#!/usr/bin/env ruby
##############################################################################
# Converts HTML colors between different formats
##############################################################################
# Handles color input in multiple formats:
#
#  * Six-character hexadecimal
#  * Three-character hexadecimal
#  * RGB
#  * HTML named color (including non-W3C colors)
#
# Three character hex codes are normalized to six characters and all
# input is normalized to lowercase. Colors can be converted from any
# one of these formats to any other.
#
# Code ported from the PHP originally used in Hextractor,
# a Corvid Works project.
# http://www.hextractor.com/
# http://www.corvidworks.com/
#
# This code is released under the terms of the MIT License
#
# Author: Kenn Wilson
# Copyright: Copyright (c) 2008 Kenn Wilson
# Version: 1.0
#
##############################################################################
# The MIT License
#
# Copyright (c) 2008 Kenn Wilson
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to permit
# persons to whom the Software is furnished to do so, subject to the
# following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
# NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
# DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
# USE OR OTHER DEALINGS IN THE SOFTWARE.
#
##############################################################################
# Example usage:
#
# Include class and instantiate cwColorMap object:
#
#     require 'colormap.rb'
#     map = CwColorMap.new
#
# Call various methods, as needed:
#
#     hex  = map.rgb_to_hex("119 125 66")         # Returns '#777d42'
#     rgb  = map.hex_to_rgb("#777d42", :string)   # Returns '119 125 66'
#     name = map.hex_to_name("#ffffff")           # Returns 'white'
#
##############################################################################

class CwColorMap

	# Hash containing complete list of named colors and their hex codes
	attr_reader :colormap
	
	# Load colormap hash
	def initialize
		load_colormap
	end
	
	# Normalize three-character hex codes to six characters
	def hex_to_six(hex)
		prefix = String.new
		if hex.include?('#')
			prefix = '#'
			hex.sub!('#', '')
		end
		if hex.length == 6
			return prefix + hex
		end
		hex3  = hex.scan(/./)
		hex6  = hex3[0] + hex3[0]
		hex6 += hex3[1] + hex3[1]
		hex6 += hex3[2] + hex3[2]
		return prefix + hex6
	end
	
	# Convert RGB colors to hex codes. 
	# Dumps values from hash into array to ensure that the  
	# iterator reads them in the correct order (r, g, b).
	def rgb_to_hex(rgb)
		hex = "#"
		rgb = [
			rgb['r'], rgb['g'], rgb['b']
		]
		rgb.each do |value|
			value = value.to_i
			value = value.to_s(16)
			value = value.rjust(2, "0")
			hex += value
		end
		return hex
	end
	
	# Converts hexadecimal colors to RGB. Defaults to returning a three-element
	# hash but can also return a space-delimited string if requested.
	def hex_to_rgb(hex, format = :hash)
		hex.sub!('#', '')
		if hex.length == 3
			hex = hex_to_six(hex)
		end
		hex = hex.scan(/./)
		rgb = {
			'r' => hex[0] + hex[1],
			'g' => hex[2] + hex[3],
			'b' => hex[4] + hex[5],
		}
		rgb['r'] = rgb['r'].to_i(16)
		rgb['g'] = rgb['g'].to_i(16)
		rgb['b'] = rgb['b'].to_i(16)
		# Accept format request as a symbol or string
		if format == :string || format == "string"
			rgb = rgb_hash_to_string(rgb)
		end
		return rgb
	end
	
	# Converts RGB hash to string
	def rgb_hash_to_string(rgb_hash)
		rgb_string  = rgb_hash['r'].to_s + ' '
		rgb_string += rgb_hash['g'].to_s + ' '
		rgb_string += rgb_hash['b'].to_s
		return rgb_string
	end
	
	# Converts RGB color string to three-element hash
	def rgb_string_to_hash(rgb_string)
		rgb_array = rgb_string.split(' ')
		rgb_hash = {
			'r' => rgb_array[0],
			'g' => rgb_array[1],
			'b' => rgb_array[2],
		}
		return rgb_hash
	end

	# Associative arrays in PHP are hashes in Ruby, so let's rename
	# these methods while preserving the original API.
	alias :rgb_array_to_string :rgb_hash_to_string
	alias :rgb_string_to_array :rgb_string_to_hash
	
