#!/usr/bin/env python3

__version__ = "1.0"

from argparse import ArgumentParser
from PIL import Image

# firmware
CPC_PAL = (
    [0, 0, 0],
    [0, 0, 128],
    [0, 0, 255],
    [128, 0, 0],
    [128, 0, 128],
    [128, 0, 255],
    [255, 0, 0],
    [255, 0, 128],
    [255, 0, 255],
    [0, 128, 0],
    [0, 128, 128],
    [0, 128, 255],
    [128, 128, 0],
    [128, 128, 128],
    [128, 128, 255],
    [255, 128, 0],
    [255, 128, 128],
    [255, 128, 255],
    [0, 255, 0],
    [0, 255, 128],
    [0, 255, 255],
    [128, 255, 0],
    [128, 255, 128],
    [128, 255, 255],
    [255, 255, 0],
    [255, 255, 128],
    [255, 255, 255],
)

SW_TO_HW = (
    0x54,
    0x44,
    0x55,
    0x5C,
    0x58,
    0x5D,
    0x4C,
    0x45,
    0x4D,
    0x56,
    0x46,
    0x57,
    0x5E,
    0x40,
    0x5F,
    0x4E,
    0x47,
    0x4F,
    0x52,
    0x42,
    0x53,
    0x5A,
    0x59,
    0x5B,
    0x4A,
    0x43,
    0x4B,
)


def main():

    parser = ArgumentParser(
        description="PNG to CPC palette (firmware)",
        epilog="Copyright (C) 2015-2023 Juan J Martinez <jjm@usebox.net>",
    )

    parser.add_argument(
        "--version", action="version", version="%(prog)s " + __version__
    )
    parser.add_argument("--header", dest="header", action="store_true")
    parser.add_argument("--hardware", dest="hardware", action="store_true")
    parser.add_argument("image", help="image to convert")
    parser.add_argument(
        "pal_dump",
        help="filename for the palette dump (variable if header flag is set)",
    )

    args = parser.parse_args()

    try:
        image = Image.open(args.image)
    except IOError:
        parser.error("failed to open the image")

    if image.mode != "P":
        parser.error("not an indexed image (no palette)")

    palette = image.getpalette()
    if not palette:
        parser.error("failed to extract the palette (is this an indexed image?)")

    rgb = []
    for i in range(0, 16 * 3, 3):
        c = palette[i : i + 3]
        if c not in CPC_PAL:
            parser.error("%r not in the CPC palette" % c)
        rgb.append(c)

    out = [CPC_PAL.index(c) for c in rgb]
    if len(out) < 16:
        out.extend([0 for _ in range(16 - len(out))])

    if args.hardware:
        out = [SW_TO_HW[c] for c in out[:]]

    if args.header:
        print("/* %s palette */" % ("hardware" if args.hardware else "firmware"))
        print("#ifdef LOCAL")
        print(
            "const unsigned char %s[] = { %s };\n"
            % (args.pal_dump, ", ".join([hex(c) for c in out]))
        )
        print("#else")
        print("extern const unsigned char %s[];\n" % (args.pal_dump))
        print("#endif")
    else:
        with open(args.pal_dump, "wb") as fd:
            fd.write(bytearray(out))


if __name__ == "__main__":
    main()