require File.join(File.dirname(__FILE__), '..', 'vcsrepo')

Puppet::Type.type(:vcsrepo).provide(:git, :parent => Puppet::Provider::Vcsrepo) do
  desc "Supports Git repositories"

  commands :git => 'git'
  defaultfor :git => :exists
  has_features :bare_repositories, :reference_tracking

  def create
    if !@resource.value(:source)
      init_repository(@resource.value(:path))
    else
      clone_repository(@resource.value(:source), @resource.value(:path))
      if @resource.value(:revision)
        if @resource.value(:ensure) == :bare
          notice "Ignoring revision for bare repository"
        else
          checkout_branch_or_reset
        end
      end
      if @resource.value(:ensure) != :bare
        update_submodules
      end
    end
  end

  def destroy
    FileUtils.rm_rf(@resource.value(:path))
  end
  
  def revision
    fetch
    update_references
    current   = at_path { git('rev-parse', 'HEAD') }
    canonical = at_path { git('rev-parse', @resource.value(:revision)) }
    if current == canonical
      @resource.value(:revision)
    else
      current
    end
  end

  def revision=(desired)
    fetch
    update_references
    if local_branch_revision?(desired)
      at_path do
        git('checkout', desired)
        git('pull', 'origin')
      end
      update_submodules
    elsif remote_branch_revision?(desired)
      at_path do
        git('checkout',
            '-b', @resource.value(:revision),
            '--track', "origin/#{@resource.value(:revision)}")
      end
      update_submodules
    else
      reset(desired)
      if @resource.value(:ensure) != :bare
        update_submodules
      end
    end
  end

  def bare_exists?
    bare_git_config_exists? && !working_copy_exists?
  end

  def working_copy_exists?
    File.directory?(File.join(@resource.value(:path), '.git'))
  end

  def exists?
    working_copy_exists? || bare_exists?
  end

  def update_references
    at_path do
      git('fetch', '--tags', 'origin')
    end
  end
  
  private

  def path_exists?
    File.directory?(@resource.value(:path))
  end

  def bare_git_config_exists?
    File.exist?(File.join(@resource.value(:path), 'config'))
  end
  
  def clone_repository(source, path)
    args = ['clone']
    if @resource.value(:ensure) == :bare
      args << '--bare'
    end
    args.push(source, path)
    git(*args)
  end

  def fetch
    at_path do
      git('fetch', 'origin')
    end
  end

  def pull
    at_path do
      git('pull', 'origin')
    end
  end
  
  def init_repository(path)
    if @resource.value(:ensure) == :bare && working_copy_exists?
      convert_working_copy_to_bare
    elsif @resource.value(:ensure) == :present && bare_exists?
      convert_bare_to_working_copy
    elsif File.directory?(@resource.value(:path))
      raise Puppet::Error, "Could not create repository (non-repository at path)"
    else
      normal_init
    end
  end

  # Convert working copy to bare
  #
  # Moves:
  #   <path>/.git
  # to:
  #   <path>/
  def convert_working_copy_to_bare
    notice "Converting working copy repository to bare repository"
    FileUtils.mv(File.join(@resource.value(:path), '.git'), tempdir)
    FileUtils.rm_rf(@resource.value(:path))
    FileUtils.mv(tempdir, @resource.value(:path))
  end

  # Convert bare to working copy
  #
  # Moves:
  #   <path>/
  # to:
  #   <path>/.git
  def convert_bare_to_working_copy
    notice "Converting bare repository to working copy repository"
    FileUtils.mv(@resource.value(:path), tempdir)
    FileUtils.mkdir(@resource.value(:path))
    FileUtils.mv(tempdir, File.join(@resource.value(:path), '.git'))
    if commits_in?(File.join(@resource.value(:path), '.git'))
      reset('HEAD')
      git('checkout', '-f')
    end
  end

  def normal_init
    FileUtils.mkdir(@resource.value(:path))
    args = ['init']
    if @resource.value(:ensure) == :bare
      args << '--bare'
    end
    at_path do
      git(*args)
    end
  end

  def commits_in?(dot_git)
    Dir.glob(File.join(dot_git, 'objects/info/*'), File::FNM_DOTMATCH) do |e|
      return true unless %w(. ..).include?(File::basename(e))
    end
    false
  end

  def checkout_branch_or_reset
    if remote_branch_revision?
      at_path do
        git('checkout', '-b', @resource.value(:revision), '--track', "origin/#{@resource.value(:revision)}")
      end
    else
      reset(@resource.value(:revision))
    end
  end

  def reset(desired)
    at_path do
      git('reset', '--hard', desired)
    end
  end

  def update_submodules
    at_path do
      git('submodule', 'init')
      git('submodule', 'update')
    end
  end

  def remote_branch_revision?(revision = @resource.value(:revision))
    at_path do
      branches.include?("origin/#{revision}")
    end
  end

  def local_branch_revision?(revision = @resource.value(:revision))
    at_path do
      branches.include?(revision)
    end
  end

  def branches
    at_path { git('branch', '-a') }.gsub('*', ' ').split(/\n/).map { |line| line.strip }
  end

end