"""
Run as:
pshell_be -l -test -c -f="users/edwin/correlation_stream.py" -args="PREFIX:'SLAAR-LBSTREAM1'"

or with additional parameters:
pshell_be -l -test -c -f="users/edwin/correlation_stream.py" -args="PREFIX:'SLAAR-LBSTREAM1',VERBOSE:False,TIME_INTERVAL:2.0"
"""

if not "PREFIX" in globals():
    PREFIX = "SLAAR-LBSTREAM1"    
if not "VERBOSE" in globals():
    VERBOSE = True
if not "TIME_INTERVAL" in globals():
    TIME_INTERVAL = 1.0

EMPTY_VALUE = 1112223330    
    
    
if PREFIX[-1] != ":":
    PREFIX = PREFIX + ":"

def get_channel_list():
    ch=[]
    try:
        for i in range(20):
           v= caget(PREFIX + "NAME" + str(i+1))
           if v.strip()=="":
                break
           ch.append(str(v.strip()))
    except:
        pass
    return ch 

def ack_channel_list(channel_list):
    try:
        s=""
        for c in channel_list:
            s=s+c+"\n"
        s=s+"\x00"
        caput(PREFIX + "PACK_LIST",[ord(c) for c in s])    
    except:
        pass
        
def start_stream(channel_list):
    try:    
        st=None    
        print "Starting stream"
        if len(channel_list)==0:
            raise Exception ("No channel defined")
        st = Stream("pulse_id", dispatcher)
        for c in channel_list:
            st.addScalar(c, c, 1, 0)   
        st.initialize()
        st.start()
        st.waitCacheChange(10000)    #Wait stream be running before starting scan
        if st.take() is None:
            raise Exception("Error initializing data stream")   
        ack_channel_list(channel_list)
        print "Stream started"                    
    except:
        stop_stream(st)
        print sys.exc_info()[1]     
    return st
        
def stop_stream(st):
    try:        
        if st:
            st.close()    
            st=None
            print "Stream closed"   
    except:
        print sys.exc_info()[1]  
    finally:
        ack_channel_list([])

#def on_start_change(val):
#    fork(start_stream if (val==1) else stop_stream)
#start = Channel(PREFIX + "START_STOP", type = 'i', monitored = True, callback=on_start_change)

t0=None
pid=None
def handle_message(msg, channel_list, buf):
    global t0, pid
    if t0 is None:
        t0  = time.time()
    now=time.time()
    num_channels = len(channel_list)
    size_buffer= 300 #int((len(buf)-100)/(len(channel_list)+1))  
    buf[0] = msg.pulseId
    buf[1] = num_channels
    buf[4] = EMPTY_VALUE
    if (pid is not None) and ((pid+1) != msg.pulseId):
        print "Missing pid: ", (pid+1)
    pid = msg.pulseId
    #Count
    if buf[2] < size_buffer:
        buf[2] = buf[2]+1    
    #Index    
    buf[3] = buf[3]+1    
    if buf[3] == size_buffer:
         buf[3]=0 
    index = int(buf[3])*(num_channels+1) + 10    
    buf[index] = msg.pulseId
    index = index+1
    for v in msg.values():
        buf[index] = EMPTY_VALUE if ((v is None) or (math.isnan(v)))else v                       
        index = index+1    
    if now >= (t0 + TIME_INTERVAL):        
        if VERBOSE:                
            print to_list(buf[0:5])        
        t0  = time.time()
        return True
    return False

def run():    
    channel_list = []   
    st=None 
    start = Channel(PREFIX + "START_STOP", type = 'i')
    outp = Channel(PREFIX + "PACK_DATA", type = '[d')
    buf = to_array([0]*outp.get_size(),'d')
    buf[2] = 0
    buf[3]= -1  

    try:        
        while True:
            started = (start.get()==1)
            if started and not st:
                print "Started"
                channel_list=get_channel_list()
                print "Channel list: ", channel_list
                st = start_stream(channel_list)                         
                
                class StreamListener (DeviceListener):                
                    def onValueChanged(self, device, value, former): 
                        if handle_message(value, channel_list, buf):
                            outp.putq(buf)   
                listener = StreamListener()                
                st.addListener(listener)
                
            elif st and not started:
                print "Stopped"
                channel_list=[]
                stop_stream(st)
                st = None
            """
            if st:
                st.waitCacheChange(0)
                if handle_message(st.take(), channel_list, buf):
                    outp.putq(buf)                    
                time.sleep(0.001)
            else:            
                time.sleep(0.1)
            """
            time.sleep(0.1)                    
    finally:
        stop_stream(st)
        if outp: outp.close()
        if start: start.close()

        
if __name__ == "__main__":
    run()