	# Convert a named color to its hexadecimal equivilant and 
	# returns hex code. Returns nil if name doesn't exist.
	def name_to_hex(name)
		name.downcase!
		colormap = downcase_keys(@colormap)
		if colormap.has_key?(name)
			return colormap[name]
		else
			return nil
		end
	end
	
	# Convert a hexadecimal color to it's named equivilant, if possible.
	# Returns the name if it exists, otherwise returns original hex code.
	def hex_to_name(hex)
		hex.downcase!
		colormap = downcase_keys(@colormap)
		colormap = colormap.invert
		if colormap.has_key?(hex)
			return colormap[hex]
		else
			return hex
		end
	end
	
	# Convert a named color to it's RGB equivilant
	def name_to_rgb(name, format = :hash)
		hex = name_to_hex(name)
		rgb = hex_to_rgb(hex, format)
		return rgb
	end
	
	# Convert an RGB color to it's named equivilant, if possible.
	def rgb_to_name(rgb)
		if rgb.class == "String"
			rgb = rgb_string_to_hash(rgb)
		end
		hex  = rgb_to_hex(rgb)
		name = hex_to_name(hex)
		return name
	end
	
	# Lowercase all hash keys. 
	# Returns new hash with keys in lowercase.
	def downcase_keys(colormap)
		colormap_lower = Hash.new
		@colormap.each do |key, value|
			colormap_lower[key.downcase] = colormap[key]
		end
		return colormap_lower
	end

