# Authors: see git history
#
# Copyright (c) 2024 Authors
# Licensed under the GNU GPL version 3.0 or later.  See the file LICENSE for details.
from threading import Event, Thread

import wx

from ...debug.debug import debug
from ...utils.threading import ExitThread


class PreviewRenderer(Thread):
    """Render stitch plan in a background thread."""

    def __init__(self, render_stitch_plan_hook, rendering_completed_hook):
        super(PreviewRenderer, self).__init__()
        self.daemon = True
        self.refresh_needed = Event()

        self.render_stitch_plan_hook = render_stitch_plan_hook
        self.rendering_completed_hook = rendering_completed_hook

        # This is read by utils.threading.check_stop_flag() to abort stitch plan
        # generation.
        self.stop = Event()

    def update(self):
        """Request to render a new stitch plan.

        self.render_stitch_plan_hook() will be called in a background thread, and then
        self.rendering_completed_hook() will be called with the resulting stitch plan.
        """

        if not self.is_alive():
            self.start()

        self.stop.set()
        self.refresh_needed.set()

    def run(self):
        while True:
            self.refresh_needed.wait()
            self.refresh_needed.clear()
            self.stop.clear()

            try:
                debug.log("update_patches")
                self.render_stitch_plan()
            except ExitThread:
                debug.log("ExitThread caught")
                self.stop.clear()

    def render_stitch_plan(self):
        try:
            stitch_plan = self.render_stitch_plan_hook()
            if stitch_plan:
                # rendering_completed() will be called in the main thread.
                wx.CallAfter(self.rendering_completed_hook, stitch_plan)
        except ExitThread:
            raise
        except:  # noqa: E722
            import traceback
            debug.log("unhandled exception in PreviewRenderer.render_stitch_plan(): " + traceback.format_exc())