# User: Vitalie Lazu
# Date: Mar 2008
# Time: 12:08:42 PM

require 'digest/md5'

require 'sorted_inifile'
require 'control_tool'

# http://trac-hacks.org/wiki/GitPlugin
# svn co http://trac-hacks.org/svn/gitplugin/0.10 gitplugin
# cd gitplugin
# python setup.py bdist_egg
# cp egg to /usr/share/trac/plugins

class Git < ControlTool

  def check
    logger.info("Git check")
    logger.warn("Dir '#{repos_dir}' is not writeable") unless test(?w, repos_dir)
    logger.warn("Dir '#{git_daemon_dir}' is not writeable") unless test(?w, git_daemon_dir)
    logger.warn("File #{gitosis_conf} is not writeable") unless test(?w, gitosis_conf)
    logger.info("Git check end")
  end

  # project_url, allow_anonymous, owner_id, owner_login, ssh_pub_keys
  def on_create(opts)
    self.settings = opts
    raise "NotAllowed" if project_name == "gitosis-admin"
    
    settings['owner_login'] ||= "NotPassed"
    dest_dir = dest_dir(settings['project_url'])

    if !test(?d, dest_dir)
      if init_repo
        # http checkout does not work without this, git - 1.5.4.4
        #run("git-update-server-info")
        if settings['copy_vcs_from']
          orig_repo_path = dest_dir(settings['copy_vcs_from'])

          if test(?d, orig_repo_path)
            cd orig_repo_path
            run("git-send-pack --all #{dest_dir}")
          end
        end

        ln_sf  "#{base_dir}/../git/git-post-receive.rb", File.join(dest_dir, 'hooks', 'post-receive')
        create_breakout_ini(dest_dir, settings)
        update_gitosis_conf
        return url(dir_suffix(project_name))
      else
        raise "Can not init repo"
      end
    else
      raise "Dest dir exists"
    end
  end

  def on_destroy(repository_name, suffix = nil)
    self.settings ||= {'project_url' => repository_name}
    raise "NotAllowed" if project_name == "gitosis-admin"
    
    lock_tmp_file do
       ini = SortedIniFile.new(gitosis_conf)
       ini["group #{project_name}"] = nil
       ini["group read:#{project_name}"] = nil
       ini["group write:#{project_name}"] = nil
       ini["repo #{project_name}"] = nil
       ini.write
       commit_gitosis_changes("Removed repository #{project_name}")
    end

    backup_dir = config['backup_dir'] + '/git'
    mkdir_p(backup_dir) unless test(?d, backup_dir)

    dir = fix_project_name(repository_name) + suffix
    # ruby can not move symlinks
    system("/bin/mv #{dest_dir(repository_name)} #{File.join(backup_dir, dir)}")
    remove_git_daemon_symlink
  end

  def upload_pub_keys
    @commit_message = "upload_pub_keys for #{project_name}"
    update_gitosis_conf
  end

  def update_permissions(repository_name, allow_anonymous)
    self.settings ||= {'project_url' => repository_name, 'allow_anonymous' => allow_anonymous}
    @commit_message = "update_permissions for #{project_name}"
    update_gitosis_conf
  end
  
# End control center methods
######################################################

  def init_repo
    mkdir_p repo_path
    cd repo_path

    run("git --bare init --shared=group")
  end

  def remove_git_daemon_symlink
    rm (git_daemon_repo_path) if test(?l, git_daemon_repo_path)
  end
  
  def dest_dir(repository_name)
    File.expand_path(File.join(repos_dir, repo_dir_name(repository_name)))
  end

  def repo_path
    dest_dir(settings['project_url'])
  end

  def repo_dir_name(repository_name)
    dir_suffix(fix_project_name(repository_name))
  end

