"""Pack project-local source art into the MASM renderer's 128px BGRA slots.

Python is an offline build tool; the shipped game has no Python dependency.
Only transparent alpha is discarded. Black, white and gold detail is retained.
"""
from pathlib import Path
from PIL import Image

ROOT = Path(__file__).resolve().parents[1]
SIZE = 128
SLOTS = 48
CHROMA = (255, 0, 255, 0)


def cells(path, columns, rows):
    image = Image.open(path).convert("RGBA")
    return [image.crop((c * image.width // columns, r * image.height // rows,
                        (c + 1) * image.width // columns, (r + 1) * image.height // rows))
            for r in range(rows) for c in range(columns)]


def sprite(cell):
    # Preserve each sheet's common anchor and scale, including internal margins.
    scale = min((SIZE - 8) / cell.width, (SIZE - 8) / cell.height)
    resized = cell.resize((round(cell.width * scale), round(cell.height * scale)),
                          Image.Resampling.LANCZOS)
    out = Image.new("RGBA", (SIZE, SIZE), (0, 0, 0, 0))
    out.alpha_composite(resized, ((SIZE - resized.width) // 2, SIZE - 4 - resized.height))
    return out


def pack(image, is_sprite=False):
    result = bytearray()
    for r, g, b, a in image.getdata():
        if is_sprite and a < 128:
            r, g, b, a = CHROMA
        result.extend((b, g, r, 0))
    return result


def main():
    raw = (ROOT / "assets/textures/casino3d.bin").read_bytes()
    assert len(raw) == SLOTS * 64 * 64 * 4
    textures = []
    for n in range(SLOTS):
        tile = Image.frombytes("RGBA", (64, 64), raw[n * 16384:(n + 1) * 16384],
                               "raw", "BGRA")
        tile.putalpha(255)
        textures.append(tile.resize((SIZE, SIZE), Image.Resampling.NEAREST))
    atlas = cells(ROOT / "assets/sprites/casino-atlas-v1.png", 4, 4)
    dancer = cells(ROOT / "assets/sprites/cabaret-loop-v1.png", 4, 3)
    sprites = {}
    for n, frame in enumerate(dancer):
        sprites[10 + n] = sprite(frame)
    for slot, cell in {24: 4, 25: 5, 26: 6, 30: 7, 31: 8, 32: 10,
                       34: 9, 35: 11, 36: 12, 37: 13, 38: 14, 39: 15}.items():
        sprites[slot] = sprite(atlas[cell])
    # The original ATM uses an explicit magenta chroma background.
    textures[33].putalpha(255)
    for slot, image in sprites.items():
        textures[slot] = image
    data = b"".join(pack(image, n in sprites) for n, image in enumerate(textures))
    assert len(data) == SLOTS * SIZE * SIZE * 4
    target = ROOT / "assets/textures/casino3d-hd.bin"
    target.write_bytes(data)
    preview = Image.new("RGBA", (SIZE * 8, SIZE * 6), (24, 29, 32, 255))
    for n, image in enumerate(textures):
        preview.alpha_composite(image, ((n % 8) * SIZE, (n // 8) * SIZE))
    preview.convert("RGB").save(ROOT / "build/graphics/texture-atlas-preview.png")
    dancer_preview = [sprites[10 + n].resize((256, 256), Image.Resampling.NEAREST)
                      for n in range(12)]
    dancer_preview[0].save(ROOT / "build/graphics/cabaret-loop-preview.gif", save_all=True,
                          append_images=dancer_preview[1:], duration=100, loop=0, disposal=2)
    print(f"Packed {SLOTS} x {SIZE}x{SIZE}: {target}")


if __name__ == "__main__":
    main()