"""Generate icon variants from the sandcage source image."""

from pathlib import Path

from PIL import Image, ImageDraw

ROOT = Path(__file__).resolve().parent.parent
SRC = ROOT / ".workpad" / "assets" / "sandcage.png"
OUT = ROOT / "local"


def square_crop(src: Path, size: int = 1024) -> Image.Image:
    img = Image.open(src).convert("RGBA")
    w, h = img.size
    side = min(w, h)
    left = (w - side) // 2
    top = (h - side) // 2
    img = img.crop((left, top, left + side, top + side))
    return img.resize((size, size), Image.LANCZOS)


def invert_rgb(img: Image.Image) -> Image.Image:
    from PIL import ImageChops
    r, g, b, a = img.split()
    return Image.merge("RGBA", (ImageChops.invert(r), ImageChops.invert(g), ImageChops.invert(b), a))


def lighten_dune_interior(img: Image.Image, grey: int = 80) -> Image.Image:
    img = img.copy()
    draw = ImageDraw.Draw(img)
    fill = (grey, grey, grey, 255)
    # tips found at (56,567) and (973,567), dune bottom at y=652
    # draw a filled arc (pieslice) from tip to tip curving below to seal the interior
    # pieslice bbox: center the ellipse so it passes through both tips
    cx = (56 + 973) // 2
    half_w = (973 - 56) // 2
    arc_depth = 120
    bbox = (cx - half_w, 567 - arc_depth, cx + half_w, 567 + arc_depth)
    # draw just the bottom arc in grey to create the barrier
    draw.arc(bbox, 0, 180, fill=fill, width=4)
    # flood fill the enclosed black region
    ImageDraw.floodfill(img, (300, 620), fill, thresh=60)
    return img


def apply_vertical_bars(img: Image.Image, bar_width: int = 48, gap_width: int = 48, opacity: float = 0.5) -> Image.Image:
    img = img.copy()
    r, g, b, a = img.split()
    bar_mask = Image.new("L", img.size, 255)
    draw = ImageDraw.Draw(bar_mask)
    bar_alpha = int(255 * opacity)
    x = 0
    while x < img.size[0]:
        draw.rectangle((x, 0, x + bar_width - 1, img.size[1]), fill=bar_alpha)
        x += bar_width + gap_width
    from PIL import ImageChops
    a = ImageChops.multiply(a, bar_mask)
    return Image.merge("RGBA", (r, g, b, a))


def apply_circle_mask(img: Image.Image, size: int = 1024) -> Image.Image:
    # circle passes through dune tips (56,567) and (973,567)
    # center at midpoint, radius = half the tip distance
    cx = (56 + 973) // 2  # 514
    cy = 567
    r = (973 - 56) // 2   # 458
    # crop to bounding box of this circle, then resize to output size
    left = max(cx - r, 0)
    top = max(cy - r, 0)
    right = min(cx + r, img.size[0])
    bottom = min(cy + r, img.size[1])
    cropped = img.crop((left, top, right, bottom))
    cropped = cropped.resize((size, size), Image.LANCZOS)
    # apply circular mask
    mask = Image.new("L", (size, size), 0)
    draw = ImageDraw.Draw(mask)
    draw.ellipse((0, 0, size, size), fill=255)
    result = Image.new("RGBA", (size, size), (0, 0, 0, 0))
    result.paste(cropped, (0, 0), mask)
    return result


def save(img: Image.Image, path: Path) -> Path:
    img.save(path)
    print(f"Wrote {path}")
    return path


if __name__ == "__main__":
    OUT.mkdir(parents=True, exist_ok=True)

    base = square_crop(SRC)
    inverted = invert_rgb(base)

    save(apply_circle_mask(base), OUT / "sandcage-round.png")
    save(apply_circle_mask(inverted), OUT / "sandcage-round-inverted.png")

    inverted_grey = lighten_dune_interior(inverted)
    save(apply_circle_mask(inverted_grey), OUT / "sandcage-round-inverted-grey.png")

    save(apply_circle_mask(apply_vertical_bars(base)), OUT / "sandcage-round-bars.png")
    save(apply_circle_mask(apply_vertical_bars(inverted)), OUT / "sandcage-round-inverted-bars.png")
    save(apply_circle_mask(apply_vertical_bars(inverted_grey)), OUT / "sandcage-round-inverted-grey-bars.png")