"""Generate the Media Server application icon.

The SVG in ``media_server/static/icons/icon.svg`` is the single source of
truth. This script rasterizes it at every Windows ICO size via ``resvg-py``
(Rust-backed, identical math to Firefox's SVG renderer) and packs them all
into a multi-resolution ``icon.ico``.

This replaces the original 16x16-only ICO that Windows was upscaling into
mush for the installer chrome, Start Menu, desktop shortcuts, and Alt+Tab.

Usage:
    python scripts/generate-icon.py

Dependencies:
    pip install resvg-py Pillow
"""

from __future__ import annotations

import io
from pathlib import Path

import resvg_py
from PIL import Image

# Sizes packed into the ICO. Windows picks the closest match per surface;
# more sizes = sharper rendering everywhere (taskbar, installer header,
# Alt+Tab, jump lists, Start tile, desktop, file explorer details/tiles).
ICO_SIZES: tuple[int, ...] = (16, 20, 24, 32, 40, 48, 64, 96, 128, 256)

# The SVG source. Squircle + diagonal teal gradient + warm parchment play
# triangle with a drop shadow + ghosted echo-chevrons hinting at broadcast.
SVG_SOURCE = """<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256" role="img" aria-label="Media Server">
  <defs>
    <linearGradient id="bg" x1="0%" y1="0%" x2="100%" y2="100%">
      <stop offset="0%"  stop-color="#0B3D3B"/>
      <stop offset="100%" stop-color="#1A6B5E"/>
    </linearGradient>
    <linearGradient id="sheen" x1="50%" y1="0%" x2="50%" y2="100%">
      <stop offset="0%"  stop-color="#FFFFFF" stop-opacity="0.18"/>
      <stop offset="55%" stop-color="#FFFFFF" stop-opacity="0"/>
    </linearGradient>
    <filter id="triShadow" x="-20%" y="-20%" width="140%" height="140%">
      <feGaussianBlur stdDeviation="3"/>
      <feOffset dx="3" dy="5"/>
      <feComponentTransfer><feFuncA type="linear" slope="0.45"/></feComponentTransfer>
      <feMerge><feMergeNode/><feMergeNode in="SourceGraphic"/></feMerge>
    </filter>
    <clipPath id="clip"><rect x="0" y="0" width="256" height="256" rx="58" ry="58"/></clipPath>
  </defs>
  <g clip-path="url(#clip)">
    <rect width="256" height="256" fill="url(#bg)"/>
    <rect width="256" height="256" fill="url(#sheen)"/>
    <g stroke="#F5F1E8" stroke-width="4.6" stroke-linecap="round" stroke-linejoin="round" fill="none" opacity="0.18">
      <polyline points="66,72 105,128 66,184"/>
      <polyline points="85,82 124,128 85,174" opacity="0.6"/>
    </g>
    <path d="M88.3 55 L88.3 201 L193.3 128 Z"
          fill="#F5F1E8"
          stroke="#F5F1E8" stroke-width="9" stroke-linejoin="round"
          filter="url(#triShadow)"/>
  </g>
  <rect x="0.5" y="0.5" width="255" height="255" rx="58" ry="58"
        fill="none" stroke="#000000" stroke-opacity="0.18" stroke-width="1"/>
</svg>
"""


def _render_png(size: int) -> Image.Image:
    """Rasterize the SVG to a PNG at ``size x size`` via resvg."""
    data = resvg_py.svg_to_bytes(
        svg_string=SVG_SOURCE,
        width=size,
        height=size,
        shape_rendering="geometric_precision",
    )
    return Image.open(io.BytesIO(bytes(data))).convert("RGBA")


def main() -> None:
    root = Path(__file__).resolve().parent.parent
    out_dir = root / "media_server" / "static" / "icons"
    out_dir.mkdir(parents=True, exist_ok=True)

    # SVG — canonical source, also used as the Web UI favicon.
    svg_path = out_dir / "icon.svg"
    svg_path.write_text(SVG_SOURCE, encoding="utf-8")
    print(f"wrote {svg_path}")

    # Rasterize every ICO size via resvg.
    frames = [_render_png(size) for size in ICO_SIZES]

    # Pack into a multi-resolution ICO. The "primary" image must be the
    # largest; the rest go via append_images. Pillow's ICO writer then
    # serializes one frame per size.
    primary = frames[-1]
    ico_path = out_dir / "icon.ico"
    primary.save(
        ico_path,
        format="ICO",
        sizes=[(s, s) for s in ICO_SIZES],
        append_images=frames[:-1],
    )
    print(f"wrote {ico_path}  ({ico_path.stat().st_size:,} bytes, sizes={list(ICO_SIZES)})")

    # Largest PNG for documentation / non-Windows surfaces.
    png_path = out_dir / "icon-256.png"
    primary.save(png_path, format="PNG", optimize=True)
    print(f"wrote {png_path}")


if __name__ == "__main__":
    main()