<?php
/**
 * AttachmentModel - Handles ticket file attachments
 */

require_once __DIR__ . '/../config/config.php';

class AttachmentModel {
    private $conn;

    public function __construct() {
        $this->conn = new mysqli(
            $GLOBALS['config']['DB_HOST'],
            $GLOBALS['config']['DB_USER'],
            $GLOBALS['config']['DB_PASS'],
            $GLOBALS['config']['DB_NAME']
        );

        if ($this->conn->connect_error) {
            throw new Exception('Database connection failed: ' . $this->conn->connect_error);
        }
    }

    /**
     * Get all attachments for a ticket
     */
    public function getAttachments($ticketId) {
        $sql = "SELECT a.*, u.username, u.display_name
                FROM ticket_attachments a
                LEFT JOIN users u ON a.uploaded_by = u.user_id
                WHERE a.ticket_id = ?
                ORDER BY a.uploaded_at DESC";

        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("s", $ticketId);
        $stmt->execute();
        $result = $stmt->get_result();

        $attachments = [];
        while ($row = $result->fetch_assoc()) {
            $attachments[] = $row;
        }

        $stmt->close();
        return $attachments;
    }

    /**
     * Get a single attachment by ID
     */
    public function getAttachment($attachmentId) {
        $sql = "SELECT a.*, u.username, u.display_name
                FROM ticket_attachments a
                LEFT JOIN users u ON a.uploaded_by = u.user_id
                WHERE a.attachment_id = ?";

        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $attachmentId);
        $stmt->execute();
        $result = $stmt->get_result();
        $attachment = $result->fetch_assoc();
        $stmt->close();

        return $attachment;
    }

    /**
     * Add a new attachment record
     */
    public function addAttachment($ticketId, $filename, $originalFilename, $fileSize, $mimeType, $uploadedBy) {
        $sql = "INSERT INTO ticket_attachments (ticket_id, filename, original_filename, file_size, mime_type, uploaded_by)
                VALUES (?, ?, ?, ?, ?, ?)";

        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("sssisi", $ticketId, $filename, $originalFilename, $fileSize, $mimeType, $uploadedBy);
        $result = $stmt->execute();

        if ($result) {
            $attachmentId = $this->conn->insert_id;
            $stmt->close();
            return $attachmentId;
        }

        $stmt->close();
        return false;
    }

    /**
     * Delete an attachment record
     */
    public function deleteAttachment($attachmentId) {
        $sql = "DELETE FROM ticket_attachments WHERE attachment_id = ?";

        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $attachmentId);
        $result = $stmt->execute();
        $stmt->close();

        return $result;
    }

    /**
     * Get total attachment size for a ticket
     */
    public function getTotalSizeForTicket($ticketId) {
        $sql = "SELECT COALESCE(SUM(file_size), 0) as total_size
                FROM ticket_attachments
                WHERE ticket_id = ?";

        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("s", $ticketId);
        $stmt->execute();
        $result = $stmt->get_result();
        $row = $result->fetch_assoc();
        $stmt->close();

        return (int)$row['total_size'];
    }

    /**
     * Get attachment count for a ticket
     */
    public function getAttachmentCount($ticketId) {
        $sql = "SELECT COUNT(*) as count FROM ticket_attachments WHERE ticket_id = ?";

        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("s", $ticketId);
        $stmt->execute();
        $result = $stmt->get_result();
        $row = $result->fetch_assoc();
        $stmt->close();

        return (int)$row['count'];
    }

    /**
     * Check if user can delete attachment (owner or admin)
     */
    public function canUserDelete($attachmentId, $userId, $isAdmin = false) {
        if ($isAdmin) {
            return true;
        }

        $attachment = $this->getAttachment($attachmentId);
        return $attachment && $attachment['uploaded_by'] == $userId;
    }

    /**
     * Format file size for display
     */
    public static function formatFileSize($bytes) {
        if ($bytes >= 1073741824) {
            return number_format($bytes / 1073741824, 2) . ' GB';
        } elseif ($bytes >= 1048576) {
            return number_format($bytes / 1048576, 2) . ' MB';
        } elseif ($bytes >= 1024) {
            return number_format($bytes / 1024, 2) . ' KB';
        } else {
            return $bytes . ' bytes';
        }
    }

    /**
     * Get file icon based on mime type
     */
    public static function getFileIcon($mimeType) {
        if (strpos($mimeType, 'image/') === 0) {
            return '🖼️';
        } elseif (strpos($mimeType, 'video/') === 0) {
            return '🎬';
        } elseif (strpos($mimeType, 'audio/') === 0) {
            return '🎵';
        } elseif ($mimeType === 'application/pdf') {
            return '📄';
        } elseif (strpos($mimeType, 'text/') === 0) {
            return '📝';
        } elseif (in_array($mimeType, ['application/zip', 'application/x-rar-compressed', 'application/x-7z-compressed', 'application/gzip'])) {
            return '📦';
        } elseif (in_array($mimeType, ['application/msword', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'])) {
            return '📘';
        } elseif (in_array($mimeType, ['application/vnd.ms-excel', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'])) {
            return '📊';
        } else {
            return '📎';
        }
    }

    /**
     * Validate file type against allowed types
     */
    public static function isAllowedType($mimeType) {
        $allowedTypes = $GLOBALS['config']['ALLOWED_FILE_TYPES'] ?? [
            'image/jpeg', 'image/png', 'image/gif', 'image/webp',
            'application/pdf',
            'text/plain', 'text/csv',
            'application/msword',
            'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
            'application/vnd.ms-excel',
            'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
            'application/zip', 'application/x-rar-compressed', 'application/x-7z-compressed',
            'application/json', 'application/xml'
        ];

        return in_array($mimeType, $allowedTypes);
    }

    public function __destruct() {
        if ($this->conn) {
            $this->conn->close();
        }
    }
}