#!/usr/bin/env python
#
# Collect and plot latency-profiling data from a running gpsd.
# Requires gnuplot.
#
import sys, os, time, getopt, gps, tempfile, time, socket

class rawplot:
    "Print basic data, ignoring timezone skew."
    name = "raw"
    def header(self, fp):
        fp.write("#GPS time        	Received	Transmitted 	Read\n")
        fp.write("#----------------	---------	----------- 	----------\n")
    def formatter(self, session, fp):
        fp.write("%.6f	%2.6f	%2.6f	%2.6f	# %s\n" \
              % (session.rs232,
                 (session.recv_time - session.gps_time) % 3600,
                 (session.emit_time - session.gps_time) % 3600,
                 (time.time() - session.gps_time) % 3600,
                 session.tag))
        return True
    def plot(self, file, title, session):
        fmt = '''
set autoscale
set key below
set key title "Raw latency data, %dN%d, %s"
plot \
     "%s" using 0:4 title "TCP/IP latency" with impulses, \
     "%s" using 0:3 title "Decode time" with impulses, \
     "%s" using 0:2 title "Other latency" with impulses, \
     "%s" using 0:1 title "RS232 time" with impulses
'''
        return fmt % (session.baudrate, session.stopbits, title,
                      file, file, file, file)

class stripplot:
    "Discard base time, throw out latencies >1 sec."
    name = "strip"
    def header(self, fp):
        fp.write("#RS-232   	Received	Transmitted 	Read\n")
        fp.write("#---------	---------	----------- 	----------\n")
    def formatter(self, session, fp):
        # Throw out total line latencies above 1 second, these are
        # serial-buffering artifacts at the start of the session
        line_latency = (session.recv_time - session.gps_time) % 3600
        if line_latency > 1:
            return False
        fp.write("%2.6f	%2.6f	%2.6f	%2.6f	# %s\n" \
              % (session.rs232, line_latency,
                 (session.emit_time - session.gps_time) % 3600,
                 (time.time() - session.gps_time) % 3600,
                 session.tag))
        return True
    def plot(self, file, title, session):
        fmt = '''
set autoscale
set key below
set key title "Filtered latency data, %dN%d, %s"
plot \
     "%s" using 0:4 title "TCP/IP latency" with impulses, \
     "%s" using 0:3 title "Decode time" with impulses, \
     "%s" using 0:2 title "Other latency" with impulses, \
     "%s" using 0:1 title "RS232 time" with impulses
'''
        return fmt % (session.baudrate, session.stopbits, title,
                      file, file, file, file)

class splitplot:
    "Discard base time, throw out latencies >1 sec."
    name = "split"
    sentences = ("GPGGA", "GPRMC", "GPGLL")
    def __init__(self):
        self.found = {}
    def header(self, fp):
        fp.write("#")
        for s in splitplot.sentences:
            fp.write(s + "    \t")
        fp.write("Received	Transmitted 	Read\n")
        fp.write("#")
        for s in splitplot.sentences:
            fp.write("---------\t")
        fp.write("---------	----------- 	----------\n")
    def formatter(self, session, fp):
        # Throw out total line latencies above 1 second, these are
        # serial-buffering artifacts at the start of the session
        line_latency = (session.recv_time - session.gps_time) % 3600
        if line_latency > 1:
            return False
        for s in splitplot.sentences:
            if s == session.tag:
                fp.write("%2.6f\t"% session.rs232)
                self.found[s] = True
            else:
                fp.write("-       \t")
        fp.write("%2.6f\t%2.6f\t%2.6f\t# %s\n" \
              % (line_latency,
                 (session.emit_time - session.gps_time) % 3600,
                 (time.time() - session.gps_time) % 3600,
                 session.tag))
        return True
    def plot(self, file, title, session):
        fixed = '''
set autoscale
set key below
set key title "Filtered latency data, %dN%d, %s"
plot \\
     "%s" using 0:%d title "TCP/IP latency" with impulses, \\
     "%s" using 0:%d title "Decode time" with impulses, \\
     "%s" using 0:%d title "Other latency" with impulses, \\
'''
        sc = len(splitplot.sentences)
        fmt = fixed % (session.baudrate, session.stopbits, title,
                       file, sc+3, file, sc+2, file, sc+1)
        for i in range(sc):
            if splitplot.sentences[i] in self.found:
                fmt += '     "%s" using 0:%d title "%s" with impulses, \\\n' % \
                       (file, i+1, splitplot.sentences[i])
        return fmt[:-4] + "\n"

formatters = (rawplot, stripplot, splitplot)

if __name__ == '__main__':
    (options, arguments) = getopt.getopt(sys.argv[1:], "f:hn:o:rt:T:")
    formatter = splitplot
    raw = False
    file = None
    terminal = None
    title = time.ctime()
    await = 100
    for (switch, val) in options:
	if (switch == '-f'):
            for formatter in formatters:
                if formatter.name == val:
                    break
            else:
                sys.stderr.write("gpsprof: no such formatter.\n")
                sys.exit(1)
	elif (switch == '-n'):
	    await = int(val)
	elif (switch == '-o'):
	    file = val
	elif (switch == '-r'):
	    raw = True
	elif (switch == '-t'):
	    title = val
	elif (switch == '-T'):
	    terminal = val
        elif (switch == '-h'):
            sys.stderr.write("usage: gpsprof [-h] [-r] [-n samplecount] "
                             + "[-f {" + "|".join(map(lambda x: x.name, formatters)) + "}] [-t title] [-o file]\n")
            sys.exit(0)
    plotter = formatter()
    if file:
        out = open(file, "w")
    elif raw:
        out = sys.stdout
    else:
        out = tempfile.NamedTemporaryFile()

    try:
        session = gps.gps()
    except socket.error:
        sys.stderr.write("gpsprof: gpsd unreachable.\n")
        sys.exit(0)
    try:
        session.query("wZ+")
        plotter.header(out)
        while await > 0:
            session.poll()
            if session.utc == "?":	# Timestamp no good, skip it.
                continue
            session.gps_time = gps.isotime(session.utc)
            session.rs232 = (session.length * (8.0+session.stopbits))/session.baudrate
            if plotter.formatter(session, out):
                await -= 1
    finally:
        session.query("wZ-")
        
    out.flush()
    if not raw:
        command = plotter.plot(out.name, title, session)
        if terminal:
            command = "set terminal " + terminal + "\n" + command
        pfp = os.popen("gnuplot -persist", "w")
        pfp.write(command)
        pfp.close()
    del session
    out.close()