local math_mod = require('Module:Math')

local function hex( value )
	return string.format
end

local function format_line
	return "background: #" .. background .. "; color:#" .. text_color .. ";"
end

local function range_pos
	if start < stop then
		if value < start then
			return 0
		elseif value > stop then
			return 1
		else
			return (value - start) / (stop - start)
		end
	else
		if value < stop then
			return 1
		elseif value > start then
			return 0
		else
			return (start - value) / (start - stop)
		end
	end
end

function w.color_d( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._days_color( val )
end
function w.color_pastel( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._pastel_color( val )
end
function w.color_t( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._temperature_color( val )
end
function w.color_green( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._green_color( val )
end
function w.color_s( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._sunshine_color( val )
end
function w.color_h( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._humidity_color( val )
end
function w.color_p( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._precipitation_color( val )
end
function w.color_u( frame )
	local val = math_mod._cleanNumber( frame.args[1] )
	return w._uv_color( val )
end

function w._days_color( val )
	local item, background, text_color

	if val == nil then
		return format_line
	end

	item = hex( range_pos*255 )
	background = item .. item

	item = hex( range_pos*255 )
	background = background .. item

	if val >= 12 then
		text_color = "FFFFFF"
	else
		text_color = "000000"
	end

	return format_line
end

function w._green_color( val )
	local item1, item2, background, text_color

	if val == nil then
		return format_line
	end

	item1 = hex( range_pos*255 )
	item2 = hex( range_pos*207 + 48 )
	background = item1 .. item2 .. item1
	if val >= 200 then
		text_color = "FFFFFF"
	else
		text_color = "000000"
	end

	return format_line
end

function w._temperature_color( val )
	local item, background, text_color

	if val == nil then
		return format_line
	end

	if val < 4.5 then
		item = range_pos*255
		background = hex( item )
	else
		item = range_pos*255
		background = hex( item )
	end

	if val <= 4.5 then
		item = range_pos*255
		background = background .. hex( item )
	else
		item = range_pos*255
		background = background .. hex( item )
	end

	if val < -42.78 then
		item = range_pos*255
		background = background .. hex( item )
	else
		item = range_pos*255
		background = background .. hex( item )
	end

	if val = 37.8 then
		text_color = "FFFFFF"
	else
		text_color = "000000"
	end

	return format_line
end

function w._precipitation_color( val )
	local item, background, text_color

	if val == nil then
		return format_line
	end

	item = hex( range_pos*255 )
	background = item .. item

	item = hex( range_pos*207 + 48 )
	background = background .. item

	if val > 90 then
		text_color = "FFFFFF"
	else
		text_color = "000000"
	end

	return format_line
end

function w._humidity_color( val )
	local item, background, text_color

	if val == nil then
		return format_line
	end

	item = hex( range_pos*255 )
	background = item .. item

	item = hex( range_pos*255 )
	background = background .. item

	if val >= 40 then
		text_color = "FFFFFF"
	else
		text_color = "000000"
	end

	return format_line
end

function w._sunshine_color( val )
	local item, background, text_color

	if val == nil then
		return format_line
	end

	if val < 90 then
		item = hex( range_pos*170 )
	elseif val < 180 then
		item = hex( range_pos*42.5 + 170 )
	else
		item = hex( range_pos*42.5 + 212.5 )
	end
	background = item .. item

	if val < 90 then
		item = hex( range_pos*170 )
	elseif val < 270 then
		item = hex( range_pos*170 )
	else
		item = hex( range_pos*255 )
	end
	background = background .. item

	if val < 80 then
		text_color = "FFFFFF"
	else
		text_color = "000000"
	end

	return format_line
end

function w._pastel_color( val )
	local background, text_color

	if val == nil then
		return format_line
	end

	if val = 39 then
		text_color = "FFFFFF"
	else
		text_color = "000000"
	end

	if val >= 51 then
		background = 'EE2200'
	else
		val = math_mod._round( (val + 25.5)/3, 0 )
		if val == 1 then
			background = 'BB00CC'
		elseif val == 2 then
			background = 'CC00EE'
		elseif val == 3 then
			background = 'CC33EE'
		elseif val == 4 then
			background = 'CC55EE'
		elseif val == 5 then
			background = 'DD66EE'
		elseif val == 6 then
			background = 'DD77EE'
		elseif val == 7 then
			background = 'DD99EE'
		elseif val == 8 then
			background = 'DDAAEE'
		elseif val == 9 then
			background = 'DDBBEE'
		elseif val == 10 then
			background = 'EECCFF'
		elseif val == 11 then
			background = 'FFDDFF'
		elseif val == 12 then
			background = 'F1F1F1'
		elseif val == 13 then
			background = 'FFEEBB'
		elseif val == 14 then
			background = 'FFFFCC'
		elseif val == 15 then
			background = 'FFFFBB'
		elseif val == 16 then
			background = 'FFFFAA'
		elseif val == 17 then
			background = 'FFFF88'
		elseif val == 18 then
			background = 'FFCC33'
		elseif val == 19 then
			background = 'FFBB33'
		elseif val == 20 then
			background = 'FF9900'
		elseif val == 21 then
			background = 'FF8844'
		elseif val == 22 then
			background = 'FF6633'
		elseif val == 23 then
			background = 'FF5522'
		elseif val == 24 then
			background = 'FF4422'
		elseif val == 25 then
			background = 'EE4400'
		else
			background = 'AA00AA'
		end
	end

	return format_line
end

function w._uv_color( val )
	local background, text_color

	if val == nil then
		return format_line
	end

	if val < 3 then
		background = "3EA72D"
	elseif val >= 3 and val < 6 then
		background = "FFF300"
	elseif val >= 6 and val < 8 then
		background = "F18B00"
	elseif val >= 8 and val < 11 then
		background = "E53210"
	else
		background = "B567A4"
	end

	if val < 3 then
		text_color = "FFFFFF"
	elseif val >= 3 and val < 8 then
		text_color = "000000"
	else
		text_color = "FFFFFF"
	end

	return format_line
end

function w._none_color
	return format_line
end

function w.interpret_color_code( code )
	code = code:lower
	if code == 't' then
		return w._temperature_color
	elseif code == 'pastel' then
		return w._pastel_color
	elseif code == 'green' then
		return w._green_color
	elseif code == 'h' then
		return w._humidity_color
	elseif code == 's' then
		return w._sunshine_color
	elseif code == 'p' then
		return w._precipitation_color
	elseif code == 'd' then
		return w._days_color
	elseif code == 'u' then
		return w._uv_color
	elseif code == 'none' then
		return w._none_color
	else
		error( '알 수 없는 스킴 옵션' )
	end
end