smuuf/primi

<?php

declare(strict_types=1);

namespace Smuuf\Primi;

use \Smuuf\Primi\Ex\EngineError;

/**
 * Static helper for providing information about current runtime environment.
 */
abstract class EnvInfo {

    private static bool $bootCheck = \false;
    private static ?bool $runningInPhar = \null;
    private static ?bool $runningInCli = \null;
    private static ?string $homeDir = \null;
    private static ?string $currentUser = \null;
    private static ?string $bestTempDir = \null;

    /**
     * Throws if Primi cannot run in current PHP runtime.
     */
    public static function bootCheck(): void {

        if (self::$bootCheck) {
            return;
        }

        $missingExt = [];
        $missingExt['bcmath'] = !\extension_loaded('bcmath');
        $missingExt['mbstring'] = !\extension_loaded('mbstring');
        $missingExt = \array_filter($missingExt);

        if ($missingExt) {
            $list = \implode(', ', \array_keys($missingExt));
            throw new EngineError("Primi requires PHP extensions: $list");
        }

        self::$bootCheck = \true;

    }

    /**
     * Get Primi build ID (if executed within compiled Phar, else 'dev').
     */
    public static function getPrimiBuild(): string {

        return self::isRunningInPhar()
            ? \constant('BUILD_ID')
            : 'dev';

    }

    /**
     * Is current runtime being executed within Phar?
     */
    public static function isRunningInPhar(): bool {
        return self::$runningInPhar
            ?? (self::$runningInPhar = self::determineIsRunningInPhar());
    }

    /**
     * Is current runtime being executed within Phar?
     */
    public static function isRunningInCli(): bool {
        return self::$runningInCli
            ?? (self::$runningInCli = \in_array(\PHP_SAPI, ['cli', 'phpdbg']));
    }

    /**
     * Return current user's HOME directory, or `null` if there's not any.
     */
    public static function getHomeDir(): ?string {
        return self::$homeDir
            ?? (self::$homeDir = (\getenv('HOME') ?: \null));
    }

    /**
     * Return current user's username.
     */
    public static function getCurrentUser(): string {
        return self::$currentUser
            ?? (self::$currentUser = \getenv('USER'));
    }

    /**
     * Return path to best temporary dir available for current runtime.
     */
    public static function getBestTempDir(): ?string {

        return self::$bestTempDir
            ?? (self::$bestTempDir = self::determineBestTempDir());

    }

    //
    // Helpers.
    //

    /**
     * Determine if Phar extension is enabled and if we're being executed
     * inside Phar.
     */
    private static function determineIsRunningInPhar(): bool {
        return \extension_loaded('phar') && \Phar::running();
    }

    /**
     * Determine best directory to use as temporary directory for Primi.
     */
    private static function determineBestTempDir(): ?string {

        // If not running inside Phar, default dir will be in Primi's temp
        // directory.
        if (!EnvInfo::isRunningInPhar()) {

            $tempDir = __DIR__ . '/../temp';
            Logger::debug("Using library temp directory '$tempDir'");
            return $tempDir;

        }

        //
        // Now we handle situations where we're being executed as Phar archive.
        //

        // Determine if we can get home directory for current user.
        $homeDir = EnvInfo::getHomeDir();
        if ($homeDir === \null) {

            $currentUser = EnvInfo::getCurrentUser();
            Logger::debug("Current user '$currentUser' has no home directory. Temp directory disabled");

            // Current user has no home directory, we're disabling temp dir.
            return \null;

        }

        // Determine if current user's home directory contains ".primi" file/dir.
        $tempDir = "{$homeDir}/.primi";
        if (!\file_exists($tempDir)) {

            // Home directory does not contain ".primi" - try creating it.
            $success = @mkdir($tempDir);
            if ($success === \false) {
                Logger::debug("Failed to create temp directory '$tempDir'. Temp directory disabled");
                return \null;
            }

        }

        // Is ".primi" file/dir in home dir a file? We need it to be a dir...
        if (\is_file($tempDir)) {
            Logger::debug("Path to temp directory '$tempDir' exists, but is a file. Temp directory disabled");
            return \null;
        }

        // And this dir needs to be writable by us...
        if (!\is_writable($tempDir)) {
            Logger::debug("Temp directory '$tempDir' is not writable. Temp directory disabled");
            return \null;
        }

        // The ".primi" in home dir is a directory and we can write to it,
        // let's use it!
        Logger::debug("Using temp directory '$tempDir'");
        return $tempDir;

    }

}