#!/usr/bin/env python
# -*- coding: UTF-8
'''
xgps -- test client for gpsd

usage: xgps [-D level] [-hV?] [-l degmfmt] [-u units] [server[:port[:device]]]
'''

gui_about = '''\
This is xgps, a test client for the gpsd daemon.

By Eric S. Raymond for the GPSD project, December 2009
'''
#
# This file is Copyright (c) 2010 by the GPSD project
# BSD terms apply: see the file COPYING in the distribution root for details.

import math
import socket
import sys
import time

import gobject
import pygtk
pygtk.require('2.0')
import gtk
import cairo

import gps
import gps.clienthelpers

# how to sort the Satellite List
# some of ("PRN","el","az","ss","used") with optional '-' to reverse sort
# by default, used at the top, then sort PRN
SKY_VIEW_SORT_FIELDS = ('-used', 'PRN')


class unit_adjustments:
    "Encapsulate adjustments for unit systems."
    def __init__(self, units=None):
        self.altfactor = gps.METERS_TO_FEET
        self.altunits = "ft"
        self.speedfactor = gps.MPS_TO_MPH
        self.speedunits = "mph"
        if units is None:
            units = gps.clienthelpers.gpsd_units()
        if units in (gps.clienthelpers.unspecified, gps.clienthelpers.imperial, "imperial", "i"):
            pass
        elif units in (gps.clienthelpers.nautical, "nautical", "n"):
            self.altfactor = gps.METERS_TO_FEET
            self.altunits = "ft"
            self.speedfactor = gps.MPS_TO_KNOTS
            self.speedunits = "knots"
        elif units in (gps.clienthelpers.metric, "metric", "m"):
            self.altfactor = 1
            self.altunits = "m"
            self.speedfactor = gps.MPS_TO_KPH
            self.speedunits = "kph"
        else:
            raise ValueError  # Should never happen


def fit_to_grid(x, y, line_width):
    "Adjust coordinates to produce sharp lines."
    if line_width % 1.0 != 0:
        # Can't have sharp lines for non-integral line widths.
        return x, y
    if line_width % 2 == 0:
        # Round to a pixel corner.
        return int(x + 0.5), int(y + 0.5)
    else:
        # Round to a pixel center.
        return int(x) + 0.5, int(y) + 0.5


def fit_circle_to_grid(x, y, radius, line_width):
    "Adjust circle coordinates and radius to produce sharp horizontal and vertical tangents."
    r = radius
    x1, y1 = fit_to_grid(x - r, y - r, line_width)
    x2, y2 = fit_to_grid(x + r, y + r, line_width)
    x, y = (x1 + x2) / 2, (y1 + y2) / 2
    r = (x2 - x1 + y2 - y1) / 4
    return x, y, r


class SkyView(gtk.DrawingArea):
    "Satellite skyview, encapsulates pygtk's draw-on-expose behavior."
    # See <http://faq.pygtk.org/index.py?req=show&file=faq18.008.htp>
    HORIZON_PAD = 40    # How much whitespace to leave around horizon
    SAT_RADIUS = 5      # Diameter of satellite circle

    def __init__(self):
        gtk.DrawingArea.__init__(self)
        self.set_size_request(400, 400)
        self.cr = None   # New cairo context for each expose event
        self.width = 0   # Updated in size-allocate handler
        self.height = 0  # Updated in size-allocate handler
        self.step_of_grid = 45  # default step of polar grid
        self.connect('size-allocate', self.on_size_allocate)
        self.connect('expose-event', self.on_expose_event)
        self.satellites = []
        self.center_x = self.center_y = self.radius = None

    def on_size_allocate(self, _unused, allocation):
        width = allocation.width
        height = allocation.height
        x = width / 2
        y = height / 2
        r = (min(width, height) - SkyView.HORIZON_PAD) / 2
        x, y, r = fit_circle_to_grid(x, y, r, 1)
        self.center_x = x
        self.center_y = y
        self.radius = r

    def set_color(self, spec):
        "Set foreground color for drawing."
        gdkcolor = gtk.gdk.color_parse(spec)
        r = gdkcolor.red / 65535.0
        g = gdkcolor.green / 65535.0
        b = gdkcolor.blue / 65535.0
        self.cr.set_source_rgb(r, g, b)

    def draw_circle(self, x, y, radius, filled=False):
        "Draw a circle centered on the specified midpoint."
        lw = self.cr.get_line_width()
        r = int(2 * radius + 0.5) / 2

        x, y, r = fit_circle_to_grid(x, y, radius, lw)

