"""Render the shared pixel maps to PNG without Aseprite.

Same source of truth as gen_sprites.lua (tools/aseprite/maps/); use
this for headless preview on boxes with no Aseprite. Output is
_ph placeholder-grade per the asset policy.

  uv run --with pillow python tools/aseprite/preview.py \
      [--maps tools/aseprite/maps] [--out assets/sprites_ph] [--zoom 8]

Writes <name>.png (1x) and, with --zoom N > 1, <name>@Nx.png
(nearest-neighbor upscale).
"""

import argparse
from pathlib import Path

from PIL import Image

SPRITES = ["m03_ph", "grunt_ph", "burster_ph", "slug_ph", "scrap_ph"]


def parse_palette(path: Path) -> dict[str, tuple[int, int, int, int]]:
    pal = {}
    for line in path.read_text().splitlines():
        parts = line.split()
        if len(parts) == 2 and len(parts[0]) == 1 and parts[0] != "#":
            v = int(parts[1], 16)
            pal[parts[0]] = ((v >> 16) & 255, (v >> 8) & 255, v & 255, 255)
    return pal


def parse_map(path: Path) -> list[str]:
    rows = [line for line in path.read_text().splitlines() if line]
    for i, row in enumerate(rows):
        if len(row) != len(rows[0]):
            raise ValueError(f"{path}: row {i + 1} width {len(row)} != {len(rows[0])}")
    return rows


def main() -> None:
    ap = argparse.ArgumentParser()
    ap.add_argument("--maps", default="tools/aseprite/maps")
    ap.add_argument("--out", default="assets/sprites_ph")
    ap.add_argument("--zoom", type=int, default=8)
    args = ap.parse_args()

    maps_dir = Path(args.maps)
    out_dir = Path(args.out)
    out_dir.mkdir(parents=True, exist_ok=True)
    pal = parse_palette(maps_dir / "palette.txt")

    for name in SPRITES:
        rows = parse_map(maps_dir / f"{name}.txt")
        w, h = len(rows[0]), len(rows)
        img = Image.new("RGBA", (w, h), (0, 0, 0, 0))
        for y, row in enumerate(rows):
            for x, ch in enumerate(row):
                if ch != ".":
                    if ch not in pal:
                        raise ValueError(f"{name}: unknown palette char {ch!r}")
                    img.putpixel((x, y), pal[ch])
        img.save(out_dir / f"{name}.png")
        if args.zoom > 1:
            big = img.resize((w * args.zoom, h * args.zoom), Image.Resampling.NEAREST)
            big.save(out_dir / f"{name}@{args.zoom}x.png")
        print(f"wrote {out_dir}/{name}.png {w}x{h}")


if __name__ == "__main__":
    main()