module Berkshelf
  class MercurialLocation < Location::ScmLocation
    set_location_key :hg
    set_valid_options :rev, :branch, :tag, :rel

    attr_accessor :uri
    attr_accessor :rel
    attr_accessor :rev
    attr_reader :options

    alias_method :tag, :rev
    alias_method :branch, :rev

    # @param [Dependency] dependency
    # @param [Hash] options
    #
    # @option options [String] :hg
    #   the URL to clone
    # @option options [String] :rev
    #   the revision to checkout
    # @option options [String] :branch
    #   same as rev
    # @option options [String] :tag
    #   same as rev
    # @option options [String] :rel
    #   the path within the repository to find the cookbook
    def initialize(dependency, options = {})
      super
      @uri = options[:hg]
      @rev = options[:rev] || options[:branch] || options[:tag] || 'default'
      @rel = options[:rel]

      Mercurial.validate_uri!(@uri)
    end

    # @return [Berkshelf::CachedCookbook]
    def do_download
      destination = Berkshelf::CookbookStore.instance.storage_path

      if cached?(destination)
        @rev ||= Berkshelf::Mercurial.rev_parse(revision_path(destination))
        return local_revision(destination)
      end

      repo_path = Berkshelf::Mercurial.clone(uri)

      Berkshelf::Mercurial.checkout(repo_path, rev || branch || tag) if rev || branch || tag
      @rev = Berkshelf::Mercurial.rev_parse(repo_path)

      tmp_path = rel ? File.join(repo_path, rel) : repo_path
      unless File.chef_cookbook?(tmp_path)
        msg = "Cookbook '#{dependency.name}' not found at #{to_s}"
        msg << " at path '#{rel}'" if rel
        raise CookbookNotFound, msg
      end

      cb_path = revision_path(destination)
      FileUtils.rm_rf(cb_path)
      FileUtils.mv(tmp_path, cb_path)

      cached = CachedCookbook.from_store_path(cb_path)
      validate_cached(cached)

      cached
    end

    def to_hash
      super.tap do |h|
        h[:value]  = self.uri
        h[:branch] = self.branch if branch
      end
    end

    def ==(other)
      other.is_a?(MercurialLocation) &&
      other.uri == uri &&
      other.rev == rev &&
      other.rel == rel
    end

    def to_s
      if rel
        "#{uri} (at #{rev}/#{rel})"
      else
        "#{uri} (at #{rev})"
      end
    end

    def to_lock
      out =  "    hg: #{uri}\n"
      out << "    rev: #{rev}\n" if rev
      out << "    rel: #{rel}\n" if rel
      out
    end

    private

      def cached?(destination)
        revision_path(destination) && File.exists?(revision_path(destination))
      end

      def local_revision(destination)
        path = revision_path(destination)
        cached = Berkshelf::CachedCookbook.from_store_path(path)
        validate_cached(cached)
        return cached
      end

      def revision_path(destination)
        return unless rev
        File.join(destination, "#{dependency.name}-#{rev}")
      end
  end
end