"""
Example that shows animated circles. The animation is run from Python.
Doing that in JS would be more efficient, but we have not implemented timers
yet.
"""

import math

from flexx import app, ui


class Circle(ui.Label):
    CSS = """
    .flx-Circle {
        background: #f00;
        border-radius: 10px;
        width: 10px;
        height: 10px;
    }
    """

class Circles(ui.Widget):

    def init(self):
        self._circles = []

        with ui.PinboardLayout():
            for i in range(32):
                x = math.sin(i*0.2)*0.3 + 0.5
                y = math.cos(i*0.2)*0.3 + 0.5
                w = Circle(pos=(x, y))
                self._circles.append(w)

        self.tick()
        # todo: animate in JS!

    def tick(self):
        if not self.session.status:
            return
        import time
        t = time.time()
        for i, circle in enumerate(self._circles):
            x = math.sin(i*0.2 + t)*0.3 + 0.5
            y = math.cos(i*0.2 + t)*0.3 + 0.5
            circle.pos = x, y
        app.call_later(0.03, self.tick)


if __name__ == '__main__':
    m = app.launch(Circles)
    app.run()