#!/usr/bin/python3
# -*- coding: utf-8 -*-
# -*- mode: Python -*-


'''

This generator reads a frame from redis
v0.1.0

Use it to create feedback loops by writing to the same frame
or to copy the frame from someone else

LICENCE : CC

by cocoa

'''

from __future__ import print_function
import ast
import argparse
import json
import redis
import sys
import time
name="generator::fromRedis"


def debug(*args, **kwargs):
    if( verbose == False ):
        return
    print(*args, file=sys.stderr, **kwargs)


argsparser      = argparse.ArgumentParser(description="Dummy generator")
argsparser.add_argument("-k","--key",required=True,help="Redis key to look after",default=30,type=str)
argsparser.add_argument("-i","--ip",help="IP address of the Redis server ",default="127.0.0.1",type=str)
argsparser.add_argument("-p","--port",help="Port of the Redis server ",default="6379",type=str)
argsparser.add_argument("-f","--fps",help="Frame Per Second",default=30,type=int)
argsparser.add_argument("-v","--verbose",action="store_true",help="Verbose output")
args = argsparser.parse_args()

fps                 = args.fps
verbose             = args.verbose
key                 = args.key
ip                  = args.ip
port                = args.port
optimal_looptime    = 1 / fps
debug(name+" optimal looptime "+str(optimal_looptime))

r = redis.Redis(
        host=ip,
        port=port)

while True:
  start = time.time()
  # Read from Redis
  line = r.get(key)
  # Decode as list of tuples
  pointsList = ast.literal_eval(line.decode('ascii'))
  # convert to list of lists
  pointsList  = [list(elem) for elem in pointsList]
  # Convert to JSON string
  line = json.dumps( pointsList )
  debug(name,"Key:{} line:{}".format(key,line))
  print(line, flush=True);
  looptime = time.time() - start
  if( looptime < optimal_looptime ):
    time.sleep( optimal_looptime - looptime)
    debug(name+" micro sleep:"+str( optimal_looptime - looptime))