<?php

function find_projects(string $path, array $projects = []): array {
  $directories = glob($path . "/{.[!.],}*", GLOB_ONLYDIR | GLOB_BRACE);
  if (($idx = array_search("$path/.git", $directories)) !== false) {
    $projects[] = substr($directories[$idx], 0, -4);
  }
  else {
    foreach ($directories as $directory) {
      $projects += find_projects($directory, $projects);
    }
  }

  return $projects;
}

function parse_log(string $path): array|null {
  $proxy = md5(strval(microtime(true)));
  $process = proc_open(
    "git -C {$path} log " . "--pretty=format:'{%n  {$proxy}commit{$proxy}: {$proxy}%H{$proxy},%n  {$proxy}author{$proxy}: {$proxy}%aN <%aE>{$proxy},%n  {$proxy}date{$proxy}: {$proxy}%ad{$proxy},%n  {$proxy}message{$proxy}: {$proxy}%s{$proxy}%n},'",
    [
      ["pipe", "r"],
      ["pipe", "w"],
      ["pipe", "w"],
    ],
    $pipes
  );

  $output = stream_get_contents($pipes[1]);
  $string = str_replace(['"', $proxy], ['\\"', '"'], $output);
  $string = "[" . rtrim($string, ",") . "]";

  $json = json_decode($string, true);

  return $json;
}

function parse_status(string $path): array {
  $process = proc_open(
    "git -C {$path} status --porcelain=v2 --branch",
    [
      ["pipe", "r"],
      ["pipe", "w"],
      ["pipe", "w"],
    ],
    $pipes
  );

  $output = stream_get_contents($pipes[1]);

  $status = ["files" => []];
  foreach (explode("\n", $output) as $line) {
    if (empty($line)) {
      continue;
    }

    $start = substr($line, 0, 1);

    if ($start == "#") {
      if (str_contains($line, "branch.oid")) {
        $status["oid"] = substr($line, strlen("# branch.oid "));
      }
      else if (str_contains($line, "branch.head")) {
        $status["head"] = substr($line, strlen("# branch.head "));
      }
      else if (str_contains($line, "branch.upstream")) {
        $status["upstream"] = substr($line, strlen("# branch.upstream "));
      }
      else if (str_contains($line, "branch.ab")) {
        $status["ab"] = substr($line, strlen("# branch.ab "));
      }
    }

    else {
      $parts = explode(" ", $line);
      $file = [
        "filename" => $parts[count($parts) - 1],
        "staged" => false,
        "unstaged" => false,
        "untracked" => false,
        "new_file" => false,
        "modified" => false,
      ];

      if ($start == "1") {
        $track_status = $parts[1];
        if (substr($track_status, 0, 1) == "A") {
          $file["staged"] = true;
          $file["new_file"] = true;
        }
        else if (substr($track_status, 0, 1) == "M") {
          $file["staged"] = true;
          $file["modified"] = true;
        }

        if (substr($track_status, 1, 1) == "M") {
          $file["unstaged"] = true;
          $file["modified"] = true;
        }

        $file = array_merge($file, [
          "previous_mode" => $parts[3],
          "new_mode" => $parts[4],
          "previous_id" => $parts[6],
          "new_id" => $parts[7],
        ]);
      }

      else if ($start == "?") {
        $file["untracked"] = true;
      }

      $status["files"][] = $file;
    }
  }

  return $status;
}

function get_file_tree(string $path, string $revision, string $tree_base_path): array
{
  $proxy = md5(strval(microtime(true)));
  $process = proc_open(
    "git -C {$path} ls-tree {$revision} {$tree_base_path}" . " --format='{%n  {$proxy}mode{$proxy}: {$proxy}%(objectmode){$proxy},%n  {$proxy}type{$proxy}: {$proxy}%(objecttype){$proxy},%n  {$proxy}name{$proxy}: {$proxy}%(objectname){$proxy},%n  {$proxy}size{$proxy}: {$proxy}%(objectsize){$proxy},%n  {$proxy}path{$proxy}: {$proxy}%(path){$proxy}%n},'",
    [
      ["pipe", "r"],
      ["pipe", "w"],
      ["pipe", "w"],
    ],
    $pipes
  );

