<?php declare(strict_types=1);

/*
 * This file is part of Composer.
 *
 * (c) Nils Adermann <naderman@naderman.de>
 *     Jordi Boggiano <j.boggiano@seld.be>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Composer\Downloader;

use Composer\Config;
use Composer\IO\IOInterface;
use Composer\Package\PackageInterface;
use Composer\Pcre\Preg;
use Composer\Util\Filesystem;
use Composer\Util\Git as GitUtil;
use Composer\Util\Url;
use Composer\Util\Platform;
use Composer\Util\ProcessExecutor;
use Composer\Cache;
use React\Promise\PromiseInterface;

/**
 * @author Jordi Boggiano <j.boggiano@seld.be>
 */
class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
{
    /**
     * @var bool[]
     * @phpstan-var array<string, bool>
     */
    private $hasStashedChanges = array();
    /**
     * @var bool[]
     * @phpstan-var array<string, bool>
     */
    private $hasDiscardedChanges = array();
    /**
     * @var GitUtil
     */
    private $gitUtil;
    /**
     * @var array
     * @phpstan-var array<int, array<string, bool>>
     */
    private $cachedPackages = array();

    public function __construct(IOInterface $io, Config $config, ProcessExecutor $process = null, Filesystem $fs = null)
    {
        parent::__construct($io, $config, $process, $fs);
        $this->gitUtil = new GitUtil($this->io, $this->config, $this->process, $this->filesystem);
    }

    /**
     * @inheritDoc
     */
    protected function doDownload(PackageInterface $package, string $path, string $url, PackageInterface $prevPackage = null): PromiseInterface
    {
        GitUtil::cleanEnv();

        $cachePath = $this->config->get('cache-vcs-dir').'/'.Preg::replace('{[^a-z0-9.]}i', '-', $url).'/';
        $gitVersion = GitUtil::getVersion($this->process);

        // --dissociate option is only available since git 2.3.0-rc0
        if ($gitVersion && version_compare($gitVersion, '2.3.0-rc0', '>=') && Cache::isUsable($cachePath)) {
            $this->io->writeError("  - Syncing <info>" . $package->getName() . "</info> (<comment>" . $package->getFullPrettyVersion() . "</comment>) into cache");
            $this->io->writeError(sprintf('    Cloning to cache at %s', ProcessExecutor::escape($cachePath)), true, IOInterface::DEBUG);
            $ref = $package->getSourceReference();
            if ($this->gitUtil->fetchRefOrSyncMirror($url, $cachePath, $ref) && is_dir($cachePath)) {
                $this->cachedPackages[$package->getId()][$ref] = true;
            }
        } elseif (null === $gitVersion) {
            throw new \RuntimeException('git was not found in your PATH, skipping source download');
        }

        return \React\Promise\resolve(null);
    }

    /**
     * @inheritDoc
     */
    protected function doInstall(PackageInterface $package, string $path, string $url): PromiseInterface
    {
        GitUtil::cleanEnv();
        $path = $this->normalizePath($path);
        $cachePath = $this->config->get('cache-vcs-dir').'/'.Preg::replace('{[^a-z0-9.]}i', '-', $url).'/';
        $ref = $package->getSourceReference();
        $flag = Platform::isWindows() ? '/D ' : '';

        if (!empty($this->cachedPackages[$package->getId()][$ref])) {
            $msg = "Cloning ".$this->getShortHash($ref).' from cache';

            $cloneFlags = '--dissociate --reference %cachePath% ';
            $transportOptions = $package->getTransportOptions();
            if (isset($transportOptions['git']['single_use_clone']) && $transportOptions['git']['single_use_clone']) {
                $cloneFlags = '';
            }

            $command =
                'git clone --no-checkout %cachePath% %path% ' . $cloneFlags
                . '&& cd '.$flag.'%path% '
                . '&& git remote set-url origin -- %sanitizedUrl% && git remote add composer -- %sanitizedUrl%';
        } else {
            $msg = "Cloning ".$this->getShortHash($ref);
            $command = 'git clone --no-checkout -- %url% %path% && cd '.$flag.'%path% && git remote add composer -- %url% && git fetch composer && git remote set-url origin -- %sanitizedUrl% && git remote set-url composer -- %sanitizedUrl%';
            if (Platform::getEnv('COMPOSER_DISABLE_NETWORK')) {
                throw new \RuntimeException('The required git reference for '.$package->getName().' is not in cache and network is disabled, aborting');
            }
        }

        $this->io->writeError($msg);

