#!/usr/bin/env ruby
# -*- ruby -*-

require 'combine_pdf'
require 'pdf-reader'
require 'optparse'
require 'ostruct'

class PDFSplitArgumentParser
    def self.parse(args)
        options = OpenStruct.new
        options.first_page = 1

        opts = OptionParser.new { |opts|
            opts.banner = "Usage: pdfsplit [options] <input> <output>"
            opts.separator ""
            opts.separator "Specific options:"

            opts.on("-f", "--first-page PAGE", Integer, "Specify the first page to begin spliting at") { |f| options.first_page = f }
            opts.on("-l", "--last-page PAGE", Integer, "Specify the last page to split") { |l| options.last_page = l }

            options[:help] = opts.help
        }

    opts.parse!(args)
    options
    end
end

options = PDFSplitArgumentParser.parse(ARGV)
if ARGV.length != 2 then
    abort options[:help]
end

input_arg = ARGV[0]
output_arg = ARGV[1]

if !input_arg.end_with?(".pdf") || !File.file?(input_arg) then
    abort "Please specify a valid input file: #{input_arg}"
end

last_page = options.last_page || PDF::Reader.new(input_arg).page_count

input_pdf = CombinePDF.load(input_arg)
output_pdf = CombinePDF.new

pages = 0
input_pdf.pages.each { |page|
    if (pages += 1) >= options.first_page && pages <= last_page then
        output_pdf << page
    end
}

output_pdf.save "#{output_arg}#{output_arg.end_with?("pdf") ? "" : ".pdf"}"