<?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_id : "--all"), "--");
		$commit_data = self::git_execute($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;
	}
	
	private static function parse_difftree($line) {
		$entry = array();
		if(preg_match('/^:([0-7]{6}) ([0-7]{6}) ([0-9a-fA-F]{40}) ([0-9a-fA-F]{40}) (.)([0-9]{0,3})\t(.*)$/i', $line, $matches)) {
			$entry['parents'] = 1;
			$entry['from_mode'] = $matches[1];
			$entry['to_mode'] = $matches[2];
			$entry['from_id'] = $matches[3];
			$entry['to_id'] = $matches[4];
			$entry['status'] = $matches[5];
			$entry['similarity'] = $matches[6];
			$entry['file'] = $matches[7];
			if($entry['status'] == 'R' || $entry['status'] == 'C') { //renamed or copied
				$files = explode("\t", $entry['file']);
				$entry['from_file'] = $files[0];
				$entry['to_file'] = $files[1];
			} else
				$entry['from_file'] = $entry['to_file'] = $entry['file'];
		} else if(preg_match('/^(::+)((?:[0-7]{6} )+)((?:[0-9a-fA-F]{40} )+)([a-zA-Z]+)\t(.*)$/i', $line, $matches)) {
			$entry['parents'] = strlen($matches[1]);
			$from_modes = explode(" ", $matches[2]);
			$entry['from_mode'] = array_slice($from_modes, 1, -1);
			$entry['to_mode'] = $from_modes[0];
			$from_ids = explode(" ", $matches[3]);
			$entry['from_id'] = array_slice($from_ids, 1, -1);
			$entry['to_id'] = $from_ids[0];
			$entry['status'] = str_split($matches[4]);
			$entry['file'] = $entry['from_file'] = $entry['to_file'] = $matches[5];
		}
		return $entry;
	}
	
	public static function get_commit_changes($git_path, $commit_id, $parents) {
		$args = array("diff-tree", "-r", "--no-commit-id");
		switch(GitConfig::DETECT_RENAME_LEVEL) {
		case 0:
			$args[] = "-M";
			break;
		case 1:
			$args[] = "-C";
			break;
		case 2:
			$args[] = "-C";
			$args[] = "--find-copies-harder";
			break;
		}
		if(GitConfig::DETECT_REWRITES)
			$args[] = "-B";
		if(is_array($parents) && count($parents) > 1)
			$args[] = "-c";
		else if(is_array($parents) && count($parents) == 1)
			$args[] = $parents[0];
		else
			$args[] = "--root";
		$args[] = $commit_id;
		$args[] = "--";
		$result = self::git_execute($args, $git_path);
		$tree = array();
		foreach(explode("\n", $result) as $line) {
			if($line == "")
				continue;
			$tree[] = self::parse_difftree($line);
		}
		return $tree;
	}
	
	public static function get_commit_diff($git_path, $commit_id, $parents) {
		$args = array("diff-tree", "-r", "--no-commit-id", "--patch-with-raw", "--full-index");
		switch(GitConfig::DETECT_RENAME_LEVEL) {
		case 0:
			$args[] = "-M";
			break;
		case 1:
			$args[] = "-C";
			break;
		case 2:
			$args[] = "-C";
			$args[] = "--find-copies-harder";
			break;
		}
		if(GitConfig::DETECT_REWRITES)
			$args[] = "-B";
		if(is_array($parents) && count($parents) > 1)
			$args[] = "--cc";
		else if(is_array($parents) && count($parents) == 1)
			$args[] = $parents[0];
		else
			$args[] = "--root";
		$args[] = $commit_id;
		$args[] = "--";
		$result = self::git_execute($args, $git_path);
		$tree = array();
		$diffs = array();
		$diff = null;
		$parse_difftree = true;
		foreach(explode("\n", $result) as $line) {
			if($line == "" && $parse_difftree)
				$parse_difftree = false;
			else if($parse_difftree)
				$tree[] = self::parse_difftree($line);
			else {
				if(preg_match('/^diff/i', $line)) {
					if($diff)
						$diffs[] = $diff;
					$diff = array();
				}
				$diff[] = $line;
			}
		}
		if($diff)
			$diffs[] = $diff;
		$diff_data['tree'] = $tree;
		return array('tree' => $tree, 'diffs' => $diffs);
	}
}