module Markdown


  class Opts
  
    def output_path=(value)
      @output_path = value
    end
  
    def output_path
      @output_path ||= '.'
    end

  end # class Opts


  class Gen

    include TextUtils::Filter   # include filters such as comments_percent_style, etc. (see textutils gem)

    attr_reader :logger
    attr_reader :opts
    
    def initialize
      @logger       = Logger.new(STDOUT)
      @logger.level = Logger::INFO
      @opts         = Opts.new
    end

    def create_doc( fn )
      dirname  = File.dirname(  fn )    
      basename = File.basename( fn, '.*' )
      extname  = File.extname(  fn )

      logger.debug "dirname=#{dirname}, basename=#{basename}, extname=#{extname}"

      if opts.output_path == '.'
        # expand output path in current dir
        outpath = File.expand_path( dirname ) 
      else
        # expand output path in user supplied dir and make sure output path exists
        outpath = File.expand_path( opts.output_path ) 
        FileUtils.makedirs( outpath ) unless File.directory? outpath 
      end
      logger.debug "outpath=#{outpath}"
      
      # todo: add a -c option to commandline? to let you set cwd?


      # change working dir to sourcefile dir (that is, dirname); push working folder/dir
      newcwd  = File.expand_path( dirname )
      oldcwd  = File.expand_path( Dir.pwd )
    
      unless newcwd == oldcwd
        logger.debug "oldcwd=>#{oldcwd}<, newcwd=>#{newcwd}<"
        Dir.chdir( newcwd )
      end  

      inname  = "#{basename}#{extname}"
      outname = "#{basename}.html"
      
      logger.debug "inname=#{inname}, outname=#{outname}"
      
      puts "*** #{inname} (#{dirname}) => #{outname} (#{(opts.output_path == '.') ? dirname : opts.output_path})..."
      
      content = File.read( inname )
      
      # step 1) run (optional) preprocessing text filters
      Markdown.filters.each do |filter|
        mn = filter.tr( '-', '_' ).to_sym  # construct method name (mn)
        content = send( mn, content )   # call filter e.g.  include_helper_hack( content )  
      end

      # step 2) convert light-weight markup to hypertext
      content = Markdown.new( content ).to_html


## todo: add Markdown.lib_options inspect/dump to banner
            
      banner =<<EOS
<!-- ======================================================================
      generated by #{Markdown.banner}
                on #{Time.now} with Markdown engine '#{Markdown.lib}'
     ====================================================================== -->
EOS
      
      out = File.new( File.join( outpath, outname ), "w+" )
####      out << banner
      out << content
      out.flush
      out.close

      ## pop/restore working folder/dir
      unless newcwd == oldcwd
        logger.debug "oldcwd=>#{oldcwd}<, newcwd=>#{newcwd}<"
        Dir.chdir( oldcwd )
      end  
            
    end # method create_doc


    def has_markdown_extension?( fn )
      dirname  = File.dirname( fn )
      basename = File.basename( fn, '.*' )
      extname  = File.extname( fn )
      logger.debug "dirname=#{dirname}, basename=#{basename}, extname=#{extname}"

      return false if extname.empty?   # no extension
      
      Markdown.extnames.include?( extname.downcase )
    end
    
    def find_file_with_markdown_extension( fn )
      dirname  = File.dirname( fn )
      basename = File.basename( fn, '.*' )
      extname  = File.extname( fn )
      logger.debug "dirname=#{dirname}, basename=#{basename}, extname=#{extname}"

      Markdown.extnames.each do |e|
        newname = File.join( dirname, "#{basename}#{e}" ) 
        logger.debug "File.exists? #{newname}"
        return newname if File.exists?( newname )
      end  # each extension (e)
      
      nil   # not found; return nil
    end

    
    def find_files( file_or_dir_or_pattern )

      filtered_files = []
      
      # assume pattern if includes * or ? or {} or []
      if file_or_dir_or_pattern =~ /[*?{}\[\]]/
        puts "searching glob pattern '#{file_or_dir_or_pattern}'..."
        Dir.glob( file_or_dir_or_pattern ).each do |file|
          if File.directory?( file )  # skip (sub)directories
            puts "  skipping folder '#{file}'..."
            next
          else
            if has_markdown_extension?( file )
              logger.debug "  adding file '#{file}'..."
              filtered_files << file
            else
              puts "  skipping file   '#{file}'..."
            end
          end
        end
      elsif File.directory?(file_or_dir_or_pattern)
        puts "searching folder '#{file_or_dir_or_pattern}'..."
        Dir.entries( file_or_dir_or_pattern ).each do |entry|
          next if entry == '.' || entry == '..' # silently skip current and up dirs
          
          if file_or_dir_or_pattern == '.'
            file = entry
          else  # add dir (if not working dir)
            file = File.join( file_or_dir_or_pattern, entry )  
          end
           
          if File.directory?( file )  # skip (sub)directories
            puts "  skipping folder '#{file}'..."
            next
          else
            if has_markdown_extension?( file )
              logger.debug "  adding file '#{file}'..."
              filtered_files << file
            else
              puts "  skipping file   '#{file}'..."
            end
          end
        end
      else  # assume it's a single file (check for missing extension)
        if File.exists?( file_or_dir_or_pattern )
          file = file_or_dir_or_pattern
          if has_markdown_extension?( file )
            logger.debug "  adding file '#{file}'..."
            filtered_files << file
          else
            puts "  skipping file   '#{file}'..."
          end
        else  # check for existing file w/ missing extension
          file = find_file_with_markdown_extension( file_or_dir_or_pattern )
          if file.nil?
            puts "  skipping missing file '#{file_or_dir_or_pattern}{#{Markdown.extnames.join(',')}}'..."
          else
            logger.debug "  adding file '#{file}'..."
            filtered_files << file
          end
        end
      end

      filtered_files
    end  # find_files
    
    def run( args )
      opt=OptionParser.new do |cmd|
    
        cmd.banner = "Usage: markdown [options] files_or_dirs"
    
        cmd.on( '-o', '--output PATH', 'Output Path' ) { |path| opts.output_path = path }

        # todo: find different letter for debug trace switch (use v for version?)
        cmd.on( "-v", "--verbose", "Show debug trace" )  do
           logger.datetime_format = "%H:%H:%S"
           logger.level = Logger::DEBUG
        end
 

## todo: add markdown.lib options (e.g. extensions,etc)
 
        usage =<<EOS

markdown - Lets you convert plain text documents (#{Markdown.extnames.join(', ')}) to hypertext (.html) with your Markdown engine of choice (#{Markdown.lib}) and preprocessing text filters (#{Markdown.filters.join(', ')}).

#{cmd.help}

Examples:
  markdown                   # Process all documents in working folder (that is, .)
  markdown quickref          # Process document or folder using Markdown
  markdown quickref.text     # Process document using Markdown
  markdown -o site quickref  # Output documents to site folder

Further information:
  http://geraldb.github.com/markdown
  
EOS

        cmd.on_tail( "-h", "--help", "Show this message" ) do
           puts usage
           exit
        end
      end

      opt.parse!( args )
  
      puts Markdown.banner
      
      # force loading of config
      Markdown.lib
      
      logger.debug "args.length: #{args.length}"
      logger.debug "args: >#{args.join(',')}<"
      
      # if no file args given; default to working folder (that is, .)
      args = ['.'] if args.length == 0

      args.each do |arg|
        files = find_files( arg )
        files.each do |file|
          create_doc( file )
        end
      end
      
      puts "Done."
      
    end   # method run 
    
  end # class Gen

end # module Markdown