class Bundler::GemHelper

def self.install_tasks(opts = {})
  dir = opts[:dir] || Dir.pwd
  self.new(dir, opts[:name]).install
end

def build_gem
  file_name = nil
  sh("gem build -V '#{spec_path}'") { |out, code|
    raise out unless out[/Successfully/]
    file_name = File.basename(built_gem_path)
    FileUtils.mkdir_p(File.join(base, 'pkg'))
    FileUtils.mv(built_gem_path, 'pkg')
    Bundler.ui.confirm "#{name} #{version} built to pkg/#{file_name}"
  }
  File.join(base, 'pkg', file_name)
end

def built_gem_path
  Dir[File.join(base, "#{name}-*.gem")].sort_by{|f| File.mtime(f)}.last
end

def clean?
  sh_with_code("git diff --exit-code")[1] == 0
end

def git_push
  perform_git_push
  perform_git_push ' --tags'
  Bundler.ui.confirm "Pushed git commits and tags"
end

def guard_already_tagged
  if sh('git tag').split(/\n/).include?(version_tag)
    raise("This tag has already been committed to the repo.")
  end
end

def guard_clean
  clean? or raise("There are files that need to be committed first.")
end

def initialize(base, name = nil)
  Bundler.ui = UI::Shell.new(Thor::Base.shell.new)
  @base = base
  gemspecs = name ? [File.join(base, "#{name}.gemspec")] : Dir[File.join(base, "{,*}.gemspec")]
  raise "Unable to determine name from existing gemspec. Use :name => 'gemname' in #install_tasks to manually set it." unless gemspecs.size == 1
  @spec_path = gemspecs.first
  @gemspec = Bundler.load_gemspec(@spec_path)
end

def install
  desc "Build #{name}-#{version}.gem into the pkg directory"
  task 'build' do
    build_gem
  end
  desc "Build and install #{name}-#{version}.gem into system gems"
  task 'install' do
    install_gem
  end
  desc "Create tag #{version_tag} and build and push #{name}-#{version}.gem to Rubygems"
  task 'release' do
    release_gem
  end
end

def install_gem
  built_gem_path = build_gem
  out, _ = sh_with_code("gem install '#{built_gem_path}'")
  raise "Couldn't install gem, run `gem install #{built_gem_path}' for more detailed output" unless out[/Successfully installed/]
  Bundler.ui.confirm "#{name} (#{version}) installed"
end

def name
  gemspec.name
end

def perform_git_push(options = '')
  cmd = "git push #{options}"
  out, code = sh_with_code(cmd)
  raise "Couldn't git push. `#{cmd}' failed with the following output:\n\n#{out}\n" unless code == 0
end

def release_gem
  guard_clean
  guard_already_tagged
  built_gem_path = build_gem
  tag_version {
    git_push
    rubygem_push(built_gem_path)
  }
end

def rubygem_push(path)
  if Pathname.new("~/.gem/credentials").expand_path.exist?
    sh("gem push '#{path}'")
    Bundler.ui.confirm "Pushed #{name} #{version} to rubygems.org"
  else
    raise "Your rubygems.org credentials aren't set. Run `gem push` to set them."
  end
end

def sh(cmd, &block)
  out, code = sh_with_code(cmd, &block)
  code == 0 ? out : raise(out.empty? ? "Running `#{cmd}' failed. Run this command directly for more detailed output." : out)
end

def sh_with_code(cmd, &block)
  cmd << " 2>&1"
  outbuf = ''
  Bundler.ui.debug(cmd)
  Dir.chdir(base) {
    outbuf = `#{cmd}`
    if $? == 0
      block.call(outbuf) if block
    end
  }
  [outbuf, $?]
end

def tag_version
  sh "git tag -a -m \"Version #{version}\" #{version_tag}"
  Bundler.ui.confirm "Tagged #{version_tag}"
  yield if block_given?
rescue
  Bundler.ui.error "Untagged #{version_tag} due to error"
  sh_with_code "git tag -d #{version_tag}"
  raise
end

def version
  gemspec.version
end

def version_tag
  "v#{version}"
end