# Blatantly stole this from Chef
class TemplateError < RuntimeError
  attr_reader :original_exception, :context
  SOURCE_CONTEXT_WINDOW = 2 unless defined? SOURCE_CONTEXT_WINDOW
  
  def initialize(original_exception, template, context)
    @original_exception, @template, @context = original_exception, template, context
  end
  
  def message
    @original_exception.message
  end
  
  def line_number
    @line_number ||= $1.to_i if original_exception.backtrace.find {|line| line =~ /\(erubis\):(\d+)/ }
  end
  
  def source_location
    "on line ##{line_number}"
  end
  
  def source_listing
		return nil if line_number.nil?
		
    @source_listing ||= begin
      line_index = line_number - 1
      beginning_line = line_index <= SOURCE_CONTEXT_WINDOW ? 0 : line_index - SOURCE_CONTEXT_WINDOW
      source_size = SOURCE_CONTEXT_WINDOW * 2 + 1
      lines = @template.split(/\n/)
      contextual_lines = lines[beginning_line, source_size]
      output = []
      contextual_lines.each_with_index do |line, index|
        line_number = (index+beginning_line+1).to_s.rjust(3)
        output << "#{line_number}: #{line}"
      end
      output.join("\n")
    end
  end
  
  def to_s
    "\n\n#{self.class} (#{message}) #{source_location}:\n\n" +
      "#{source_listing}\n\n  #{original_exception.backtrace.join("\n  ")}\n\n"
  end
end

module Sprinkle
  module Installers
    # Beware, another strange "installer" coming your way.
    #
    # = File transfer installer
    #
    # This installer pushes files from the local disk to remote servers.
    # 
    # == Example Usage
    #
    # Installing a nginx.conf onto remote servers
    #
    #   package :nginx_conf do
    #     transfer 'files/nginx.conf', '/etc/nginx.conf'
    #   end
    #
    # If you user has access to 'sudo' and theres a file that requires
    # priveledges, you can pass :sudo => true 
    #
    #   package :nginx_conf do
    #     transfer 'files/nginx.conf', '/etc/nginx.conf', :sudo => true
    #   end
    #
		# By default, transfers are recursive and you can move whole directories
		# via this method. If you wish to disable recursive transfers, you can pass
		# recursive => false, although it will not be obeyed when using the Vlad actor.
    #
		# If you pass the option :render => true, this tells transfer that the source file
		# is an ERB template to be rendered locally before being transferred (you can declare
		# variables in the package scope). When render is true, recursive is turned off.
		#   
		#   package :nginx_conf do
		#     nginx_port = 8080
		#     transfer 'files/nginx.conf', '/etc/nginx.conf', :render => true
		#   end
		#
		# Finally, should you need to run commands before or after the file transfer (making
		# directories or changing permissions), you can use the pre/post :install directives
		# and they will be run.
    class Transfer < Installer
      attr_accessor :source, :destination #:nodoc:

      def initialize(parent, source, destination, options={}, &block) #:nodoc:
        super parent, options, &block
        @source = source
        @destination = destination
      end

			def install_commands
				nil
			end
			
			def self.render_template(template, context, prefix)
				require 'tempfile'
				require 'erubis'

				begin
          eruby = Erubis::Eruby.new(template)
          output = eruby.result(context)
        rescue Object => e
          raise TemplateError.new(e, template, context)
        end

        final_tempfile = Tempfile.new(prefix)
        final_tempfile.print(output)
        final_tempfile.close
				final_tempfile
			end
			
			def render_template(template, context, prefix)
				self.class.render_template(template, context, prefix)
			end
			
			def render_template_file(path, context, prefix)
				template = File.read(path)
				tempfile = render_template(template, binding(), @package.name)
				tempfile
			end
			
      def process(roles) #:nodoc:
        assert_delivery

        if logger.debug?
          logger.debug "transfer: #{@source} -> #{@destination} for roles: #{roles}\n"
        end

        unless Sprinkle::OPTIONS[:testing]
					pre = pre_commands(:install)
					unless pre.empty?
						sequence = pre; sequence = sequence.join('; ') if sequence.is_a? Array
						logger.info "#{@package.name} pre-transfer commands: #{sequence} for roles: #{roles}\n"
						@delivery.process @package.name, sequence, roles
					end
					
					recursive = @options[:recursive]
					
					if options[:render] 
						tempfile = render_template_file(@source, binding(), @package.name)
						sourcepath = tempfile.path
						logger.info "Rendering template #{@source} to temporary file #{sourcepath}"
						recursive = false
					else
						sourcepath = @source
					end
					
					logger.info "--> Transferring #{sourcepath} to #{@destination} for roles: #{roles}"
          @delivery.transfer(@package.name, sourcepath, @destination, roles, recursive)
					
					post = post_commands(:install)
					unless post.empty?
						sequence = post; sequence = sequence.join('; ') if sequence.is_a? Array
						logger.info "#{@package.name} post-transfer commands: #{sequence} for roles: #{roles}\n"
						@delivery.process @package.name, sequence, roles
					end
        end
      end
    end
  end
end