#--###########################################################
# Copyright 2006, Ben Bleything <ben@bleything.net> and      #
# Patrick May <patrick@hexane.org>                           #
#                                                            #
# Distributed under the MIT license.                         #
##############################################################
#++
# See Plist::Emit.
module Plist
  # === Create a plist
  # You can dump an object to a plist in one of two ways:
  #
  # * <tt>Plist::Emit.dump(obj)</tt>
  # * <tt>obj.to_plist</tt>
  #   * This requires that you mixin the <tt>Plist::Emit</tt> module, which is already done for +Array+ and +Hash+.
  #
  # The following Ruby classes are converted into native plist types:
  #   Array, Bignum, Date, DateTime, Fixnum, Float, Hash, Integer, String, Symbol, Time, true, false
  # * +Array+ and +Hash+ are both recursive; their elements will be converted into plist nodes inside the <array> and <dict> containers (respectively).
  # * +IO+ (and its descendants) and +StringIO+ objects are read from and their contents placed in a <data> element.
  # * User classes may implement +to_plist_node+ to dictate how they should be serialized; otherwise the object will be passed to <tt>Marshal.dump</tt> and the result placed in a <data> element.
  #
  # For detailed usage instructions, refer to USAGE[link:files/docs/USAGE.html] and the methods documented below.
  module Emit
    # Helper method for injecting into classes.  Calls <tt>Plist::Emit.dump</tt> with +self+.
    def to_plist(envelope = true)
      return Plist::Emit.dump(self, envelope)
    end

    # Helper method for injecting into classes.  Calls <tt>Plist::Emit.save_plist</tt> with +self+.
    def save_plist(filename)
      Plist::Emit.save_plist(self, filename)
    end

    # The following Ruby classes are converted into native plist types:
    #   Array, Bignum, Date, DateTime, Fixnum, Float, Hash, Integer, String, Symbol, Time
    #
    # Write us (via RubyForge) if you think another class can be coerced safely into one of the expected plist classes.
    #
    # +IO+ and +StringIO+ objects are encoded and placed in <data> elements; other objects are <tt>Marshal.dump</tt>'ed unless they implement +to_plist_node+.
    #
    # The +envelope+ parameters dictates whether or not the resultant plist fragment is wrapped in the normal XML/plist header and footer.  Set it to false if you only want the fragment.
    def self.dump(obj, envelope = true)
      output = plist_node(obj)

      output = wrap(output) if envelope

      return output
    end

    # Writes the serialized object's plist to the specified filename.
    def self.save_plist(obj, filename)
      File.open(filename, 'wb') do |f|
        f.write(Plist::Emit.dump(obj))
      end
    end

    private
    def self.plist_node(element)
      output = ''

      if element.respond_to? :to_plist_node
        output << element.to_plist_node
      else
        case element
        when Array
          if element.empty?
            output << "<array/>\n"
          else
            output << tag('array') {
              element.collect {|e| plist_node(e)}
            }
          end
        when Hash
          if element.empty?
            output << "<dict/>\n"
          else
            inner_tags = []

            element.keys.sort.each do |k|
              v = element[k]
              inner_tags << tag('key', CGI::escapeHTML(k.to_s))
              inner_tags << plist_node(v)
            end

            output << tag('dict') {
              inner_tags
            }
          end
        when true, false
          output << "<#{element}/>\n"
        when Time
          output << tag('date', element.utc.strftime('%Y-%m-%dT%H:%M:%SZ'))
        when Date # also catches DateTime
          output << tag('date', element.strftime('%Y-%m-%dT%H:%M:%SZ'))
        when String, Symbol, Fixnum, Bignum, Integer, Float
          output << tag(element_type(element), CGI::escapeHTML(element.to_s))
        when IO, StringIO
          element.rewind
          contents = element.read
          # note that apple plists are wrapped at a different length then
          # what ruby's base64 wraps by default.
          # I used #encode64 instead of #b64encode (which allows a length arg)
          # because b64encode is b0rked and ignores the length arg.
          data = "\n"
          Base64::encode64(contents).gsub(/\s+/, '').scan(/.{1,68}/o) { data << $& << "\n" }
          output << tag('data', data)
        else
          output << comment( 'The <data> element below contains a Ruby object which has been serialized with Marshal.dump.' )
          data = "\n"
          Base64::encode64(Marshal.dump(element)).gsub(/\s+/, '').scan(/.{1,68}/o) { data << $& << "\n" }
          output << tag('data', data )
        end
      end

      return output
    end

    def self.comment(content)
      return "<!-- #{content} -->\n"
    end

    def self.tag(type, contents = '', &block)
      out = nil

      if block_given?
        out = IndentedString.new
        out << "<#{type}>"
        out.raise_indent

        out << block.call

        out.lower_indent
        out << "</#{type}>"
      else
        out = "<#{type}>#{contents.to_s}</#{type}>\n"
      end

      return out.to_s
    end

    def self.wrap(contents)
      output = ''

      output << '<?xml version="1.0" encoding="UTF-8"?>' + "\n"
      output << '<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">' + "\n"
      output << '<plist version="1.0">' + "\n"

      output << contents

      output << '</plist>' + "\n"

      return output
    end

    def self.element_type(item)
      return case item
        when String, Symbol;          'string'
        when Fixnum, Bignum, Integer; 'integer'
        when Float;                   'real'
        else
          raise "Don't know about this data type... something must be wrong!"
      end
    end
    private
    class IndentedString #:nodoc:
      attr_accessor :indent_string

      @@indent_level = 0

      def initialize(str = "\t")
        @indent_string = str
        @contents = ''
      end

      def to_s
        return @contents
      end

      def raise_indent
        @@indent_level += 1
      end

      def lower_indent
        @@indent_level -= 1 if @@indent_level > 0
      end

      def <<(val)
        if val.is_a? Array
          val.each do |f|
            self << f
          end
        else
          # if it's already indented, don't bother indenting further
          unless val =~ /\A#{@indent_string}/
            indent = @indent_string * @@indent_level

            @contents << val.gsub(/^/, indent)
          else
            @contents << val
          end

          # it already has a newline, don't add another
          @contents << "\n" unless val =~ /\n$/
        end
      end
    end
  end
end

# we need to add this so sorting hash keys works properly
class Symbol #:nodoc:
  def <=> (other)
    self.to_s <=> other.to_s
  end
end

class Array #:nodoc:
  include Plist::Emit
end

class Hash #:nodoc:
  include Plist::Emit
end
