#!/usr/bin/env ruby

if ARGV.size != 2
    puts "Usage: $0 <filename.pcx> <Palette name>"
    exit 1
end

FILENAME = ARGV[0]
PALETTENAME = ARGV[1]

f = File.open(FILENAME)

# In a 256-colour PCX file, the palette is stored in the final 768 bytes as RGB
# triplets, and the byte before that should be 0x0C: https://en.wikipedia.org/wiki/PCX#Color_palette
f.seek(-769, IO::SEEK_END)

raise "Check byte is wrong" unless f.read(1) == "\x0C"

puts <<EOF
package palettes

import "image/color"

var (
	#{PALETTENAME}Palette = color.Palette{
EOF

# bytes.shift(3) # Ignore idx 0 so we can make it transparent

256.times do
  r, g, b = f.read(3).bytes

  puts "\t\tcolor.RGBA{R: #{r}, G: #{g}, B: #{b}, A: 255},"
end

puts <<EOF
	}
)

func init() {
	Palettes["#{PALETTENAME}"] = #{PALETTENAME}Palette
}
EOF