"""Load and execute ArContext configuration."""

"""
This program is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <https://www.gnu.org/licenses/>.
"""

__author__ = "Théo de la Hogue"
__credits__ = []
__copyright__ = "Copyright 2023, Ecole Nationale de l'Aviation Civile (ENAC)"
__license__ = "GPLv3"

import argparse
import logging
import json
import contextlib
import os

from . import load
from .ArFeatures import ArCamera, ArContext

import cv2

# Manage arguments
parser = argparse.ArgumentParser(description=__doc__.split('-')[0])
parser.add_argument('context_file', metavar='CONTEXT_FILE', type=str, help='JSON context filepath')
parser.add_argument('-v', '--verbose', action='store_true', default=False, help='enable verbose mode to print information in console')
parser.add_argument('-p', '--pipe_path', metavar='PIPE_PATH', type=str, default=None, help='enable pipe communication to execute external commands')

args = parser.parse_args()

# Manage logging
logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.DEBUG if args.verbose else logging.INFO)

# Manage pipe communication
if args.pipe_path is not None:

	if not os.path.exists(args.pipe_path):

	    os.mkfifo(args.pipe_path)

	# Open the fifo in non-blocking mode or it will stalls until someone opens it for writting
	pipe_file = os.open(args.pipe_path, os.O_RDONLY | os.O_NONBLOCK)

	logging.info('%s pipe opened', args.pipe_path)

# Load context from JSON file
with load(args.context_file) as context:

	# Loaded object must be a subclass of ArContext
	if not issubclass(type(context), ArContext):

		raise TypeError('Loaded object is not a subclass of ArContext')

	if args.verbose:

		print(context)

	# Create a window to display context
	cv2.namedWindow(context.name, cv2.WINDOW_AUTOSIZE)

	# Waiting for 'ctrl+C' interruption
	with contextlib.suppress(KeyboardInterrupt), os.fdopen(pipe_file) if args.pipe_path is not None else contextlib.nullcontext() as pipe:

		# Visualization loop
		while context.is_running():

			# Read message from pipe if required
			if args.pipe_path is not None:

				message = pipe.read().rstrip('\n')

				if message:

					logging.info('%s: %s', args.pipe_path, message)

					try:

						exec(message)

					except Exception as e:

						logging.error('%s', e)

			# Display context
			cv2.imshow(context.name, context.image())

			# Head-mounted eye tracker case: display environment frames image
			if issubclass(type(context.pipeline), ArCamera):

				for scene_frame in context.pipeline.scene_frames():

					cv2.imshow(scene_frame.name, scene_frame.image())

			# Key interaction
			key_pressed = cv2.waitKey(10)

			# Esc: close window
			if key_pressed == 27:

				raise KeyboardInterrupt()

			# Space bar: pause/resume pipeline processing
			if key_pressed == 32:

				try:

					if context.is_paused():

						context.resume()

					else:

						context.pause()

				except NotImplementedError:

					pass

	# Stop frame display
	cv2.destroyAllWindows()