class DownloadManager

class DownloadManager {
    
    /** @var IOInterface */
    private $io;
    
    /** @var bool */
    private $preferDist = false;
    
    /** @var bool */
    private $preferSource;
    
    /** @var array<string, string> */
    private $packagePreferences = [];
    
    /** @var Filesystem */
    private $filesystem;
    
    /** @var array<string, DownloaderInterface> */
    private $downloaders = [];
    
    /**
     * Initializes download manager.
     *
     * @param IOInterface     $io           The Input Output Interface
     * @param bool            $preferSource prefer downloading from source
     * @param Filesystem|null $filesystem   custom Filesystem object
     */
    public function __construct(IOInterface $io, bool $preferSource = false, ?Filesystem $filesystem = null) {
        $this->io = $io;
        $this->preferSource = $preferSource;
        $this->filesystem = $filesystem ?: new Filesystem();
    }
    
    /**
     * Makes downloader prefer source installation over the dist.
     *
     * @param  bool            $preferSource prefer downloading from source
     * @return DownloadManager
     */
    public function setPreferSource(bool $preferSource) : self {
        $this->preferSource = $preferSource;
        return $this;
    }
    
    /**
     * Makes downloader prefer dist installation over the source.
     *
     * @param  bool            $preferDist prefer downloading from dist
     * @return DownloadManager
     */
    public function setPreferDist(bool $preferDist) : self {
        $this->preferDist = $preferDist;
        return $this;
    }
    
    /**
     * Sets fine tuned preference settings for package level source/dist selection.
     *
     * @param array<string, string> $preferences array of preferences by package patterns
     *
     * @return DownloadManager
     */
    public function setPreferences(array $preferences) : self {
        $this->packagePreferences = $preferences;
        return $this;
    }
    
    /**
     * Sets installer downloader for a specific installation type.
     *
     * @param  string              $type       installation type
     * @param  DownloaderInterface $downloader downloader instance
     * @return DownloadManager
     */
    public function setDownloader(string $type, DownloaderInterface $downloader) : self {
        $type = strtolower($type);
        $this->downloaders[$type] = $downloader;
        return $this;
    }
    
    /**
     * Returns downloader for a specific installation type.
     *
     * @param  string                    $type installation type
     * @throws \InvalidArgumentException if downloader for provided type is not registered
     */
    public function getDownloader(string $type) : DownloaderInterface {
        $type = strtolower($type);
        if (!isset($this->downloaders[$type])) {
            throw new \InvalidArgumentException(sprintf('Unknown downloader type: %s. Available types: %s.', $type, implode(', ', array_keys($this->downloaders))));
        }
        return $this->downloaders[$type];
    }
    
    /**
     * Returns downloader for already installed package.
     *
     * @param  PackageInterface          $package package instance
     * @throws \InvalidArgumentException if package has no installation source specified
     * @throws \LogicException           if specific downloader used to load package with
     *                                           wrong type
     */
    public function getDownloaderForPackage(PackageInterface $package) : ?DownloaderInterface {
        $installationSource = $package->getInstallationSource();
        if ('metapackage' === $package->getType()) {
            return null;
        }
        if ('dist' === $installationSource) {
            $downloader = $this->getDownloader($package->getDistType());
        }
        elseif ('source' === $installationSource) {
            $downloader = $this->getDownloader($package->getSourceType());
        }
        else {
            throw new \InvalidArgumentException('Package ' . $package . ' does not have an installation source set');
        }
        if ($installationSource !== $downloader->getInstallationSource()) {
            throw new \LogicException(sprintf('Downloader "%s" is a %s type downloader and can not be used to download %s for package %s', get_class($downloader), $downloader->getInstallationSource(), $installationSource, $package));
        }
        return $downloader;
    }
    public function getDownloaderType(DownloaderInterface $downloader) : string {
        return array_search($downloader, $this->downloaders);
    }
    
