<?php
/* GitCommand.class.php - phpgitweb
 * Copyright (C) 2011-2012  Philipp Kreil (pk910)
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License 
 * along with this program. If not, see <http://www.gnu.org/licenses/>. 
 */

class GitCommand {
	private static $git = null;
	private static $counter = 0;
	
	private static function command_header() {
		if(!self::$git) {
			//find git executable
			if(GitConfig::GIT_EXEC)
				self::$git = GitConfig::GIT_EXEC;
			else
				self::$git = str_replace(array("\n", "\r"), array("", ""), `which git`);
			if(!self::$git) {
				trigger_error("Can not find git executable.", E_USER_ERROR);
				self::$git = "git";
			}
		}
		$command = self::$git;
		
		return $command;
	}
	
	private static function git_execute($params, $git_path = null) {
		$result = array();
		
		if($git_path) {
			$args = array("--git-dir=".$git_path);
			$args = array_merge($args, $params);
		} else
			$args = $params;
		
		$command = self::command_header();
		foreach($args as $arg) {
			$command .= ' '.escapeshellarg($arg);
		}
		
		exec($command, $result);
		self::$counter++;
		return implode("\n", $result);
	}
	
	public static function core_version() {
		$args = array("--version");
		$version = self::git_execute($args);
		preg_match("/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/i", $version, $result);
		return $result[0];
	}
	
	public static function last_activity($git_path, $ref = null) {
		$args = array("for-each-ref", "--format=%(committer)", "--sort=-committerdate", "--count=1");
		if($ref)
			$args[] = $ref;
		$age = self::git_execute($args, $git_path);
		preg_match("/[0-9]{9,}/i", $age, $result);
		return $result[0];
	}
	
	private static function parse_commit($commit_data) {
		$commit = array();
		$rev_lines = explode("\n", str_replace("\r", "", $commit_data));
		$commit['id'] = $rev_lines[0];
		$commit['parent'] = array();
		if(!preg_match("/^[a-f0-9]{40}$/i", $commit['id']))
			return null;
		foreach($rev_lines as $rev_line) {
			if(substr($rev_line, 0, 4) == "    ") {
				if(array_key_exists('text', $commit))
					$commit['text'] .= "\n";
				else
					$commit['text'] = '';
				$commit['text'] .= substr($rev_line, 4);
			} else {
				$opt = explode(" ", $rev_line, 2);
				if($opt[0] == "tree")
					$commit['tree'] = $opt[1];
				else if($opt[0] == "parent")
					$commit['parent'][] = $opt[1];
				else if($opt[0] == "author") {
					preg_match('/(.*) <([^>]*)> ([0-9]*) ([+\-0-9]{5})/i', $opt[1], $matches);
					$commit['author'] = $matches[1];
					$commit['author_mail'] = $matches[2];
					$commit['author_time'] = $matches[3];
					$commit['author_timezone'] = $matches[4];
				} else if($opt[0] == "committer") {
					preg_match('/(.*) <([^>]*)> ([0-9]*) ([+\-0-9]{5})/i', $opt[1], $matches);
					$commit['committer'] = $matches[1];
					$commit['committer_mail'] = $matches[2];
					$commit['committer_time'] = $matches[3];
					$commit['committer_timezone'] = $matches[4];
				}
			}
		}
		return $commit;
	}
	
	public static function get_commits($git_path, $head, $maxcount, $skip, $file = null) {
		$args = array("rev-list", "--header", "--max-count=".$maxcount, "--skip=".$skip, ($head ? $head : "--all"), "--");
		if($file)
			$args[] = $file;
		$commit_list = self::git_execute($args, $git_path);
		$commits = array();
		foreach(explode("\000", $commit_list) as $commit) {
			if($commit)
				$commits[] = self::parse_commit($commit);
		}
		return $commits;
	}
	
	public static function get_commit($git_path, $commit_id) {
		$args = array("rev-list", "--header", "--max-count=1", $commit_id, "--");
		$commit_data = self::git_execute($args, $git_path);
		$commit = self::parse_commit($commit_data);
		return $commit;
	}
	
	public static function get_hash($git_path, $ref) {
		$args = array("rev-parse", "--verify", "-q", $ref);
		$result = self::git_execute($args, $git_path);
		if(preg_match("#([a-f0-9]{40})#i", $result, $match))
			return $match[1];
		return null;
	}
	
}