require 'optparse'
require 'erb'
require 'redcloth'
require 'maruku'
require 'logger'
require 'fileutils'
require 'ftools'
require 'hpricot'
require 'uv'


module Slideshow

class Params
  
  def initialize( name, headers )
      @svgname =  "#{name}.svg"
      @cssname =  "#{name}.css"
      @headers =  headers
  end
    
  def params_binding
      binding
  end

end

def Slideshow.cache_dir
    PLATFORM =~ /win32/ ? win32_cache_dir : File.join(File.expand_path("~"), ".slideshow")
end

def Slideshow.win32_cache_dir
    unless File.exists?(home = ENV['HOMEDRIVE'] + ENV['HOMEPATH'])
      puts "No HOMEDRIVE or HOMEPATH environment variable.  Set one to save a" +
           "local cache of stylesheets for syntax highlighting and more."
      return false
    else
      return File.join(home, 'slideshow')
    end
end

def Slideshow.load_template( name )

  templatesdir = "#{File.dirname(__FILE__)}/templates"
  logger.debug "templatesdir=#{templatesdir}"

  File.read( "#{templatesdir}/#{name}" )
end

def Slideshow.render_template( content, b=TOPLEVEL_BINDING )
  ERB.new( content ).result( b )
end


def Slideshow.create_slideshow( fn )

  if get_boolean_option( 's5', false )
    headerdoc   = load_template( 's5/header.html.erb' )
    footerdoc   = load_template( 's5/footer.html.erb' )
    styledoc    = load_template( 's5/style.css.erb' )
  else
    headerdoc   = load_template( 'header.html.erb' )
    footerdoc   = load_template( 'footer.html.erb' )
    styledoc    = load_template( 'style.css.erb' )    
  end
  
  # background theming shared between s5/s9
  gradientdoc = load_template( 'gradient.svg.erb' )

  basename = File.basename( fn, '.*' )
  extname  = File.extname( fn )

  known_textile_extnames = [ '.textile', '.t' ]
  known_markdown_extnames =  [ '.markdown', '.mark', '.m', '.txt', '.text' ]
  known_extnames = known_textile_extnames + known_markdown_extnames
                
  if extname.eql?("") then
    extname  = ".textile"   # default to .textile 
    
    known_extnames.each { |e|
       logger.debug "File.exists? #{basename}#{e}"
       if File.exists?( "#{basename}#{e}" ) then         
          extname = e
          logger.debug "extname=#{extname}"
          break
       end
    }     
  end

  inname  =  "#{basename}#{extname}"
  outname =  "#{basename}.html"
  svgname =  "#{basename}.svg"
  cssname =  "#{basename}.css"

  logger.debug "inname=#{inname}"
  
  content = File.read( inname )
  
  # read source document
  # strip leading optional headers (key/value pairs) including optional empty lines

  read_headers = true
  content = ""

  File.open( inname ).readlines.each do |line|
    if read_headers && line =~ /^\s*(\w[\w-]*)[ \t]*:[ \t]*(.*)/
      key = $1.downcase
      value = $2.strip
    
      logger.debug "  adding option: key=>#{key}< value=>#{value}<"
      store_option( key, value )
    elsif line =~ /^\s*$/
      content << line  unless read_headers
    else
      read_headers =false
      content << line
    end
  end

  # run pre-filters (built-in macros)
  # o replace {{{  w/ <pre class='code'>
  # o replace }}}  w/ </pre>
  content.gsub!( "{{{{{{", "<pre class='code'>_S9BEGIN_" )
  content.gsub!( "}}}}}}", "_S9END_</pre>" )  
  content.gsub!( "{{{", "<pre class='code'>" )
  content.gsub!( "}}}", "</pre>" )
  # restore escaped {{{}}} I'm sure there's a better way! Rubyize this! Anyone?
  content.gsub!( "_S9BEGIN_", "{{{" )
  content.gsub!( "_S9END_", "}}}" )

  set_default_options()
  params = Params.new( basename, $options )

  puts "Preparing slideshow theme '#{svgname}'..."
  
  out = File.new( svgname, "w+" )
  out << render_template( gradientdoc, params.params_binding )
  out.flush
  out.close 
  
  puts "Preparing slideshow '#{outname}'..."

