require 'expression_parser'
require 'uri'

module WikiCloth

class WikiBuffer::Var < WikiBuffer

  def initialize(data="",options={})
    super(data,options)
    self.buffer_type = "var"
    @in_quotes = false
    @tag_start = true
    @tag_size = 2
    @close_size = 2
    @fname = nil
  end

  def tag_size
    @tag_size
  end

  def tag_size=(val)
    @tag_size = val
  end

  def skip_links?
    true
  end

  def skip_html?
    false
  end

  def tag_start
    @tag_start
  end

  def tag_start=(val)
    @tag_start = val
  end

  def function_name
    @fname
  end

  def to_s
    if self.is_function?
      ret = default_functions(function_name,params.collect { |p| p.strip })
      ret ||= @options[:link_handler].function(function_name, params.collect { |p| p.strip })
      ret.to_s
    elsif self.is_param?
      ret = nil
      @options[:buffer].buffers.reverse.each do |b|
        ret = b.get_param(params[0].downcase,params[1]) if b.instance_of?(WikiBuffer::HTMLElement) && b.element_name == "template"
      end
      ret.to_s
    else
      # put template at beginning of buffer
      template_stack = @options[:buffer].buffers.collect { |b| b.get_param("__name") if b.instance_of?(WikiBuffer::HTMLElement) && 
        b.element_name == "template" }.compact
      if template_stack.last == params[0]
        debug_tree = @options[:buffer].buffers.collect { |b| b.debug }.join("-->")
        "<span class=\"error\">Template loop detected: &#123;&#123;#{debug_tree}&#125;&#125;</span>"
      else
        ret = @options[:link_handler].include_resource("#{params[0]}".strip,params[1..-1]).to_s
        ret.gsub!(/<!--(.|\s)*?-->/,"")
        count = 0
        tag_attr = self.params[1..-1].collect { |p|
          if p.instance_of?(Hash)
            "#{p[:name].downcase}=\"#{p[:value]}\""
          else
            count += 1
            "#{count}=\"#{p}\""
          end
        }.join(" ")
        self.data = ret.blank? ? "" : "<template __name=\"#{params[0]}\" #{tag_attr}>#{ret}</template>"
        ""
      end
    end
  end

  def default_functions(name,params)
    case name
    when "#if"
      params.first.blank? ? params[2] : params[1]
    when "#switch"
      match = params.first
      default = nil
      for p in params[1..-1]
        temp = p.split("=")
        if temp.length == 1 && p == params.last
          return p
        elsif temp.instance_of?(Array) && temp.length > 1
          test = temp.first.strip
          default = temp[1].strip if test == "#default"
          return temp[1].strip if test == match
        end
      end
      default.nil? ? "" : default
    when "#expr"
      begin
        ExpressionParser::Parser.new.parse(params.first)
      rescue RuntimeError
        "Expression error: #{$!}"
      end
    when "#ifexpr"
      val = false
      begin
        val = ExpressionParser::Parser.new.parse(params.first)
      rescue RuntimeError
      end
      if val
        params[1]
      else
        params[2]
      end
    when "#ifeq"
      if params[0] =~ /^[0-9A-Fa-f]+$/ && params[1] =~ /^[0-9A-Fa-f]+$/
        params[0].to_i == params[1].to_i ? params[2] : params[3]
      else
        params[0] == params[1] ? params[2] : params[3]
      end
    when "#len"
      params.first.length
    when "#sub"
      params.first[params[1].to_i,params[2].to_i]
    when "#pad"
      case params[3]
      when "right"
        params[0].ljust(params[1].to_i,params[2])
      when "center"
        params[0].center(params[1].to_i,params[2])
      else
        params[0].rjust(params[1].to_i,params[2])
      end
    when "#iferror"
      params.first =~ /error/ ? params[1] : params[2]
    when "#capture"
      @options[:params][params.first] = params[1]
      ""
    when "urlencode"
      URI.escape(params.first, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
    when "lc"
      params.first.downcase
    when "uc"
      params.first.upcase
    when "ucfirst"
      params.first.capitalize
    when "lcfirst"
      params.first[0,1].downcase + params.first[1,-1]
    when "plural"
      params.first.to_i > 1 ? params[1] : params[2]
    when "ns"
      values = { "" => "", "0" => "", "1" => "Talk", "talk" => "Talk", "2" => "User", "user" => "User",
	"3" => "User talk", "user_talk" => "User talk", "4" => "Meta", "project" => "Meta",
	"5" => "Meta talk", "project_talk" => "Meta talk", "6" => "File", "image" => "File",
	"7" => "File talk", "image_talk" => "File talk", "8" => "MediaWiki", "mediawiki" => "MediaWiki",
	"9" => "MediaWiki talk", "mediawiki_talk" => "MediaWiki talk", "10" => "Template",
	"template" => "Template", "11" => "Template talk", "template_talk" => "Template talk",
	"12" => "Help", "help" => "Help", "13" => "Help talk", "help_talk" => "Help talk",
	"14" => "Category", "category" => "Category", "15" => "Category talk", "category_talk" => "Category talk",
	"-2" => "Media", "media" => "Media", "-1" => "Special", "special" => "Special" }
      values[params.first.gsub(/\s+/,'_').downcase]
    when "debug"
      ret = nil
      case params.first
      when "param"
        @options[:buffer].buffers.reverse.each do |b|
          if b.instance_of?(WikiBuffer::HTMLElement) && b.element_name == "template"
             ret = b.get_param(params[1])
          end
        end
        ret
      when "buffer"
        ret = "<pre>"
        buffer = @options[:buffer].buffers
        buffer.each do |b|
          ret += " --- #{b.class}"
          ret += b.instance_of?(WikiBuffer::HTMLElement) ? " -- #{b.element_name}\n" : " -- #{b.data}\n"
        end
        "#{ret}</pre>"
      end
    end
  end

  def is_param?
    @tag_size == 3 ? true : false
  end

  def is_function?
    self.function_name.nil? || self.function_name.blank? ? false : true
  end

  protected
  def function_name=(val)
    @fname = val
  end

  def new_char()
    case
    when current_char == '|' && @in_quotes == false
      self.current_param = self.data
      self.data = ""
      self.params << ""

    # Start of either a function or a namespace change
    when current_char == ':' && @in_quotes == false && self.params.size <= 1
      self.function_name = self.data
      self.data = ""

    # Dealing with variable names within functions
    # and variables
    when current_char == '=' && @in_quotes == false && !is_function?
      self.current_param = self.data
      self.data = ""
      self.name_current_param()

    # End of a template, variable, or function
    when current_char == '}' && previous_char == '}'
      if @close_size == @tag_size
        self.data.chop!
        self.current_param = self.data
        self.data = ""
        return false
      else
        @close_size += 1
      end

    else
      self.data += current_char
      if @tag_start
        # FIXME: template params and templates colliding
        if @tag_size > 3
          if @tag_size == 5
            @options[:buffer].buffers << WikiBuffer::Var.new(self.data,@options)
            @options[:buffer].buffers[-1].tag_start = false
            self.data = ""
            @tag_size = 3
            return true
          end
        end
        @tag_start = false
      end
    end

    return true
  end

end

end