        self.cr.arc(x, y, r, 0, math.pi * 2.0)
        self.cr.close_path()

        if filled:
            self.cr.fill()
        else:
            self.cr.stroke()

    def draw_line(self, x1, y1, x2, y2):
        "Draw a line between specified points."
        lw = self.cr.get_line_width()
        x1, y1 = fit_to_grid(x1, y1, lw)
        x2, y2 = fit_to_grid(x2, y2, lw)

        self.cr.move_to(x1, y1)
        self.cr.line_to(x2, y2)

        self.cr.stroke()

    def draw_square(self, x, y, radius, filled=False):
        "Draw a square centered on the specified midpoint."
        lw = self.cr.get_line_width()
        x1, y1 = fit_to_grid(x - radius, y - radius, lw)
        x2, y2 = fit_to_grid(x + radius, y + radius, lw)

        self.cr.rectangle(x1, y1, x2 - x1, y2 - y1)

        if filled:
            self.cr.fill()
        else:
            self.cr.stroke()

    def draw_string(self, x, y, text, centered=True):
        "Draw a text on the skyview."
        self.cr.select_font_face("Sans", cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_BOLD)
        self.cr.set_font_size(10)

        if centered:
            extents = self.cr.text_extents(text)
            # width / 2 + x_bearing
            x -= extents[2] / 2 + extents[0]
            # height / 2 + y_bearing
            y -= extents[3] / 2 + extents[1]

        self.cr.move_to(x, y)
        self.cr.show_text(text)
        self.cr.new_path()

    def pol2cart(self, az, el):
        "Polar to Cartesian coordinates within the horizon circle."
        az *= (math.pi / 180)  # Degrees to radians
        # Exact spherical projection would be like this:
        # el = sin((90.0 - el) * DEG_2_RAD);
        el = ((90.0 - el) / 90.0)
        xout = self.center_x + math.sin(az) * el * self.radius
        yout = self.center_y - math.cos(az) * el * self.radius
        return (xout, yout)

    def on_expose_event(self, widget, _unused):
        self.cr = widget.window.cairo_create()

        self.cr.set_line_width(1)

        self.cr.set_source_rgb(0, 0, 0)
        self.cr.paint()

        self.cr.set_source_rgb(1, 1, 1)
        # The zenith marker
        self.draw_circle(self.center_x, self.center_y, 6, filled=False)

        # The horizon circle
        if self.step_of_grid == 45:
            # The circle corresponding to 45 degrees elevation.
            # There are two ways we could plot this.  Projecting the sphere
            # on the display plane, the circle would have a diameter of
            # sin(45) ~ 0.7.  But the naive linear mapping, just splitting
            # the horizon diameter in half, seems to work better visually.
            self.draw_circle(self.center_x, self.center_y, self.radius / 2, filled=False)
        elif self.step_of_grid == 30:
            self.draw_circle(self.center_x, self.center_y, self.radius * 2 / 3, filled=False)
            self.draw_circle(self.center_x, self.center_y, self.radius / 3, filled=False)
        self.draw_circle(self.center_x, self.center_y, self.radius, filled=False)

        (x1, y1) = self.pol2cart(0, 0)
        (x2, y2) = self.pol2cart(180, 0)
        self.draw_line(x1, y1, x2, y2)

        (x1, y1) = self.pol2cart(90, 0)
        (x2, y2) = self.pol2cart(270, 0)
        self.draw_line(x1, y1, x2, y2)

        # The compass-point letters
        (x, y) = self.pol2cart(0, 0)
        self.draw_string(x, y - 10, "N")
        (x, y) = self.pol2cart(90, 0)
        self.draw_string(x + 10, y, "E")
        (x, y) = self.pol2cart(180, 0)
        self.draw_string(x, y + 10, "S")
        (x, y) = self.pol2cart(270, 0)
        self.draw_string(x - 10, y, "W")

        # The satellites
        self.cr.set_line_width(2)
        for sat in self.satellites:
            (x, y) = self.pol2cart(sat.az, sat.el)
            if sat.ss < 10:
                self.set_color("Gray")
            elif sat.ss < 30:
                self.set_color("Red")
            elif sat.ss < 35:
                self.set_color("Yellow")
            elif sat.ss < 40:
                self.set_color("Green3")
            else:
                self.set_color("Green1")
            if gps.is_sbas(sat.PRN):
                self.draw_square(x, y, SkyView.SAT_RADIUS, sat.used)
            else:
                self.draw_circle(x, y, SkyView.SAT_RADIUS, sat.used)

