#! /usr/bin/env ruby
# coding: utf-8
#
# TODO
#   完結した tex としてコンパイル 
#   document 環境としてコンパイル 
#   equation 環境としてコンパイル 
#   eqnarray 環境としてコンパイル。開始式番号指定 


DEFAULT_DENSITY = 150

USAGE = <<HERE
  Usage: #{File.basename("#{__FILE__}")} tex_file

  Default:
    - Output png image.
    - Density for conversion is #{DEFAULT_DENSITY}.
HERE

LATEX    = 'latexmk'
CONVERT = 'convert'

require "optparse"
require "pp"
require "pathname"
require "fileutils"

## option analysis
options = {}
op = OptionParser.new
op.banner = USAGE
op.on("-j"    , "--jpg"    , "Output jpg image, alternative to png."){ options[:img] = :jpg}
op.on("-d val", "--density=val", "Set density for raster conversion"){|v| options[:density] = v}
op.parse!(ARGV)

options[:img] ||= :png
img_ext = options[:img].to_s

density = DEFAULT_DENSITY
density = options[:density].to_i if options[:density]

def execute(commands)
  commands.each do |c|
    puts c
    system c
  end
end

if ARGV.empty?
  puts "Need one tex file in argument. Exit."
  puts USAGE
  exit
end

tex_file = ARGV[0]
dvi_file = Pathname(tex_file).sub_ext(".dvi").to_s
img_file = Pathname(tex_file).sub_ext(".#{img_ext}").to_s


commands = []
commands << "#{LATEX} #{tex_file} > /dev/null"
commands << "#{CONVERT} -background white -alpha deactivate -trim -density #{density}x#{density} #{dvi_file} #{img_file}"
execute(commands)
commands = []

trash_exts = [ 'aux', 'dvi', 'fdb_latexmk', 'fls', 'log']
trash_exts.each do |ext|
  file = Pathname(tex_file).sub_ext(".#{ext}").to_s
  FileUtils.rm file if File.exist? file
end