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<?php
    /**
     * Default implementation of IGit interface
     *
     * @author  Jan Pecha, <janpecha@email.cz>
     * @license New BSD License (BSD-3), see file license.md
     */

    namespace Cz\Git;

    class GitRepository implements IGit
    {
        /** @var  string */
        protected $repository;

        /** @var  string|NULL  @internal */
        protected $cwd;


        /**
         * @param  string
         * @throws GitException
         */
        public function __construct($repository)
        {
            if(basename($repository) === '.git')
            {
                $repository = dirname($repository);
            }

            $this->repository = realpath($repository);

            if($this->repository === FALSE)
            {
                throw new GitException("Repository '$repository' not found.");
            }
        }


        /**
         * @return string
         */
        public function getRepositoryPath()
        {
            return $this->repository;
        }


        /**
         * Creates a tag.
         * `git tag <name>`
         * @param  string
         * @param  array|NULL
         * @throws GitException
         * @return self
         */
        public function createTag($name, $options = NULL)
        {
            return $this->begin()
                ->run('git tag', $options, $name)
                ->end();
        }


        /**
         * Removes tag.
         * `git tag -d <name>`
         * @param  string
         * @throws GitException
         * @return self
         */
        public function removeTag($name)
        {
            return $this->begin()
                ->run('git tag', array(
                    '-d' => $name,
                ))
                ->end();
        }


        /**
         * Renames tag.
         * `git tag <new> <old>`
         * `git tag -d <old>`
         * @param  string
         * @param  string
         * @throws GitException
         * @return self
         */
        public function renameTag($oldName, $newName)
        {
            return $this->begin()
                // http://stackoverflow.com/a/1873932
                // create new as alias to old (`git tag NEW OLD`)
                ->run('git tag', $newName, $oldName)
                // delete old (`git tag -d OLD`)
                ->removeTag($oldName) // WARN! removeTag() calls end() method!!!
                ->end();
        }


        /**
         * Returns list of tags in repo.
         * @return string[]|NULL  NULL => no tags
         * @throws GitException
         */
        public function getTags()
        {
            return $this->extractFromCommand('git tag', 'trim');
        }


        /**
         * Merges branches.
         * `git merge <options> <name>`
         * @param  string
         * @param  array|NULL
         * @throws GitException
         * @return self
         */
        public function merge($branch, $options = NULL)
        {
            return $this->begin()
                ->run('git merge', $options, $branch)
                ->end();
        }


        /**
         * Creates new branch.
         * `git branch <name>`
         * (optionaly) `git checkout <name>`
         * @param  string
         * @param  bool
         * @throws GitException
         * @return self
         */
        public function createBranch($name, $checkout = FALSE)
        {
            $this->begin();

            // git branch $name
            $this->run('git branch', $name);

            if($checkout)
            {
                $this->checkout($name);
            }

            return $this->end();
        }


        /**
         * Removes branch.
         * `git branch -d <name>`
         * @param  string
         * @throws GitException
         * @return self
         */
        public function removeBranch($name)
        {
            return $this->begin()
                ->run('git branch', array(
                    '-d' => $name,
                ))
                ->end();
        }


        /**
         * Gets name of current branch
         * `git branch` + magic
         * @return string
         * @throws GitException
         */
        public function getCurrentBranchName()
        {
            try
            {
                $branch = $this->extractFromCommand('git branch -a', function($value) {
                    if(isset($value[0]) && $value[0] === '*')
                    {
                        return trim(substr($value, 1));
                    }

                    return FALSE;
                });

                if(is_array($branch))
                {
                    return $branch[0];
                }
            }
            catch(GitException $e) {}
            throw new GitException('Getting current branch name failed.');
        }


        /**
         * Returns list of all (local & remote) branches in repo.
         * @return string[]|NULL  NULL => no branches
         * @throws GitException
         */
        public function getBranches()
        {
            return $this->extractFromCommand('git branch -a', function($value) {
                return trim(substr($value, 1));
            });
        }


        /**
         * Returns list of remote branches in repo.
         * @return string[]|NULL  NULL => no branches
         * @throws GitException
         */
        public function getRemoteBranches()
        {
            return $this->extractFromCommand('git branch -r', function($value) {
                return trim(substr($value, 1));
            });
        }


        /**
         * Returns list of local branches in repo.
         * @return string[]|NULL  NULL => no branches
         * @throws GitException
         */
        public function getLocalBranches()
        {
            return $this->extractFromCommand('git branch', function($value) {
                return trim(substr($value, 1));
            });
        }


        /**
         * Checkout branch.
         * `git checkout <branch>`
         * @param  string
         * @throws GitException
         * @return self
         */
        public function checkout($name)
        {
            return $this->begin()
                ->run('git checkout', $name)
                ->end();
        }


