<?php

/**
 * Log a message depending on CLI or web context
 */
function log_message(string $message, bool $is_cli, ?string $target = null): void {
    if ($is_cli) {
        file_put_contents($target ?? '/dev/stdout', $message . PHP_EOL);
    } else {
        error_log($message);
    }
}

/**
 * Exit the script with an error message
 */
function fail(string $message, bool $is_cli, ?string $target = null, int $http_code = 400): void {
    if ($is_cli) {
        log_message($message, $is_cli, $target);
    } else {
        http_response_code($http_code);
        echo $message;
    }
    exit(1);
}

/**
 * Sanitize an email component to use in file paths
 */
function sanitize_path_part(string $part): string {
    return preg_replace('/[^a-zA-Z0-9_.+-]/', '_', $part);
}

/**
 * Ensure Maildir structure exists for a given email
 */
function ensure_maildir(string $maildir_path, bool $is_cli, ?string $target): void {
    if (is_dir($maildir_path)) return;

    if (!mkdir($maildir_path, 0775, true)) {
        log_message("Failed to create Maildir structure: $maildir_path", $is_cli, $target);
        return;
    }

    foreach (['new', 'cur', 'tmp'] as $sub) {
        mkdir("$maildir_path/$sub", 0775, true);
    }
}

/**
 * Save an email message to a given Maildir
 */
function save_email(string $path, string $msg, bool $is_cli, ?string $target): void {
    if (file_put_contents($path, $msg) === false) {
        log_message("Failed to save email to $path", $is_cli, $target);
    } else {
        log_message("Email saved to $path", $is_cli, $target);
    }
}

/**
 * Get input payload depending on the environment
 */
function get_input(bool $is_cli): string {
    if ($is_cli) {
        $options = getopt('', ['cli']);
        if (!isset($options['cli'])) {
            fail("Missing --cli option for CLI execution.", true, '/dev/stderr');
        }
        return file_get_contents('php://stdin');
    }

    if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
        fail("Method not allowed. Use POST.", false, null, 405);
    }

    return file_get_contents('php://input');
}
/**
 * Logs metadata about an incoming or outgoing email into a local SQLite3 database.
 *
 * This function ensures the database exists, creates the schema if it's the first run,
 * extracts basic metadata (user, domain, subject, size), and inserts it into a table.
 *
 * @param string $email     The recipient or sender email address.
 * @param string $raw_msg   The full raw email content.
 * @param string $direction Direction of the email: 'incoming' or 'outgoing'. Default is 'incoming'.
 */
function log_email_to_sqlite(string $email, string $raw_msg, string $direction = 'incoming'): void {
    $db_path = '/home/pi/emails.db';
    $db_initialized = file_exists($db_path);

    try {
        // Open (or create) the SQLite3 database
        $db = new SQLite3($db_path);

        // Initialize the schema only if the database file did not previously exist
        if (!$db_initialized) {
            $db->exec("
                CREATE TABLE emails (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    direction TEXT CHECK(direction IN ('incoming', 'outgoing')) NOT NULL,
                    user TEXT,
                    domain TEXT,
                    subject TEXT,
                    date TEXT,
                    attachments_no INTEGER,
                    sizeKb INTEGER
                )
            ");
        }

        // Extract local part and domain from the email address
        $local = preg_replace('/[^a-zA-Z0-9_.+-]/', '_', strstr($email, '@', true));
        $domain = preg_replace('/[^a-zA-Z0-9_.+-]/', '_', substr(strstr($email, '@'), 1));

        // Attempt to parse the Subject header from the raw message
        $subject = '';
        if (preg_match('/^Subject:\s*(.*)$/mi', $raw_msg, $matches)) {
            $subject = trim($matches[1]);
        }

        // Calculate message size in kilobytes
        $size_kb = (int)(strlen($raw_msg) / 1024);

        // Use the current timestamp as the 'date'
        $timestamp = date('Y-m-d H:i:s');

        // Prepare and execute the insert query
        $stmt = $db->prepare("
            INSERT INTO emails (direction, user, domain, subject, date, attachments_no, sizeKb)
            VALUES (:direction, :user, :domain, :subject, :date, :attachments, :size)
        ");
        $stmt->bindValue(':direction', $direction, SQLITE3_TEXT);
        $stmt->bindValue(':user', $local, SQLITE3_TEXT);
        $stmt->bindValue(':domain', $domain, SQLITE3_TEXT);
        $stmt->bindValue(':subject', $subject, SQLITE3_TEXT);
        $stmt->bindValue(':date', $timestamp, SQLITE3_TEXT);
        $stmt->bindValue(':attachments', 0, SQLITE3_INTEGER); // Can be extended later to count real attachments
        $stmt->bindValue(':size', $size_kb, SQLITE3_INTEGER);
        $stmt->execute();

        // Close the database connection
        $db->close();

    } catch (Exception $e) {
        // Log any unexpected SQLite errors (e.g., permission issues)
        error_log("SQLite error: " . $e->getMessage());
    }
}