<?php

/* CONFIG */
$repo_path = "/srv/gitosis/repositories/";
$project_list = "/srv/gitosis/gitosis/projects.list";

$size = 20;
$header_height = false; //false = dynamic
$tile_size = 20; /* do not edit */

$max_branches = 30;
$use_local_branches = true;
$use_remote_branches = true;

$colors = array(
    NULL,
    array(255, 0, 0),
    array(array(0, 255, 0), array(0, 192, 0)),
    array(0, 0, 255),
    array(128, 128, 128),
    array(128, 128, 0),
    array(0, 128, 128),
    array(128, 0, 128)
);
/* END CONFIG */

session_start();

//parse ; seprated query args
$args = explode(";", $_SERVER["QUERY_STRING"]);
foreach($args as $arg) {
    $arg = explode("=", $arg, 2);
    $_GET[$arg[0]] = $arg[1];
}

if($_SESSION['gitgraph_maxbranch'])
    $max_branches = $_SESSION['gitgraph_maxbranch'];
if($_GET['maxbranch']) {
    $_SESSION['gitgraph_maxbranch'] = $_GET['maxbranch'];
    die("maxbranch set.");
}

//check if project is in $project_list
$project = NULL;
if($project_list) {
    $projects = file_get_contents($project_list);
    foreach(explode("\n", $projects) as $cproject) {
        $cproject = explode(" ", $cproject);
        if(strtolower($_GET['p']) == strtolower($cproject[0])) {
            if(file_exists($repo_path.$cproject[0]))
                $project = $cproject[0];
            break;
        }
    }
} else {
    if(!preg_match('#^[a-z0-9.-_]*$#i', $_GET['p']))
        die("ERROR 0x01");
    if(file_exists($repo_path.$_GET['p']))
        $project = $_GET['p'];
}
if(!$project)
    die("ERROR 0x02");

//check other args
if(!preg_match('#^[a-z0-9/.-_]*$#i', $_GET['h']))
    die("ERROR 0x03");
if(!preg_match('#^[a-z0-9]*$#i', $_GET['c']))
    die("ERROR 0x04");
if(!preg_match('#^[0-9]*$#i', $_GET['from']))
    die("ERROR 0x05");
if(!preg_match('#^[0-9]*$#i', $_GET['to']))
    die("ERROR 0x06");

//load old cache
$data = array();
if($_SESSION['git_graph']) {
    $old_data = unserialize($_SESSION['git_graph']);
    if($old_data['r'] == $_GET['r'])
        $data = $old_data;
}

function parse_commit($commit_data) {
    $commit = array();
    $rev_lines = explode("\n", str_replace("\r", "", $commit_data));
    $commit['id'] = $rev_lines[0];
    foreach($rev_lines as $rev_line) {
        if(substr($rev_line, 0, 4) == "    ") {
            if($commit['text'])
                $commit['text'] .= "\n";
            $commit['text'] .= substr($rev_line, 4);
        } else {
            $opt = explode(" ", $rev_line);
            if($opt[0] == "tree")
                $commit['tree'] = $opt[1];
            else if($opt[0] == "parent")
                $commit['parent'][] = $opt[1];
            else if($opt[0] == "author") {
                $commit['author'] = $opt[1];
                $commit['author_mail'] = $opt[2];
                $commit['author_time'] = $opt[3];
            } else if($opt[0] == "committer") {
                $commit['committer'] = $opt[1];
                $commit['committer_mail'] = $opt[2];
                $commit['committer_time'] = $opt[3];
            }
        }
    }
    return $commit;
}

//load rev-list
if(!$data['commits']) {
    $cmd = "git --git-dir=".$repo_path.$project." rev-list --header --max-count=".($_GET['to'] + 1)." ".($_GET['h'] =="all" ? "--all" : $_GET['h']);
    $rev_list = shell_exec($cmd);
    foreach(explode("\000", $rev_list) as $rev) {
        $data['commits'][] = parse_commit($rev);
    }
}

//save cache
$_SESSION['git_graph'] = serialize($data);

