.gemspec

# encoding: utf-8

require 'yaml'

module DotRuby

  #
  class GemSpec

    # For which revision of .ruby is this gemspec intended?
    REVISION = 0 unless defined?(REVISION)

    #
    PATTERNS = {
      :bin_files  => 'bin/*',
      :lib_files  => 'lib/{**/}*.rb',
      :ext_files  => 'ext/{**/}extconf.rb',
      :doc_files  => '*.{txt,rdoc,md,markdown,tt,textile}',
      :test_files => '{test/{**/}*_test.rb,spec/{**/}*_spec.rb}'
    } unless defined?(PATTERNS)

    #
    def self.instance
      new.to_gemspec
    end

    attr :metadata

    attr :manifest

    #
    def initialize
      @metadata = YAML.load_file('.ruby')
      @manifest = Dir.glob('manifest{,.txt}', File::FNM_CASEFOLD).first

      if @metadata['revision'].to_i != REVISION
        warn "You have the wrong revision. Trying anyway..."
      end
    end

    #
    def scm
      @scm ||= \
        case
        when File.directory?('.git')
          :git
        end
    end

    #
    def files
      @files ||= \
        #glob_files[patterns[:files]]
        case
        when manifest
          File.readlines(manifest).
            map{ |line| line.strip }.
            reject{ |line| line.empty? || line[0,1] == '#' }
        when scm == :git
         `git ls-files -z`.split("\0")
        else
          Dir.glob('{**/}{.*,*}')  # TODO: be more specific using standard locations ?
        end.select{ |path| File.file?(path) }
    end

    #
    def glob_files(pattern)
      Dir.glob(pattern).select { |path|
        File.file?(path) && files.include?(path)
      }
    end

    #
    def patterns
      PATTERNS
    end

    #
    def executables
      @executables ||= \
        glob_files(patterns[:bin_files]).map do |path|
          File.basename(path)
        end
    end

    def extensions
      @extensions ||= \
        glob_files(patterns[:ext_files]).map do |path|
          File.basename(path)
        end
    end

    #
    def name
      metadata['name'] || metadata['title'].downcase.gsub(/\W+/,'_')
    end

    #
    def to_gemspec
      Gem::Specification.new do |gemspec|
        gemspec.name        = name
        gemspec.version     = metadata['version']
        gemspec.summary     = metadata['summary'].sub("\n", ' ')
        gemspec.description = metadata['description'].sub("\n", ' ')

        metadata['authors'].each do |author|
          gemspec.authors << author['name']

          if author.has_key?('email')
            if gemspec.email
              gemspec.email << author['email']
            else
              gemspec.email = [author['email']]
            end
          end
        end

        gemspec.licenses = metadata['copyrights'].map{ |c| c['license'] }.compact.uniq

        metadata['requirements'].each do |req|
          name    = req['name']
          version = req['version']
          groups  = req['groups'] || []

          case version
          when /^(.*?)\+$/
            version = ">= #{$1}"
          when /^(.*?)\-$/
            version = "< #{$1}"
          when /^(.*?)\~$/
            version = "~> #{$1}"
          end

          if groups.empty? or groups.include?('runtime')
            # populate runtime dependencies  
            if gemspec.respond_to?(:add_runtime_dependency)
              gemspec.add_runtime_dependency(name,*version)
            else
              gemspec.add_dependency(name,*version)
            end
          else
            # populate development dependencies
            if gemspec.respond_to?(:add_development_dependency)
              gemspec.add_development_dependency(name,*version)
            else
              gemspec.add_dependency(name,*version)
            end
          end
        end

        # convert external dependencies into a requirements
        if metadata['external_dependencies']
          ##gemspec.requirements = [] unless metadata['external_dependencies'].empty?
          metadata['external_dependencies'].each do |req|
            gemspec.requirements << req.to_s
          end
        end

        # determine homepage from resources
        homepage = metadata['resources'].find{ |key, url| key =~ /^home/ }
        gemspec.homepage = homepage.last if homepage

        gemspec.require_paths        = metadata['load_path'] || ['lib']
        gemspec.post_install_message = metadata['install_message']

        # RubyGems specific metadata
        gemspec.files       = files
        gemspec.extensions  = extensions
        gemspec.executables = executables

        if Gem::VERSION < '1.7.'
          gemspec.default_executable = gemspec.executables.first
        end

        gemspec.test_files = glob_files(patterns[:test_files])

        unless gemspec.files.include?('.document')
          gemspec.extra_rdoc_files = glob_files(patterns[:doc_files])
        end
      end
    end

  end #class GemSpec

end

DotRuby::GemSpec.instance