => {
        if(data.success) {
            const statusDisplay = document.getElementById('statusDisplay');
            if (statusDisplay) {
                statusDisplay.className = `status-${data.status}`;
                statusDisplay.textContent = data.status;
            }
            toast.success('Ticket updated successfully');
        } else {
            console.error('Error in API response:', data.error || 'Unknown error');
        }
    })
    .catch(error => {
        console.error('Error updating ticket:', error);
    });
}

function toggleEditMode() {
    const editButton = document.getElementById('editButton');
    const titleField = document.querySelector('.title-input');
    const descriptionField = document.querySelector('textarea[data-field="description"]');
    const metadataFields = document.querySelectorAll('.editable-metadata');
    const isEditing = editButton.classList.contains('active');

    if (!isEditing) {
        editButton.textContent = 'Save Changes';
        editButton.classList.add('active');

        // Enable title (contenteditable div)
        if (titleField) {
            titleField.setAttribute('contenteditable', 'true');
            titleField.focus();
        }

        // Enable description (textarea)
        if (descriptionField) {
            descriptionField.disabled = false;
        }

        // Enable metadata fields (priority, category, type)
        metadataFields.forEach(field => {
            field.disabled = false;
        });
    } else {
        saveTicket();
        editButton.textContent = 'Edit Ticket';
        editButton.classList.remove('active');

        // Disable title
        if (titleField) {
            titleField.setAttribute('contenteditable', 'false');
        }

        // Disable description
        if (descriptionField) {
            descriptionField.disabled = true;
        }

        // Disable metadata fields
        metadataFields.forEach(field => {
            field.disabled = true;
        });
    }
}

function addComment() {
    const commentText = document.getElementById('newComment').value;
    if (!commentText.trim()) {
        console.error('Comment text cannot be empty');
        return;
    }
    
    const ticketId = getTicketIdFromUrl();
    
    if (!ticketId) {
        console.error('Could not determine ticket ID');
        return;
    }
    
    const isMarkdownEnabled = document.getElementById('markdownMaster').checked;

    fetch('/api/add_comment.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            ticket_id: ticketId,
            comment_text: commentText,
            markdown_enabled: isMarkdownEnabled
        })
    })
    .then(response => {
        if (!response.ok) {
            return response.text().then(text => {
                console.error('Server response:', text);
                throw new Error('Network response was not ok');
            });
        }
        return response.json();
    })
    .then(data => {
        if(data.success) {
            // Clear the comment box
            document.getElementById('newComment').value = '';
            
            // Format the comment text for display
            let displayText;
            if (isMarkdownEnabled) {
                // For markdown, use parseMarkdown (sanitizes HTML)
                displayText = parseMarkdown(commentText);
            } else {
                // For non-markdown, convert line breaks to <br> and escape HTML
                displayText = commentText
                    .replace(/&/g, '&amp;')
                    .replace(/</g, '&lt;')
                    .replace(/>/g, '&gt;')
                    .replace(/"/g, '&quot;')
                    .replace(/'/g, '&#39;')
                    .replace(/\n/g, '<br>');
            }
            
            // Add new comment to the list (using safe DOM API to prevent XSS)
            const commentsList = document.querySelector('.comments-list');

            const commentDiv = document.createElement('div');
            commentDiv.className = 'comment';

            const headerDiv = document.createElement('div');
            headerDiv.className = 'comment-header';

            const userSpan = document.createElement('span');
            userSpan.className = 'comment-user';
            userSpan.textContent = data.user_name; // Safe - auto-escapes

            const dateSpan = document.createElement('span');
            dateSpan.className = 'comment-date';
            dateSpan.textContent = data.created_at; // Safe - auto-escapes

            const textDiv = document.createElement('div');
            textDiv.className = 'comment-text';
            textDiv.innerHTML = displayText; // displayText already sanitized above

            headerDiv.appendChild(userSpan);
            headerDiv.appendChild(dateSpan);
            commentDiv.appendChild(headerDiv);
            commentDiv.appendChild(textDiv);

            commentsList.insertBefore(commentDiv, commentsList.firstChild);
        } else {
            console.error('Error adding comment:', data.error || 'Unknown error');
        }
    })
    .catch(error => {
        console.error('Error adding comment:', error);
    });
}

function togglePreview() {
    const preview = document.getElementById('markdownPreview');
    const textarea = document.getElementById('newComment');
    const isPreviewEnabled = document.getElementById('markdownToggle').checked;
    
    preview.style.display = isPreviewEnabled ? 'block' : 'none';
    
    if (isPreviewEnabled) {
        preview.innerHTML = parseMarkdown(textarea.value);
        textarea.addEventListener('input', updatePreview);
    } else {
        textarea.removeEventListener('input', updatePreview);
    }
}

