# -*- encoding: utf-8 -*-
#
# Author:: Fletcher Nichol (<fnichol@nichol.ca>)
#
# Copyright (C) 2013, Fletcher Nichol
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

require "kitchen/command"
require "kitchen/diagnostic"

require "yaml"

module Kitchen

  module Command

    # Command to log into to instance.
    #
    # @author Fletcher Nichol <fnichol@nichol.ca>
    class Diagnose < Kitchen::Command::Base

      # Invoke the command.
      def call
        instances = record_failure { load_instances }

        loader = record_failure { load_loader }

        puts Kitchen::Diagnostic.new(
          :loader => loader, :instances => instances).read.to_yaml
      end

      private

      # Loads and returns instances if they are requested.
      #
      # @return [Array<Instance>] an array of instances or an empty array
      # @api private
      def load_instances
        if options[:all] || options[:instances]
          parse_subcommand(args.first)
        else
          []
        end
      end

      # Loads and returns loader configuration if it is requested.
      #
      # @return [Hash,nil] a hash or nil
      # @api private
      def load_loader
        if options[:all] || options[:loader]
          @loader
        else
          nil
        end
      end

      # Returns a hash with exception detail if an exception is raised in the
      # yielded block.
      #
      # @return [yield,Hash] the result of the yielded block or an error hash
      # @api private
      def record_failure
        yield
      rescue => e
        {
          :error => {
            :exception => e.inspect,
            :message => e.message,
            :backtrace => e.backtrace
          }
        }
      end
    end
  end
end