//generate graph data
$data['branches'] = array();
$data['ubranches'] = array();
$brach_id = 1;
$branch_uid = 1;
$graph_commit = NULL;
$first_commit = true;

if($_GET['h'] == "all") {
    //set master branch as first branch
    $cmd = "git --git-dir=".$repo_path.$project." rev-list --header --max-count=1 HEAD";
    $head_list = shell_exec($cmd);
    $head = parse_commit($head_list);
    $first_commit = false;
    $data['branches'][count($data['branches'])] = array();
    $branch = &$data['branches'][count($data['branches'])-1];
    $branch['id'] = $brach_id++;
    $branch['uid'] = $branch_uid++;
    $branch['active'] = true;
    $branch['sticky'] = true;
    $branch['next'] = $head['id'];
    unset($branch);
    if($use_local_branches) {
        $cmd = "git --git-dir=".$repo_path.$project." for-each-ref --sort=-committerdate refs/heads/";
        $head_list = shell_exec($cmd);
        foreach(explode("\n", str_replace("\r", "", $head_list)) as $head) {
            $head = explode(" ", $head);
            $name = explode("/", $head[1]);
            $name = $name[count($name)-1];
            if(!$head[0])
                continue;
            $existing = false;
            foreach($data['branches'] as &$branch) {
                if($branch['next'] == $head[0]) {
                    $existing = true;
                    $branch['name'][] = $name;
                    break;
                }
            }
            unset($branch);
            if($existing)
                continue;
            $data['branches'][count($data['branches'])] = array(
                "id" => $brach_id++,
                "uid" => $branch_uid++,
                "active" => true,
                "sticky" => true,
                "name" => array($name),
                "next" => $head[0]
            );
        }
    }
    if($use_remote_branches) {
        $cmd = "git --git-dir=".$repo_path.$project." for-each-ref --sort=-committerdate refs/remotes/";
        $head_list = shell_exec($cmd);
        foreach(explode("\n", str_replace("\r", "", $head_list)) as $head) {
            $head = explode(" ", $head);
            $name = explode("/", $head[1]);
            $name = $name[count($name)-2];
            if(!$head[0])
                continue;
            $existing = false;
            foreach($data['branches'] as &$branch) {
                if($branch['next'] == $head[0]) {
                    $existing = true;
                    $branch['name'][] = $name;
                    break;
                }
            }
            unset($branch);
            if($existing)
                continue;
            $data['branches'][count($data['branches'])] = array(
                "id" => $brach_id++,
                "uid" => $branch_uid++,
                "active" => true,
                "sticky" => true,
                "name" => array($name),
                "next" => $head[0]
            );
        }
    }
}

if($_GET['c'] == "header") {
    $count = count($data['branches']);
    if($count > $max_branches)
        $count = $max_branches;
    if(!$header_height) {
        $maxlen = 0;
        foreach($data['branches'] as $branch) {
            if($branch['sticky'] && count($branch['name'])) {
                if(strlen($branch['name'][0]) > $maxlen)
                    $maxlen = strlen($branch['name'][0]);
            }
        }
        $header_height = $maxlen * 2 + 15;
    }
    $image = imagecreatetruecolor($count * $size + 60, $header_height);
    $transparentIndex = imagecolorallocate($image, 217, 216, 209);
    imagefill($image, 0, 0, $transparentIndex);
    $branches = 0;
    foreach($data['branches'] as $branch) {
        if($branch['sticky'] && count($branch['name'])) {
            $branches++;
            $color = get_color($branch['id'], true);
            $color = imagecolorallocatealpha($image, $color[0], $color[1], $color[2], 0);
            imagettftext($image, 8, 28, ($branch['id']-1) * $size + 10, $header_height-2, $color, $_SERVER['DOCUMENT_ROOT']."/arial.ttf", $branch['name'][0]);
        }
    }
    if(!$branches) die();
    imagecolortransparent($image, $transparentIndex);
    header('Content-Type: image/png');
    imagepng($image);
    imagedestroy($image);
    die();
}

