"""Small activity spinner: a rotating accent-coloured arc. Runs only while visible."""
from PySide6.QtCore import QRectF, QTimer, Qt
from PySide6.QtGui import QColor, QPainter, QPen
from PySide6.QtWidgets import QWidget

from . import icons

STEP_MS = 16
STEP_DEG = 9


def paint_arc(p, rect, angle, color=icons.ACCENT):
    """Draw the spinner (faint ring + 100 degree arc) into rect; used by Spinner and the waveform overlay."""
    w = max(1.5, rect.width() / 8)
    r = rect.adjusted(w / 2, w / 2, -w / 2, -w / 2)
    p.save()
    p.setRenderHint(QPainter.RenderHint.Antialiasing)
    ring = QColor(color)
    ring.setAlpha(45)
    p.setPen(QPen(ring, w))
    p.drawEllipse(r)
    pen = QPen(QColor(color), w)
    pen.setCapStyle(Qt.PenCapStyle.RoundCap)
    p.setPen(pen)
    p.drawArc(r, int(-angle * 16), 100 * 16)
    p.restore()


class Spinner(QWidget):
    def __init__(self, size=16, parent=None):
        super().__init__(parent)
        self.setFixedSize(size, size)
        self.angle = 0
        self.timer = QTimer(self)
        self.timer.setInterval(STEP_MS)
        self.timer.timeout.connect(self._step)
        self.hide()

    def _step(self):
        self.angle = (self.angle + STEP_DEG) % 360
        self.update()

    def showEvent(self, e):
        self.timer.start()
        super().showEvent(e)

    def hideEvent(self, e):
        self.timer.stop()
        super().hideEvent(e)

    def paintEvent(self, _):
        p = QPainter(self)
        paint_arc(p, QRectF(self.rect()), self.angle)