    /**
     * Downloads package into target dir.
     *
     * @param PackageInterface      $package     package instance
     * @param string                $targetDir   target dir
     * @param PackageInterface|null $prevPackage previous package instance in case of updates
     * @phpstan-return PromiseInterface<void|null>
     *
     * @throws \InvalidArgumentException if package have no urls to download from
     * @throws \RuntimeException
     */
    public function download(PackageInterface $package, string $targetDir, ?PackageInterface $prevPackage = null) : PromiseInterface {
        $targetDir = $this->normalizeTargetDir($targetDir);
        $this->filesystem
            ->ensureDirectoryExists(dirname($targetDir));
        $sources = $this->getAvailableSources($package, $prevPackage);
        $io = $this->io;
        $download = function ($retry = false) use (&$sources, $io, $package, $targetDir, &$download, $prevPackage) {
            $source = array_shift($sources);
            if ($retry) {
                $io->writeError('    <warning>Now trying to download from ' . $source . '</warning>');
            }
            $package->setInstallationSource($source);
            $downloader = $this->getDownloaderForPackage($package);
            if (!$downloader) {
                return \React\Promise\resolve(null);
            }
            $handleError = static function ($e) use ($sources, $source, $package, $io, $download) {
                if ($e instanceof \RuntimeException && !$e instanceof IrrecoverableDownloadException) {
                    if (!$sources) {
                        throw $e;
                    }
                    $io->writeError('    <warning>Failed to download ' . $package->getPrettyName() . ' from ' . $source . ': ' . $e->getMessage() . '</warning>');
                    return $download(true);
                }
                throw $e;
            };
            try {
                $result = $downloader->download($package, $targetDir, $prevPackage);
            } catch (\Exception $e) {
                return $handleError($e);
            }
            $res = $result->then(static function ($res) {
                return $res;
            }, $handleError);
            return $res;
        };
        return $download();
    }
    
    /**
     * Prepares an operation execution
     *
     * @param string                $type        one of install/update/uninstall
     * @param PackageInterface      $package     package instance
     * @param string                $targetDir   target dir
     * @param PackageInterface|null $prevPackage previous package instance in case of updates
     * @phpstan-return PromiseInterface<void|null>
     */
    public function prepare(string $type, PackageInterface $package, string $targetDir, ?PackageInterface $prevPackage = null) : PromiseInterface {
        $targetDir = $this->normalizeTargetDir($targetDir);
        $downloader = $this->getDownloaderForPackage($package);
        if ($downloader) {
            return $downloader->prepare($type, $package, $targetDir, $prevPackage);
        }
        return \React\Promise\resolve(null);
    }
    
    /**
     * Installs package into target dir.
     *
     * @param PackageInterface $package   package instance
     * @param string           $targetDir target dir
     * @phpstan-return PromiseInterface<void|null>
     *
     * @throws \InvalidArgumentException if package have no urls to download from
     * @throws \RuntimeException
     */
    public function install(PackageInterface $package, string $targetDir) : PromiseInterface {
        $targetDir = $this->normalizeTargetDir($targetDir);
        $downloader = $this->getDownloaderForPackage($package);
        if ($downloader) {
            return $downloader->install($package, $targetDir);
        }
        return \React\Promise\resolve(null);
    }
    
    /**
     * Updates package from initial to target version.
     *
     * @param PackageInterface $initial   initial package version
     * @param PackageInterface $target    target package version
     * @param string           $targetDir target dir
     * @phpstan-return PromiseInterface<void|null>
     *
     * @throws \InvalidArgumentException if initial package is not installed
     */
    public function update(PackageInterface $initial, PackageInterface $target, string $targetDir) : PromiseInterface {
        $targetDir = $this->normalizeTargetDir($targetDir);
        $downloader = $this->getDownloaderForPackage($target);
        $initialDownloader = $this->getDownloaderForPackage($initial);
        // no downloaders present means update from metapackage to metapackage, nothing to do
        if (!$initialDownloader && !$downloader) {
            return \React\Promise\resolve(null);
        }
        // if we have a downloader present before, but not after, the package became a metapackage and its files should be removed
        if (!$downloader) {
            return $initialDownloader->remove($initial, $targetDir);
        }
        $initialType = $this->getDownloaderType($initialDownloader);
        $targetType = $this->getDownloaderType($downloader);
        if ($initialType === $targetType) {
            try {
                return $downloader->update($initial, $target, $targetDir);
            } catch (\RuntimeException $e) {
                if (!$this->io
                    ->isInteractive()) {
                    throw $e;
                }
                $this->io
                    ->writeError('<error>    Update failed (' . $e->getMessage() . ')</error>');
                if (!$this->io
                    ->askConfirmation('    Would you like to try reinstalling the package instead [<comment>yes</comment>]? ')) {
                    throw $e;
                }
            }
        }
        // if downloader type changed, or update failed and user asks for reinstall,
        // we wipe the dir and do a new install instead of updating it
        $promise = $initialDownloader->remove($initial, $targetDir);
        return $promise->then(function ($res) use ($target, $targetDir) : PromiseInterface {
            return $this->install($target, $targetDir);
        });
    }
    