function updatePreview() {
    const commentText = document.getElementById('newComment').value;
    const previewDiv = document.getElementById('markdownPreview');
    const isMarkdownEnabled = document.getElementById('markdownMaster').checked;
    
    if (isMarkdownEnabled && commentText.trim()) {
        // For markdown preview, use parseMarkdown which handles line breaks correctly
        previewDiv.innerHTML = parseMarkdown(commentText);
        previewDiv.style.display = 'block';
    } else {
        previewDiv.style.display = 'none';
    }
}

function toggleMarkdownMode() {
    const previewToggle = document.getElementById('markdownToggle');
    const isMasterEnabled = document.getElementById('markdownMaster').checked;
    
    previewToggle.disabled = !isMasterEnabled;
    if (!isMasterEnabled) {
        previewToggle.checked = false;
        document.getElementById('markdownPreview').style.display = 'none';
    }
}

document.addEventListener('DOMContentLoaded', function() {
    // Show description tab by default
    showTab('description');

    // Auto-resize function for textareas
    function autoResizeTextarea(textarea) {
        // Reset height to auto to get the correct scrollHeight
        textarea.style.height = 'auto';
        // Set the height to match the scrollHeight
        textarea.style.height = textarea.scrollHeight + 'px';
    }

    // Auto-resize the description textarea to fit content
    const descriptionTextarea = document.querySelector('textarea[data-field="description"]');
    if (descriptionTextarea) {
        // Initial resize
        autoResizeTextarea(descriptionTextarea);

        // Resize on input when in edit mode
        descriptionTextarea.addEventListener('input', function() {
            autoResizeTextarea(this);
        });
    }

    // Initialize assignment handling
    handleAssignmentChange();

    // Initialize metadata field handlers (priority, category, type)
    handleMetadataChanges();
});

/**
 * Handle ticket assignment dropdown changes
 */
function handleAssignmentChange() {
    const assignedToSelect = document.getElementById('assignedToSelect');
    if (!assignedToSelect) return;

    assignedToSelect.addEventListener('change', function() {
        const ticketId = window.ticketData.id;
        const assignedTo = this.value || null;

        fetch('/api/assign_ticket.php', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRF-Token': window.CSRF_TOKEN
            },
            body: JSON.stringify({ ticket_id: ticketId, assigned_to: assignedTo })
        })
        .then(response => response.json())
        .then(data => {
            if (!data.success) {
                toast.error('Error updating assignment');
                console.error(data.error);
            }
        })
        .catch(error => {
            console.error('Error updating assignment:', error);
            toast.error('Error updating assignment: ' + error.message);
        });
    });
}

/**
 * Handle metadata field changes (priority, category, type)
 */
function handleMetadataChanges() {
    const prioritySelect = document.getElementById('prioritySelect');
    const categorySelect = document.getElementById('categorySelect');
    const typeSelect = document.getElementById('typeSelect');

    // Helper function to update ticket field
    function updateTicketField(fieldName, newValue) {
        const ticketId = window.ticketData.id;

        fetch('/api/update_ticket.php', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRF-Token': window.CSRF_TOKEN
            },
            body: JSON.stringify({
                ticket_id: ticketId,
                [fieldName]: fieldName === 'priority' ? parseInt(newValue) : newValue
            })
        })
        .then(response => response.json())
        .then(data => {
            if (!data.success) {
                toast.error(`Error updating ${fieldName}`);
                console.error(data.error);
            } else {
                // Update window.ticketData
                window.ticketData[fieldName] = fieldName === 'priority' ? parseInt(newValue) : newValue;

                // For priority, also update the priority indicator if it exists
                if (fieldName === 'priority') {
                    const priorityIndicator = document.querySelector('.priority-indicator');
                    if (priorityIndicator) {
                        priorityIndicator.className = `priority-indicator priority-${newValue}`;
                        priorityIndicator.textContent = 'P' + newValue;
                    }

                    // Update ticket container priority attribute
                    const ticketContainer = document.querySelector('.ticket-container');
                    if (ticketContainer) {
                        ticketContainer.setAttribute('data-priority', newValue);
                    }
                }
            }
        })
        .catch(error => {
            console.error(`Error updating ${fieldName}:`, error);
            toast.error(`Error updating ${fieldName}: ` + error.message);
        });
    }

    // Priority change handler
    if (prioritySelect) {
        prioritySelect.addEventListener('change', function() {
            updateTicketField('priority', this.value);
        });
    }

    // Category change handler
    if (categorySelect) {
        categorySelect.addEventListener('change', function() {
            updateTicketField('category', this.value);
        });
    }

    // Type change handler
    if (typeSelect) {
        typeSelect.addEventListener('change', function() {
            updateTicketField('type', this.value);
        });
    }
}

function updateTicketStatus() {
    const statusSelect = document.getElementById('statusSelect');
    const selectedOption = statusSelect.options[statusSelect.selectedIndex];
    const newStatus = selectedOption.value;
    const requiresComment = selectedOption.dataset.requiresComment === '1';
    const requiresAdmin = selectedOption.dataset.requiresAdmin === '1';

