#!/usr/bin/env python3
"""Generiert das PulseGate-Icon als .ico (und .png) ohne externe Abhängigkeiten."""
from __future__ import annotations

import struct
import sys
import zlib
from pathlib import Path

ACCENT = (0x00, 0xFF, 0x99)
SURFACE = (0x0D, 0x1B, 0x15)
BG = (0x07, 0x11, 0x0D)

ROOT = Path(__file__).resolve().parent.parent
OUT_DIR = ROOT / "assets"
SIZES = [16, 32, 48, 64, 128, 256]


def pixel(size: int, x: int, y: int) -> tuple[int, int, int, int]:
    nx = (x + 0.5) / size
    ny = (y + 0.5) / size

    if nx < 0.08 or nx > 0.92 or ny < 0.08 or ny > 0.92:
        return (*ACCENT, 255)

    if 0.34 < nx < 0.66 and 0.34 < ny < 0.66:
        return (*ACCENT, 255)

    if 0.24 < nx < 0.76 and 0.24 < ny < 0.76:
        return (*SURFACE, 255)

    return (*BG, 255)


def bmp_data(size: int) -> bytes:
    header = struct.pack("<IiiHHIIiiII", 40, size, size * 2, 1, 32, 0, size * size * 4, 0, 0, 0, 0)
    xor = bytearray()
    for y in range(size - 1, -1, -1):
        for x in range(size):
            r, g, b, a = pixel(size, x, y)
            xor += bytes((b, g, r, a))
    return header + bytes(xor)


def write_ico(path: Path) -> None:
    blocks = [bmp_data(size) for size in SIZES]
    count = len(SIZES)
    total_size = 6 + 16 * count + sum(len(b) for b in blocks)

    out = bytearray(struct.pack("<HHH", 0, 1, count))
    offset = 6 + 16 * count
    for size, block in zip(SIZES, blocks):
        entry = struct.pack(
            "<BBBBHHII",
            size % 256,
            size % 256,
            0,
            0,
            1,
            32,
            len(block),
            offset,
        )
        out += entry
        offset += len(block)
    for block in blocks:
        out += block
    path.write_bytes(bytes(out))


def write_png(path: Path, size: int) -> None:
    raw = bytearray()
    for y in range(size):
        raw += b"\x00"
        for x in range(size):
            raw += bytes(pixel(size, x, y))
    ihdr = struct.pack(">IIBBBBB", size, size, 8, 6, 0, 0, 0)
    chunks = []
    for chunk_type, data in ((b"IHDR", ihdr), (b"IDAT", zlib.compress(bytes(raw), 9)), (b"IEND", b"")):
        crc = zlib.crc32(chunk_type + data) & 0xFFFFFFFF
        chunks.append(struct.pack(">I", len(data)) + chunk_type + data + struct.pack(">I", crc))
    path.write_bytes(b"\x89PNG\r\n\x1a\n" + b"".join(chunks))


def main() -> int:
    OUT_DIR.mkdir(parents=True, exist_ok=True)
    write_ico(OUT_DIR / "pulsegate.ico")
    write_png(OUT_DIR / "pulsegate.png", 256)
    print(f"Assets erzeugt in {OUT_DIR}")
    return 0


if __name__ == "__main__":
    sys.exit(main())