#!/usr/bin/env ruby
#--
#   Copyright (C) 2011-2012 Gitorious AS
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
#   You should have received a copy of the GNU Affero General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
#++
#
# Alternative to script/git-daemon which uses the native git-daemon
# instead. Run this script on port 9418 and it will handle all git://
# access. As the name implies, this script simply acts as a proxy, translating
# the git urls presented in the web view to the hashed paths on the file system
# (which the native git-daemon then handles).
#
# Using script/git-proxy with git-daemon as an alternative to script/git-daemon
# has the advantage of being more stable, but requires two daemons instead of
# one, which complicates matters slightly.
#
# Running it
#
# First of all, make sure the native git-daemon is running. This example uses
# port 9400, but you can use any port of your liking:
#
#     $ git daemon --listen=0.0.0.0 --port=9400 --syslog --export-all \
#             --pid-file=/path/to/gitorious/tmp/pids/git-daemon-9400.pid \
#             --base-path=/path/to/gitorious/repositories --verbose --reuseaddr \
#             /path/to/gitorious/repositories
#
# NOTE: If you change the port for git-daemon, make sure to update
# config/git-proxymachine.rb to reflect the change (:remote, l40).
#
# Then run the git-proxy script:
#
#     $ bundle exec /path/to/gitorious/script/git-proxy
#
# Test by issuing:
#
#     $ git ls-remote git://gitorious.local/some/repo.git
#
#Bundler.require(:default, :git_proxy) if defined?(Bundler)

require "pathname"
require (Pathname(__FILE__) + "../../config/environment.rb").realpath
require "optparse"
require "proxymachine"
require "daemons"
require "yaml"

ROOT_DIR = File.expand_path( File.join(File.dirname(__FILE__), "../") )

if Rails.env.production? && Process.uid == 0
  config = YAML::load_file(ROOT_DIR + "/config/gitorious.yml")
  git_user = config["user"] || (config[Rails.env] && config[Rails.env]["user"])
  if git_user
    uid = Etc.getpwnam(git_user).uid
    gid = Etc.getpwnam(git_user).gid
    Process::GID.change_privilege(gid)
    Process::UID.change_privilege(uid)
  end
end

begin
  options = {
    :host => "0.0.0.0",
    :port => 9418,
    :detach => false,
    :logfile => File.join(ROOT_DIR, "log", "git-proxy.log")
  }

  opts = OptionParser.new do |opts|
    opts.banner = <<-EOF
  Usage:
    git-proxy [-h <host>] [-p <port>]

  Options:
EOF

    opts.on("-cCONFIG", "--config CONFIG", "Configuration file") do |x|
      options[:config] = x
    end

    opts.on("-hHOST", "--host HOST", "Hostname to bind. Default 0.0.0.0") do |x|
      options[:host] = x
    end

    opts.on("-pPORT", "--port PORT", "Port to listen on. Default 9418") do |x|
      options[:port] = x
    end

    opts.on("-d", "--detach", "Run in background",
      "Default: #{options[:detach].inspect}") do |o|
      options[:detach] = o
    end

    opts.on("-l", "--log=[file]", "File to log to",
      "Default: #{options[:logfile]}") do |o|
      options[:logfile] = o
    end

    opts.on("-P", "--pid=[file]", "PID file to use (if daemonized)",
      "Default: #{options[:pidfile]}") do |o|
      options[:pidfile] = o
    end
  end

  opts.parse!

  Daemonize.daemonize if options[:detach]
  if options[:pidfile]
    File.open(options[:pidfile], "w") do |f|
      f.write(Process.pid)
    end
  end
  if options[:logfile]
    ::LOGGER = Logger.new(options[:logfile])
  end
  load(File.join(ROOT_DIR, "config/git-proxymachine.rb"))
  ProxyMachine.run("git-proxy", options[:host], options[:port])
rescue Exception => e
  if e.instance_of?(SystemExit)
    raise
  else
    LOGGER.info 'Uncaught exception'
    LOGGER.info e.class.name + ": " + e.message
    LOGGER.info e.backtrace.join("\n")
  end
end