module BBCode

# File lib/bbcode-rails.rb, line 12
def self.get_tag_by_name name
  if defined?(Rails) && Rails.env.development?
    begin
      "#{name}_tag".camelize.constantize
    rescue NameError
    end
  end
  @tags["#{name.to_s.downcase}tag"]
end

# File lib/bbcode-rails.rb, line 22
def self.parse str, raise_error=false
  str = str.dup

  str.gsub!('&', '&')
  str.gsub!('<', '&lt;')
  str.gsub!('>', '&gt;')
  str.gsub!('"', '&quot;')
  str.gsub!("'", '&apos;')

  # Let's iterate over the pieces to build a tree
  # It works like this:
  # For each object you have two things:
  #   1. It is a tag name a la [img]
  #   2. It is a simple string, something like 'Hello'
  #
  # Now, we want a tree that looks like this
  #
  # -> |
  #    | ImgTag src: http://adada
  #    | String This cat
  #    | BTag is -> |
  #                 | ITag funny!
  # In the end we just recursively append

  result = []

  tag_open          = /\[/
  tag_close         = /\]/
  tag_close_prefix  = /\//
  tag_arg           = /=/
  tag_arg_delim     = /&quot;/
  tag_name          = /[-_a-z0-9]/

  current_state = :text
  current_tag = result

  begin
    pos = 0
    while pos < str.length
      case current_state
      when :text
        tmp = ""
        # We iterate through the string either until the end or if we find a [
        while not str[pos] =~ tag_open and pos < str.length
          tmp << str[pos]
          pos = pos.next
        end
        current_tag << tmp
        current_state = :tag_name if pos < str.length # Okay, we have found the beginning of a possible tag!
        pos = pos.next
      when :tag_name
        name = ""
        if str[pos-1] =~ tag_open and str[pos] =~ tag_close_prefix
          # It's a closing tag!
          # Let's check if it applies to our current tag..

          broke_out = false
          tag = current_tag
          until tag.is_a? Array
            len = tag.name.length
            if str[pos+1,len] == tag.name and str[pos+len+1] =~ tag_close
              # If it's the current one?
              if current_tag == tag
                current_tag = tag.parent
                pos += len+1
                broke_out = true
                break
              else
                # It's not the current one! Invalid construct
                raise BBCode::ParseError, "Invalid nested tags"
              end
            end
            tag = tag.parent
          end

          # It's not a closing tag we recognize, so it's text really!
          # Let's restore this!
          if not broke_out
            current_tag << "[/"
          end
          current_state = :text
          pos = pos.next
          next
        end
        while not (str[pos] =~ tag_close and str[pos] =~ tag_arg and pos < str.length) and str[pos] =~ tag_name
          name << str[pos]
          pos = pos.next
        end

        if str[pos] =~ tag_arg or str[pos] =~ tag_close
          if self.get_tag_by_name(name)
            new_tag = self.get_tag_by_name(name).new(current_tag)
            current_tag  << new_tag
            if new_tag.has_option(:content) or new_tag.has_option(:argument)
              current_tag = new_tag
            end
            if str[pos] =~ tag_arg
              if new_tag.has_option :argument
                current_state = :tag_arg
              else
                raise BBCode::ParseError
              end
            else
              current_state = :text
            end
            pos = pos.next
          else
            current_tag << "[#{name}"
            current_state = :text
          end
          next
        end


        # Did we hit the end? Let's get out
        current_tag << name
        current_state = :text
      when :tag_arg
        arg = ""
        while not str[pos] =~ tag_close and pos < str.length
          arg << str[pos]
          pos = pos.next
        end

        current_tag.argument = arg.gsub(/^#{tag_arg_delim}(.*)#{tag_arg_delim}$/, '\1')
        if not current_tag.has_option(:content)
          current_tag = current_tag.parent
        end
        current_state = :text
        pos = pos.next
      else
        pos = pos.next
      end
    end

    result_str = result.map(&:to_s).join('').strip

    # extracted from bb-ruby, which extracted it from Rails ActionPack
    start_tag = '<p>'
    result_str.gsub!(/\r\n?/, "\n")                   # \r\n and \r => \n
    result_str.gsub!(/\n\n+/, "</p>\n\n#{start_tag}") # 2+ newline  => paragraph
    #result_str.gsub!(/([^\n>]\n)(?=[^\n<])/, '\1<br>')# 1 newline   => br
    result_str.insert 0, start_tag
    result_str << '</p>'
  rescue BBCode::ParseError => e
    if raise_error
      raise e
    else
      str
    end
  end
end

# File lib/bbcode-rails.rb, line 8
def self.tags
  @tags
end