for($i = 0; $i <= intval($_GET['to']); $i++) {
//for($i = 0; $i < count($data['commits']); $i++) {
    $commit = &$data['commits'][$i];
    //get current branch
    if($first_commit) {
        $first_commit = false;
        $data['branches'][0] = array();
        $branch = &$data['branches'][0];
        $branch['id'] = $brach_id++;
        $branch['uid'] = $branch_uid++;
        $branch['active'] = true;
    } else {
        $first = true;
        foreach($data['branches'] as $id => &$cbranch) {
            if($cbranch['next'] == $commit['id']) {
                if($first && !$cbranch['pre_merge']) {
                    $branch = &$data['branches'][$id];
                    $first = false;
                }
            }
        }
        foreach($data['branches'] as $id => &$cbranch) {
            if($cbranch['next'] == $commit['id']) {
                if($first) {
                    $branch = &$data['branches'][$id];
                    $first = false;
                } else if($cbranch['id'] == $branch['id']) {
                } else {
                    $commit['merge'][] = array("point" => $cbranch['id'], "start" => true);
                    $cbranch['active'] = false;
                    if($cbranch['pre_merge']) {
                        $cbranch['pre_merge_start'] = true;
                        $cbranch['pre_merge_id'] = $branch['id'];
                        $data['ubranches'][$cbranch['uid']] = $data['branches'][$cbranch['id']-1];
                    }
                }
            }
        }
        unset($cbranch);
        if($first) {
            $data['branches'][count($data['branches'])] = array();
            $branch = &$data['branches'][count($data['branches'])-1];
            $branch['id'] = $brach_id++;
            $branch['uid'] = $branch_uid++;
            $branch['active'] = true;
        }
    }
    
    if(count($commit['parent']) > 1) {
        //merge(s)
        for($j = 1; $j < count($commit['parent']); $j++) {
            $add = true;
            foreach($data['branches'] as $cbranch) {
                if($cbranch['next'] == $commit['parent'][$j]) {
                    $add = false;
                    break;
                }
            }
            if($add) {
                $cadd = true;
                foreach($data['branches'] as $bid => &$cbranch) {
                    if(!$cbranch['active']) {
                        $cadd = false;
                        break;
                    }
                }
                if($cadd) {
                    $data['branches'][count($data['branches'])] = array();
                    $cbranch = &$data['branches'][count($data['branches'])-1];
                    $cbranch['id'] = $brach_id++;
                }
                $cbranch['uid'] = $branch_uid++;
                $cbranch['active'] = true;
                $cbranch['pre_merge'] = true;
                $cbranch['next'] = $commit['parent'][$j];
            }
            $commit['merge'][] = array("point" => $cbranch['id'], "end" => $add);
            $commit['dot_merge'] = true;
            $data['ubranches'][$cbranch['uid']] = $data['branches'][$cbranch['id']-1];
            unset($cbranch);
        }
    } else if(count($commit['parent']) == 0) {
        $branch['active'] = false;
        $commit['dot_init'] = true;
    }
    $branch['next'] = $commit['parent'][0];
    $branch['pre_merge'] = false;
    $data['ubranches'][$branch['uid']] = $data['branches'][$branch['id']-1];
    
    $commit['dot'] = $branch['id'];
    
    foreach($data['branches'] as $id => $cbranch) {
        $commit['branches'][$id] = $cbranch;
    }
    
    if($commit['id'] == $_GET['c']) {
        //yeaaa  i've found a PHP Bug :D
        //$graph_commit['branches'] still gets updated.. (damn references)
        //we need a fully independent copy of the array....
        $graph_commit = $commit;
    }
}

//DEV Breakpoint
//print_r($data);
//die();

//generate image

if($graph_commit == NULL)
    die("ERROR 0x07");