        $commandCallable = function (string $url) use ($path, $command, $cachePath): string {
            return str_replace(
                array('%url%', '%path%', '%cachePath%', '%sanitizedUrl%'),
                array(
                    ProcessExecutor::escape($url),
                    ProcessExecutor::escape($path),
                    ProcessExecutor::escape($cachePath),
                    ProcessExecutor::escape(Preg::replace('{://([^@]+?):(.+?)@}', '://', $url)),
                ),
                $command
            );
        };

        $this->gitUtil->runCommand($commandCallable, $url, $path, true);
        $sourceUrl = $package->getSourceUrl();
        if ($url !== $sourceUrl && $sourceUrl !== null) {
            $this->updateOriginUrl($path, $sourceUrl);
        } else {
            $this->setPushUrl($path, $url);
        }

        if ($newRef = $this->updateToCommit($package, $path, (string) $ref, $package->getPrettyVersion())) {
            if ($package->getDistReference() === $package->getSourceReference()) {
                $package->setDistReference($newRef);
            }
            $package->setSourceReference($newRef);
        }

        return \React\Promise\resolve(null);
    }

    /**
     * @inheritDoc
     */
    protected function doUpdate(PackageInterface $initial, PackageInterface $target, string $path, string $url): PromiseInterface
    {
        GitUtil::cleanEnv();
        $path = $this->normalizePath($path);
        if (!$this->hasMetadataRepository($path)) {
            throw new \RuntimeException('The .git directory is missing from '.$path.', see https://getcomposer.org/commit-deps for more information');
        }

        $cachePath = $this->config->get('cache-vcs-dir').'/'.Preg::replace('{[^a-z0-9.]}i', '-', $url).'/';
        $ref = $target->getSourceReference();

        if (!empty($this->cachedPackages[$target->getId()][$ref])) {
            $msg = "Checking out ".$this->getShortHash($ref).' from cache';
            $command = '(git rev-parse --quiet --verify %ref% || (git remote set-url composer -- %cachePath% && git fetch composer && git fetch --tags composer)) && git remote set-url composer -- %sanitizedUrl%';
        } else {
            $msg = "Checking out ".$this->getShortHash($ref);
            $command = '(git remote set-url composer -- %url% && git rev-parse --quiet --verify %ref% || (git fetch composer && git fetch --tags composer)) && git remote set-url composer -- %sanitizedUrl%';
            if (Platform::getEnv('COMPOSER_DISABLE_NETWORK')) {
                throw new \RuntimeException('The required git reference for '.$target->getName().' is not in cache and network is disabled, aborting');
            }
        }

        $this->io->writeError($msg);

        $commandCallable = function ($url) use ($ref, $command, $cachePath): string {
            return str_replace(
                array('%url%', '%ref%', '%cachePath%', '%sanitizedUrl%'),
                array(
                    ProcessExecutor::escape($url),
                    ProcessExecutor::escape($ref.'^{commit}'),
                    ProcessExecutor::escape($cachePath),
                    ProcessExecutor::escape(Preg::replace('{://([^@]+?):(.+?)@}', '://', $url)),
                ),
                $command
            );
        };

        $this->gitUtil->runCommand($commandCallable, $url, $path);
        if ($newRef = $this->updateToCommit($target, $path, (string) $ref, $target->getPrettyVersion())) {
            if ($target->getDistReference() === $target->getSourceReference()) {
                $target->setDistReference($newRef);
            }
            $target->setSourceReference($newRef);
        }

        $updateOriginUrl = false;
        if (
            0 === $this->process->execute('git remote -v', $output, $path)
            && Preg::isMatch('{^origin\s+(?P<url>\S+)}m', $output, $originMatch)
            && Preg::isMatch('{^composer\s+(?P<url>\S+)}m', $output, $composerMatch)
        ) {
            if ($originMatch['url'] === $composerMatch['url'] && $composerMatch['url'] !== $target->getSourceUrl()) {
                $updateOriginUrl = true;
            }
        }
        if ($updateOriginUrl && $target->getSourceUrl() !== null) {
            $this->updateOriginUrl($path, $target->getSourceUrl());
        }

        return \React\Promise\resolve(null);
    }

    /**
     * @inheritDoc
     */
    public function getLocalChanges(PackageInterface $package, string $path): ?string
    {
        GitUtil::cleanEnv();
        if (!$this->hasMetadataRepository($path)) {
            return null;
        }

        $command = 'git status --porcelain --untracked-files=no';
        if (0 !== $this->process->execute($command, $output, $path)) {
            throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
        }

        $output = trim($output);

        return strlen($output) > 0 ? $output : null;
    }

    /**
     * @return null|string
     */
    public function getUnpushedChanges(PackageInterface $package, string $path): ?string
    {
        GitUtil::cleanEnv();
        $path = $this->normalizePath($path);
        if (!$this->hasMetadataRepository($path)) {
            return null;
        }

