#!/usr/bin/env python3

'''
rpslam.py : BreezySLAM Python with SLAMTECH RP A1 Lidar
                 
Copyright (C) 2018 Simon D. Levy

This code is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as 
published by the Free Software Foundation, either version 3 of the 
License, or (at your option) any later version.

This code 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 Lesser General Public License 
along with this code.  If not, see <http://www.gnu.org/licenses/>.
'''

MAP_SIZE_PIXELS         = 500
MAP_SIZE_METERS         = 10
LIDAR_DEVICE            = '/dev/ttyUSB0'

from breezyslam.algorithms import RMHC_SLAM
from breezyslam.sensors import RPLidarA1 as LaserModel

from rplidar import RPLidar as Lidar

from pltslamshow import SlamShow

if __name__ == '__main__':

    # Connect to Lidar unit
    lidar = Lidar(LIDAR_DEVICE)

    # Create an RMHC SLAM object with a laser model and optional robot model
    slam = RMHC_SLAM(LaserModel(), MAP_SIZE_PIXELS, MAP_SIZE_METERS)

    # Set up a SLAM display
    display = SlamShow(MAP_SIZE_PIXELS, MAP_SIZE_METERS*1000/MAP_SIZE_PIXELS, 'SLAM')

    # Initialize an empty trajectory
    trajectory = []

    # Initialize empty map
    mapbytes = bytearray(MAP_SIZE_PIXELS * MAP_SIZE_PIXELS)

    # Create an iterator to collect scan data from the RPLidar
    iterator = lidar.iter_scans()

    while True:

        try:

            # Extract (quality, angle, distance) triples from current scan
            items = [item for item in next(iterator)]

            # Extract distances and angles from triples
            distances = [item[2] for item in items]
            angles    = [item[1] for item in items]

            print(len(distances), len(angles))

            # Update SLAM with current Lidar scan and scan angles
            slam.update(distances, scan_angles_degrees=angles)

        except KeyboardInterrupt:

            break

        # Get current robot position
        #x, y, theta = slam.getpos()

        # Get current map bytes as grayscale
        #slam.getmap(mapbytes)

        # Display the map
        #display.displayMap(mapbytes)

        # Display the robot's pose in the map
        #display.setPose(x, y, theta)

        # Break on window close
        #if not display.refresh():
        #    break

    # Shut down the lidar connection
    from time import sleep
    lidar.stop()
    lidar.disconnect()