<?php
/**
 * Support Ticket Attachment Helper
 * Shared across: admin-support.php, user-support.php, partner-support-creation.php
 * 
 * Usage:
 *   require_once __DIR__ . '/support-upload-helper.php';
 *   $attachmentIds = handleSupportAttachments($pdo, $messageId, $_FILES['attachments']);
 *   $attachments = getAttachmentsForMessages($pdo, [1, 2, 3]);
 */

define('SUPPORT_UPLOAD_DIR', __DIR__ . '/uploads/support/');
define('SUPPORT_UPLOAD_URL', '/uploads/support/');
define('SUPPORT_MAX_FILE_SIZE', 5 * 1024 * 1024); // 5MB
define('SUPPORT_MAX_FILES', 3);

define('SUPPORT_ALLOWED_TYPES', [
    // Images
    'image/jpeg', 'image/png', 'image/gif', 'image/webp',
    // Documents
    'application/pdf',
    'application/msword',
    'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
    'application/vnd.ms-excel',
    'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
    'text/plain',
    'text/csv',
]);

define('SUPPORT_ALLOWED_EXTENSIONS', [
    'jpg', 'jpeg', 'png', 'gif', 'webp',
    'pdf', 'doc', 'docx', 'xls', 'xlsx', 'txt', 'csv'
]);

/**
 * Handle file uploads for a support message
 * @param PDO $pdo Database connection
 * @param int $messageId The support_messages.id to attach files to
 * @param array $files $_FILES['attachments'] array
 * @return array Array of inserted attachment IDs
 */
function handleSupportAttachments($pdo, $messageId, $files) {
    $attachmentIds = [];
    
    if (empty($files) || empty($files['name'][0])) {
        return $attachmentIds;
    }
    
    // Create upload directory if not exists
    if (!file_exists(SUPPORT_UPLOAD_DIR)) {
        mkdir(SUPPORT_UPLOAD_DIR, 0755, true);
    }
    
    // Create monthly subdirectory
    $monthDir = date('Y-m');
    $uploadPath = SUPPORT_UPLOAD_DIR . $monthDir . '/';
    if (!file_exists($uploadPath)) {
        mkdir($uploadPath, 0755, true);
    }
    
    $fileCount = min(count($files['name']), SUPPORT_MAX_FILES);
    
    for ($i = 0; $i < $fileCount; $i++) {
        if ($files['error'][$i] !== UPLOAD_ERR_OK) {
            continue;
        }
        
        $originalName = basename($files['name'][$i]);
        $fileSize = $files['size'][$i];
        $fileType = $files['type'][$i];
        $tmpName = $files['tmp_name'][$i];
        
        // Validate file size
        if ($fileSize > SUPPORT_MAX_FILE_SIZE) {
            continue;
        }
        
        // Validate extension
        $ext = strtolower(pathinfo($originalName, PATHINFO_EXTENSION));
        if (!in_array($ext, SUPPORT_ALLOWED_EXTENSIONS)) {
            continue;
        }
        
        // Validate MIME type
        $finfo = new finfo(FILEINFO_MIME_TYPE);
        $detectedType = $finfo->file($tmpName);
        if (!in_array($detectedType, SUPPORT_ALLOWED_TYPES)) {
            continue;
        }
        
        // Generate unique filename
        $storedName = 'support_' . $messageId . '_' . uniqid() . '.' . $ext;
        $fullPath = $uploadPath . $storedName;
        $relativePath = SUPPORT_UPLOAD_URL . $monthDir . '/' . $storedName;
        
        if (move_uploaded_file($tmpName, $fullPath)) {
            try {
                $stmt = $pdo->prepare("
                    INSERT INTO support_attachments (message_id, file_name, original_name, file_path, file_type, file_size)
                    VALUES (?, ?, ?, ?, ?, ?)
                ");
                $stmt->execute([$messageId, $storedName, $originalName, $relativePath, $detectedType, $fileSize]);
                $attachmentIds[] = $pdo->lastInsertId();
            } catch (Exception $e) {
                // Clean up file if DB insert fails
                @unlink($fullPath);
            }
        }
    }
    
    return $attachmentIds;
}

/**
 * Get attachments for multiple messages (batch load)
 * @param PDO $pdo
 * @param array $messageIds Array of message IDs
 * @return array Keyed by message_id => [attachments]
 */
function getAttachmentsForMessages($pdo, $messageIds) {
    $result = [];
    if (empty($messageIds)) return $result;
    
    $placeholders = implode(',', array_fill(0, count($messageIds), '?'));
    $stmt = $pdo->prepare("
        SELECT * FROM support_attachments 
        WHERE message_id IN ($placeholders) 
        ORDER BY created_at ASC
    ");
    $stmt->execute($messageIds);
    $attachments = $stmt->fetchAll();
    
    foreach ($attachments as $att) {
        $result[$att['message_id']][] = $att;
    }
    
    return $result;
}

/**
 * Render attachment HTML for display
 * @param array $attachments Array of attachment rows
 * @return string HTML string
 */
function renderAttachmentsHTML($attachments) {
    if (empty($attachments)) return '';
    