        $command = 'git show-ref --head -d';
        if (0 !== $this->process->execute($command, $output, $path)) {
            throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
        }

        $refs = trim($output);
        if (!Preg::isMatch('{^([a-f0-9]+) HEAD$}mi', $refs, $match)) {
            // could not match the HEAD for some reason
            return null;
        }

        $headRef = $match[1];
        if (!Preg::isMatchAll('{^'.$headRef.' refs/heads/(.+)$}mi', $refs, $matches)) {
            // not on a branch, we are either on a not-modified tag or some sort of detached head, so skip this
            return null;
        }

        $candidateBranches = $matches[1];
        // use the first match as branch name for now
        $branch = $candidateBranches[0];
        $unpushedChanges = null;
        $branchNotFoundError = false;

        // do two passes, as if we find anything we want to fetch and then re-try
        for ($i = 0; $i <= 1; $i++) {
            $remoteBranches = array();

            // try to find matching branch names in remote repos
            foreach ($candidateBranches as $candidate) {
                if (Preg::isMatchAll('{^[a-f0-9]+ refs/remotes/((?:[^/]+)/'.preg_quote($candidate).')$}mi', $refs, $matches)) {
                    foreach ($matches[1] as $match) {
                        $branch = $candidate;
                        $remoteBranches[] = $match;
                    }
                    break;
                }
            }

            // if it doesn't exist, then we assume it is an unpushed branch
            // this is bad as we have no reference point to do a diff so we just bail listing
            // the branch as being unpushed
            if (!$remoteBranches) {
                $unpushedChanges = 'Branch ' . $branch . ' could not be found on any remote and appears to be unpushed';
                $branchNotFoundError = true;
            } else {
                // if first iteration found no remote branch but it has now found some, reset $unpushedChanges
                // so we get the real diff output no matter its length
                if ($branchNotFoundError) {
                    $unpushedChanges = null;
                }
                foreach ($remoteBranches as $remoteBranch) {
                    $command = sprintf('git diff --name-status %s...%s --', $remoteBranch, $branch);
                    if (0 !== $this->process->execute($command, $output, $path)) {
                        throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
                    }

                    $output = trim($output);
                    // keep the shortest diff from all remote branches we compare against
                    if ($unpushedChanges === null || strlen($output) < strlen($unpushedChanges)) {
                        $unpushedChanges = $output;
                    }
                }
            }

            // first pass and we found unpushed changes, fetch from all remotes to make sure we have up to date
            // remotes and then try again as outdated remotes can sometimes cause false-positives
            if ($unpushedChanges && $i === 0) {
                $this->process->execute('git fetch --all', $output, $path);

                // update list of refs after fetching
                $command = 'git show-ref --head -d';
                if (0 !== $this->process->execute($command, $output, $path)) {
                    throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
                }
                $refs = trim($output);
            }

            // abort after first pass if we didn't find anything
            if (!$unpushedChanges) {
                break;
            }
        }

        return $unpushedChanges;
    }

    /**
     * @inheritDoc
     */
    protected function cleanChanges(PackageInterface $package, string $path, bool $update): PromiseInterface
    {
        GitUtil::cleanEnv();
        $path = $this->normalizePath($path);

        $unpushed = $this->getUnpushedChanges($package, $path);
        if ($unpushed && ($this->io->isInteractive() || $this->config->get('discard-changes') !== true)) {
            throw new \RuntimeException('Source directory ' . $path . ' has unpushed changes on the current branch: '."\n".$unpushed);
        }

        if (null === ($changes = $this->getLocalChanges($package, $path))) {
            return \React\Promise\resolve(null);
        }

        if (!$this->io->isInteractive()) {
            $discardChanges = $this->config->get('discard-changes');
            if (true === $discardChanges) {
                return $this->discardChanges($path);
            }
            if ('stash' === $discardChanges) {
                if (!$update) {
                    return parent::cleanChanges($package, $path, $update);
                }

                return $this->stashChanges($path);
            }

            return parent::cleanChanges($package, $path, $update);
        }

        $changes = array_map(function ($elem): string {
            return '    '.$elem;
        }, Preg::split('{\s*\r?\n\s*}', $changes));
        $this->io->writeError('    <error>'.$package->getPrettyName().' has modified files:</error>');
        $this->io->writeError(array_slice($changes, 0, 10));
        if (count($changes) > 10) {
            $this->io->writeError('    <info>' . (count($changes) - 10) . ' more files modified, choose "v" to view the full list</info>');
        }

        while (true) {
            switch ($this->io->ask('    <info>Discard changes [y,n,v,d,'.($update ? 's,' : '').'?]?</info> ', '?')) {
                case 'y':
                    $this->discardChanges($path);
                    break 2;

                case 's':
                    if (!$update) {
                        goto help;
                    }

