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

modes = ["base16","xresources"]
RED, YELLOW, GREEN, CYAN, BLUE, MAGENTA = 0, 60, 120, 200, 240, 300
blendTargets = ["background","foreground","accent"]

parser = optparse.OptionParser(usage="usage: %prog [options] background accent [foreground]")
parser.add_option("-a", "--author",
                  action="store",
                  dest="author",
                  default="acid16",
                  help="author name")
parser.add_option("-b", "--hue-blend",
                  action="store",
                  dest="hueBlend",
                  default=0.0,
                  help="mix ratio between hues and background")
parser.add_option("-B", "--hue-blend-target",
                  action="store",
                  dest="hueBlendTarget",
                  default="background",
                  help="what to blend the hues with: background (default), foreground, accent")
parser.add_option("-c", "--contrast",
                  action="store",
                  dest="foreContrast",
                  default=7.0,
                  help="contrast between foreground and background (default 7)")
parser.add_option("-e", "--equiluminant",
                  action="store_true",
                  dest="equiluminant",
                  default=0.0,
                  help="use the same luminance for last hues")
parser.add_option("-m", "--mode",
                  action="store",
                  dest="mode",
                  default="base16",
                  help="what to generate ({})".format(", ".join(modes)))
parser.add_option("-n", "--name",
                  action="store",
                  dest="name",
                  default="acid16",
                  help="scheme name")
parser.add_option("-p", "--preview",
                  action="store_true",
                  dest="showPreview",
                  default=False,
                  help="generate a preview image")
parser.add_option("--hsl",
                  action="store_true",
                  dest="hsl",
                  default=0.0,
                  help="treat background color as gamma-encoded HSL")

base16Options = optparse.OptionGroup(parser, "Base16 options")
base16Options.add_option("-l", "--light-brown",
                         action="store_true",
                         dest="lightBrown",
                         default=0.0,
                         help="don't darken last color")

parser.add_option_group(base16Options)

(options, args) = parser.parse_args()

def dieIf(cond, message):
    cond and parser.error(message)

dieIf(options.mode not in modes, "unknown mode \"{}\"".format(options.mode))
dieIf(len(args) < 2, "need background and accent colors minimum")
dieIf(options.hueBlendTarget not in blendTargets, "unknown hue blend target \"{}\"".format(options.hueBlendTarget))

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

def floatOrDie(fl, errSt):
    try:
        return float(fl)
    except:
        parser.error(errSt)

class ImageHandler:
    def __init__(self, color):
        self.font = ImageFont.truetype("LiberationMono-Regular.ttf", 20)
        self.image = Image.new("RGB", (640, 480), usable(color))
        self.draw = ImageDraw.Draw(self.image)
    def size(self):
        return self.image.size
    def desc(self, t, a, b):
        return "{} (contrast {:.1f})".format(t, contrast(luminance(a), luminance(b)))
    def text(self, x, y, t, col, other):
        self.draw.text((x, y), self.desc(t, col, other), usable(col), self.font)
    def show(self):
        self.image.show()
    def drawPalette(self, cols):
        w, h = self.size()
        for i in range(len(cols)):
            im.draw.rectangle((i*40,h-40,i*40+39,h), usable(cols[i]))

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

foreContrast = floatOrDie(options.foreContrast, "foreground contrast must be a number")
bgHue, bgSat, origLum = parseTuple(args[0])
bgLum = luminance(toLinear(colorsys.hls_to_rgb(bgHue, origLum, bgSat))) if options.hsl else origLum

accentHue, accentSat = parseTuple(args[1])

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

hueBlend = floatOrDie(options.hueBlend, "hue blend must be a number")

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

def collapse(l):
    return [y for x in l for y in x]

def reposition(a, b, t, c, d):
    return lerp(c, d, (t - a) / (b - a))

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

def hue(col):
    return colorsys.rgb_to_hls(*col)[0]

def saturation(col):
    return colorsys.rgb_to_hls(*col)[2]