  $output = stream_get_contents($pipes[1]);
  $string = str_replace(['"', $proxy], ['\\"', '"'], $output);
  $string = "[" . rtrim(trim($string), ",") . "]";

  $tree = json_decode($string, true);

  return $tree;
}


function template_root(string $content, array $meta = []): string
{
  $meta = array_replace_recursive([
    "title" => "phpgit - single file git web frontend",
  ], $meta);
  
  ob_start();

  ?>
  <html>
  <head>
    <title><?php echo $meta["title"]; ?></title>
  </head>
  <body><?php echo $content; ?></body>
  </html>
  <?php

  return ob_get_clean();
}


$projects_path = realpath($_ENV["PHPGIT_PROJECTS_PATH"]);

$url = parse_url("http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]");

ob_start();

if ($url["path"] == "/") {
  $projects = find_projects($projects_path);

  // sort by date
  usort($projects, function ($a, $b) {
    $a_log = parse_log($a);

    if (file_exists(".git/info/web/last-modified")) {
      $a_date = new DateTime(file_get_contents(".git/info/web/last-modified"));
    } else if (count($a_log) > 0) {
      $a_date = new DateTime($a_log[0]["date"]);
    } else {
      $a_date = date_create()->setTimestamp(0);
    }
  
    $b_log = parse_log($b);
  
    if (file_exists(".git/info/web/last-modified")) {
      $b_date = new DateTime(file_get_contents(".git/info/web/last-modified"));
    } else if (count($b_log) > 0) {
      $b_date = new DateTime($b_log[0]["date"]);
    } else {
      $b_date = date_create()->setTimestamp(0);
    }
  
    return $b_date <=> $a_date;
  });

  // build list
  ?>
  <table>
  <thead>
    <tr>
      <td>Name</td>
      <td>Description</td>
      <td>Last Activity</td>
    </tr>
  </thead>
  <tbody>
  <?php

  foreach ($projects as $project) {
    $name = trim(str_replace($projects_path, "", $project), "/");

    ?><tr><?php

    ?><td><a href="<?php echo $name; ?>/tree"><?php
    echo $name;
    ?></a></td><?php

    $status = parse_status($project);

    echo "<td></td>";

    $log = parse_log($project);

    if (count($log) > 0) {
      $date = new DateTime($log[0]["date"]);
      echo "<td>" . $date->format("Y-m-d") . "</td>";   
    }

    ?></tr><?php
  }

  ?>
  </tbody>
  </table>
  <?php
}


// /$project/tree/$file_path
elseif (preg_match("#(.*)/tree/?(.*)#", $url["path"], $matches)) {
  $project = ltrim($matches[1], "/");
  $file_path = rtrim($matches[2], "/");

  // get tree
  $tree = get_file_tree("$projects_path/$project", "HEAD", "./{$file_path}/");

  // show breadcrumbs
  $breadcrumbs = explode("/", $file_path);
  echo "<a href='/$project/tree'>root</a>";
  $crumb_parts = "";
  foreach ($breadcrumbs as $idx => $crumb) {
    $crumb_parts .= "/$crumb";
    echo "/<a href='/$project/tree$crumb_parts'>$crumb</a>";
  }

  // build list
  ?>
  <table>
  <thead>
    <tr>
      <td>File</td>
    </tr>
  </thead>
  <tbody>
  <?php
  
  foreach ($tree as $file) {
    $relative_path = str_replace("$file_path/", "", $file["path"]);
    
    ?><tr><?php

    ?><td><a href="<?php echo "$url[path]/$relative_path"; ?>"><?php echo $relative_path; ?></a><td><?php
    
    ?></tr><?php
  }

  ?>
  </tbody>
  </table>
  <?php
}

else {
  $path = $projects_path . $url["path"];
  var_dump(parse_log($path));
}

// display
echo template_root(ob_get_clean());