                    $this->stashChanges($path);
                    break 2;

                case 'n':
                    throw new \RuntimeException('Update aborted');

                case 'v':
                    $this->io->writeError($changes);
                    break;

                case 'd':
                    $this->viewDiff($path);
                    break;

                case '?':
                default:
                    help :
                    $this->io->writeError(array(
                        '    y - discard changes and apply the '.($update ? 'update' : 'uninstall'),
                        '    n - abort the '.($update ? 'update' : 'uninstall').' and let you manually clean things up',
                        '    v - view modified files',
                        '    d - view local modifications (diff)',
                    ));
                    if ($update) {
                        $this->io->writeError('    s - stash changes and try to reapply them after the update');
                    }
                    $this->io->writeError('    ? - print help');
                    break;
            }
        }

        return \React\Promise\resolve(null);
    }

    /**
     * @inheritDoc
     */
    protected function reapplyChanges(string $path): void
    {
        $path = $this->normalizePath($path);
        if (!empty($this->hasStashedChanges[$path])) {
            unset($this->hasStashedChanges[$path]);
            $this->io->writeError('    <info>Re-applying stashed changes</info>');
            if (0 !== $this->process->execute('git stash pop', $output, $path)) {
                throw new \RuntimeException("Failed to apply stashed changes:\n\n".$this->process->getErrorOutput());
            }
        }

        unset($this->hasDiscardedChanges[$path]);
    }

    /**
     * Updates the given path to the given commit ref
     *
     * @param  string            $path
     * @param  string            $reference
     * @param  string            $prettyVersion
     * @throws \RuntimeException
     * @return null|string       if a string is returned, it is the commit reference that was checked out if the original could not be found
     */
    protected function updateToCommit(PackageInterface $package, string $path, string $reference, string $prettyVersion): ?string
    {
        $force = !empty($this->hasDiscardedChanges[$path]) || !empty($this->hasStashedChanges[$path]) ? '-f ' : '';

        // This uses the "--" sequence to separate branch from file parameters.
        //
        // Otherwise git tries the branch name as well as file name.
        // If the non-existent branch is actually the name of a file, the file
        // is checked out.
        $template = 'git checkout '.$force.'%s -- && git reset --hard %1$s --';
        $branch = Preg::replace('{(?:^dev-|(?:\.x)?-dev$)}i', '', $prettyVersion);

        $branches = null;
        if (0 === $this->process->execute('git branch -r', $output, $path)) {
            $branches = $output;
        }

        // check whether non-commitish are branches or tags, and fetch branches with the remote name
        $gitRef = $reference;
        if (!Preg::isMatch('{^[a-f0-9]{40}$}', $reference)
            && null !== $branches
            && Preg::isMatch('{^\s+composer/'.preg_quote($reference).'$}m', $branches)
        ) {
            $command = sprintf('git checkout '.$force.'-B %s %s -- && git reset --hard %2$s --', ProcessExecutor::escape($branch), ProcessExecutor::escape('composer/'.$reference));
            if (0 === $this->process->execute($command, $output, $path)) {
                return null;
            }
        }

        // try to checkout branch by name and then reset it so it's on the proper branch name
        if (Preg::isMatch('{^[a-f0-9]{40}$}', $reference)) {
            // add 'v' in front of the branch if it was stripped when generating the pretty name
            if (null !== $branches && !Preg::isMatch('{^\s+composer/'.preg_quote($branch).'$}m', $branches) && Preg::isMatch('{^\s+composer/v'.preg_quote($branch).'$}m', $branches)) {
                $branch = 'v' . $branch;
            }

            $command = sprintf('git checkout %s --', ProcessExecutor::escape($branch));
            $fallbackCommand = sprintf('git checkout '.$force.'-B %s %s --', ProcessExecutor::escape($branch), ProcessExecutor::escape('composer/'.$branch));
            $resetCommand = sprintf('git reset --hard %s --', ProcessExecutor::escape($reference));

            if (0 === $this->process->execute("($command || $fallbackCommand) && $resetCommand", $output, $path)) {
                return null;
            }
        }

        $command = sprintf($template, ProcessExecutor::escape($gitRef));
        if (0 === $this->process->execute($command, $output, $path)) {
            return null;
        }

        $exceptionExtra = '';