            self.cr.set_source_rgb(1, 1, 1)
            self.draw_string(x + SkyView.SAT_RADIUS, y + (SkyView.SAT_RADIUS * 2), str(sat.PRN), centered=False)

        self.cr = None

    def redraw(self, satellites):
        "Redraw the skyview."
        self.satellites = satellites
        self.queue_draw()


class NoiseView:
    "Encapsulate view object for watching noise statistics."
    COLUMNS = 2
    ROWS = 4
    noisefields = (
        # First column
        ("Time", "time"),
        ("Latitude", "lat"),
        ("Longitude", "lon"),
        ("Altitude", "alt"),
        # Second column
        ("RMS", "rms"),
        ("Major", "major"),
        ("Minor", "minor"),
        ("Orient", "orient"),
    )

    def __init__(self):
        self.widget = gtk.Table(NoiseView.COLUMNS, NoiseView.ROWS, False)
        self.noisewidgets = []
        for i in range(len(NoiseView.noisefields)):
            colbase = (i / NoiseView.ROWS) * 2
            label = gtk.Label(NoiseView.noisefields[i][0] + ": ")
            # Wacky way to force right alignment
            label.set_alignment(xalign=1, yalign=0.5)
            self.widget.attach(
                label, colbase, colbase + 1,
                i % NoiseView.ROWS, i % NoiseView.ROWS + 1)
            entry = gtk.Entry()
            # The right size for the ISO8601 timestamp
            entry.set_width_chars(20)
            entry.set_text("n/a")
            self.widget.attach(
                entry, colbase + 1, colbase + 2,
                i % NoiseView.ROWS, i % NoiseView.ROWS + 1)
            self.noisewidgets.append((NoiseView.noisefields[i][1], entry))

    def update(self, noise):
        "Update the GPGST data fields."
        for (attrname, widget) in self.noisewidgets:
            if hasattr(noise, attrname):
                widget.set_text(str(getattr(noise, attrname)))
            else:
                widget.set_text("n/a")


class MaidenheadView:
    "Encapsulate view object for watching Maidenhead grid location."
    def __init__(self):
        self.widget = gtk.Entry()
        self.widget.set_editable(False)

    def update(self, tpv):
        if tpv.mode >= gps.MODE_2D and hasattr(tpv, "lat") and hasattr(tpv, "lon"):
            self.widget.set_text(gps.clienthelpers.maidenhead(tpv.lat, tpv.lon))
        else:
            return self.widget.set_text("n/a")


class AISView:
    "Encapsulate store and view objects for watching AIS data."
    AIS_ENTRIES = 10
    DWELLTIME = 360

    def __init__(self, deg_type):
        "Initialize the store and view."
        self.deg_type = deg_type
        self.name_to_mmsi = {}
        self.named = {}
        self.store = gtk.ListStore(str, str, str, str, str, str)
        self.widget = gtk.ScrolledWindow()
        self.widget.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_AUTOMATIC)
        self.view = gtk.TreeView(model=self.store)
        self.widget.set_size_request(-1, 300)
        self.widget.add_with_viewport(self.view)

        for (i, label) in enumerate(('#', 'Name:', 'Callsign:', 'Destination:', "Lat/Lon:", "Information")):
            column = gtk.TreeViewColumn(label)
            renderer = gtk.CellRendererText()
            column.pack_start(renderer)
            column.add_attribute(renderer, 'text', i)
            self.view.append_column(column)

    def enter(self, ais, name):
        "Add a named object (ship or station) to the store."
        if ais.mmsi in self.named:
            return False
        else:
            ais.entry_time = time.time()
            self.named[ais.mmsi] = ais
            self.name_to_mmsi[name] = ais.mmsi
            # Garbage-collect old entries
            try:
                for i in range(len(self.store)):
                    here = self.store.get_iter(i)
                    name = self.store.get_value(here, 1)
                    mmsi = self.name_to_mmsi[name]
                    if self.named[mmsi].entry_time < time.time() - AISView.DWELLTIME:
                        del self.named[mmsi]
                        if name in self.name_to_mmsi:
                            del self.name_to_mmsi[name]
                        self.store.remove(here)
            except (ValueError, KeyError):  # Invalid TreeIters throw these
                pass
            return True

    def latlon(self, lat, lon):
        "Latitude/longitude display in nice format."
        if lat < 0:
            latsuff = "S"
        elif lat > 0:
            latsuff = "N"
        else:
            latsuff = ""
        lat = abs(lat)
        lat = gps.clienthelpers.deg_to_str(self.deg_type, lat)
        if lon < 0:
            lonsuff = "W"
        elif lon > 0:
            lonsuff = "E"
        else:
            lonsuff = ""
        lon = abs(lon)
        lon = gps.clienthelpers.deg_to_str(gps.clienthelpers.deg_ddmmss, lon)
        return lat + latsuff + "/" + lon + lonsuff

