module MasterView

  # Mixin services for directive implementation classes.
  # 
  # Subclasses of MasterView::DirectiveBase inherit this mixin.
  # 
  module DirectiveHelpers

    CRLF = "\r\n"

    # start of ERB which is evaluated but does not contribute content to the document
    ERB_EVAL_START = '<% '
    # end of ERB which is evaluated but does not contribute content to the document
    ERB_EVAL_END = ' -%>'

    # start of ERB whose evaluation results in content in the document
    ERB_CONTENT_START = '<%= '
    # end of ERB whose evaluation results in content in the document
    ERB_CONTENT_END = ' %>'

    ####OBSOLETE: SWEEP AND REMOVE
    ERB_START = ERB_EVAL_START #:nodoc:  #WAS: '<% '
    ERB_EVAL = ERB_CONTENT_START #:nodoc: #WAS: '<%= '
    ERB_END = ERB_CONTENT_END #:nodoc:  #WAS: ' %>'

    #convenience constants defined to allow priority to directives
    #higher priority (lower value) will be executed first in chain
    module DirectivePriorities
      Highest = 0
      UltraHigh = 0x3FFFFFFF/16
      VeryHigh =   0x3FFFFFFF/8
      High =   0x3FFFFFFF/4
      MediumHigh = 0x3FFFFFFF/3
      Medium = 0x3FFFFFFF/2
      MediumLow = (0x3FFFFFFF/3)*2
      Low =    (0x3FFFFFFF/4)*3
      VeryLow = (0x3FFFFFFF/8)*7
      UltraLow = (0x3FFFFFFF/16)*15
      Lowest = 0x3FFFFFFF 
    end

    # convert render_partial_name to file_name, ex foo/bar to foo/_bar.rhtml
    def render_partial_name_to_file_name(render_partial_name, default_extension)
      pathname = Pathname.for_path(render_partial_name)
      dir_pathname = pathname.dirname
      base = pathname.basename(pathname.extname).to_s
      filename = '_'+base
      filename += default_extension if default_extension
      path = (dir_pathname+filename).to_s
    end

    
    # find the last string that fully matches exactly the 
    # parent tags content string array
    # It looks for something that has been output as a unit in 
    # the array not a substring
    # returns the ref to the string which you can operate on 
    # using replace
    def find_last_in_parent(tag, full_string)
      ret = nil
      parent = tag.parent
      unless parent.nil?
        parent.content.reverse.each do |str|
          if str == full_string
            ret = str
            break
          end
        end
      end
      ret
    end

    # set the last occurence to empty string
    # returns true if found and set to empty string
    def delete_last_in_parent(tag, full_string)
      str = find_last_in_parent(tag, full_string)
      found = !str.nil?
      str.replace('') if found
      found
    end

    # find a hash value from inside a simple str containing a hash
    # non-evaling, looks for a :key => 'foo/bar' returning foo/bar string
    def find_string_val_in_string_hash(str, key_or_sym)
      key = key_or_sym.to_s
      m = str.match( Regexp.new( Regexp.escape(key)+"\s*=>\s*'([^']*)'" ) ) #try single quote
      m = str.match( Regexp.new( Regexp.escape(key)+"\s*=>\s*\"([^\"]*)\"" ) ) if m.nil? #try double quote
      return nil if m.nil?
      m[1]
    end

    #returns an array of args by parsing and evaling the str value passed in
    #uses evaling, so can't have any variables only simple strings, numbers, booleans
    def parse_eval_into_array(value)
      return [] if value.nil? || value.empty?
      val = value.strip
      args = []
      until val.empty?
        if val =~ /^[:'"%\[{&*]/ #starts with quote or ruby lang char
          v = nil
          val = '{'+val+'}' if val =~ /^:/ #starts with colon, assume hash so wrap with brackets
          eval 'v = '+ val #rest is all evaled
          if v.is_a? Array
            args += v
          else 
            args << v
          end
          break
        else
          unquoted_string = val.slice!( /^[^,]+/ ) #pull off everything up to a comma
          unquoted_string.strip!
          args.push unquoted_string
          val.slice!( /^,/ ) #strip off comma if exists
          val.strip!
        end
      end
      args
    end