  # convert light-weight markup to hypertext
  
  if known_markdown_extnames.include?( extname )
    content = Maruku.new( content, {:on_error => :raise} ).to_html
    # old code: content = BlueCloth.new( content ).to_html
  else
    content = RedCloth.new( content ).to_html
  end
  

  # post-processing

  slide_counter = 0
  content2 = ''
  
  # wrap h1's in slide divs; note use just <h1 since some processors add ids e.g. <h1 id='x'>
  content.each_line { |line|
     if line.include?( '<h1' ) then
        content2 << "\n\n</div>"  if slide_counter > 0
        content2 << "<div class='slide'>\n\n"
        slide_counter += 1
     end
     content2 << line
  }
  content2 << "\n\n</div>"   if slide_counter > 0

  ## todo: run syntax highlighting before markup/textilize? lets us add textile to highlighted code?
  ##  avoid undoing escaped entities?
  
  include_code_stylesheet = false
  # syntax highlight code
  # todo: can the code handle escaped entities? e.g. &gt; 
  doc = Hpricot(content2)
    doc.search("pre.code, pre > code").each do |e|
      if e.inner_html =~ /^\s*#!(\w+)/
        lang = $1.downcase
        if e.inner_html =~ /^\{\{\{/  # {{{ assumes escape/literal #!lang 
          # do nothing; next
          logger.debug "  skipping syntax highlighting using lang=#{lang}; assumimg escaped literal"
        else         
          logger.debug "  syntax highlighting using lang=#{lang}"
          if Uv.syntaxes.include?(lang)
            code = e.inner_html.sub(/^\s*#!\w+/, '').strip
            
            code.gsub!( "&lt;", "<" )
            code.gsub!( "&gt;", ">" )
            code.gsub!( "&amp;", "&" )
            # todo: missing any other entities? use CGI::unescapeHTML?
            logger.debug "code=>#{code}<"
            
            # get options using headers
            code_line_numbers = get_boolean_option( 'code-line-numbers', true )
            code_theme        = get_option( 'code-theme', 'amy' )
            code_highlighted = Uv.parse( code, "xhtml", lang, code_line_numbers, code_theme )
            # old code: e.inner_html = code_highlighted
            # todo: is it ok to replace the pre.code enclosing element to avoid duplicates?
            e.swap( code_highlighted )
            include_code_stylesheet = true
          end
        end
      end
    end

   content2 = doc.to_s


  out = File.new( outname, "w+" )
  out << render_template( headerdoc, params.params_binding )
  out << content2 
  out << render_template( footerdoc, params.params_binding )
  out.flush
  out.close

  puts "Preparing slideshow stylesheet '#{cssname}'..."

  out = File.new( cssname, "w+" )
  out << render_template( styledoc, params.params_binding )
  
  if include_code_stylesheet
     logger.debug "cache_dir=#{cache_dir}"

     FileUtils.mkdir(cache_dir) unless File.exists?(cache_dir) if cache_dir
     Uv.copy_files "xhtml", cache_dir

     theme = get_option( 'code-theme', 'amy' )
  
     theme_content = File.read( "#{cache_dir}/css/#{theme}.css" )
     
     out << "/* styles for code syntax highlighting theme '#{theme}' */\n"
     out << "\n"
     out << theme_content
  end
  
  out.flush
  out.close

  # copy s5 machinery to s5 folder
  
  if get_boolean_option( 's5', false )
    # todo/fix: is there a better way to check if the dir exists?
    Dir.mkdir( 's5' ) unless File.directory?( 's5' )
  
