<?php
class CommentModel {
    private $conn;

    public function __construct($conn) {
        $this->conn = $conn;
    }

    /**
     * Extract @mentions from comment text
     *
     * @param string $text Comment text
     * @return array Array of mentioned usernames
     */
    public function extractMentions($text) {
        $mentions = [];
        // Match @username patterns (alphanumeric, underscores, hyphens)
        if (preg_match_all('/@([a-zA-Z0-9_-]+)/', $text, $matches)) {
            $mentions = array_unique($matches[1]);
        }
        return $mentions;
    }

    /**
     * Get user IDs for mentioned usernames
     *
     * @param array $usernames Array of usernames
     * @return array Array of user records with user_id, username, display_name
     */
    public function getMentionedUsers($usernames) {
        if (empty($usernames)) {
            return [];
        }

        $placeholders = str_repeat('?,', count($usernames) - 1) . '?';
        $sql = "SELECT user_id, username, display_name FROM users WHERE username IN ($placeholders)";
        $stmt = $this->conn->prepare($sql);

        $types = str_repeat('s', count($usernames));
        $stmt->bind_param($types, ...$usernames);
        $stmt->execute();
        $result = $stmt->get_result();

        $users = [];
        while ($row = $result->fetch_assoc()) {
            $users[] = $row;
        }
        $stmt->close();

        return $users;
    }
    
    public function getCommentsByTicketId($ticketId) {
        $sql = "SELECT tc.*, u.display_name, u.username
                FROM ticket_comments tc
                LEFT JOIN users u ON tc.user_id = u.user_id
                WHERE tc.ticket_id = ?
                ORDER BY tc.created_at DESC";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("s", $ticketId); // Changed to string since ticket_id is varchar
        $stmt->execute();
        $result = $stmt->get_result();

        $comments = [];
        while ($row = $result->fetch_assoc()) {
            // Use display_name from users table if available, fallback to user_name field
            if (!empty($row['display_name'])) {
                $row['display_name_formatted'] = $row['display_name'];
            } else {
                $row['display_name_formatted'] = $row['user_name'] ?? 'Unknown User';
            }
            $comments[] = $row;
        }

        return $comments;
    }
    
    public function addComment($ticketId, $commentData, $userId = null) {
        $sql = "INSERT INTO ticket_comments (ticket_id, user_id, user_name, comment_text, markdown_enabled)
                VALUES (?, ?, ?, ?, ?)";

        $stmt = $this->conn->prepare($sql);

        // Set default username (kept for backward compatibility)
        $username = $commentData['user_name'] ?? 'User';
        $markdownEnabled = isset($commentData['markdown_enabled']) && $commentData['markdown_enabled'] ? 1 : 0;

        // Preserve line breaks in the comment text
        $commentText = $commentData['comment_text'];

        $stmt->bind_param(
            "sissi",
            $ticketId,
            $userId,
            $username,
            $commentText,
            $markdownEnabled
        );

        if ($stmt->execute()) {
            $commentId = $this->conn->insert_id;

            return [
                'success' => true,
                'comment_id' => $commentId,
                'user_name' => $username,
                'created_at' => date('M d, Y H:i'),
                'markdown_enabled' => $markdownEnabled,
                'comment_text' => $commentText
            ];
        } else {
            return [
                'success' => false,
                'error' => $this->conn->error
            ];
        }
    }

    /**
     * Get a single comment by ID
     */
    public function getCommentById($commentId) {
        $sql = "SELECT tc.*, u.display_name, u.username
                FROM ticket_comments tc
                LEFT JOIN users u ON tc.user_id = u.user_id
                WHERE tc.comment_id = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $commentId);
        $stmt->execute();
        $result = $stmt->get_result();
        return $result->fetch_assoc();
    }

    /**
     * Update an existing comment
     * Only the comment owner or an admin can update
     */
    public function updateComment($commentId, $commentText, $markdownEnabled, $userId, $isAdmin = false) {
        // First check if user owns this comment or is admin
        $comment = $this->getCommentById($commentId);

        if (!$comment) {
            return ['success' => false, 'error' => 'Comment not found'];
        }

        if ($comment['user_id'] != $userId && !$isAdmin) {
            return ['success' => false, 'error' => 'You do not have permission to edit this comment'];
        }

        $sql = "UPDATE ticket_comments SET comment_text = ?, markdown_enabled = ?, updated_at = NOW() WHERE comment_id = ?";
        $stmt = $this->conn->prepare($sql);
        $markdownInt = $markdownEnabled ? 1 : 0;
        $stmt->bind_param("sii", $commentText, $markdownInt, $commentId);

        if ($stmt->execute()) {
            return [
                'success' => true,
                'comment_id' => $commentId,
                'comment_text' => $commentText,
                'markdown_enabled' => $markdownInt,
                'updated_at' => date('M d, Y H:i')
            ];
        } else {
            return ['success' => false, 'error' => $this->conn->error];
        }
    }

    /**
     * Delete a comment
     * Only the comment owner or an admin can delete
     */
    public function deleteComment($commentId, $userId, $isAdmin = false) {
        // First check if user owns this comment or is admin
        $comment = $this->getCommentById($commentId);

        if (!$comment) {
            return ['success' => false, 'error' => 'Comment not found'];
        }

        if ($comment['user_id'] != $userId && !$isAdmin) {
            return ['success' => false, 'error' => 'You do not have permission to delete this comment'];
        }

        $ticketId = $comment['ticket_id'];

        $sql = "DELETE FROM ticket_comments WHERE comment_id = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $commentId);

        if ($stmt->execute()) {
            return [
                'success' => true,
                'comment_id' => $commentId,
                'ticket_id' => $ticketId
            ];
        } else {
            return ['success' => false, 'error' => $this->conn->error];
        }
    }
}
?>