# encoding: utf-8
require 'fedux_org_stdlib/plugins/no_plugin'
require 'fedux_org_stdlib/plugins/plugin'

module FeduxOrgStdlib
  module Plugins
    # Plugin Manager
    # 
    # Make sure you've got a class method `.plugin_prefix` on your main module
    #
    # @example
    #    # main module
    #    module FeduxOrgStdlib
    #      @plugin_manager = PluginManager.new
    #      @plugin_prefix  = Regexp.new("^#{self.name.downcase.underscore}-")
    #  
    #      class << self
    #        attr_reader :plugin_prefix, :plugin_manager
    #      end
    #    end
    class PluginManager
      private

      attr_reader :plugins

      public

      def initialize(plugins: [])
        @plugins = plugins
      end

      # Find all installed plugins and store them in an internal array.
      def locate_plugins
        Gem.refresh

        (Gem::Specification.respond_to?(:each) ? Gem::Specification : Gem.source_index.find_name('')).each do |gem|
          next if gem.name !~ self.class.deconstantize.plugin_prefix

          plugin_name = gem.name.split('-', 2).last
          @plugins << Plugin.new(plugin_name, gem.name, gem, true) if !gem_located?(gem.name)
        end

        @plugins
      end

      # @return [Hash] A hash with all plugin names (minus the '<prefix>-') as
      #   keys and Plugin objects as values.
      def plugins
        h = Hash.new { |_, key| NoPlugin.new(key) }

        @plugins.each do |plugin|
          h[plugin.name] = plugin
        end

        h
      end

      # Require all enabled plugins, disabled plugins are skipped.
      def load_plugins
        @plugins.each do |plugin|
          plugin.activate! if plugin.enabled?
        end
      end

      private

      def gem_located?(gem_name)
        @plugins.any? { |plugin| plugin.gem_name == gem_name }
      end
    end
  end
end