import struct
import sys

from PIL import Image
from twiddle import texture as twiddle_texture, npot

class color_format:
    def gbgr1555(r, g, b, a): # nintendo ds
        r5 = (r >> 3) & 31
        g6 = (g >> 3) & 31
        g6_l = (g >> 2) & 1
        b5 = (b >> 3) & 31
        return (g6_l << 15) | (b5 << 10) | (g6 << 5) | (r5 << 0)

    def argb4444(r, g, b, a):
        a4 = (a >> 4) & 15
        r4 = (r >> 4) & 15
        g4 = (g >> 4) & 15
        b4 = (b >> 4) & 15
        return (a4 << 12) | (r4 << 8) | (g4 << 4) | (b4 << 0)

    def argb1555(r, g, b, a):
        a1 = (a >> 7) & 1
        r5 = (r >> 3) & 31
        g5 = (g >> 3) & 31
        b5 = (b >> 3) & 31
        return (a1 << 15) | (r5 << 10) | (g5 << 5) | (b5 << 0)

    def rgb565(r, g, b, a):
        r5 = (r >> 3) & 31
        g6 = (g >> 2) & 63
        b5 = (b >> 3) & 31
        return (r5 << 11) | (g6 << 5) | (b5 << 0)

    def axxx4444(r, g, b, a):
        a4 = (a >> 4) & 15
        return (a4 << 12)

    def from_string(s):
        return dict([
            ("gbgr1555", color_format.gbgr1555),
            ("argb4444", color_format.argb4444),
            ("argb1555", color_format.argb1555),
            ("rgb565", color_format.rgb565),
            ("axxx4444", color_format.axxx4444),
        ])[s]

class unconvert_color_format:
    def argb1555(value):
        a = (value >> 15) & 0b1
        r = (value >> 10) & 0b11111
        g = (value >> 5 ) & 0b11111
        b = (value >> 0 ) & 0b11111
        return (r * 8, g * 8, b * 8, a * 255)

    def from_string(s):
        return dict([
            #("gbgr1555", unconvert_color_format.gbgr1555),
            #("argb4444", unconvert_color_format.argb4444),
            ("argb1555", unconvert_color_format.argb1555),
            #("rgb565", unconvert_color_format.rgb565),
            #("axxx4444", unconvert_color_format.axxx4444),
        ])[s]

def convert_colors(convert, colors):
    for color in colors:
        value = convert(*color)
        yield value

def convert_indices(palette, pixels):
    if len(palette) <= 4:
        for i in range(len(pixels) // 4):
            a = pixels[i * 4 + 0]
            b = pixels[i * 4 + 1]
            c = pixels[i * 4 + 2]
            d = pixels[i * 4 + 3]
            assert a <= 3 and b <= 3 and c <= 3 and d <= 3, (a, b, c, d)
            pixel = (d << 6) | (c << 4) | (b << 2) | (a << 0)
            assert False, len(palette)
            yield pixel
    elif len(palette) <= 16:
        for i in range(len(pixels) // 2):
            a = pixels[i * 2 + 0]
            b = pixels[i * 2 + 1]
            assert a <= 15 and b <= 15, (a, b)
            pixel = (b << 4) | (a << 0)
            yield pixel
    elif len(palette) <= 256:
        for pixel in pixels:
            assert pixel <= 255
            yield pixel
    else:
        assert False, len(palette)

def pack_colors(f, colors):
    for value in colors:
        f.write(struct.pack("<H", value))

def pack_indices(f, indices):
    for value in indices:
        f.write(struct.pack("<B", value))

def mip_levels(n):
    while n > 0:
        yield n
        n = n >> 1

def resize(im, l):
    new = im.resize(
        size=(l, l),
        resample=Image.Resampling.LANCZOS,
    )
    new.save(f"{l:03}.png")
    return new

def generate_mips(im):
    w, h = im.size
    assert w == h and npot(w) == w, (w, h)
    assert w >= 8, (w, h)

    images = [im] + [resize(im, l) for l in mip_levels(w >> 1)]

    return list(reversed(images))

def write_mip(f, mip: Image, is_twiddled: bool, convert):
    width, height = mip.size
    #print("mip", width, "offset", f"{f.tell():06x}")
    pixels = list(mip.convert("RGBA").getdata())
    colors = list(convert_colors(convert, pixels))
    assert len(colors) == width * height, len(colors)
    if is_twiddled:
        new_colors = [0] * width * height
        max_twiddle_ix = twiddle_texture(new_colors, colors, width, height)
        assert max_twiddle_ix + 1 == width * height, (max_twiddle_ix, width, height)
        colors = new_colors[:max_twiddle_ix+1]
    pack_colors(f, colors)

def write_mips(f, im: Image, is_twiddled: bool, convert):
    for mip in generate_mips(im):
        write_mip(f, mip, is_twiddled, convert)

def write_png_reference(size, filename, unconvert, colors):
    im = Image.new("RGBA", size)
    data = [unconvert(value) for value in colors]
    im.putdata(data)
    im.save(filename)

def main():
    in_file = sys.argv[1]
    format = sys.argv[2]
    assert sys.argv[3] in {"twiddled", "non_twiddled"}
    is_twiddled = sys.argv[3] == "twiddled"
    assert sys.argv[4] in {"mipmapped", "non_mipmapped"}
    is_mipmapped = sys.argv[4] == "mipmapped"
    out_file = sys.argv[5]
    ref_file = sys.argv[6] if len(sys.argv) > 6 else None

    convert = color_format.from_string(format)

    with Image.open(in_file) as im:
        width, height = im.size
        assert width <= 1024 and height <= 1024, (width, height)
        assert not im.palette
        #if not im.palette:
        if True:
            with open(out_file, 'wb') as f:
                if is_mipmapped:
                    f.write(bytes([0] * 6))
                    write_mips(f, im, is_twiddled, convert)
                else:
                    write_mip(f, im, is_twiddled, convert)
            """
            if ref_file is not None:
                unconvert = unconvert_color_format.from_string(format)
                write_png_reference(im.size, ref_file, unconvert, colors)
            """
        else:
            assert False
            pixels = list(im.convert("P").getdata())
            palette = list(im.palette.colors)
            indices = list(convert_indices(palette, pixels))
            colors = list(convert_colors(convert, [(*c, 255) for c in palette]))

            if is_twiddled:
                new_indices = [0] * len(indices)
                twiddle_texture(new_indices, indices, width, height)
                indices = new_indices

            with open(out_file + '.pal', 'wb') as f:
                pack_colors(f, colors)

            with open(out_file, 'wb') as f:
                pack_indices(f, indices)

if __name__ == "__main__":
    main()