<%
require 'delegate'
# Template for generate documents by Pandoc
class MarkupNode < SimpleDelegator
  def title
    s = super
    s = ".#{id.split(/\./).last}" if s.empty?
    "#{'#' * nesting_level} #{s} {##{url(id)}}"
  end

  def meta
    return '' if nesting_level == 0
    return '' if super[:skip_meta]

    hsh = {id: id}.merge(super)
    hsh.delete(:order_index)
    hsh.delete(:filename)
    hsh.delete(:parent)
    [].tap{|ary|
      ary << "Attribute | Value"
      ary << "--------- | -----"
      hsh.each{|k,v| ary << "#{k} | #{v}"}
    }.join("\n")
  end

  def body
    # links replacement
    txt = String.new(super)
    links.each{|l| txt.gsub! "[[#{l}]]", link(l)}
    # macro substitution
    macro.each{|m| txt.gsub! m.regex, m.substitution}
    txt
  end

  def link(ref)
    node = root.find{|n| n.id == ref}
    return "[#{ref}](#unknown)" unless node
    "[#{node.title}](##{url(ref)})"
  end

  def url(id)
    r = id.start_with?(/[[:digit:]]/) ? "p#{id}" : id
    r.downcase
     .gsub(/[^A-Za-z0-9]{1,}/, '-')
     .gsub(/^-/, '')
     .gsub(/-$/, '')
  end

  class Macro
    attr_reader :regex
    def initialize(regex, &substitution)
      @regex, @substitution = regex, substitution
    end

    def substitution
      @substitution.call()
    end
  end

  def macro
    [].tap do |ary|
      ary << Macro.new(/{{@@skip[\s\S]*?}}/, &Proc.new{ '' })
      ary << Macro.new("{{@@list}}", &Proc.new{list})
      ary << Macro.new("{{@@tree}}", &Proc.new{tree})
    end
  end

  def tree
    this_level = nesting_level + 1
    to_a.drop(1).inject([]) do |ary, n|
      lead_spaces = '   ' * (n.nesting_level - this_level)
      ary << "#{lead_spaces}* [#{n.title}](##{url(n.id)})"
    end.join("\n")
  end

  def list
    items.inject([]) do |ary, n|
      ary << "* [#{n.title}](##{url(n.id)})"
    end.join("\n")
  end
end
-%>
% <%= @object.title %>
% generated by Clerq on <%= Time.now.strftime('%B %e, %Y at %H:%M') %>
% pandoc template

<% for @node in @object.to_a.drop(1) -%>
<%   n = MarkupNode.new(@node) -%>
<%=  [n.title, n.meta, n.body].select{|t| !t.empty?}.join("\n\n") %>

<% end %>