    // Check if transitioning to the same status (current)
    if (selectedOption.text.includes('(current)')) {
        return; // No change needed
    }

    // Warn if comment is required
    if (requiresComment) {
        showConfirmModal(
            'Status Change Requires Comment',
            `This transition to "${newStatus}" requires a comment explaining the reason.\n\nPlease add a comment before changing the status.`,
            'warning',
            () => {
                // User confirmed, proceed with status change
                performStatusChange(statusSelect, selectedOption, newStatus);
            },
            () => {
                // User cancelled, reset to current status
                statusSelect.selectedIndex = 0;
            }
        );
        return;
    }

    performStatusChange(statusSelect, selectedOption, newStatus);
}

// Extract status change logic into reusable function
function performStatusChange(statusSelect, selectedOption, newStatus) {
    const ticketId = getTicketIdFromUrl();

    if (!ticketId) {
        statusSelect.selectedIndex = 0;
        return;
    }

    // Update status via API
    fetch('/api/update_ticket.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            ticket_id: ticketId,
            status: newStatus
        })
    })
    .then(async response => {
        const text = await response.text();

        if (!response.ok) {
            console.error('Server error response:', text);
            try {
                const data = JSON.parse(text);
                throw new Error(data.error || 'Server returned an error');
            } catch (parseError) {
                throw new Error(text || 'Network response was not ok');
            }
        }

        try {
            return JSON.parse(text);
        } catch (parseError) {
            console.error('Failed to parse JSON:', text);
            throw new Error('Invalid JSON response from server');
        }
    })
    .then(data => {
        if (data.success) {
            // Update the dropdown to show new status as current
            const newClass = 'status-' + newStatus.toLowerCase().replace(/ /g, '-');
            statusSelect.className = 'editable status-select ' + newClass;

            // Update the selected option text to show as current
            selectedOption.text = newStatus + ' (current)';

            // Move the selected option to the top
            statusSelect.remove(statusSelect.selectedIndex);
            statusSelect.insertBefore(selectedOption, statusSelect.firstChild);
            statusSelect.selectedIndex = 0;

            // Reload page to refresh activity timeline
            setTimeout(() => {
                window.location.reload();
            }, 500);
        } else {
            console.error('Error updating status:', data.error || 'Unknown error');
            toast.error('Error updating status: ' + (data.error || 'Unknown error'));
            // Reset to current status
            statusSelect.selectedIndex = 0;
        }
    })
    .catch(error => {
        console.error('Error updating status:', error);
        toast.error('Error updating status: ' + error.message);
        // Reset to current status
        statusSelect.selectedIndex = 0;
    });
}

function showTab(tabName) {
    // Hide all tab contents
    const descriptionTab = document.getElementById('description-tab');
    const commentsTab = document.getElementById('comments-tab');
    const attachmentsTab = document.getElementById('attachments-tab');
    const dependenciesTab = document.getElementById('dependencies-tab');
    const activityTab = document.getElementById('activity-tab');

    if (!descriptionTab || !commentsTab) {
        console.error('Tab elements not found');
        return;
    }

    // Hide all tabs
    descriptionTab.style.display = 'none';
    commentsTab.style.display = 'none';
    if (attachmentsTab) {
        attachmentsTab.style.display = 'none';
    }
    if (dependenciesTab) {
        dependenciesTab.style.display = 'none';
    }
    if (activityTab) {
        activityTab.style.display = 'none';
    }

    // Remove active class from all buttons
    document.querySelectorAll('.tab-btn').forEach(btn => {
        btn.classList.remove('active');
    });

    // Show selected tab and activate its button
    document.getElementById(`${tabName}-tab`).style.display = 'block';
    document.querySelector(`[onclick="showTab('${tabName}')"]`).classList.add('active');

    // Load attachments when tab is shown
    if (tabName === 'attachments') {
        loadAttachments();
        initializeUploadZone();
    }

    // Load dependencies when tab is shown
    if (tabName === 'dependencies') {
        loadDependencies();
    }
}