    [ 'opera.css', 'outline.css', 'print.css', 's5-core.css', 'slides.js' ].each do |name|

      source = "#{File.dirname(__FILE__)}/templates/s5/#{name}"
      dest   = "s5/#{name}"
        
      logger.debug "copying '#{source} ' to '#{dest}'"     
      File.copy( source, dest )
    end
  end

  puts "Done."
end

def Slideshow.logger 
   if @@logger.nil?
      @@logger = Logger.new(STDOUT)
   end
   @@logger
end


def Slideshow.set_default_options()
  defaults =
  [
    [ 'title',             'Untitled Slide Show' ],
    [ 'gradient-theme',    'dark' ],
    [ 'gradient-color1',   'red' ],
    [ 'gradient-color2',   'black' ],
    [ 'code-theme',        'amy' ],
    [ 'code-line-numbers', 'true' ]
  ]
  
  defaults.each do | item |
     key   = item[0]
     value = item[1]
     $options[ key ] = value if $options[ key ].nil?
  end
end

def Slideshow.store_option( key, value )
  key = key.downcase
  if key.eql? 'code-theme' then
    $options[ 'code-theme' ] = value.tr( '-', '_' )
  elsif key.eql? 'gradient' then
    values = value.split( ' ' )
    $options[ 'gradient-theme'  ] = values[0].tr( '-', '_' )
    $options[ 'gradient-color1' ] = values[1] if values[1] 
    $options[ 'gradient-color2' ] = values[2] if values[2]
  elsif key.eql? 'gradient-colors' then
    values = value.split( ' ' )
    $options[ 'gradient-color1' ] = values[0] 
    $options[ 'gradient-color2' ] = values[1] if values[1]
  elsif key.eql? 'gradient-color' then
    $options[ 'gradient-color1' ] = value
  elsif key.eql? 'gradient-theme' then
    $options[ 'gradient-theme' ] = value.tr( '-', '_' )
  else
    $options[ key ] = value
  end
end

def Slideshow.get_option( key, default )
   value = $options[ key ]
   value.nil? ? default : value
end

def Slideshow.get_boolean_option( key, default )
   value = $options[ key ]
   if value.nil?
      default
   else
      if( value == true || value.downcase == 'true' || value.downcase == 'yes' || value.downcase == 'on' )
         true
      else
         false
      end
   end
end

def Slideshow.main

  @@logger = nil
  $options = {}

  logger.level = Logger::INFO

  opt=OptionParser.new do |opts|
    opts.banner = "Usage: slideshow [options] name"
    
    #todo/fix: use -s5 option without optional hack? possible with OptionParser package/lib?
    # use -5 switch instead?
    opts.on( '-s[OPTIONAL]', '--s5', 'S5 Compatible Slide Show' ) { $options[ 's5' ] = true;  }
    # opts.on( "-s", "--style STYLE", "Select Stylesheet" ) { |s| $options[:style]=s }
    # opts.on( "-v", "--version", "Show version" )  {}
    opts.on( "-t", "--trace", "Show debug trace" ) {
       logger.datetime_format = "%H:%H:%S"
       logger.level = Logger::DEBUG
     }
    opts.on_tail( "-h", "--help", "Show this message" ) {
         puts 
         puts "Slide Show (S9) is a free web alternative to PowerPoint or KeyNote in Ruby"
         puts
         puts opts.help
         puts
         puts "Examples:"
         puts "  slideshow microformats"
         puts "  slideshow microformats.textile"
         puts "  slideshow -s5 microformats  # S5 compatible"
         puts
         puts "Further information:"
         puts "  http://slideshow.rubyforge.org" 
         exit
       }
  end

  opt.parse!

  puts "Slide Show (S9) Version: 0.5 on Ruby #{RUBY_VERSION} (#{RUBY_RELEASE_DATE}) [#{RUBY_PLATFORM}]"

  ARGV.each { |fn| Slideshow.create_slideshow( fn ) }
end

end

Slideshow.main if __FILE__ == $0