require "log4r"

module Vagrant
  module Plugin
    module V2
      # This class maintains a list of all the registered plugins as well
      # as provides methods that allow querying all registered components of
      # those plugins as a single unit.
      class Manager
        attr_reader :registered
        attr_reader :required

        def initialize
          @logger = Log4r::Logger.new("vagrant::plugin::v2::manager")
          @registered = []
          @required = []
        end

        # This returns all the action hooks.
        #
        # @return [Array]
        def action_hooks(hook_name)
          result = []

          @registered.each do |plugin|
            result += plugin.components.action_hooks[Plugin::ALL_ACTIONS]
            result += plugin.components.action_hooks[hook_name]
          end

          result
        end

        # This returns all the registered commands.
        #
        # @return [Hash]
        def commands
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.command)
            end
          end
        end

        # This returns all the registered communicators.
        #
        # @return [Hash]
        def communicators
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.communicator)
            end
          end
        end

        # This returns all the registered configuration classes.
        #
        # @return [Hash]
        def config
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.components.configs[:top])
            end
          end
        end

        # This returns all the registered guests.
        #
        # @return [Hash]
        def guests
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.components.guests)
            end
          end
        end

        # This returns all the registered guest capabilities.
        #
        # @return [Hash]
        def guest_capabilities
          results = Hash.new { |h, k| h[k] = Registry.new }

          @registered.each do |plugin|
            plugin.components.guest_capabilities.each do |guest, caps|
              results[guest].merge!(caps)
            end
          end

          results
        end

        # This returns all registered host classes.
        #
        # @return [Hash]
        def hosts
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.host)
            end
          end
        end

        # This returns all registered providers.
        #
        # @return [Hash]
        def providers
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.components.providers)
            end
          end
        end

        # This returns all the config classes for the various providers.
        #
        # @return [Hash]
        def provider_configs
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.components.configs[:provider])
            end
          end
        end

        # This returns all the config classes for the various provisioners.
        #
        # @return [Registry]
        def provisioner_configs
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.components.configs[:provisioner])
            end
          end
        end

        # This returns all registered provisioners.
        #
        # @return [Hash]
        def provisioners
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.provisioner)
            end
          end
        end

        # This returns all synced folder implementations.
        #
        # @return [Registry]
        def synced_folders
          Registry.new.tap do |result|
            @registered.each do |plugin|
              result.merge!(plugin.components.synced_folders)
            end
          end
        end

        # This registers a plugin. This should _NEVER_ be called by the public
        # and should only be called from within Vagrant. Vagrant will
        # automatically register V2 plugins when a name is set on the
        # plugin.
        def register(plugin)
          if !@registered.include?(plugin)
            @logger.info("Registered plugin: #{plugin.name}")
            @registered << plugin
          end
        end

        # This registers a required plugin. This should _NEVER_ be called by
        # the public and should only be called from within Vagrant.
        def plugin_required(gem_name)
          if !@required.include?(gem_name)
            @logger.info("Registered required plugin: #{gem_name}")
            @required << gem_name
          end
        end

        # This clears out all the registered plugins. This is only used by
        # unit tests and should not be called directly.
        def reset!
          @registered.clear
          @required.clear
        end

        # This unregisters a plugin so that its components will no longer
        # be used. Note that this should only be used for testing purposes.
        def unregister(plugin)
          if @registered.include?(plugin)
            @logger.info("Unregistered: #{plugin.name}")
            @registered.delete(plugin)
          end
        end
      end
    end
  end
end
