#!/usr/bin/env ruby
# Script to automatically install Vim bundles to ~/.vim/bundle/
# 
# See vim/bundles for a sample file

require 'getoptlong'

# Shut up about warnings
BUNDLE_ROOT = '/.vim/bundle/'

def vim_bundle(bundle, tag=nil)
  if $transport == 'ssh'
    url = 'git@github.com:'
  elsif $transport == 'https'
    url = 'https://github.com/'
  elsif $transport == 'git'
    url = 'git://github.com/'
  else
    $stderr.puts "#{$an}: Unrecognized transport layer '#{transport}' (try --help)"
    exit 1
  end

  if bundle =~ /^[A-Za-z0-9-]+\/[A-Za-z0-9._-]+$/
    url += bundle + '.git'
  elsif bundle =~ /^[A-Za-z0-9._-]+$/
    url += 'vim-scripts/' + bundle + '.git'
  else
    # We are using a service other than GitHub. Specifying the URL directly
    url = bundle
  end

  bundle_name = bundle.sub(/^.*\//, '').sub(/\.git$/, '')

  if $dry_run
    puts "URL #{url} Bundle #{bundle_name} Tag #{tag.to_s}"
    return
  else
    dir = ENV['HOME'] + BUNDLE_ROOT + bundle_name
    pwd = Dir.pwd
    $VERBOSE = nil
    if File.directory?(dir)
      if $update # Don't update if the no-update option was passed
        if File.directory?(dir + '/.git')
          puts "Updating bundle #{bundle_name}..."
          Dir.chdir(dir)
          `git fetch`
          Dir.chdir(pwd)
          puts
        else
          $stderr.puts "#{$an}: #{bundle_name} is not a Git repository."
          return
        end
      else
        $stderr.puts "#{$an}: Skipping update for #{bundle_name}"
        return
      end

    else
      # Directory doesn't exist, need to pull
      puts "Installing bundle #{bundle_name}..."
      Dir.chdir(ENV['HOME'] + BUNDLE_ROOT)
      `git clone #{url} #{bundle_name}`
      Dir.chdir(pwd)
      puts
    end

    tag ||= 'origin/HEAD'
    Dir.chdir(dir)
    `git stash`
    `git checkout #{tag}`
    `git stash pop`
    Dir.chdir(pwd)
    $VERBOSE = false
  end
end

opts = GetoptLong.new(
  [ '--help', '-h', GetoptLong::NO_ARGUMENT ],
  [ '--transport', '-t', GetoptLong::REQUIRED_ARGUMENT ],
  [ '--no-update', GetoptLong::NO_ARGUMENT ],
  [ '--dry-run', '-n', GetoptLong::NO_ARGUMENT ]
)

$an = $0.sub(/^.*\//, '')
file = nil
$transport = 'ssh'
$update = true
$dry_run = false

opts.each do |opt, arg|
  case opt
    when '--help'
      puts <<-EOF
#{$an} manages vim bundles in ~/.vim/bundles
Usage: #{$an} [OPTIONS] FILE

Options:
  --transport,    Use the specified transport layer to download git bundles.
    -t <option>   Transport layer can be one of git, ssh or https.

  --no-update     Do not update existing bundles, only download new ones.

  --dry-run, -n   Just print what would be done, do not execute anything.

  --help, -h      Display this help message

The specified file must have the path to the bundle's repository on GitHub.
If you are using any other service, you must specify the full URL, and the
transport option will not be applied. You may optionally specify a tag or SHA
to checkout, otherwise, it will checkout the HEAD version.

EOF
      exit 0

    when '--transport'
      unless arg == 'ssh' or arg == 'https' or arg == 'git'
        $stderr.puts "#{$an}: Transport option must be one of git, https or ssh"
        exit 1
      end

      $transport = arg

    when '--no-update'
      $update = false

    when '--dry-run'
      $dry_run = true
  end
end

if ARGV.length != 1
  $stderr.puts "#{$an}: Missing FILE argument (try --help)"
  exit 1
end

file = ARGV.shift

# Read the file contents
unless File.file?(file) and File.readable?(file)
  $stderr.puts "#{$an}: Unable to read file #{file}"
  exit 1
end

File.open(file).each do |line|
  # Chop off comments
  line.sub!(/#.*$/, '')
  # Strip leading and trailing spaces
  line.sub!(/^\s*/, '')
  line.sub!(/\s*$/, '')

  args = line.split
  bname = args[0]
  tag = args[1]

  vim_bundle(bname, tag) if (bname)
end