    /**
     * Removes package from target dir.
     *
     * @param PackageInterface $package   package instance
     * @param string           $targetDir target dir
     * @phpstan-return PromiseInterface<void|null>
     */
    public function remove(PackageInterface $package, string $targetDir) : PromiseInterface {
        $targetDir = $this->normalizeTargetDir($targetDir);
        $downloader = $this->getDownloaderForPackage($package);
        if ($downloader) {
            return $downloader->remove($package, $targetDir);
        }
        return \React\Promise\resolve(null);
    }
    
    /**
     * Cleans up a failed operation
     *
     * @param string                $type        one of install/update/uninstall
     * @param PackageInterface      $package     package instance
     * @param string                $targetDir   target dir
     * @param PackageInterface|null $prevPackage previous package instance in case of updates
     * @phpstan-return PromiseInterface<void|null>
     */
    public function cleanup(string $type, PackageInterface $package, string $targetDir, ?PackageInterface $prevPackage = null) : PromiseInterface {
        $targetDir = $this->normalizeTargetDir($targetDir);
        $downloader = $this->getDownloaderForPackage($package);
        if ($downloader) {
            return $downloader->cleanup($type, $package, $targetDir, $prevPackage);
        }
        return \React\Promise\resolve(null);
    }
    
    /**
     * Determines the install preference of a package
     *
     * @param PackageInterface $package package instance
     */
    protected function resolvePackageInstallPreference(PackageInterface $package) : string {
        foreach ($this->packagePreferences as $pattern => $preference) {
            $pattern = '{^' . str_replace('\\*', '.*', preg_quote($pattern)) . '$}i';
            if (Preg::isMatch($pattern, $package->getName())) {
                if ('dist' === $preference || !$package->isDev() && 'auto' === $preference) {
                    return 'dist';
                }
                return 'source';
            }
        }
        return $package->isDev() ? 'source' : 'dist';
    }
    
    /**
     * @return string[]
     * @phpstan-return array<'dist'|'source'>&non-empty-array
     */
    private function getAvailableSources(PackageInterface $package, ?PackageInterface $prevPackage = null) : array {
        $sourceType = $package->getSourceType();
        $distType = $package->getDistType();
        // add source before dist by default
        $sources = [];
        if ($sourceType) {
            $sources[] = 'source';
        }
        if ($distType) {
            $sources[] = 'dist';
        }
        if (empty($sources)) {
            throw new \InvalidArgumentException('Package ' . $package . ' must have a source or dist specified');
        }
        if ($prevPackage && in_array($prevPackage->getInstallationSource(), $sources, true) && !(!$prevPackage->isDev() && $prevPackage->getInstallationSource() === 'dist' && $package->isDev())) {
            $prevSource = $prevPackage->getInstallationSource();
            usort($sources, static function ($a, $b) use ($prevSource) : int {
                return $a === $prevSource ? -1 : 1;
            });
            return $sources;
        }
        // reverse sources in case dist is the preferred source for this package
        if (!$this->preferSource && ($this->preferDist || 'dist' === $this->resolvePackageInstallPreference($package))) {
            $sources = array_reverse($sources);
        }
        return $sources;
    }
    
    /**
     * Downloaders expect a /path/to/dir without trailing slash
     *
     * If any Installer provides a path with a trailing slash, this can cause bugs so make sure we remove them
     */
    private function normalizeTargetDir(string $dir) : string {
        if ($dir === '\\' || $dir === '/') {
            return $dir;
        }
        return rtrim($dir, '\\/');
    }

}