        /**
         * Removes file(s).
         * `git rm <file>`
         * @param  string|string[]
         * @throws GitException
         * @return self
         */
        public function removeFile($file)
        {
            if(!is_array($file))
            {
                $file = func_get_args();
            }

            $this->begin();

            foreach($file as $item)
            {
                $this->run('git rm', $item, '-r');
            }

            return $this->end();
        }


        /**
         * Adds file(s).
         * `git add <file>`
         * @param  string|string[]
         * @throws GitException
         * @return self
         */
        public function addFile($file)
        {
            if(!is_array($file))
            {
                $file = func_get_args();
            }

            $this->begin();

            foreach($file as $item)
            {
                // make sure the given item exists
                // this can be a file or an directory, git supports both
                $path = self::isAbsolute($item) ? $item : ($this->getRepositoryPath() . DIRECTORY_SEPARATOR . $item);

                if (!file_exists($path)) {
                    throw new GitException("The path at '$item' does not represent a valid file.");
                }

                $this->run('git add', $item);
            }

            return $this->end();
        }


        /**
         * Adds all created, modified & removed files.
         * `git add --all`
         * @throws GitException
         * @return self
         */
        public function addAllChanges()
        {
            return $this->begin()
                ->run('git add --all')
                ->end();
        }


        /**
         * Renames file(s).
         * `git mv <file>`
         * @param  string|string[]  from: array('from' => 'to', ...) || (from, to)
         * @param  string|NULL
         * @throws GitException
         * @return self
         */
        public function renameFile($file, $to = NULL)
        {
            if(!is_array($file)) // rename(file, to);
            {
                $file = array(
                    $file => $to,
                );
            }

            $this->begin();

            foreach($file as $from => $to)
            {
                $this->run('git mv', $from, $to);
            }

            return $this->end();
        }


        /**
         * Commits changes
         * `git commit <params> -m <message>`
         * @param  string
         * @param  string[]  param => value
         * @throws GitException
         * @return self
         */
        public function commit($message, $params = NULL)
        {
            if(!is_array($params))
            {
                $params = array();
            }

            return $this->begin()
                ->run("git commit", $params, array(
                    '-m' => $message,
                ))
                ->end();
        }


        /**
         * Returns last commit ID on current branch
         * `git log --pretty=format:"%H" -n 1`
         * @return string|NULL
         * @throws GitException
         */
        public function getLastCommitId()
        {
            $this->begin();
            $lastLine = exec('git log --pretty=format:"%H" -n 1 2>&1');
            $this->end();
            if (preg_match('/^[0-9a-f]{40}$/i', $lastLine)) {
                return $lastLine;
            }
            return NULL;
        }


        /**
         * Exists changes?
         * `git status` + magic
         * @return bool
         * @throws GitException
         */
        public function hasChanges()
        {
            // Make sure the `git status` gets a refreshed look at the working tree.
            $this->begin()
                ->run('git update-index -q --refresh')
                ->end();

            $output = $this->extractFromCommand('git status --porcelain');
            return !empty($output);
        }


        /**
         * @deprecated
         * @throws GitException
         */
        public function isChanges()
        {
            return $this->hasChanges();
        }


        /**
         * Pull changes from a remote
         * @param  string|NULL
         * @param  array|NULL
         * @return self
         * @throws GitException
         */
        public function pull($remote = NULL, array $params = NULL)
        {
            if(!is_array($params))
            {
                $params = array();
            }

            return $this->begin()
                ->run("git pull $remote", $params)
                ->end();
        }


        /**
         * Push changes to a remote
         * @param  string|NULL
         * @param  array|NULL
         * @return self
         * @throws GitException
         */
        public function push($remote = NULL, array $params = NULL)
        {
            if(!is_array($params))
            {
                $params = array();
            }

            return $this->begin()
                ->run("git push $remote", $params)
                ->end();
        }


        /**
         * Run fetch command to get latest branches
         * @param  string|NULL
         * @param  array|NULL
         * @return self
         * @throws GitException
         */
        public function fetch($remote = NULL, array $params = NULL)
        {
            if(!is_array($params))
            {
                $params = array();
            }

            return $this->begin()
                ->run("git fetch $remote", $params)
                ->end();
        }


        /**
         * Adds new remote repository
         * @param  string
         * @param  string
         * @param  array|NULL
         * @return self
         * @throws GitException
         */
        public function addRemote($name, $url, array $params = NULL)
        {
            return $this->begin()
                ->run('git remote add', $params, $name, $url)
                ->end();
        }


        /**
         * Renames remote repository
         * @param  string
         * @param  string
         * @return self
         * @throws GitException
         */
        public function renameRemote($oldName, $newName)
        {
            return $this->begin()
                ->run('git remote rename', $oldName, $newName)
                ->end();
        }