        // reference was not found (prints "fatal: reference is not a tree: $ref")
        if (false !== strpos($this->process->getErrorOutput(), $reference)) {
            $this->io->writeError('    <warning>'.$reference.' is gone (history was rewritten?)</warning>');
            $exceptionExtra = "\nIt looks like the commit hash is not available in the repository, maybe ".($package->isDev() ? 'the commit was removed from the branch' : 'the tag was recreated').'? Run "composer update '.$package->getPrettyName().'" to resolve this.';
        }

        throw new \RuntimeException(Url::sanitize('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput() . $exceptionExtra));
    }

    /**
     * @param string $path
     * @param string $url
     *
     * @return void
     */
    protected function updateOriginUrl(string $path, string $url): void
    {
        $this->process->execute(sprintf('git remote set-url origin -- %s', ProcessExecutor::escape($url)), $output, $path);
        $this->setPushUrl($path, $url);
    }

    /**
     * @param string $path
     * @param string $url
     *
     * @return void
     */
    protected function setPushUrl(string $path, string $url): void
    {
        // set push url for github projects
        if (Preg::isMatch('{^(?:https?|git)://'.GitUtil::getGitHubDomainsRegex($this->config).'/([^/]+)/([^/]+?)(?:\.git)?$}', $url, $match)) {
            $protocols = $this->config->get('github-protocols');
            $pushUrl = 'git@'.$match[1].':'.$match[2].'/'.$match[3].'.git';
            if (!in_array('ssh', $protocols, true)) {
                $pushUrl = 'https://' . $match[1] . '/'.$match[2].'/'.$match[3].'.git';
            }
            $cmd = sprintf('git remote set-url --push origin -- %s', ProcessExecutor::escape($pushUrl));
            $this->process->execute($cmd, $ignoredOutput, $path);
        }
    }

    /**
     * @inheritDoc
     */
    protected function getCommitLogs(string $fromReference, string $toReference, string $path): string
    {
        $path = $this->normalizePath($path);
        $command = sprintf('git log %s..%s --pretty=format:"%%h - %%an: %%s"'.GitUtil::getNoShowSignatureFlag($this->process), ProcessExecutor::escape($fromReference), ProcessExecutor::escape($toReference));

        if (0 !== $this->process->execute($command, $output, $path)) {
            throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
        }

        return $output;
    }

    /**
     * @param string $path
     *
     * @return PromiseInterface
     *
     * @throws \RuntimeException
     */
    protected function discardChanges(string $path): PromiseInterface
    {
        $path = $this->normalizePath($path);
        if (0 !== $this->process->execute('git clean -df && git reset --hard', $output, $path)) {
            throw new \RuntimeException("Could not reset changes\n\n:".$output);
        }

        $this->hasDiscardedChanges[$path] = true;

        return \React\Promise\resolve(null);
    }

    /**
     * @param string $path
     *
     * @return PromiseInterface
     *
     * @throws \RuntimeException
     */
    protected function stashChanges(string $path): PromiseInterface
    {
        $path = $this->normalizePath($path);
        if (0 !== $this->process->execute('git stash --include-untracked', $output, $path)) {
            throw new \RuntimeException("Could not stash changes\n\n:".$output);
        }

        $this->hasStashedChanges[$path] = true;

        return \React\Promise\resolve(null);
    }

    /**
     * @param string $path
     *
     * @return void
     *
     * @throws \RuntimeException
     */
    protected function viewDiff(string $path): void
    {
        $path = $this->normalizePath($path);
        if (0 !== $this->process->execute('git diff HEAD', $output, $path)) {
            throw new \RuntimeException("Could not view diff\n\n:".$output);
        }

        $this->io->writeError($output);
    }

    /**
     * @param string $path
     *
     * @return string
     */
    protected function normalizePath(string $path): string
    {
        if (Platform::isWindows() && strlen($path) > 0) {
            $basePath = $path;
            $removed = array();

            while (!is_dir($basePath) && $basePath !== '\\') {
                array_unshift($removed, basename($basePath));
                $basePath = dirname($basePath);
            }

            if ($basePath === '\\') {
                return $path;
            }

            $path = rtrim(realpath($basePath) . '/' . implode('/', $removed), '/');
        }

        return $path;
    }

    /**
     * @inheritDoc
     */
    protected function hasMetadataRepository(string $path): bool
    {
        $path = $this->normalizePath($path);

        return is_dir($path.'/.git');
    }

    /**
     * @param  string $reference
     * @return string
     */
    protected function getShortHash(string $reference): string
    {
        if (!$this->io->isVerbose() && Preg::isMatch('{^[0-9a-f]{40}$}', $reference)) {
            return substr($reference, 0, 10);
        }

        return $reference;
    }
}