    def update(self, ais):
        "Update the AIS data fields."
        if ais.type in (1, 2, 3, 18):
            if ais.mmsi in self.named:
                for i in range(len(self.store)):
                    here = self.store.get_iter(i)
                    name = self.store.get_value(here, 1)
                    if name in self.name_to_mmsi:
                        mmsi = self.name_to_mmsi[name]
                        if mmsi == ais.mmsi:
                            latlon = self.latlon(ais.lat, ais.lon)
                            self.store.set_value(here, 4, latlon)
        elif ais.type == 4:
            if self.enter(ais, ais.mmsi):
                where = self.latlon(ais.lat, ais.lon)
                self.store.prepend(
                    (ais.type, ais.mmsi, "(shore)", ais.timestamp, where, ais.epfd_text))
        elif ais.type == 5:
            if self.enter(ais, ais.shipname):
                self.store.prepend(
                    (ais.type, ais.shipname, ais.callsign, ais.destination, "", ais.shiptype))
        elif ais.type == 12:
            sender = ais.mmsi
            if sender in self.named:
                sender = self.named[sender].shipname
            recipient = ais.dest_mmsi
            if recipient in self.named and hasattr(self.named[recipient], "shipname"):
                recipient = self.named[recipient].shipname
            self.store.prepend(
                (ais.type, sender, "", recipient, "", ais.text))
        elif ais.type == 14:
            sender = ais.mmsi
            if sender in self.named:
                sender = self.named[sender].shipname
            self.store.prepend(
                (ais.type, sender, "", "(broadcast)", "", ais.text))
        elif ais.type in (19, 24):
            if self.enter(ais, ais.shipname):
                self.store.prepend(
                    (ais.type, ais.shipname, "(class B)", "", "", ais.shiptype_text))
        elif ais.type == 21:
            if self.enter(ais, ais.name):
                where = self.latlon(ais.lat, ais.lon)
                self.store.prepend(
                    (ais.type, ais.name, "(%s navaid)" % ais.epfd_text, "", where, ais.aid_type_text))


class Base:
    COLUMNS = 3
    ROWS = 7
    gpsfields = (
        # First column
        ("Time", lambda s, r: s.update_time(r)),
        ("Latitude", lambda s, r: s.update_latitude(r)),
        ("Longitude", lambda s, r: s.update_longitude(r)),
        ("Altitude", lambda s, r: s.update_altitude(r)),
        ("Speed", lambda s, r: s.update_speed(r)),
        ("Climb", lambda s, r: s.update_climb(r)),
        ("Track", lambda s, r: s.update_track(r)),
        # Second column
        ("Status", lambda s, r: s.update_status(r)),
        ("EPX", lambda s, r: s.update_err(r, "epx")),
        ("EPY", lambda s, r: s.update_err(r, "epy")),
        ("EPV", lambda s, r: s.update_err(r, "epv")),
        ("EPS", lambda s, r: s.update_err_speed(r, "eps")),
        ("EPC", lambda s, r: s.update_err_speed(r, "epc")),
        ("EPD", lambda s, r: s.update_err_degrees(r, "epd")),
    )

    def __init__(self, deg_type):
        self.deg_type = deg_type
        self.conversions = unit_adjustments()
        self.saved_mode = -1
        self.ais_latch = False
        self.noise_latch = False

        self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
        if not self.window.get_display():
            raise Exception("Can't open display")
        self.window.set_title("xgps")
        self.window.connect("delete_event", self.delete_event)
        self.window.set_resizable(False)

        vbox = gtk.VBox(False, 0)
        self.window.add(vbox)

        self.window.connect("destroy", lambda _unused: gtk.main_quit())