	# Private methods	
	private
	
	# Set instance variable with colormap hash
	def load_colormap
		@colormap = {
			'AliceBlue'            => '#f0f8ff',
			'AntiqueWhite'         => '#faebd7',
			'Aqua'                 => '#00ffff',
			'Aquamarine'           => '#7fffd4',
			'Azure'                => '#f0ffff',
			'Beige'                => '#f5f5dc',
			'Bisque'               => '#ffe4c4',
			'Black'                => '#000000',
			'BlanchedAlmond'       => '#ffebcd',
			'Blue'                 => '#0000ff',
			'BlueViolet'           => '#8a2be2',
			'Brown'                => '#a52a2a',
			'Burlywood'            => '#deb887',
			'CadetBlue'            => '#5f9ea0',
			'Chartreuse'           => '#7fff00',
			'Chocolate'            => '#d2691e',
			'Coral'                => '#ff7f50',
			'CornflowerBlue'       => '#6495ed',
			'Cornsilk'             => '#fff8dc',
			'Crimson'              => '#dc143c',
			'Cyan'                 => '#00ffff',
			'DarkBlue'             => '#00008b',
			'DarkCyan'             => '#008b8b',
			'DarkGoldenrod'        => '#b8860b',
			'DarkGray'             => '#a9a9a9',
			'DarkGrey'             => '#a9a9a9',
			'DarkGreen'            => '#006400',
			'DarkKhaki'            => '#bdb76b',
			'DarkMagenta'          => '#8b008b',
			'DarkOliveGreen'       => '#556b2f',
			'DarkOrange'           => '#ff8c00',
			'DarkOrchid'           => '#9932cc',
			'DarkRed'              => '#8b0000',
			'DarkSalmon'           => '#e9967a',
			'DarkSeaGreen'         => '#8fbc8f',
			'DarkSlateBlue'        => '#483d8b',
			'DarkSlateGray'        => '#2f4f4f',
			'DarkSlateGrey'        => '#2f4f4f',
			'DarkTurquoise'        => '#00ced1',
			'DarkViolet'           => '#9400d3',
			'DeepPink'             => '#ff1493',
			'DeepSkyBlue'          => '#00bfff',
			'DimGray'              => '#696969',
			'DimGrey'              => '#696969',
			'DodgerBlue'           => '#1e90ff',
			'FireBrick'            => '#b22222',
			'FloralWhite'          => '#fffaf0',
			'ForestGreen'          => '#228b22',
			'Fuchsia'              => '#ff00ff',
			'Gainsboro'            => '#dcdcdc',
			'GhostWhite'           => '#f8f8ff',
			'Gold'                 => '#ffd700',
			'Goldenrod'            => '#daa520',
			'Gray'                 => '#808080',
			'Grey'                 => '#808080',
			'Green'                => '#008000',
			'GreenYellow'          => '#adff2f',
			'Honeydew'             => '#f0fff0',
			'HotPink'              => '#ff69b4',
			'IndianRed'            => '#cd5c5c',
			'Indigo'               => '#4b0082',
			'Ivory'                => '#fffff0',
			'Khaki'                => '#f0e68c',
			'Lavender'             => '#e6e6fa',
			'LavenderBlush'        => '#fff0f5',
			'LawnGreen'            => '#7cfc00',
			'LemonChiffon'         => '#fffacd',
			'LightBlue'            => '#add8e6',
			'LightCoral'           => '#f08080',
			'LightCyan'            => '#e0ffff',
			'LightGoldenrodYellow' => '#fafad2',
			'LightGray'            => '#d3d3d3',
			'LightGrey'            => '#d3d3d3',
			'LightGreen'           => '#90ee90',
			'LightPink'            => '#ffb6c1',
			'LightSalmon'          => '#ffa07a',
			'LightSeaGreen'        => '#20b2aa',
			'LightSkyBlue'         => '#87cefa',
			'LightSlateGray'       => '#778899',
			'LightSlateGrey'       => '#778899',
			'LightSteelBlue'       => '#b0c4de',
			'LightYellow'          => '#ffffe0',
			'Lime'                 => '#00ff00',
			'Limegreen'            => '#32cd32',
			'Linen'                => '#faf0e6',
			'Magenta'              => '#ff00ff',
			'Maroon'               => '#800000',
			'MediumAquamarine'     => '#66cdaa',
			'MediumBlue'           => '#0000cd',
			'MediumOrchid'         => '#ba55d3',
			'MediumPurple'         => '#9370d8',
			'MediumSeaGreen'       => '#3cb371',
			'MediumSlateBlue'      => '#7b68ee',
			'MediumSpringGreen'    => '#00fa9a',
			'MediumTurquoise'      => '#48d1cc',
			'MediumVioletRed'      => '#c71585',
			'MidnightBlue'         => '#191970',
			'MintCream'            => '#f5fffa',
			'MistyRose'            => '#ffe4e1',
			'Moccasin'             => '#ffe4b5',
			'NavajoWhite'          => '#ffdead',
			'Navy'                 => '#000080',
			'OldLace'              => '#fdf5e6',
			'Olive'                => '#808000',
			'OliveDrab'            => '#6b8e23',
			'Orange'               => '#ffa500',
			'OrangeRed'            => '#ff4500',
			'Orchid'               => '#da70d6',
			'PaleGoldenrod'        => '#eee8aa',
			'PaleGreen'            => '#98fb98',
			'PaleTurquoise'        => '#afeeee',
			'PaleVioletRed'        => '#d87093',
			'PapayaWhip'           => '#ffefd5',
			'PeachPuff'            => '#ffdab9',
			'Peru'                 => '#cd853f',
			'Pink'                 => '#ffc0cb',
			'Plum'                 => '#dda0dd',
			'PowderBlue'           => '#b0e0e6',
			'Purple'               => '#800080',
			'Red'                  => '#ff0000',
			'RosyBrown'            => '#bc8f8f',
			'RoyalBlue'            => '#4169e1',
			'SaddleBrown'          => '#8b4513',
			'Salmon'               => '#fa8072',
			'SandyBrown'           => '#f4a460',
			'SeaGreen'             => '#2e8b57',
			'Seashell'             => '#fff5ee',
			'Sienna'               => '#a0522d',
			'Silver'               => '#c0c0c0',
			'SkyBlue'              => '#87ceeb',
			'SlateBlue'            => '#6a5acd',
			'SlateGray'            => '#708090',
			'SlateGrey'            => '#708090',
			'Snow'                 => '#fffafa',
			'SpringGreen'          => '#00ff7f',
			'SteelBlue'            => '#4682b4',
			'Tan'                  => '#d2b48c',
			'Teal'                 => '#008080',
			'Thistle'              => '#d8bfd8',
			'Tomato'               => '#ff6347',
			'Turquoise'            => '#40e0d0',
			'Violet'               => '#ee82ee',
			'Wheat'                => '#f5deb3',
			'White'                => '#ffffff',
			'WhiteSmoke'           => '#f5f5f5',
			'Yellow'               => '#ffff00',
			'YellowGreen'          => '#9acd32',
		}
	end
	
	
end