#!/usr/bin/env ruby

# ------------------------------------
#  Grab dimensions from JPEG header.
# ------------------------------------

def get_size(file)
  w = h = nil
  File.open(file) do |fh|
    x = fh.sysread(2).unpack('n').first
    if x != 0xFFD8
      $stderr.puts("#{file}: not jpeg")
      break
    end
    while str = fh.sysread(4)
      x, l = str.unpack('nn')
      if x == 0xFFC0 || x == 0xFFC2
        h, w = fh.sysread(5).unpack('xnn')
        break
      # elsif x < 0xFF00
      #   $stderr.puts('Invalid header!')
      #   exit 1
      else
        fh.sysseek(l - 2, IO::SEEK_CUR)
      end
    end
  end
  return [w, h]
end

# --------------------------------
#  Set size in database via API.
# --------------------------------

def set_size(id, w, h)
  require 'net/http'
  require 'uri'
  if id.to_s == ''
    puts "#{w} #{h}"
  else
    http = Net::HTTP.new('localhost')
    http.put("/api/images?id=#{id}&set_width=#{w}&set_height=#{h}")
  end
end

# ----------------------------
#  Main program.
# ----------------------------

case ARGV[0]

# Help message
when '-h', '--help'
  # Fall through to display help.

# Given file of files.
when '-f', '--file'
  file = ARGV[1]
  any = false
  File.readlines(file).each do |line|
    file2 = line.chomp
    w, h = get_size(file2)
    if w
      $stdout.puts("#{file2}: #{w} #{h}")
      any = true
    end
  end
  exit(any ? 0 : 1)

# Given file and ID of images record.
when '-s', '--set'
  id, file = ARGV[1..2]
  w, h = get_size(file)
  if w && set_size(id, w, h)
    exit(0)
  else
    exit(1)
  end

# Just given single filename.
else
  if (ARGV.length == 1) and !ARGV[0].match(/^-/)
    file = ARGV[0]
    w, h = get_size(file)
    if w
      $stdout.puts("#{w} #{h}")
      exit(0)
    else
      exit(1)
    end
  end
end

# Help message whenever screw up command line.
$stderr.puts %(
  USAGE
    script/jpegsize <file>.jpg
    script/jpegsize -f <file_list>.txt
    script/jpegsize -s <id> <file>.jpg

  DESCRIPTION
    Reports the size of one or more JPEG files.

  OPTIONS
    -h --help             Print this message.
    -f --file <file>      Report size of all files listed in <file>.
    -s --set <id> <file>  Set size of <file> in database for image #<id>.

)
exit(1)