# 
# parse_dependencies_for
# 
def parse_project_gemfile
  required_gems, required_fake_gems = [], []
  gem_file = "#{project_dir}/lib/#{project[:name]}/gems.rb"

  if File.exist? gem_file
    # puts "Parsing gemfile #{gem_file}"
    
    code = File.open(gem_file){|f| f.read}
    
    stub_class = Class.new
    stub_class.send(:define_method, :gem){|*args| required_gems << args}
    stub_class.send(:define_method, :fake_gem){|*args| required_fake_gems << args}
    stub = stub_class.new
    stub.instance_eval code, __FILE__, __LINE__
  end
  
  return required_gems, required_fake_gems
end


# 
# Install gems
# 
namespace :gem do
  desc "Install gem required by project"
  task :install do
    gems, fake_gems = parse_project_gemfile    
    gems.each do |name, version|
      puts "Installing gem #{name} #{version}"
      %x(gem install #{name}#{" -v #{version}" if version} --ignore-dependencies)
    end
  end  
  
  desc "List all gems required by project"
  task :list do
    puts "Gems required for #{project[:official_name]}:"
    gems, fake_gems = parse_project_gemfile
    puts(gems + fake_gems)
  end
  
  desc "Install all gem required by project (including fake gems)"
  task :install_all do
    gems, fake_gems = parse_project_gemfile    
    (gems + fake_gems).each do |name, version|
      puts "Installing gem #{name} #{version}"
      %x(gem install #{name} #{"-v #{version}" if version})
    end
  end
end

# 
# Gem Spec, for sample look at Rakefile
# 
require 'rake/clean'
require 'rake/gempackagetask'
require 'tmpdir'

class GemHelper
  class << self
    def next_version gem_name
      %x(gem list --remote #{gem_name}).scan /#{gem_name} \((\d+\.\d+\.\d+)\)/ do |s|
        v = s.first.split('.').collect{|d| d.to_i}
        v[-1] = v[-1] + 1
        return v.join('.')
      end
      return '0.0.1'
    end
    
    def prepare_gem_metadata
      spec = Gem::Specification.new do |s|
        gems, fake_gems = parse_project_gemfile
        gems = gems + fake_gems

        gems.each{|name_version| s.add_dependency *name_version}

        options = project.clone

        options.delete(:name)
        options.delete(:gem) || raise("this project isn't a gem!")
        name = options.delete(:official_name)

        s.name = name
        s.platform = options.delete(:platform) || Gem::Platform::RUBY
        s.has_rdoc = options.delete(:has_rdoc) == nil ? false : true
        s.require_path = options.delete(:lib) || "lib"
        s.files = options.delete(:files) || (%w{Rakefile readme.md} + Dir.glob("{lib,spec}/**/*"))
        s.bindir = options.delete(:bin) if options.include? :bin

        s.version = options.delete(:version) || GemHelper.next_version(name)

        # s.name = options[:name)
        # s.author = options[:author)
        # s.homepage = options[:homepage)

        options.each{|k, v| s.send "#{k}=", v}    
      end

      Rake::GemPackageTask.new(spec) do |p|
        p.need_tar = true if RUBY_PLATFORM !~ /mswin/
        p.need_zip = true
        p.package_dir = package_dir
      end
    end
    
    def package_dir
      Dir.tmpdir + "/#{project[:official_name]}_tmp"
    end
  end
end

namespace :gem do
  task :ensure_gem do
    GemHelper.prepare_gem_metadata
  end
  
  task push: :ensure_gem do    
    gem_file = Dir.glob("#{GemHelper.package_dir}/#{project[:official_name]}*.gem").first
    system "gem push #{gem_file}"
  end

  task clean: :ensure_gem do
    GemHelper.prepare_gem_metadata
    system "rm -r #{GemHelper.package_dir}"
  end
  
  desc "Build and publish project as gem"  
  task release: [:ensure_gem, :gem, :push, :clean]
end