    #returns a hash, for values that are not already part of hash it adds them using default_key
    #uses evaling so it cannot have any variables or non-simple types
    def parse_eval_into_hash(value, default_key)
      h = {}
      a = parse_eval_into_array(value)
      a.each do |v|
        if v.is_a?(Hash)
          h.merge!(v)
        else #it adds any additional non-hash args using default key, if key,val exists, it changes to array and appends
          prev = h[default_key]
          if prev.nil? #nil just add it
            h[default_key] = v
          elsif prev.is_a?(Array) #was array, concat
            h[default_key] = prev+v
          else #anything else, make it into array
            h[default_key] = [prev, v]
          end
        end
      end
      h
    end

    #parse into array of strings, containing the various arguments without evaling
    #looks for %q{}, %q[], hash, array, function call using (), values deliminated by commas,
    def parse(str)
      AttrStringParser.parse(str)
    end


    #remove any strings that were prepended to the hashes, typically these are overridden by other values, so 
    # we need to strip them off leaving only the hashes, returns a string with only hashes
    def remove_prepended_strings(full_string)
      return full_string if full_string.nil? || full_string.strip.empty?
      hashes = full_string.scan( /(\{?)\s*(\S+\s*=>.*)/ ).flatten
      hashes.join.strip
    end

    #merge hash_to_merge values into the hash contained in the full_string, hash_arg is zero based index of which
    #hash this needes to be merged to if there are multiple ones.
    def merge_into_embedded_hash(full_string, hash_arg, hash_to_merge)
      return full_string if hash_to_merge.empty? 
      full_string ||= ""
      sorted_hash_to_merge = hash_to_merge.sort { |a,b| a.to_s <=> b.to_s } #sort, remember the keys might be symbols so use to_s
      str_to_merge = sorted_hash_to_merge.collect{ |h,v| "#{h.inspect} => #{v.inspect}" }.join(', ')

      hashes = full_string.scan( /(\{?[^{}]+=>[^{}]+\}?)\s*,?\s*/ ).flatten
      hash_str = hashes[hash_arg] #be careful to use methods to update string in place or else put back in hash

      if hash_str.nil? 
        hashes.each do |v| #make sure each prior hash has brackets, since we are adding a hash
          unless v.index '}'
            v.insert(0, '{')
            v.insert(-1, '}')
          end
        end
        hashes[hash_arg] = hash_str = ""
      end

      closing_brack = hash_str.index '}'
      if closing_brack
        hash_str.insert(closing_brack, ', '+str_to_merge)
      else
        hash_str << ', ' unless hash_str.empty?
        hash_str << str_to_merge
      end
      
      hashes.join(', ')
    end

    #return attributes with lowercase keys
    def lowercase_attribute_keys(attributes)
      lcattrs = {}
      attributes.each { |k,v| lcattrs[k.downcase] = v }
      lcattrs
    end

    #return attributes with lowercase keys and values
    def lowercase_attribute_keys_and_values(attributes)
      lcattrs = {}
      attributes.each { |k,v| lcattrs[k.downcase] = v.downcase }
      lcattrs
    end

    # using hash, symbolize keys, sort keys, serialize to string
    def symbolize_sort_and_serialize_hash_to_str(hash)
      symbolized = {}
      hash.each{ |k,v| symbolized[k.to_sym] = v } #symbolize
      sorted = symbolized.sort{ |a,b| a[0].to_s <=> b[0].to_s } # sort the keys
      sorted_strings = sorted.collect{ |k,v| "#{k.inspect} => '#{v}'"} # create strings
      sorted_strings.join(', ') # finally combine them
    end

  end

end