#
# Author:: Adam Jacob (<adam@opscode.com>)
# Author:: Christopher Brown (<cb@opscode.com>)
# Author:: Daniel DeLeo (<dan@opscode.com>)
# Copyright:: Copyright (c) 2009, 2011 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# 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 'forwardable'
require 'chef/platform/query_helpers'
require 'chef/knife/core/generic_presenter'
require 'tempfile'

class Chef
  class Knife

    #==Chef::Knife::UI
    # The User Interaction class used by knife.
    class UI

      extend Forwardable

      attr_reader :stdout
      attr_reader :stderr
      attr_reader :stdin
      attr_reader :config

      attr_reader :presenter

      def_delegator :@presenter, :format_list_for_display
      def_delegator :@presenter, :format_for_display
      def_delegator :@presenter, :format_cookbook_list_for_display

      def initialize(stdout, stderr, stdin, config)
        @stdout, @stderr, @stdin, @config = stdout, stderr, stdin, config
        @presenter = Chef::Knife::Core::GenericPresenter.new(self, config)
      end

      # Creates a new +presenter_class+ object and uses it to format structured
      # data for display. By default, a Chef::Knife::Core::GenericPresenter
      # object is used.
      def use_presenter(presenter_class)
        @presenter = presenter_class.new(self, config)
      end

      def highline
        @highline ||= begin
          require 'highline'
          HighLine.new
        end
      end

      # Prints a message to stdout. Aliased as +info+ for compatibility with
      # the logger API.
      def msg(message)
        begin
          stdout.puts message
        rescue Errno::EPIPE => e
          raise e if @config[:verbosity] >= 2
          exit 0
        end
      end

      alias :info :msg

      # Prints a msg to stderr. Used for warn, error, and fatal.
      def err(message)
        begin
          stderr.puts message
        rescue Errno::EPIPE => e
          raise e if @config[:verbosity] >= 2
          exit 0
        end
      end

      # Print a warning message
      def warn(message)
        err("#{color('WARNING:', :yellow, :bold)} #{message}")
      end

      # Print an error message
      def error(message)
        err("#{color('ERROR:', :red, :bold)} #{message}")
      end

      # Print a message describing a fatal error.
      def fatal(message)
        err("#{color('FATAL:', :red, :bold)} #{message}")
      end

      def color(string, *colors)
        if color?
          highline.color(string, *colors)
        else
          string
        end
      end

      # Should colored output be used? For output to a terminal, this is
      # determined by the value of `config[:color]`. When output is not to a
      # terminal, colored output is never used
      def color?
        Chef::Config[:color] && stdout.tty? && !Chef::Platform.windows?
      end

      def ask(*args, &block)
        highline.ask(*args, &block)
      end

      def list(*args)
        highline.list(*args)
      end

      # Formats +data+ using the configured presenter and outputs the result
      # via +msg+. Formatting can be customized by configuring a different
      # presenter. See +use_presenter+
      def output(data)
        msg @presenter.format(data)
      end

      # Determines if the output format is a data interchange format, i.e.,
      # JSON or YAML
      def interchange?
        @presenter.interchange?
      end

      def ask_question(question, opts={})
        question = question + "[#{opts[:default]}] " if opts[:default]

        if opts[:default] and config[:defaults]
          opts[:default]
        else
          stdout.print question
          a = stdin.readline.strip

          if opts[:default]
            a.empty? ? opts[:default] : a
          else
            a
          end
        end
      end

      def pretty_print(data)
        begin
          stdout.puts data
        rescue Errno::EPIPE => e
          raise e if @config[:verbosity] >= 2
          exit 0
        end
      end

      def edit_data(data, parse_output=true)
        output = Chef::JSONCompat.to_json_pretty(data)

        if (!config[:disable_editing])
          Tempfile.open([ 'knife-edit-', '.json' ]) do |tf|
            tf.sync = true
            tf.puts output
            tf.close
            raise "Please set EDITOR environment variable" unless system("#{config[:editor]} #{tf.path}")

            output = IO.read(tf.path)
          end
        end

        parse_output ? Chef::JSONCompat.from_json(output) : output
      end

      def edit_object(klass, name)
        object = klass.load(name)

        output = edit_data(object)

        # Only make the save if the user changed the object.
        #
        # Output JSON for the original (object) and edited (output), then parse
        # them without reconstituting the objects into real classes
        # (create_additions=false). Then, compare the resulting simple objects,
        # which will be Array/Hash/String/etc.
        #
        # We wouldn't have to do these shenanigans if all the editable objects
        # implemented to_hash, or if to_json against a hash returned a string
        # with stable key order.
        object_parsed_again = Chef::JSONCompat.from_json(Chef::JSONCompat.to_json(object), :create_additions => false)
        output_parsed_again = Chef::JSONCompat.from_json(Chef::JSONCompat.to_json(output), :create_additions => false)
        if object_parsed_again != output_parsed_again
          output.save
          self.msg("Saved #{output}")
        else
          self.msg("Object unchanged, not saving")
        end
        output(format_for_display(object)) if config[:print_after]
      end

      def confirm(question, append_instructions=true)
        return true if config[:yes]

        stdout.print question
        stdout.print "? (Y/N) " if append_instructions
        answer = stdin.readline
        answer.chomp!
        case answer
        when "Y", "y"
          true
        when "N", "n"
          self.msg("You said no, so I'm done here.")
          exit 3
        else
          self.msg("I have no idea what to do with #{answer}")
          self.msg("Just say Y or N, please.")
          confirm(question)
        end
      end

    end
  end
end
