module Bhook
  class ArgsParser
    Options = Struct.new(:source, :output, :watch, :verbose, :theme, :generate_theme)
        
    def initialize(argv)
      @args = Options.new(nil, nil, false, false, nil, nil)
      @argv = argv.clone
      @opt_parser = build_opt_parser
    end
    
    def parse
      begin
        @opt_parser.parse(@argv)
      rescue OptionParser::ParseError => e
        puts
        puts "Error! #{e.message}"
        puts
        puts @opt_parser
        exit
      end
      
      if source_or_output_paths_missing? && generate_theme_missing?
        puts @opt_parser
        exit
      end
      @args
    end
    
    private
        
    def source_or_output_paths_missing?
      !@args.source || !@args.output
    end
    
    def generate_theme_missing?
      !@args.generate_theme
    end
    
    def build_opt_parser      
      OptionParser.new do |opts|
        opts.banner = "Usage: bhook --source /source/path --output /output/path"

        opts.on("-sSOURCE", "--source=SOURCE", 
                String, "Path to version controlled directory containing source md files") do |source_path|
          @args.source = source_path
        end

        opts.on("-oOUTPUT", "--output=OUTPUT", 
                String, "Path to directory where output files are to be generated") do |out_path|
          @args.output = out_path
        end

        opts.on("-w", "--watch", 
                FalseClass, 
                "Continuously watch the source directory for changes and generate output") do
          @args.watch = true
        end

        opts.on("-v", "--verbose", 
                FalseClass, 
                "Print detailed information about files as they are processed") do
          @args.verbose = true
        end

        opts.on("-tPATH", "--theme=PATH",
                String, 
                "Path to directory containing theme files to use when generating html") do |path|
          @args.theme = path
        end

        opts.on("--generate-theme=PATH",
                String, 
                "Generate a baseline theme that you can then modify to your needs") do |path|
          @args.generate_theme = path
        end

        opts.on("-h", "--help", "Prints this help") do
          puts opts
          exit
        end
      end      
    end
  end
end