"""Render assets/icon.png and a multi-size assets/icon.ico. Run once; outputs are committed."""

import os
import struct
import sys
from pathlib import Path

os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")

from PySide6.QtCore import QBuffer, QPointF, QRectF, Qt
from PySide6.QtGui import QColor, QGuiApplication, QImage, QLinearGradient, QPainter, QPainterPath, QPolygonF

ASSETS = Path(__file__).resolve().parent.parent / "assets"


def render(size: int) -> QImage:
    img = QImage(size, size, QImage.Format_ARGB32)
    img.fill(Qt.transparent)
    p = QPainter(img)
    p.setRenderHint(QPainter.Antialiasing)
    s = size / 256
    grad = QLinearGradient(0, 0, 0, size)
    grad.setColorAt(0, QColor("#2f80ed"))
    grad.setColorAt(1, QColor("#1b4f9c"))
    path = QPainterPath()
    path.addRoundedRect(QRectF(8 * s, 8 * s, 240 * s, 240 * s), 52 * s, 52 * s)
    p.fillPath(path, grad)
    # Film strip holes along the top and bottom edges.
    p.setBrush(QColor(255, 255, 255, 70))
    p.setPen(Qt.NoPen)
    for i in range(6):
        x = (38 + i * 34) * s
        p.drawRoundedRect(QRectF(x, 22 * s, 18 * s, 14 * s), 3 * s, 3 * s)
        p.drawRoundedRect(QRectF(x, 220 * s, 18 * s, 14 * s), 3 * s, 3 * s)
    # Two chevrons: "convert from -> to".
    p.setBrush(QColor("white"))
    for dx in (0, 62):
        p.drawPolygon(QPolygonF([QPointF((70 + dx) * s, 72 * s), QPointF((136 + dx) * s, 128 * s),
                                 QPointF((70 + dx) * s, 184 * s), QPointF((70 + dx) * s, 152 * s),
                                 QPointF((100 + dx) * s, 128 * s), QPointF((70 + dx) * s, 104 * s)]))
    p.end()
    return img


def png_bytes(img: QImage) -> bytes:
    buf = QBuffer()
    buf.open(QBuffer.WriteOnly)
    img.save(buf, "PNG")
    return bytes(buf.data())


def write_ico(path: Path, sizes=(16, 24, 32, 48, 64, 128, 256)) -> None:
    images = [png_bytes(render(n)) for n in sizes]
    header = struct.pack("<HHH", 0, 1, len(images))
    offset = 6 + 16 * len(images)
    entries, blobs = b"", b""
    for n, data in zip(sizes, images):
        entries += struct.pack("<BBBBHHII", n % 256, n % 256, 0, 0, 1, 32, len(data), offset)
        offset += len(data)
        blobs += data
    path.write_bytes(header + entries + blobs)


if __name__ == "__main__":
    app = QGuiApplication(sys.argv)
    ASSETS.mkdir(exist_ok=True)
    render(256).save(str(ASSETS / "icon.png"))
    write_ico(ASSETS / "icon.ico")
    print("wrote", ASSETS / "icon.png", ASSETS / "icon.ico")