        /**
         * Removes remote repository
         * @param  string
         * @return self
         * @throws GitException
         */
        public function removeRemote($name)
        {
            return $this->begin()
                ->run('git remote remove', $name)
                ->end();
        }


        /**
         * Changes remote repository URL
         * @param  string
         * @param  string
         * @param  array|NULL
         * @return self
         * @throws GitException
         */
        public function setRemoteUrl($name, $url, array $params = NULL)
        {
            return $this->begin()
                ->run('git remote set-url', $params, $name, $url)
                ->end();
        }


        /**
         * @param  string|string[]
         * @return string[]  returns output
         * @throws GitException
         */
        public function execute($cmd)
        {
            if (!is_array($cmd)) {
                $cmd = array($cmd);
            }

            array_unshift($cmd, 'git');
            $cmd = self::processCommand($cmd);

            $this->begin();
            exec($cmd . ' 2>&1', $output, $ret);
            $this->end();

            if($ret !== 0)
            {
                throw new GitException("Command '$cmd' failed (exit-code $ret).", $ret);
            }

            return $output;
        }


        /**
         * @return self
         */
        protected function begin()
        {
            if($this->cwd === NULL) // TODO: good idea??
            {
                $this->cwd = getcwd();
                chdir($this->repository);
            }

            return $this;
        }


        /**
         * @return self
         */
        protected function end()
        {
            if(is_string($this->cwd))
            {
                chdir($this->cwd);
            }

            $this->cwd = NULL;
            return $this;
        }


        /**
         * @param  string
         * @param  callback|NULL
         * @return string[]|NULL
         * @throws GitException
         */
        protected function extractFromCommand($cmd, $filter = NULL)
        {
            $output = array();
            $exitCode = NULL;

            $this->begin();
            exec("$cmd", $output, $exitCode);
            $this->end();

            if($exitCode !== 0 || !is_array($output))
            {
                throw new GitException("Command $cmd failed.");
            }

            if($filter !== NULL)
            {
                $newArray = array();

                foreach($output as $line)
                {
                    $value = $filter($line);

                    if($value === FALSE)
                    {
                        continue;
                    }

                    $newArray[] = $value;
                }

                $output = $newArray;
            }

            if(!isset($output[0])) // empty array
            {
                return NULL;
            }

            return $output;
        }


        /**
         * Runs command.
         * @param  string|array
         * @return self
         * @throws GitException
         */
        protected function run($cmd/*, $options = NULL*/)
        {
            $args = func_get_args();
            $cmd = self::processCommand($args);
            exec($cmd . ' 2>&1', $output, $ret);

            if($ret !== 0)
            {
                throw new GitException("Command '$cmd' failed (exit-code $ret).", $ret);
            }

            return $this;
        }


        protected static function processCommand(array $args)
        {
            $cmd = array();

            $programName = array_shift($args);

            foreach($args as $arg)
            {
                if(is_array($arg))
                {
                    foreach($arg as $key => $value)
                    {
                        $_c = '';

                        if(is_string($key))
                        {
                            $_c = "$key ";
                        }

                        $cmd[] = $_c . escapeshellarg($value);
                    }
                }
                elseif(is_scalar($arg) && !is_bool($arg))
                {
                    $cmd[] = escapeshellarg($arg);
                }
            }

            return "$programName " . implode(' ', $cmd);
        }


        /**
         * Init repo in directory
         * @param  string
         * @param  array|NULL
         * @return self
         * @throws GitException
         */
        public static function init($directory, array $params = NULL)
        {
            if(is_dir("$directory/.git"))
            {
                throw new GitException("Repo already exists in $directory.");
            }

            if(!is_dir($directory) && !@mkdir($directory, 0777, TRUE)) // intentionally @; not atomic; from Nette FW
            {
                throw new GitException("Unable to create directory '$directory'.");
            }

            $cwd = getcwd();
            chdir($directory);
            exec(self::processCommand(array(
                'git init',
                $params,
                $directory,
            )), $output, $returnCode);

            if($returnCode !== 0)
            {
                throw new GitException("Git init failed (directory $directory).");
            }

            $repo = getcwd();
            chdir($cwd);

            return new static($repo);
        }


        /**
         * Clones GIT repository from $url into $directory
         * @param  string
         * @param  string|NULL
         * @param  array|NULL
         * @return self
         * @throws GitException
         */
        public static function cloneRepository($url, $directory = NULL, array $params = NULL)
        {
            if($directory !== NULL && is_dir("$directory/.git"))
            {
                throw new GitException("Repo already exists in $directory.");
            }

            $cwd = getcwd();

            if($directory === NULL)
            {
                $directory = self::extractRepositoryNameFromUrl($url);
                $directory = "$cwd/$directory";
            }
            elseif(!self::isAbsolute($directory))
            {
                $directory = "$cwd/$directory";
            }

            if ($params === NULL) {
                $params = '-q';
            }

            $descriptorspec = array(
                0 => array('pipe', 'r'), // stdout
                1 => array('pipe', 'w'), // stdin
                2 => array('pipe', 'w'), // stderr
            );