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

def lumFromContrast(lum, ratio):
    hi = ratio*lum + (ratio - 1)*0.05
    lo = (lum + 0.05 - ratio * 0.05) / ratio

    if hi == min(1.0, hi): return hi
    if lo == max(0.0, lo): return lo
    
    hiCon = 1.05 / (lum + 0.05)
    loCon = (lum + 0.05) / 0.05
    return hi if hiCon > loCon else lo

def clamp(x):
    return min(1.0, max(x, 0.0))

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 makeBackground():
    return makeColor(bgHue, bgLum, bgSat)

def foregroundLum(bg = bgLum):
    return lumFromContrast(bg, foreContrast)

CONSTRAIN_LOWER = False
CONSTRAIN_UPPER = True
def constrain(orig, compare, limit, mode=CONSTRAIN_UPPER):
    comp = lambda a, b: a > b if mode else a < b
    return lumFromContrast(compare, limit) if comp(contrast(orig, compare), limit) else orig

def genRainbow(hues, minCon, maxCon):
    target = {"background": (bgHue,bgSat),
              "foreground": (foreHue, foreSat),
              "accent": (accentHue, accentSat)}[options.hueBlendTarget]
    backFull = colorsys.hls_to_rgb(target[0], 0.5, target[1])
    
    rainbow = [mixColors(colorsys.hls_to_rgb(hue/360.0, 0.5, 1.0), backFull, hueBlend) for hue in hues]
    
    rainLums = [luminance(col) for col in rainbow]
    hiLum, loLum = max(rainLums), min(rainLums)
    minLum, maxLum = sorted((lumFromContrast(bgLum, minCon), lumFromContrast(bgLum, minCon if options.equiluminant else maxCon )))
    maxLum = min(1.0, maxLum)
    
    darkenBrown = (options.equiluminant or options.lightBrown)
    
    rainHLS = [colorsys.rgb_to_hls(*col) for col in rainbow]
    return [makeColor(rainHLS[c][0], reposition(loLum, hiLum+0.00001, rainLums[c], minLum, maxLum) if c < 7 or darkenBrown else minLum, rainHLS[c][2] / (1 if c < 7 else 1.5)) for c in range(len(rainbow))]

def printBanner(commentChar):
    say = lambda st: print(commentChar+" "+st)
    sayIf = lambda cond, st: say(st) if cond else None
    say("generated by acid16 - https://git.lain.church/whut/acid16")
    say("--- settings ---")
    say("background {}: {} {} {}".format("HSL" if options.hsl else "HCL", bgHue, bgSat, origLum))
    say("accent HC     : {} {}".format(accentHue, accentSat))
    say("foreground HC : {} {}".format(foreHue, foreSat))
    sayIf(hueBlend > 0.0, "hue blend     : {}, with {}".format(hueBlend, options.hueBlendTarget))
    sayIf(foreContrast != 7, "fg contrast   : {}".format(foreContrast))
    sayIf(options.equiluminant, "equiluminant hues")
    sayIf(options.hsl, "using gamma-encoded HSL")

def usable(col):
    return tuple(int(x*255+0.5) for x in toSRGB(col))

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

def base16Generate():
    background = makeBackground()
    foreLum = clamp(foregroundLum())
    foreCon = contrast(foreLum, bgLum)
    foreground = makeColor(foreHue, foreLum, foreSat)
    commentLum = lumFromContrast(bgLum, max(4.5, 1.0 + foreCon / 2.0))
    comment = makeColor(accentHue, commentLum, accentSat)

    accentLum = constrain(lumFromContrast(foreLum, 4.5), bgLum, 2.0)
    accent = makeColor(accentHue, accentLum, accentSat)

    statusBgLum = lumFromContrast(bgLum, 1.25)
    backStatus = makeColor(bgHue, statusBgLum, bgSat)
    
    foreStatus = makeColor(foreHue, lumFromContrast(statusBgLum, 7.0), foreSat)
    