$count = count($data['branches']);
if($count > $max_branches)
    $count = $max_branches;
$image = imagecreatetruecolor($count * $size, $size);
$transparentIndex = imagecolorallocate($image, 0xFF, 0xFF, 0xFF);
imagefill($image, 0, 0, $transparentIndex);

function image_set_color($src, $color) {
    global $size;
    imagesavealpha($src, true);
    imagealphablending($src, false);
    // scan image pixels
    for ($x = 0; $x < $size; $x++) {
        for ($y = 0; $y < $size; $y++) {
            $src_pix = imagecolorat($src,$x,$y);
            $src_pix_array = imagecolorsforindex($src, $src_pix);
            
            imagesetpixel($src, $x, $y, imagecolorallocatealpha($src, $color[0], $color[1], $color[2], $src_pix_array['alpha']));
        }
    }
}

function overlay_image($name, $left, $color = false) {
    global $image, $size, $tile_size;
    $image2 = imagecreatefrompng($name);

    if($color) {
        image_set_color($image2, $color);
    }
    imagecopyresampled($image, $image2, $left, 0, 0, 0, $size, $size, $tile_size, $tile_size);
}

function get_color($id, $text = false) {
    global $colors, $graph_commit, $data;
    if($graph_commit['branches'][($id-1)]['pre_merge']) {
        $branch = $data['ubranches'][$graph_commit['branches'][($id-1)]['uid']];
        if($branch['pre_merge'] && $branch['pre_merge_start'])
            $id = $branch['pre_merge_id'];
    }
    $color_array = $colors[($id - 1) % count($colors)];
    if($text && is_array($color_array[0]) && $color_array[1])
        return $color_array[1];
    return (is_array($color_array[0]) ? $color_array[0] : $color_array);
}

foreach($graph_commit['branches'] as $branch) {
    $left = ($branch['id']-1) * $size;
    if($branch['active']) {
        if($graph_commit['dot'] == $branch['id']) continue;
        $show = true;
        if($graph_commit['merge']) {
            foreach($graph_commit['merge'] as $merge) {
                if($merge['point'] == $branch['id']) {
                    $show = false;
                    break;
                }
            }
        }
        if(!$show) continue;
        if($branch['id'] > $max_branches) continue;
        overlay_image("images/line.png", $left, get_color($branch['id']));
    }
}

if($graph_commit['merge']) {
    foreach($graph_commit['merge'] as $merge) {
        $dot_dir = ($graph_commit['dot'] < $merge['point'] ? "right" : "left");
        $merge_dir = ($graph_commit['dot'] < $merge['point'] ? "left" : "right");
        
        if($graph_commit['dot'] <= $max_branches)
            overlay_image("images/dot_merge_".$dot_dir.".png", ($graph_commit['dot'] - 1) * $size, get_color($merge['point']));
        
        if($merge['point'] <= $max_branches) {
            overlay_image("images/".($merge['start'] ? "branch" : "merge")."_".$merge_dir.".png", ($merge['point'] - 1) * $size, get_color($merge['point']));
            if(!$merge['start'] && !$merge['end'])
                overlay_image("images/line.png", ($merge['point'] - 1) * $size, get_color($merge['point']));
        }
        $min = ($graph_commit['dot'] < $merge['point'] ? $graph_commit['dot'] : $merge['point']) + 1;
        $max = ($graph_commit['dot'] < $merge['point'] ? $merge['point'] : $graph_commit['dot']);
        for($i = $min; $i < $max; $i++) {
            if($i > $max_branches) continue;
            overlay_image("images/line_h.png", ($i - 1) * $size, get_color($merge['point']));
        }
    }
    if($graph_commit['dot'] <= $max_branches) {
        if($graph_commit['dot_merge'])
            overlay_image("images/dot_merge.png", ($graph_commit['dot'] - 1) * $size, get_color($graph_commit['dot']));
        else
            overlay_image("images/dot.png", ($graph_commit['dot'] - 1) * $size, get_color($graph_commit['dot']));
    }
} else if($graph_commit['dot_init']) {
    if($graph_commit['dot'] <= $max_branches)
        overlay_image("images/dot_init.png", ($graph_commit['dot'] - 1) * $size, get_color($graph_commit['dot']));
} else if($graph_commit['dot']) {
    if($graph_commit['dot'] <= $max_branches)
        overlay_image("images/dot.png", ($graph_commit['dot'] - 1) * $size, get_color($graph_commit['dot']));
}

imagecolortransparent($image, $transparentIndex);

header('Content-Type: image/png');
imagepng($image);
imagedestroy($image);

?>