# retoor <retoor@molodetz.nl>
import hashlib
from functools import lru_cache
from html import escape

PALETTE = (
    ("#1b1a17", "#e2a100"),
    ("#141414", "#c9c2b2"),
    ("#1d1b16", "#b98a2e"),
    ("#121417", "#8fa3a8"),
    ("#191512", "#d9b779"),
)


@lru_cache(maxsize=4096)
def render_avatar_svg(seed, size=64):
    size = max(16, min(int(size), 512))
    try:
        digest = hashlib.sha256(seed.encode("utf-8")).digest()
        background, ink = PALETTE[digest[0] % len(PALETTE)]
        cells = []
        unit = size / 5
        for row in range(5):
            for col in range(3):
                if digest[1 + row * 3 + col] % 2 == 0:
                    for mirrored in {col, 4 - col}:
                        cells.append(
                            f'<rect x="{mirrored * unit:.2f}" y="{row * unit:.2f}" width="{unit:.2f}" height="{unit:.2f}" fill="{ink}"/>'
                        )
        body = "".join(cells)
    except Exception:
        background, ink = PALETTE[0]
        letter = escape((seed or "?")[:1].upper())
        body = f'<text x="50%" y="58%" text-anchor="middle" font-family="Georgia, serif" font-size="{size // 2}" fill="{ink}">{letter}</text>'
    return (
        f'<svg xmlns="http://www.w3.org/2000/svg" width="{size}" height="{size}" viewBox="0 0 {size} {size}">'
        f'<rect width="{size}" height="{size}" fill="{background}"/>{body}</svg>'
    )


def avatar_url(seed, size=64):
    return f"/avatar/svg/{seed}?size={size}"