  def repos_dir
    config['git']['base_dir']
  end

  alias vcs_dir dest_dir

  def dir_suffix(dir)
    dir + '.git'
  end

  def project_name
    fix_project_name(settings['project_url'])
  end
  
  def url(dir)
    config['git']['base_url'] + ':' + dir
  end

  def gitosis_dir
    config['git']['gitosis_dir']
  end

  def gitosis_conf
    File.join(gitosis_dir, 'gitosis.conf')
  end

  def update_gitosis_conf
    lock_tmp_file do
      ini = SortedIniFile.new(gitosis_conf)
      ini["group #{project_name}"] = gitosis_group if settings['ssh_pub_keys']
      special_gitosis_group(ini, :read)
      special_gitosis_group(ini, :write)

      if settings['allow_anonymous']
        ini["repo #{project_name}"] = {'daemon' => 'yes'}
        ln_sf dest_dir(settings['project_url']), git_daemon_repo_path
      else
        remove_git_daemon_symlink
      end

      ini.write
      commit_gitosis_changes(@commit_message || "Created repository #{project_name}, owner login/id: #{settings['owner_login']}/#{settings['owner_id']}")
    end
  end

  # Set special group for git repository access 
  # <tt>access</tt> -> :read or :write
  def special_gitosis_group(ini, access)
    key = "ssh_#{access}_keys"

    return unless settings[key]

    ini_key = "group #{access}:#{project_name}"

    if settings[key].size == 0
      ini[ini_key] = nil
    else
      members = []

      settings[key].each do |ssh_key|
        key_id = "f-" + Digest::MD5.hexdigest(ssh_key)
        members << key_id
        key_path = File.join(gitosis_dir, 'keydir', "#{key_id}.pub")

        write_ssh_key(ssh_key, key_path)
      end

      ini[ini_key] = { 'members' => members.sort * ' ', access == :read ? 'readonly' : 'writable' => project_name}
    end
  end

  def gitosis_group
    # add group
    gr = {'writable' => project_name}

    users = []

    for row in settings['ssh_pub_keys']
      user_id, ssh_key = row
      users << gitosis_user_id(user_id)

      write_ssh_key(ssh_key, user_ssh_key_file(user_id))
    end

    gr['members'] = users.size > 0 ? users.join(' ') : nil
    
    gr
  end

  def write_ssh_key(ssh_key, dest_path)
    File.open(dest_path, "w") do |f|
      f.write(ssh_key.tr("\r\n", '') + "\n")
    end
  end

  def git_daemon_repo_path
    "#{git_daemon_dir}/#{repo_dir_name(settings['project_url'])}"
  end

  def commit_gitosis_changes(msg)
    dir = Dir.pwd
    cd gitosis_dir

    run("git-add .")
    run("git-commit -a -m \"#{msg}\"")
    run("git-push")
    run("git-pull")
    cd dir
  end

  def lock_tmp_file
    File.open(File.join(tmp_dir, 'git.lock'), "w") do |f|
      if f.flock(File::LOCK_EX)
        begin
          yield
        ensure
          f.close
        end
      end
    end
  end

  def git_daemon_dir
    config['git']['git_daemon_dir']
  end

  def exists_rsa_key?(user_id)
    test(?f, user_ssh_key_file(user_id))
  end

  def user_ssh_key_file(user_id)
    File.join(gitosis_dir, 'keydir', "#{gitosis_user_id user_id}.pub")
  end

  def gitosis_user_id(user_id)
    "u-#{user_id}"
  end

  def disk_space(settings)
    dir = dest_dir(settings['dir_name'])
    dir_disk_space(dir)
  end
end

# Sample Apache conf
#<VirtualHost *:80>
#ServerName git.host.com
#
#DocumentRoot "/var/www/"
#Alias /git/ "/opt/beta/git/"
#
#<Directory "/opt/beta/git/">
#  Order allow,deny
#  Allow from all
#</Directory>
#
#ErrorLog /var/log/tools/git-error.log
#LogLevel debug
#CustomLog /var/log/tools/git-access.log combined
#
#SetHandler mod_python
#PythonDebug On
#
#<Location /git/>
#    DAV on
#    AuthType Basic
#    AuthName "Git Restricted Area"
#    PythonAccessHandler breakout.svn_access
#    PythonAuthenHandler breakout.svn_access
#</Location>
#</VirtualHost>
#