    $html = '<div class="support-attachments">';
    foreach ($attachments as $att) {
        $isImage = strpos($att['file_type'], 'image/') === 0;
        $sizeFormatted = formatFileSize($att['file_size']);
        $escapedName = htmlspecialchars($att['original_name']);
        $escapedPath = htmlspecialchars($att['file_path']);
        
        if ($isImage) {
            $html .= '<div class="attachment-item attachment-image">';
            $html .= '<a href="' . $escapedPath . '" target="_blank" title="' . $escapedName . '">';
            $html .= '<img src="' . $escapedPath . '" alt="' . $escapedName . '" loading="lazy">';
            $html .= '</a>';
            $html .= '<div class="attachment-name">' . $escapedName . ' (' . $sizeFormatted . ')</div>';
            $html .= '</div>';
        } else {
            $icon = getFileIcon($att['file_type'], $att['original_name']);
            $html .= '<div class="attachment-item attachment-file">';
            $html .= '<a href="' . $escapedPath . '" target="_blank" download class="attachment-link">';
            $html .= '<i class="fas ' . $icon . '"></i> ';
            $html .= $escapedName . ' <span class="attachment-size">(' . $sizeFormatted . ')</span>';
            $html .= '</a>';
            $html .= '</div>';
        }
    }
    $html .= '</div>';
    return $html;
}

/**
 * Get Font Awesome icon class for file type
 */
function getFileIcon($mimeType, $fileName) {
    $ext = strtolower(pathinfo($fileName, PATHINFO_EXTENSION));
    $icons = [
        'pdf' => 'fa-file-pdf',
        'doc' => 'fa-file-word', 'docx' => 'fa-file-word',
        'xls' => 'fa-file-excel', 'xlsx' => 'fa-file-excel',
        'csv' => 'fa-file-csv',
        'txt' => 'fa-file-alt',
    ];
    return $icons[$ext] ?? 'fa-file';
}

/**
 * Format file size to human readable
 */
function formatFileSize($bytes) {
    if ($bytes >= 1048576) return round($bytes / 1048576, 1) . ' MB';
    if ($bytes >= 1024) return round($bytes / 1024, 1) . ' KB';
    return $bytes . ' B';
}

/**
 * CSS for attachments (include once per page)
 */
function getAttachmentCSS() {
    return '
    <style>
    .support-attachments {
        margin-top: 10px;
        display: flex;
        flex-wrap: wrap;
        gap: 8px;
    }
    .attachment-item {
        border-radius: 8px;
        overflow: hidden;
    }
    .attachment-image {
        max-width: 200px;
    }
    .attachment-image img {
        width: 100%;
        max-height: 150px;
        object-fit: cover;
        border-radius: 8px;
        border: 1px solid #dee2e6;
        display: block;
        cursor: pointer;
        transition: opacity 0.2s;
    }
    .attachment-image img:hover {
        opacity: 0.85;
    }
    .attachment-image .attachment-name {
        font-size: 11px;
        color: #666;
        padding: 3px 0;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }
    .attachment-file {
        background: #f8f9fa;
        border: 1px solid #dee2e6;
        border-radius: 8px;
        padding: 8px 14px;
    }
    .attachment-link {
        text-decoration: none;
        color: #1565c0;
        font-size: 13px;
        font-weight: 500;
        display: flex;
        align-items: center;
        gap: 6px;
    }
    .attachment-link:hover {
        color: #0d47a1;
    }
    .attachment-link i {
        font-size: 16px;
        color: #dc3545;
    }
    .attachment-link i.fa-file-word { color: #2b579a; }
    .attachment-link i.fa-file-excel { color: #217346; }
    .attachment-link i.fa-file-csv { color: #217346; }
    .attachment-link i.fa-file-alt { color: #666; }
    .attachment-size {
        color: #999;
        font-weight: 400;
        font-size: 12px;
    }
    .file-upload-input {
        margin-top: 8px;
    }
    .file-upload-input label {
        display: inline-flex;
        align-items: center;
        gap: 6px;
        padding: 7px 14px;
        background: #f0f0f0;
        border: 1px dashed #bbb;
        border-radius: 8px;
        cursor: pointer;
        font-size: 13px;
        color: #555;
        transition: background 0.2s;
    }
    .file-upload-input label:hover {
        background: #e8e8e8;
    }
    .file-upload-input input[type="file"] {
        display: none;
    }
    .file-upload-info {
        font-size: 11px;
        color: #999;
        margin-top: 4px;
    }
    .selected-files {
        margin-top: 6px;
        font-size: 12px;
        color: #555;
    }
    .selected-files span {
        display: inline-block;
        background: #e3f2fd;
        padding: 2px 8px;
        border-radius: 4px;
        margin: 2px 4px 2px 0;
    }
    </style>';
}

/**
 * Generate file input HTML for forms
 * @param string $inputName Name attribute for file input (default: attachments)
 * @return string HTML for file upload section
 */
function getFileUploadHTML($inputName = 'attachments') {
    return '
    <div class="file-upload-input">
        <label>
            <i class="fas fa-paperclip"></i> Attach Files
            <input type="file" name="' . $inputName . '[]" multiple 
                   accept=".jpg,.jpeg,.png,.gif,.webp,.pdf,.doc,.docx,.xls,.xlsx,.txt,.csv"
                   onchange="showSelectedFiles(this)">
        </label>
        <div class="file-upload-info">Max 3 files, 5MB each. Images, PDF, Word, Excel, Text.</div>
        <div class="selected-files" id="selectedFiles_' . $inputName . '"></div>
    </div>';
}

/**
 * JavaScript for showing selected file names (include once per page)
 */
function getFileUploadJS() {
    return '
    <script>
    function showSelectedFiles(input) {
        var container = input.closest(".file-upload-input").querySelector(".selected-files");
        container.innerHTML = "";
        if (input.files.length > 3) {
            container.innerHTML = "<span style=\"color:#dc3545;\">Max 3 files allowed. Only first 3 will be uploaded.</span>";
        }
        var max = Math.min(input.files.length, 3);
        for (var i = 0; i < max; i++) {
            var f = input.files[i];
            var sizeMB = (f.size / 1024 / 1024).toFixed(1);
            container.innerHTML += "<span>" + f.name + " (" + sizeMB + " MB)</span> ";
        }
    }
    </script>';
}