// ========================================
// Dependency Management Functions
// ========================================

function loadDependencies() {
    const ticketId = window.ticketData.id;

    fetch(`/api/ticket_dependencies.php?ticket_id=${ticketId}`)
        .then(response => {
            if (!response.ok) {
                throw new Error(`HTTP ${response.status}`);
            }
            return response.json();
        })
        .then(data => {
            if (data.success) {
                renderDependencies(data.dependencies);
                renderDependents(data.dependents);
            } else {
                console.error('Error loading dependencies:', data.error);
                showDependencyError(data.error || 'Failed to load dependencies');
            }
        })
        .catch(error => {
            console.error('Error loading dependencies:', error);
            showDependencyError('Failed to load dependencies. The feature may not be available.');
        });
}

function showDependencyError(message) {
    const dependenciesList = document.getElementById('dependenciesList');
    const dependentsList = document.getElementById('dependentsList');

    if (dependenciesList) {
        dependenciesList.innerHTML = `<p style="color: var(--terminal-amber);">${escapeHtml(message)}</p>`;
    }
    if (dependentsList) {
        dependentsList.innerHTML = `<p style="color: var(--terminal-amber);">${escapeHtml(message)}</p>`;
    }
}

function renderDependencies(dependencies) {
    const container = document.getElementById('dependenciesList');
    if (!container) return;

    const typeLabels = {
        'blocks': 'Blocks',
        'blocked_by': 'Blocked By',
        'relates_to': 'Relates To',
        'duplicates': 'Duplicates'
    };

    let html = '';
    let hasAny = false;

    for (const [type, items] of Object.entries(dependencies)) {
        if (items.length > 0) {
            hasAny = true;
            html += `<div class="dependency-group">
                <h4 style="color: var(--terminal-amber); margin: 0.5rem 0;">${typeLabels[type]}</h4>`;

            items.forEach(dep => {
                const statusClass = 'status-' + dep.status.toLowerCase().replace(/ /g, '-');
                html += `<div class="dependency-item" style="display: flex; justify-content: space-between; align-items: center; padding: 0.5rem; border-bottom: 1px dashed var(--terminal-green-dim);">
                    <div>
                        <a href="/ticket/${escapeHtml(dep.depends_on_id)}" style="color: var(--terminal-green);">
                            #${escapeHtml(dep.depends_on_id)}
                        </a>
                        <span style="margin-left: 0.5rem;">${escapeHtml(dep.title)}</span>
                        <span class="status-badge ${statusClass}" style="margin-left: 0.5rem; font-size: 0.8rem;">${escapeHtml(dep.status)}</span>
                    </div>
                    <button onclick="removeDependency('${dep.dependency_id}')" class="btn btn-small" style="padding: 0.25rem 0.5rem; font-size: 0.8rem;">Remove</button>
                </div>`;
            });

            html += '</div>';
        }
    }

    if (!hasAny) {
        html = '<p style="color: var(--terminal-green-dim);">No dependencies configured.</p>';
    }

    container.innerHTML = html;
}

function renderDependents(dependents) {
    const container = document.getElementById('dependentsList');
    if (!container) return;

    if (dependents.length === 0) {
        container.innerHTML = '<p style="color: var(--terminal-green-dim);">No tickets depend on this one.</p>';
        return;
    }

    let html = '';
    dependents.forEach(dep => {
        const statusClass = 'status-' + dep.status.toLowerCase().replace(/ /g, '-');
        html += `<div class="dependency-item" style="display: flex; justify-content: space-between; align-items: center; padding: 0.5rem; border-bottom: 1px dashed var(--terminal-green-dim);">
            <div>
                <a href="/ticket/${escapeHtml(dep.ticket_id)}" style="color: var(--terminal-green);">
                    #${escapeHtml(dep.ticket_id)}
                </a>
                <span style="margin-left: 0.5rem;">${escapeHtml(dep.title)}</span>
                <span class="status-badge ${statusClass}" style="margin-left: 0.5rem; font-size: 0.8rem;">${escapeHtml(dep.status)}</span>
                <span style="margin-left: 0.5rem; color: var(--terminal-amber);">(${escapeHtml(dep.dependency_type)})</span>
            </div>
        </div>`;
    });

    container.innerHTML = html;
}

function addDependency() {
    const ticketId = window.ticketData.id;
    const dependsOnId = document.getElementById('dependencyTicketId').value.trim();
    const dependencyType = document.getElementById('dependencyType').value;

    if (!dependsOnId) {
        toast.warning('Please enter a ticket ID', 3000);
        return;
    }

    fetch('/api/ticket_dependencies.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            ticket_id: ticketId,
            depends_on_id: dependsOnId,
            dependency_type: dependencyType
        })
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            toast.success('Dependency added', 3000);
            document.getElementById('dependencyTicketId').value = '';
            loadDependencies();
        } else {
            toast.error('Error: ' + (data.error || 'Unknown error'), 4000);
        }
    })
    .catch(error => {
        console.error('Error adding dependency:', error);
        toast.error('Error adding dependency', 4000);
    });
}

function removeDependency(dependencyId) {
    if (!confirm('Are you sure you want to remove this dependency?')) {
        return;
    }

    fetch('/api/ticket_dependencies.php', {
        method: 'DELETE',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            dependency_id: dependencyId
        })
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            toast.success('Dependency removed', 3000);
            loadDependencies();
        } else {
            toast.error('Error: ' + (data.error || 'Unknown error'), 4000);
        }
    })
    .catch(error => {
        console.error('Error removing dependency:', error);
        toast.error('Error removing dependency', 4000);
    });
}

