#!/usr/bin/env python3
import colorsys, optparse, collections
from PIL import Image, ImageDraw, ImageFont

parser = optparse.OptionParser(usage="usage: %prog [options] background accent [foreground]")
parser.add_option("-p", "--preview",
                  action="store_true",
                  dest="showPreview",
                  default=False,
                  help="show preview")
parser.add_option("-n", "--name",
                  action="store",
                  dest="name",
                  default="acid16",
                  help="scheme name")
parser.add_option("-a", "--author",
                  action="store",
                  dest="author",
                  default="acid16",
                  help="author name")
parser.add_option("-r", "--rainbow-blend",
                  action="store",
                  dest="rainbowBlend",
                  default=0.0,
                  help="mix ratio between last 8 colors' hues and background")

(options, args) = parser.parse_args()
if len(args) < 2:
    parser.error("need background and accent colors minimum")

def parseTuple(st):
    return tuple(float(x) for x in st.split(","))

bgHue, bgSat, bgLum = parseTuple(args[0])

accentHue, accentSat = parseTuple(args[1])

foreHue, foreSat = parseTuple(args[2]) if len(args) > 2 else (0.0, 0.0)

try:
    rainbowBlend = float(options.rainbowBlend)
except:
    parser.error("rainbow blend must be a number")

def lerp(a, b, t):
    return a + (b - a) * t

def mixColors(a, b, t):
    return tuple(lerp(a[i], b[i], t) for i in range(3))

def luminance(col):
    return col[0]*0.2126+col[1]*0.7152+col[2]*0.0722

def contrast(a, b):
    lo, hi = min(a, b), max(a, b)
    return (hi + 0.05) / (lo + 0.05)

def getContrast(lum, ratio):
    hi = ratio*lum + (ratio - 1)*0.05
    lo = (lum + 0.05 - ratio * 0.05) / ratio
    return hi if hi < 1.0 or lo < 0.0 else lo

def makeColor(hue, lum, sat = 1.0):
    orig = luminance(colorsys.hls_to_rgb(hue, 0.5, sat))
    return tuple(min(1.0, x) for x in colorsys.hls_to_rgb(hue, 0.5 * (lum / orig) if lum < orig else (0.5 + 0.5 * ((lum - orig) / (1.0 - orig))), sat))

def toLinear(col):
    return tuple(x/12.92 if x < 0.04045 else ((x+0.055)/1.055)**2.4 for x in col)

def toSRGB(col):
    return tuple(x*12.92 if x < 0.0031308 else 1.055*x**(1/2.4) - 0.055 for x in col)

def usable(col):
    return tuple(int(x*255) for x in toSRGB(col))

def toHex(col):
    return "".join(["{:02x}".format(x) for x in usable(col)])

background = makeColor(bgHue, bgLum, bgSat)
foreLum = getContrast(bgLum, 7)
foreground = makeColor(foreHue, foreLum, foreSat)
commentLum = getContrast(bgLum, 3)
comment = makeColor(accentHue, commentLum, accentSat)
accentLum = getContrast(foreLum, 4.5)
accent = makeColor(accentHue, accentLum, accentSat)

foreDark = makeColor(foreHue, (commentLum + foreLum) * 0.5, foreSat)
backLighter = makeColor(bgHue, (bgLum + accentLum) * 0.5, bgSat)

# supposedly these two are rarely used so i don't care
lastTwo = [lerp(foreLum, 1.0 if foreLum > bgLum else 0.0, (x + 1) / 3) for x in range(2)]

foreLight = makeColor(foreHue, lastTwo[0], foreSat)
backLight = makeColor(bgHue, lastTwo[1], bgSat)

rainHues = [0, 20, 55, 120, 180, 240, 280, 330]

backFull = colorsys.hls_to_rgb(bgHue, 0.5, bgSat)
rainbow = [mixColors(colorsys.hls_to_rgb(hue/360.0, 0.5, 1.0), backFull, rainbowBlend) for hue in rainHues]
rainbow = [makeColor(colorsys.rgb_to_hls(*col)[0], getContrast(bgLum, 3.5), 1.0) for col in rainbow]

cols = [background, backLighter, accent, comment, foreDark, foreground, foreLight, backLight] + rainbow

print("scheme: \"{}\"".format(options.name))
print("author: \"{}\"".format(options.author))

for i in range(len(cols)):
    print("base{:02X}: \"{}\"".format(i, toHex(cols[i])))

if options.showPreview:
    font = ImageFont.truetype("/usr/share/fonts/TTF/LiberationMono-Regular.ttf", 20)

    im = Image.new("RGB", (640, 640), usable(background))
    draw = ImageDraw.Draw(im)
    
    draw.rectangle((2, 2, 638, 32), usable(accent))
    draw.text((5,  5), "Foreground (contrast {:.1f}:1 w/ highlight)".format(contrast(luminance(foreground), luminance(accent))), usable(foreground), font)
    draw.text((5, 45), "Foreground (contrast {:.1f}:1 w/ background)".format(contrast(luminance(foreground), luminance(background))), usable(foreground), font)
    draw.text((5, 85), "# Comment color (contrast {:.1f}:1)".format(contrast(luminance(comment), luminance(background))), usable(comment), font)

    for i in range(len(rainbow)):
        draw.rectangle((4, 120+i*40, 84, 150+i*40), usable(rainbow[i]))
        draw.text((90, 125+i*40), "Text (contrast 3.5:1)".format(contrast(luminance(rainbow[i]), luminance(background))), usable(rainbow[i]), font)
    
    draw.rectangle((0, 560, 640, 600), usable(backLighter))
    draw.text((5, 565), "'Dark' foreground (contrast {:.2f}:1)".format(contrast(luminance(backLighter), luminance(foreDark))), usable(foreDark), font)
    draw.line((0, 598, 640, 598), usable(foreground), 2)
    
    for i in range(len(cols)):
        draw.rectangle((i*40,600,i*40+39,639), usable(cols[i]))
        
    im.show()