<?php
require_once __DIR__ . '/../utils/Config.php';
class SmtpHandler {
    private $socket;
    private $clientIp;
    private $logger;
    private $config;
    private $state = 'init';
    private $heloHost = '';
    private $fromAddress = '';
    private $toAddresses = [];
    private $dataBuffer = '';
    private $dataSize = 0;
    private $maxDataSize = 10485760;
    public function __construct($socket, $clientIp, $logger) {
        $this->socket = $socket;
        $this->clientIp = $clientIp;
        $this->logger = $logger;
        $this->config = Config::getInstance();
        $this->maxDataSize = $this->config->get('server.max_email_size', 10485760);
    }
    public function handle($data) {
        if ($this->state === 'data') { $this->handleDataContent($data); }
        else {
            $lines = explode("\r\n", $data);
            foreach ($lines as $line) {
                $line = trim($line);
                if (empty($line)) { continue; }
                $this->processCommand($line);
            }
        }
    }
    private function processCommand($command) {
        $parts = preg_split('/\\s+/', $command, 2);
        $cmd = strtoupper($parts[0]);
        $params = isset($parts[1]) ? $parts[1] : '';
        switch ($cmd) {
            case 'HELO':
            case 'EHLO':
                $this->heloHost = $params;
                $this->state = 'helo';
                $this->sendResponse(250, "250 {domain} Hello {host} [{ip}]");
                break;
            case 'MAIL':
                if ($this->state !== 'helo') { $this->sendResponse(503, "503 Bad sequence of commands"); return; }
                preg_match('/^FROM:\\s*<([^>]*)>/i', $params, $matches);
                if (empty($matches)) { $this->sendResponse(501, "501 Syntax error in parameters or arguments"); return; }
                $sender = $matches[1];
                if (!filter_var($sender, FILTER_VALIDATE_EMAIL)) { $this->sendResponse(553, "553 5.1.8 Invalid sender email address"); return; }
                $this->fromAddress = $sender;
                $this->state = 'mail';
                $this->toAddresses = [];
                $this->sendResponse(250, "250 2.1.0 Sender OK");
                break;
            case 'RCPT':
                if ($this->state !== 'mail') { $this->sendResponse(503, "503 Bad sequence of commands"); return; }
                preg_match('/^TO:\\s*<([^>]*)>/i', $params, $matches);
                if (empty($matches)) { $this->sendResponse(501, "501 Syntax error in parameters or arguments"); return; }
                $toAddress = $matches[1];
                if (!filter_var($toAddress, FILTER_VALIDATE_EMAIL)) { $this->sendResponse(553, "553 5.1.8 Invalid recipient email address"); return; }
                if (count($this->toAddresses) >= 100) { $this->sendResponse(452, "452 4.5.3 Too many recipients"); return; }
                $this->toAddresses[] = $toAddress;
                $this->sendResponse(250, "250 2.1.5 Recipient OK");
                break;
            case 'DATA':
                if ($this->state !== 'mail' || empty($this->toAddresses)) { $this->sendResponse(503, "503 Bad sequence of commands"); return; }
                $this->state = 'data';
                $this->dataBuffer = '';
                $this->dataSize = 0;
                $this->sendResponse(354, "354 Start mail input; end with <CRLF>.<CRLF>");
                break;
            case 'RSET':
                $this->state = 'helo';
                $this->fromAddress = '';
                $this->toAddresses = [];
                $this->dataBuffer = '';
                $this->dataSize = 0;
                $this->sendResponse(250, "250 2.0.0 OK");
                break;
            case 'NOOP':
                $this->sendResponse(250, "250 2.0.0 OK");
                break;
            case 'QUIT':
                $this->sendResponse(221, "221 2.0.0 Bye");
                break;
            default:
                $this->sendResponse(500, "500 Syntax error, command unrecognized");
                break;
        }
    }
    private function handleDataContent($data) {
        $this->dataBuffer .= $data;
        $this->dataSize += strlen($data);
        if ($this->dataSize > $this->maxDataSize) {
            $this->sendResponse(552, "552 5.2.3 Message exceeds maximum size");
            $this->state = 'helo';
            $this->dataBuffer = '';
            $this->dataSize = 0;
            return;
        }
        if (substr($this->dataBuffer, -5) === "\r\n.\r\n") {
            $emailContent = substr($this->dataBuffer, 0, -5);
            $this->processEmail($emailContent);
            $this->state = 'helo';
            $this->dataBuffer = '';
            $this->dataSize = 0;
        }
    }
    private function processEmail($emailContent) {
        $headers = $this->parseHeaders($emailContent);
        $subject = $headers['Subject'] ?? '';
        $body = $this->extractBody($emailContent);
        $this->saveEmail($headers, $subject, $body, $emailContent);
        $this->sendResponse(250, "250 2.0.0 OK: queued as {message_id}");
    }
    private function parseHeaders($emailContent) {
        $headers = [];
        $lines = explode("\r\n", $emailContent);
        foreach ($lines as $line) {
            if (empty($line)) { break; }
            if (preg_match('/^\\s+/', $line)) {
                $last = array_key_last($headers);
                $headers[$last] = isset($headers[$last]) ? $headers[$last] . ' ' . trim($line) : trim($line);
            } else {
                $parts = explode(':', $line, 2);
                if (count($parts) === 2) {
                    $name = trim($parts[0]);
                    $value = trim($parts[1]);
                    $headers[$name] = $value;
                }
            }
        }
        return $headers;
    }
    private function extractBody($emailContent) {
        $parts = explode("\r\n\r\n", $emailContent, 2);
        return isset($parts[1]) ? $parts[1] : '';
    }
    private function saveEmail($headers, $subject, $body, $raw) {
        try {
            require_once __DIR__ . '/../utils/Database.php';
            $db = Database::getInstance();
            foreach ($this->toAddresses as $toAddress) {
                $username = null;
                $user = $db->fetchOne("SELECT username FROM user WHERE email = ? AND is_deleted = 0", [$toAddress]);
                if ($user && isset($user['username'])) { $username = $user['username']; }
                if (!$username) {
                    $parts = explode('@', $toAddress);
                    $username = $parts[0] ?? $toAddress;
                }
                $id = uniqid('', true);
                $dateHeader = $headers['Date'] ?? date('Y-m-d H:i:s');
                $toHeader = $headers['To'] ?? implode(', ', $this->toAddresses);
                $fromHeader = $headers['From'] ?? $this->fromAddress;
                $length = strlen($raw);
                $sql = "INSERT INTO email (id, ip, helo, mail_from, rcpt_to, `from`, `to`, subject, `date`, `data`, datagram, `length`, `state`, is_read, folder, created_at, is_deleted) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, NOW(), 0)";
                $db->insert($sql, [$id, $this->clientIp, $this->heloHost, $this->fromAddress, $username, $fromHeader, $toHeader, $subject, $dateHeader, $body, $raw, $length, 1, 0, 'inbox']);
            }
        } catch (Exception $e) {
            $this->logger->error("Failed to save email: {error}", ['error' => $e->getMessage()]);
        }
    }
    private function sendResponse($code, $message) {
        $domain = $this->config->get('server.domain', 'test.com');
        $message = str_replace('{domain}', $domain, $message);
        $message = str_replace('{ip}', $this->clientIp, $message);
        $message = str_replace('{host}', $this->heloHost, $message);
        $response = $message . "\r\n";
        socket_write($this->socket, $response, strlen($response));
    }
}