    # 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)

    rainbow = genRainbow([RED, 23, YELLOW, GREEN, CYAN, BLUE, MAGENTA, 15], 4.5, 7.0)
    cols = [background, backStatus, accent, comment, foreStatus, foreground, foreLight, backLight] + rainbow
    
    printBanner("#")
    if options.lightBrown:
        print("# not darkening last color (brown)")

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

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

def base16Preview(im, cols):
    background, foreground, accent, comment, backLighter, foreDark, rainbow = cols[0], cols[5], cols[2], cols[3], cols[1], cols[4], cols[8:]
    
    w, h = im.size()
    
    im.draw.rectangle((2, 2, w-2, 32), usable(accent))
    im.text(5, 5, "Foreground on highlight", foreground, accent)
    im.text(5, 45, "Foreground on background", foreground, background)
    im.text(5, 85, "# Comment color", comment, background)

    for i in range(len(rainbow)):
        im.draw.rectangle((4, 120+i*35, 84, 145+i*35), usable(rainbow[i]))
        im.text(90, 123+i*35, "Colored text", rainbow[i], background)
    
    im.draw.rectangle((0, h-80, w, h-40), usable(backLighter))
    im.text(5, h-75, "Status foreground", foreDark, backLighter)
    im.draw.line((0, h-42, w, h-42), usable(foreground), 2)
    
    im.drawPalette(cols)

def xresourcesGenerate():
    background = makeBackground()
    foreLum = clamp(foregroundLum())
    foreground = makeColor(foreHue, foreLum, foreSat)
    cursor = makeColor(accentHue, constrain(lumFromContrast(foreLum, 3), bgLum, 2.0), accentSat)
    
    rainHues = [RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN]
    
    hiCon, loCon = (4.5, 7.0), (3.0, 4.5)
    
    loRainbow = genRainbow(rainHues, *loCon)
    hiRainbow = [makeColor(hue(c), lumFromContrast(luminance(c), 3) if foreLum > bgLum else luminance(c) / 3, saturation(c)) for c in loRainbow]
    darkRainbow, lightRainbow = (loRainbow, hiRainbow) if foreLum > bgLum else (hiRainbow, loRainbow)
    firstGrey = min(lumFromContrast(bgLum, 3), lumFromContrast(bgLum, 4.5))
    
    greys = [makeColor(0, lum, 0) for lum in sorted((firstGrey, lumFromContrast(firstGrey, 3)))]

    minLum, maxLum = sorted((bgLum, foreLum))
    black = makeColor(0, minLum / 2.0, 0)
    white = makeColor(0, (1.0 + maxLum) / 2.0, 0)
    
    cols = [black] + darkRainbow + [greys[1], greys[0]] + lightRainbow + [white]

    print("*foreground: #"+toHex(foreground))
    print("*background: #"+toHex(background))
    print("*cursorColor: #"+toHex(cursor))

    for i in range(len(cols)):
        print("*color{}: #{}".format(i, toHex(cols[i])))

    return [background, foreground, cursor] + cols

def xresourcesPreview(im, cols):
    background, foreground, cursor = cols[:3]
    cols = cols[3:]
    w, h = im.size()

    im.text(5, 5, "Foreground on background", foreground, background)
    im.draw.rectangle((2, 27, w-2, 52), usable(cursor))
    im.text(5, 30, "Foreground on cursor color", foreground, cursor)

    for i in range(len(cols)):
        x, y = (i // 8) * 300, (i % 8) * 30
        im.text(20+x, 80+y, "Color", cols[i], background)

    im.drawPalette(cols)

cols = globals()[options.mode+"Generate"]()
if options.showPreview:
    im = ImageHandler(cols[0])
    globals()[options.mode+"Preview"](im, cols)
    im.show()