#!/usr/bin/env python3
"""Generate Lyra PWA icons with no third-party deps (pure stdlib PNG writer).

Design: RTO warm/low-glow — near-black field, a soft orange ambient glow, and a
luminous gold-orange ring (the "orb/portal"). iOS masks corners itself, so icons
are full-bleed squares. Run from anywhere; writes PNGs into ./static.
"""
import math
import os
import struct
import zlib

HERE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "static")

BG = (7, 7, 7)            # #070707
ORANGE = (255, 122, 0)    # #ff7a00 accent
GOLD = (255, 179, 71)     # #ffb347 hot core


def _png(width, height, rgb_rows):
    def chunk(tag, data):
        return (struct.pack(">I", len(data)) + tag + data
                + struct.pack(">I", zlib.crc32(tag + data) & 0xFFFFFFFF))

    raw = bytearray()
    for row in rgb_rows:
        raw.append(0)  # filter type 0 (None)
        raw.extend(row)
    ihdr = struct.pack(">IIBBBBB", width, height, 8, 2, 0, 0, 0)  # 8-bit RGB
    return (b"\x89PNG\r\n\x1a\n"
            + chunk(b"IHDR", ihdr)
            + chunk(b"IDAT", zlib.compress(bytes(raw), 9))
            + chunk(b"IEND", b""))


def render(n):
    c = (n - 1) / 2.0
    sigma_glow = n * 0.30
    ring_r = n * 0.30
    ring_w = n * 0.050
    core_sigma = n * 0.11
    rows = []
    for y in range(n):
        row = bytearray()
        for x in range(n):
            dx, dy = x - c, y - c
            d = math.hypot(dx, dy)
            r, g, b = BG
            # ambient orange glow
            glow = math.exp(-(d * d) / (2 * sigma_glow * sigma_glow)) * 0.50
            # soft hot core
            core = math.exp(-(d * d) / (2 * core_sigma * core_sigma)) * 0.45
            # luminous ring
            rr = d - ring_r
            ring = math.exp(-(rr * rr) / (2 * ring_w * ring_w))
            r += ORANGE[0] * glow + GOLD[0] * (ring + core)
            g += ORANGE[1] * glow + GOLD[1] * (ring + core)
            b += ORANGE[2] * glow + GOLD[2] * (ring + core)
            row += bytes((min(255, int(r)), min(255, int(g)), min(255, int(b))))
        rows.append(row)
    return rows


def write(name, n):
    rows = render(n)
    with open(os.path.join(HERE, name), "wb") as f:
        f.write(_png(n, n, rows))
    print(f"wrote {name} ({n}x{n})")


if __name__ == "__main__":
    write("icon-512.png", 512)
    write("icon-192.png", 192)
    write("apple-touch-icon.png", 180)
    write("icon-maskable-512.png", 512)