            $pipes = [];
            $command = self::processCommand(array(
                'git clone',
                $params,
                $url,
                $directory
            ));
            $process = proc_open($command, $descriptorspec, $pipes);

            if (!$process)
            {
                throw new GitException("Git clone failed (directory $directory).");
            }

            // Reset output and error
            $stdout = '';
            $stderr = '';

            while (TRUE)
            {
                // Read standard output
                $output = fgets($pipes[0], 1024);

                if ($output)
                {
                    $stdout .= $output;
                }

                // Read error output
                $output_err = fgets($pipes[2], 1024);

                if ($output_err)
                {
                    $stderr .= $output_err;
                }

                // We are done
                if ((feof($pipes[0]) OR $output === FALSE) AND (feof($pipes[2]) OR $output_err === FALSE))
                {
                    break;
                }
            }

            $returnCode = proc_close($process);

            if($returnCode !== 0)
            {
                throw new GitException("Git clone failed (directory $directory)." . ($stderr !== '' ? ("\n$stderr") : ''));
            }

            return new static($directory);
        }


        /**
         * @param  string
         * @param  array|NULL
         * @return bool
         */
        public static function isRemoteUrlReadable($url, array $refs = NULL)
        {
            $env = '';

            if (DIRECTORY_SEPARATOR === '\\') { // Windows
                $env = 'set GIT_TERMINAL_PROMPT=0 &&';

            } else {
                $env = 'GIT_TERMINAL_PROMPT=0';
            }

            exec(self::processCommand(array(
                $env . ' git ls-remote',
                '--heads',
                '--quiet',
                '--exit-code',
                $url,
                $refs,
            )) . ' 2>&1', $output, $returnCode);

            return $returnCode === 0;
        }


        /**
         * @param  string  /path/to/repo.git | host.xz:foo/.git | ...
         * @return string  repo | foo | ...
         */
        public static function extractRepositoryNameFromUrl($url)
        {
            // /path/to/repo.git => repo
            // host.xz:foo/.git => foo
            $directory = rtrim($url, '/');
            if(substr($directory, -5) === '/.git')
            {
                $directory = substr($directory, 0, -5);
            }

            $directory = basename($directory, '.git');

            if(($pos = strrpos($directory, ':')) !== FALSE)
            {
                $directory = substr($directory, $pos + 1);
            }

            return $directory;
        }


        /**
         * Is path absolute?
         * Method from Nette\Utils\FileSystem
         * @link   https://github.com/nette/nette/blob/master/Nette/Utils/FileSystem.php
         * @return bool
         */
        public static function isAbsolute($path)
        {
            return (bool) preg_match('#[/\\\\]|[a-zA-Z]:[/\\\\]|[a-z][a-z0-9+.-]*://#Ai', $path);
        }


        /**
         * Returns commit message from specific commit
         * `git log -1 --format={%s|%B} )--pretty=format:'%H' -n 1`
         * @param  string  commit ID
         * @param  bool    use %s instead of %B if TRUE
         * @return string
         * @throws GitException
         */
        public function getCommitMessage($commit, $oneline = FALSE)
        {
            $this->begin();
            exec('git log -1 --format=' . ($oneline ? '%s' : '%B') . ' ' . $commit . ' 2>&1', $message);
            $this->end();
            return implode(PHP_EOL, $message);
        }


        /**
         * Returns array of commit metadata from specific commit
         * `git show --raw <sha1>`
         * @param  string  commit ID
         * @return array
         * @throws GitException
         */
        public function getCommitData($commit)
        {
            $message = $this->getCommitMessage($commit);
            $subject = $this->getCommitMessage($commit, TRUE);

            $this->begin();
            exec('git show --raw ' . $commit . ' 2>&1', $output);
            $this->end();
            $data = array(
                'commit' => $commit,
                'subject' => $subject,
                'message' => $message,
                'author' => NULL,
                'committer' => NULL,
                'date' => NULL,
            );

            // git show is a porcelain command and output format may changes
            // in future git release or custom config.
            foreach ($output as $index => $info) {
                if (preg_match('`Author: *(.*)`', $info, $author)) {
                    $data['author'] = trim($author[1]);
                    unset($output[$index]);
                }

                if (preg_match('`Commit: *(.*)`', $info, $committer)) {
                    $data['committer'] = trim($committer[1]);
                    unset($output[$index]);
                }

                if (preg_match('`Date: *(.*)`', $info, $date)) {
                    $data['date'] = trim($date[1]);
                    unset($output[$index]);
                }
            }

            return $data;
        }

    }