require_relative 'exceptions'

module Rocktumbler
  class Gem
    def initialize(gem_dependency)
      @gem_dependency = gem_dependency
    end

    def print(prepend="")
      gem_info = retrieve_gem_information(@gem_dependency.name)
      str = "#{prepend}# #{gem_info.summary}\n"
      str += "#{prepend}# #{gem_info.homepage}\n"
      str += "#{prepend}gem '#{@gem_dependency.name}'"
      str += ",'#{@gem_dependency.requirement}'" unless @gem_dependency.requirement.none?
      str += generate_gem_source(@gem_dependency.source.options) if @gem_dependency.source
      str += generate_require(@gem_dependency.autorequire) if @gem_dependency.autorequire
      str += "\n\n"
    end

    private

    def generate_require(autorequire)
      if autorequire.count > 1
        # Array.to_s will output double quotes so we gsub them to singles.
        return ", require: #{autorequire.to_s.gsub(/"/,'\'')}"
      elsif autorequire.first.is_a?(String)
        return ", require: '#{autorequire.first}'"
      else
        return ", require: #{!autorequire.empty?}"
      end
    end

    def generate_gem_source(source_options)
      ['git','github','git_source','source','path','gist','bitbucket'].each do | source_type |
        return ", #{source_type}: '#{source_options[source_type]}'" if source_options[source_type]
      end
    end

    def retrieve_gem_information(gem_name)
      bundled_gem = Bundler.definition.specs.select{|g| g.name == gem_name}.first
      if bundled_gem
        OpenStruct.new(summary: bundled_gem.summary.slice(0,80), homepage: bundled_gem.homepage)
      else
        rubygems_gem_information(gem_name)
      end
    end

    def rubygems_gem_information(gem_name)
      begin
        json = open("https://rubygems.org/api/v1/gems/#{gem_name}.json").read
        gem_info = JSON.parse(json)
        OpenStruct.new(summary: gem_info['info'].slice(0,80), homepage: gem_info['homepage_uri'])
      rescue OpenURI::HTTPError => e
        if e.message == '404 Not Found'
          raise GemInformationNotFoundError, "No details found locally or on rubygems for '#{gem_name}'"
        else
          raise e
        end
      end
    end
  end
end