"""Offline packer for the native MASM roulette sprite renderer."""
from pathlib import Path
from collections import deque
from PIL import Image

ROOT = Path(__file__).resolve().parents[2]
SIZE = 256


def cells(path):
    image = Image.open(path).convert("RGBA")
    for index in range(8):
        col, row = index % 4, index // 4
        yield image.crop((round(col * image.width / 4),
                          round(row * image.height / 2),
                          round((col + 1) * image.width / 4),
                          round((row + 1) * image.height / 2)))


def main():
    sprites = ROOT / "assets/sprites/roulette"
    frames = []
    weapon_cells = list(cells(sprites / "revolver-actions-v1.png"))
    for frame_index, image in enumerate(weapon_cells):
        # Remove tiny disconnected atlas fragments, retaining muzzle flash components.
        pixels = bytearray(image.getchannel("A").point(lambda a: 255 if a >= 128 else 0).tobytes())
        clean = bytearray(len(pixels))
        components = []
        for start, opacity in enumerate(pixels):
            if not opacity:
                continue
            component, queue = [], deque([start])
            pixels[start] = 0
            while queue:
                index = queue.popleft()
                component.append(index)
                x, y = index % image.width, index // image.width
                neighbors = []
                if x: neighbors.append(index - 1)
                if x + 1 < image.width: neighbors.append(index + 1)
                if y: neighbors.append(index - image.width)
                if y + 1 < image.height: neighbors.append(index + image.width)
                for neighbor in neighbors:
                    if pixels[neighbor]:
                        pixels[neighbor] = 0
                        queue.append(neighbor)
            components.append(component)
        largest = max(map(len, components), default=0)
        for component in components:
            if len(component) == largest or (frame_index == 5 and len(component) >= largest * 0.07):
                for index in component:
                    clean[index] = 255
        image.putalpha(Image.frombytes("L", image.size, bytes(clean)))
        # Match the runtime alpha test so faint atlas noise cannot alter the anchor.
        bounds = image.getchannel("A").point(lambda a: 255 if a >= 128 else 0).getbbox()
        if bounds is None:
            raise ValueError("Empty revolver frame")
        image = image.crop(bounds)
        image.thumbnail((238, 238), Image.Resampling.LANCZOS)
        frame = Image.new("RGBA", (SIZE, SIZE))
        frame.alpha_composite(image, ((SIZE - image.width) // 2,
                                      (SIZE - image.height) // 2))
        frames.append(frame)
    for image in cells(sprites / "gman-talk-v1.png"):
        frame = image.resize((SIZE, SIZE), Image.Resampling.LANCZOS)
        frame.putalpha(255)
        frames.append(frame)
    target = ROOT / "assets/animations/roulette/roulette-scenes.bin"
    target.parent.mkdir(parents=True, exist_ok=True)
    target.write_bytes(b"".join(frame.tobytes("raw", "BGRA") for frame in frames))
    assert target.stat().st_size == 16 * SIZE * SIZE * 4
    contact = Image.new("RGBA", (4 * SIZE, 4 * SIZE), (20, 32, 30, 255))
    for index, frame in enumerate(frames):
        contact.alpha_composite(frame, ((index % 4) * SIZE, (index // 4) * SIZE))
    contact.convert("RGB").save(ROOT / "build/actions/roulette-contact.png")
    print(f"Packed {len(frames)} frames: {target}")


if __name__ == "__main__":
    main()