// ========================================
// Attachment Management Functions
// ========================================

let uploadZoneInitialized = false;

function initializeUploadZone() {
    if (uploadZoneInitialized) return;

    const uploadZone = document.getElementById('uploadZone');
    const fileInput = document.getElementById('fileInput');

    if (!uploadZone || !fileInput) return;

    // Drag and drop events
    uploadZone.addEventListener('dragover', (e) => {
        e.preventDefault();
        e.stopPropagation();
        uploadZone.classList.add('drag-over');
    });

    uploadZone.addEventListener('dragleave', (e) => {
        e.preventDefault();
        e.stopPropagation();
        uploadZone.classList.remove('drag-over');
    });

    uploadZone.addEventListener('drop', (e) => {
        e.preventDefault();
        e.stopPropagation();
        uploadZone.classList.remove('drag-over');

        const files = e.dataTransfer.files;
        if (files.length > 0) {
            handleFileUpload(files);
        }
    });

    // File input change event
    fileInput.addEventListener('change', (e) => {
        if (e.target.files.length > 0) {
            handleFileUpload(e.target.files);
        }
    });

    // Click on upload zone to trigger file input
    uploadZone.addEventListener('click', (e) => {
        if (e.target.tagName !== 'BUTTON' && e.target.tagName !== 'INPUT') {
            fileInput.click();
        }
    });

    uploadZoneInitialized = true;
}

function handleFileUpload(files) {
    const ticketId = window.ticketData.id;
    const progressDiv = document.getElementById('uploadProgress');
    const progressFill = document.getElementById('progressFill');
    const statusText = document.getElementById('uploadStatus');

    let uploadedCount = 0;
    const totalFiles = files.length;

    progressDiv.style.display = 'block';
    statusText.textContent = `Uploading 0 of ${totalFiles} files...`;
    progressFill.style.width = '0%';

    Array.from(files).forEach((file, index) => {
        const formData = new FormData();
        formData.append('file', file);
        formData.append('ticket_id', ticketId);
        formData.append('csrf_token', window.CSRF_TOKEN);

        const xhr = new XMLHttpRequest();

        xhr.upload.addEventListener('progress', (e) => {
            if (e.lengthComputable) {
                const fileProgress = (e.loaded / e.total) * 100;
                const overallProgress = ((uploadedCount * 100) + fileProgress) / totalFiles;
                progressFill.style.width = overallProgress + '%';
            }
        });

        xhr.addEventListener('load', () => {
            uploadedCount++;
            statusText.textContent = `Uploading ${uploadedCount} of ${totalFiles} files...`;
            progressFill.style.width = ((uploadedCount / totalFiles) * 100) + '%';

            if (xhr.status === 200 || xhr.status === 201) {
                try {
                    const response = JSON.parse(xhr.responseText);
                    if (response.success) {
                        if (uploadedCount === totalFiles) {
                            toast.success(`${totalFiles} file(s) uploaded successfully`, 3000);
                            loadAttachments();
                            resetUploadUI();
                        }
                    } else {
                        toast.error(`Error uploading ${file.name}: ${response.error}`, 4000);
                    }
                } catch (e) {
                    toast.error(`Error parsing response for ${file.name}`, 4000);
                }
            } else {
                toast.error(`Error uploading ${file.name}: Server error`, 4000);
            }

            if (uploadedCount === totalFiles) {
                setTimeout(resetUploadUI, 2000);
            }
        });

        xhr.addEventListener('error', () => {
            uploadedCount++;
            toast.error(`Error uploading ${file.name}: Network error`, 4000);
            if (uploadedCount === totalFiles) {
                setTimeout(resetUploadUI, 2000);
            }
        });

        xhr.open('POST', '/api/upload_attachment.php');
        xhr.send(formData);
    });
}

function resetUploadUI() {
    const progressDiv = document.getElementById('uploadProgress');
    const fileInput = document.getElementById('fileInput');

    progressDiv.style.display = 'none';
    if (fileInput) {
        fileInput.value = '';
    }
}

function loadAttachments() {
    const ticketId = window.ticketData.id;
    const container = document.getElementById('attachmentsList');

    if (!container) return;

    fetch(`/api/upload_attachment.php?ticket_id=${ticketId}`)
        .then(response => response.json())
        .then(data => {
            if (data.success) {
                renderAttachments(data.attachments || []);
            } else {
                container.innerHTML = '<p style="color: var(--terminal-green-dim);">Error loading attachments.</p>';
            }
        })
        .catch(error => {
            console.error('Error loading attachments:', error);
            container.innerHTML = '<p style="color: var(--terminal-green-dim);">Error loading attachments.</p>';
        });
}

