#!/usr/bin/env ruby
require 'RMagick'

class XtermPeg
	def initialize( filename )
		@filename = filename

		@cache = {}
		@colormap = {}
		File.open( "colors.txt" ) do |f|
			f.each do |l|
				a = l.strip.split( / / )

				@colormap[ a[0].to_i ] = [ a[1].to_i(16), a[2].to_i(16), a[3].to_i(16) ]
			end
		end
	end

	def find_best_color( r, g, b )
		m = r*65536+g*256+b
		return @cache[ m ] if @cache[ m ]

		bestidx = nil
		best = 256*256*256

		#  Find the best fit for the pixel
		@colormap.each do |k, v|
			#  Calculate the distance between the colour we want, and the colour we're considering
			d = ( ( ( v[0] - r ).abs**2 + ( v[1] - g ).abs**2 + ( v[2] - b ).abs**2 ) ** 0.5 ).to_i

			if d < best
				bestidx = k
				best = d
			end
		end

		@cache[ m ] = bestidx
	end

	def run
		pic = Magick::Image.read( @filename )[0]

		(0...pic.rows).each do |r|
			next if r%2 == 1   #  Terminal characters are usually (and roughly) twice as high as they are wide.

			pic.get_pixels( 0, r, pic.columns, 1 ).each_with_index do |pixel, c|
				print 27.chr + "[48;5;" + find_best_color( pixel.red/256, pixel.green/256, pixel.blue/256 ).to_s + "m "
			end

			print 27.chr + "[48;5;0m"
			puts
		end
	end
end

xterm = XtermPeg.new( ARGV[0] )
xterm.run