function renderAttachments(attachments) {
    const container = document.getElementById('attachmentsList');
    if (!container) return;

    if (attachments.length === 0) {
        container.innerHTML = '<p style="color: var(--terminal-green-dim);">No files attached to this ticket.</p>';
        return;
    }

    let html = '<div class="attachments-grid">';

    attachments.forEach(att => {
        const uploaderName = att.display_name || att.username || 'Unknown';
        const uploadDate = new Date(att.uploaded_at).toLocaleDateString('en-US', {
            year: 'numeric',
            month: 'short',
            day: 'numeric',
            hour: '2-digit',
            minute: '2-digit'
        });

        html += `<div class="attachment-item" data-id="${att.attachment_id}">
            <div class="attachment-icon">${escapeHtml(att.icon || '📎')}</div>
            <div class="attachment-info">
                <div class="attachment-name" title="${escapeHtml(att.original_filename)}">
                    <a href="/api/download_attachment.php?id=${att.attachment_id}" target="_blank" style="color: var(--terminal-green);">
                        ${escapeHtml(att.original_filename)}
                    </a>
                </div>
                <div class="attachment-meta">
                    ${escapeHtml(att.file_size_formatted || formatFileSize(att.file_size))} • ${escapeHtml(uploaderName)} • ${escapeHtml(uploadDate)}
                </div>
            </div>
            <div class="attachment-actions">
                <a href="/api/download_attachment.php?id=${att.attachment_id}" class="btn btn-small" title="Download">⬇</a>
                <button onclick="deleteAttachment(${att.attachment_id})" class="btn btn-small btn-danger" title="Delete">✕</button>
            </div>
        </div>`;
    });

    html += '</div>';
    container.innerHTML = html;
}

function formatFileSize(bytes) {
    if (bytes >= 1073741824) {
        return (bytes / 1073741824).toFixed(2) + ' GB';
    } else if (bytes >= 1048576) {
        return (bytes / 1048576).toFixed(2) + ' MB';
    } else if (bytes >= 1024) {
        return (bytes / 1024).toFixed(2) + ' KB';
    } else {
        return bytes + ' bytes';
    }
}

function deleteAttachment(attachmentId) {
    if (!confirm('Are you sure you want to delete this attachment?')) {
        return;
    }

    fetch('/api/delete_attachment.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            attachment_id: attachmentId,
            csrf_token: window.CSRF_TOKEN
        })
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            toast.success('Attachment deleted', 3000);
            loadAttachments();
        } else {
            toast.error('Error: ' + (data.error || 'Unknown error'), 4000);
        }
    })
    .catch(error => {
        console.error('Error deleting attachment:', error);
        toast.error('Error deleting attachment', 4000);
    });
}

// ========================================
// @Mention Autocomplete Functions
// ========================================

let mentionAutocomplete = null;
let mentionUsers = [];
let mentionStartPos = -1;
let selectedMentionIndex = 0;

/**
 * Initialize mention autocomplete for a textarea
 */
function initMentionAutocomplete() {
    const textarea = document.getElementById('newComment');
    if (!textarea) return;

    // Create autocomplete dropdown
    mentionAutocomplete = document.createElement('div');
    mentionAutocomplete.className = 'mention-autocomplete';
    mentionAutocomplete.id = 'mentionAutocomplete';
    textarea.parentElement.style.position = 'relative';
    textarea.parentElement.appendChild(mentionAutocomplete);

    // Fetch users list
    fetchMentionUsers();

    // Input event to detect @ symbol
    textarea.addEventListener('input', handleMentionInput);
    textarea.addEventListener('keydown', handleMentionKeydown);
    textarea.addEventListener('blur', () => {
        // Delay hiding to allow click on option
        setTimeout(hideMentionAutocomplete, 200);
    });
}

/**
 * Fetch available users for mentions
 */
function fetchMentionUsers() {
    fetch('/api/get_users.php')
        .then(response => response.json())
        .then(data => {
            if (data.success && data.users) {
                mentionUsers = data.users;
            }
        })
        .catch(error => {
            console.error('Error fetching users for mentions:', error);
        });
}

/**
 * Handle input events to detect @ mentions
 */
function handleMentionInput(e) {
    const textarea = e.target;
    const text = textarea.value;
    const cursorPos = textarea.selectionStart;

    // Find @ symbol before cursor
    let atPos = -1;
    for (let i = cursorPos - 1; i >= 0; i--) {
        const char = text[i];
        if (char === '@') {
            atPos = i;
            break;
        }
        if (char === ' ' || char === '\n') {
            break;
        }
    }

    if (atPos >= 0) {
        const query = text.substring(atPos + 1, cursorPos).toLowerCase();
        mentionStartPos = atPos;
        showMentionSuggestions(query, textarea);
    } else {
        hideMentionAutocomplete();
    }
}

/**
 * Handle keyboard navigation in autocomplete
 */
function handleMentionKeydown(e) {
    if (!mentionAutocomplete || !mentionAutocomplete.classList.contains('active')) {
        return;
    }

    const options = mentionAutocomplete.querySelectorAll('.mention-option');

    switch (e.key) {
        case 'ArrowDown':
            e.preventDefault();
            selectedMentionIndex = Math.min(selectedMentionIndex + 1, options.length - 1);
            updateMentionSelection(options);
            break;
        case 'ArrowUp':
            e.preventDefault();
            selectedMentionIndex = Math.max(selectedMentionIndex - 1, 0);
            updateMentionSelection(options);
            break;
        case 'Enter':
        case 'Tab':
            e.preventDefault();
            if (options[selectedMentionIndex]) {
                selectMention(options[selectedMentionIndex].dataset.username);
            }
            break;
        case 'Escape':
            hideMentionAutocomplete();
            break;
    }
}

/**
 * Update visual selection in autocomplete
 */
function updateMentionSelection(options) {
    options.forEach((opt, i) => {
        opt.classList.toggle('selected', i === selectedMentionIndex);
    });
}

/**
 * Show mention suggestions
 */
function showMentionSuggestions(query, textarea) {
    const filtered = mentionUsers.filter(user => {
        const username = (user.username || '').toLowerCase();
        const displayName = (user.display_name || '').toLowerCase();
        return username.includes(query) || displayName.includes(query);
    }).slice(0, 5);

    if (filtered.length === 0) {
        hideMentionAutocomplete();
        return;
    }

    let html = '';
    filtered.forEach((user, index) => {
        const isSelected = index === 0 ? 'selected' : '';
        html += `<div class="mention-option ${isSelected}" data-username="${escapeHtml(user.username)}" onclick="selectMention('${escapeHtml(user.username)}')">
            <span class="mention-username">@${escapeHtml(user.username)}</span>
            ${user.display_name ? `<span class="mention-displayname">${escapeHtml(user.display_name)}</span>` : ''}
        </div>`;
    });

    mentionAutocomplete.innerHTML = html;
    mentionAutocomplete.classList.add('active');
    selectedMentionIndex = 0;

    // Position dropdown below cursor
    const rect = textarea.getBoundingClientRect();
    mentionAutocomplete.style.left = '0';
    mentionAutocomplete.style.top = (textarea.offsetTop + textarea.offsetHeight) + 'px';
}

/**
 * Hide mention autocomplete
 */
function hideMentionAutocomplete() {
    if (mentionAutocomplete) {
        mentionAutocomplete.classList.remove('active');
    }
    mentionStartPos = -1;
}

/**
 * Select a mention from autocomplete
 */
function selectMention(username) {
    const textarea = document.getElementById('newComment');
    if (!textarea || mentionStartPos < 0) return;

    const text = textarea.value;
    const before = text.substring(0, mentionStartPos);
    const after = text.substring(textarea.selectionStart);

    textarea.value = before + '@' + username + ' ' + after;
    textarea.focus();
    const newPos = mentionStartPos + username.length + 2;
    textarea.setSelectionRange(newPos, newPos);

    hideMentionAutocomplete();
}

/**
 * Highlight mentions in comment text
 */
function highlightMentions(text) {
    return text.replace(/@([a-zA-Z0-9_-]+)/g, '<span class="mention">$1</span>');
}

// Initialize mention autocomplete when DOM is ready
document.addEventListener('DOMContentLoaded', function() {
    initMentionAutocomplete();

    // Highlight existing mentions in comments
    document.querySelectorAll('.comment-text').forEach(el => {
        if (!el.hasAttribute('data-markdown')) {
            el.innerHTML = highlightMentions(el.innerHTML);
        }
    });
});

// ========================================
// Comment Edit/Delete Functions
// ========================================

/**
 * Edit a comment
 */
function editComment(commentId) {
    const commentDiv = document.querySelector(`.comment[data-comment-id="${commentId}"]`);
    if (!commentDiv) return;

    const textDiv = document.getElementById(`comment-text-${commentId}`);
    const rawTextarea = document.getElementById(`comment-raw-${commentId}`);
    if (!textDiv || !rawTextarea) return;

    // Check if already in edit mode
    if (commentDiv.classList.contains('editing')) {
        cancelEditComment(commentId);
        return;
    }

    // Get original text and markdown setting
    const originalText = rawTextarea.value;
    const markdownEnabled = commentDiv.dataset.markdownEnabled === '1';

    // Create edit form
    const editForm = document.createElement('div');
    editForm.className = 'comment-edit-form';
    editForm.id = `comment-edit-form-${commentId}`;
    editForm.innerHTML = `
        <textarea id="comment-edit-textarea-${commentId}" class="comment-edit-textarea">${escapeHtml(originalText)}</textarea>
        <div class="comment-edit-controls">
            <label class="markdown-toggle-small">
                <input type="checkbox" id="comment-edit-markdown-${commentId}" ${markdownEnabled ? 'checked' : ''}>
                Markdown
            </label>
            <div class="comment-edit-buttons">
                <button type="button" class="btn btn-small" onclick="saveEditComment(${commentId})">Save</button>
                <button type="button" class="btn btn-secondary btn-small" onclick="cancelEditComment(${commentId})">Cancel</button>
            </div>
        </div>
    `;

    // Hide original text, show edit form
    textDiv.style.display = 'none';
    textDiv.after(editForm);
    commentDiv.classList.add('editing');

    // Focus the textarea
    document.getElementById(`comment-edit-textarea-${commentId}`).focus();
}

/**
 * Save edited comment
 */
function saveEditComment(commentId) {
    const textarea = document.getElementById(`comment-edit-textarea-${commentId}`);
    const markdownCheckbox = document.getElementById(`comment-edit-markdown-${commentId}`);

    if (!textarea) return;

    const newText = textarea.value.trim();
    if (!newText) {
        showToast('Comment cannot be empty', 'error');
        return;
    }

    const markdownEnabled = markdownCheckbox ? markdownCheckbox.checked : false;

    // Send update request
    fetch('/api/update_comment.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            comment_id: commentId,
            comment_text: newText,
            markdown_enabled: markdownEnabled
        })
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            // Update the comment display
            const commentDiv = document.querySelector(`.comment[data-comment-id="${commentId}"]`);
            const textDiv = document.getElementById(`comment-text-${commentId}`);
            const rawTextarea = document.getElementById(`comment-raw-${commentId}`);
            const editForm = document.getElementById(`comment-edit-form-${commentId}`);

            // Update raw text storage
            rawTextarea.value = newText;

            // Update markdown attribute
            commentDiv.dataset.markdownEnabled = markdownEnabled ? '1' : '0';

            // Update displayed text
            if (markdownEnabled) {
                textDiv.setAttribute('data-markdown', '');
                textDiv.textContent = newText;
                // Re-render markdown
                if (typeof parseMarkdown === 'function') {
                    textDiv.innerHTML = parseMarkdown(newText);
                }
            } else {
                textDiv.removeAttribute('data-markdown');
                // Convert newlines to <br> and highlight mentions
                let displayText = escapeHtml(newText).replace(/\n/g, '<br>');
                displayText = highlightMentions(displayText);
                // Auto-link URLs
                if (typeof autoLinkUrls === 'function') {
                    displayText = autoLinkUrls(displayText);
                }
                textDiv.innerHTML = displayText;
            }

            // Remove edit form and show text
            if (editForm) editForm.remove();
            textDiv.style.display = '';
            commentDiv.classList.remove('editing');

            showToast('Comment updated successfully', 'success');
        } else {
            showToast(data.error || 'Failed to update comment', 'error');
        }
    })
    .catch(error => {
        console.error('Error updating comment:', error);
        showToast('Failed to update comment', 'error');
    });
}

/**
 * Cancel editing a comment
 */
function cancelEditComment(commentId) {
    const commentDiv = document.querySelector(`.comment[data-comment-id="${commentId}"]`);
    const textDiv = document.getElementById(`comment-text-${commentId}`);
    const editForm = document.getElementById(`comment-edit-form-${commentId}`);

    if (editForm) editForm.remove();
    if (textDiv) textDiv.style.display = '';
    if (commentDiv) commentDiv.classList.remove('editing');
}

/**
 * Delete a comment
 */
function deleteComment(commentId) {
    if (!confirm('Are you sure you want to delete this comment? This cannot be undone.')) {
        return;
    }

    fetch('/api/delete_comment.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-Token': window.CSRF_TOKEN
        },
        body: JSON.stringify({
            comment_id: commentId
        })
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            // Remove the comment from the DOM
            const commentDiv = document.querySelector(`.comment[data-comment-id="${commentId}"]`);
            if (commentDiv) {
                commentDiv.style.transition = 'opacity 0.3s, transform 0.3s';
                commentDiv.style.opacity = '0';
                commentDiv.style.transform = 'translateX(-20px)';
                setTimeout(() => commentDiv.remove(), 300);
            }
            showToast('Comment deleted successfully', 'success');
        } else {
            showToast(data.error || 'Failed to delete comment', 'error');
        }
    })
    .catch(error => {
        console.error('Error deleting comment:', error);
        showToast('Failed to delete comment', 'error');
    });
}

// Expose functions globally
window.editComment = editComment;
window.saveEditComment = saveEditComment;
window.cancelEditComment = cancelEditComment;
window.deleteComment = deleteComment;