        self.uimanager = gtk.UIManager()
        self.accelgroup = self.uimanager.get_accel_group()
        self.window.add_accel_group(self.accelgroup)
        self.actiongroup = gtk.ActionGroup('xgps')
        self.actiongroup.add_actions(
            [('Quit', gtk.STOCK_QUIT, '_Quit', None,
              'Quit the Program', lambda _unused: gtk.main_quit()),
             ('File', None, '_File'),
             ('View', None, '_View'),
             ('Units', None, '_Units'),
             ('Step of grid', None, '_Step of grid')])
        self.actiongroup.add_toggle_actions(
            [('Skyview', None, '_Skyview', '<Control>s',
              'Enable Skyview', self.view_toggle),
             ('Responses', None, '_Responses', '<Control>r',
              'Enable Response Reports', self.view_toggle),
             ('GPS', None, '_GPS Data', '<Control>g',
              'Enable GPS Data', self.view_toggle),
             ('Noise', None, '_Noise Statistics', '<Control>n',
              'Enable Noise Statistics', self.view_toggle),
             ('Maidenhead', None, '_Maidenhead', '<Control>m',
              'Enable Maidenhead locator', self.view_toggle),
             ('AIS', None, '_AIS Data', '<Control>a',
              'Enable AIS Data', self.view_toggle),
             ])
        self.actiongroup.add_radio_actions(
            [('Imperial', None, '_Imperial', '<Control>i',
              'Imperial units', 0),
             ('Nautical', None, '_Nautical', '<Control>n',
              'Nautical units', 1),
             ('Metric', None, '_Metric', '<Control>m',
              'Metric Units', 2),
             ], 0, lambda a, _unused: self.set_units(['i', 'n', 'm'][a.get_current_value()]))
        self.actiongroup.add_radio_actions(
            [('30°', None, '30°', None, '30°', 30),
             ('45°', None, '45°', None, '45°', 45),
             ('Off', None, 'Off', None, 'Off', 0),
             ], 45, lambda a, _unused: self.set_step_of_grid(a.get_current_value()))
        self.uimanager.insert_action_group(self.actiongroup, 0)
        self.uimanager.add_ui_from_string('''
<ui>
    <menubar name="MenuBar">
      <menu action="File">
        <menuitem action="Quit"/>
      </menu>
      <menu action="View">
        <menuitem action="Skyview"/>
        <menuitem action="Responses"/>
        <menuitem action="GPS"/>
        <menuitem action="Noise"/>
        <menuitem action="Maidenhead"/>
        <menuitem action="AIS"/>
      </menu>
      <menu action="Units">
        <menuitem action="Imperial"/>
        <menuitem action="Nautical"/>
        <menuitem action="Metric"/>
      </menu>
      <menu action="Step of grid">
        <menuitem action="30°"/>
        <menuitem action="45°"/>
        <menuitem action="Off"/>
      </menu>
    </menubar>
</ui>
''')
        self.uimanager.get_widget('/MenuBar/View/Skyview').set_active(True)
        self.uimanager.get_widget('/MenuBar/View/Responses').set_active(True)
        self.uimanager.get_widget('/MenuBar/View/GPS').set_active(True)
        self.uimanager.get_widget('/MenuBar/View/Noise').set_active(True)
        self.uimanager.get_widget('/MenuBar/View/Maidenhead').set_active(True)
        self.uimanager.get_widget('/MenuBar/View/AIS').set_active(True)
        menubar = self.uimanager.get_widget('/MenuBar')
        vbox.pack_start(menubar, False)

        self.satbox = gtk.HBox(False, 0)
        vbox.add(self.satbox)

        skyframe = gtk.Frame(label="Satellite List")
        self.satbox.add(skyframe)

        self.satlist = gtk.ListStore(str, str, str, str, str)
        view = gtk.TreeView(model=self.satlist)

        for (i, label) in enumerate(('PRN:', 'Elev:', 'Azim:', 'SNR:', 'Used:')):
            column = gtk.TreeViewColumn(label)
            renderer = gtk.CellRendererText()
            column.pack_start(renderer)
            column.add_attribute(renderer, 'text', i)
            view.append_column(column)

        self.row_iters = []
        for i in range(gps.MAXCHANNELS):
            self.satlist.append(["", "", "", "", ""])
            self.row_iters.append(self.satlist.get_iter(i))

        skyframe.add(view)

        viewframe = gtk.Frame(label="Skyview")
        self.satbox.add(viewframe)
        self.skyview = SkyView()
        viewframe.add(self.skyview)

        self.rawdisplay = gtk.Entry()
        self.rawdisplay.set_editable(False)
        vbox.add(self.rawdisplay)

        self.dataframe = gtk.Frame(label="GPS data")
        datatable = gtk.Table(Base.COLUMNS, Base.ROWS, False)
        self.dataframe.add(datatable)
        gpswidgets = []
        for i in range(len(Base.gpsfields)):
            colbase = (i / Base.ROWS) * 2
            label = gtk.Label(Base.gpsfields[i][0] + ": ")
            # Wacky way to force right alignment
            label.set_alignment(xalign=1, yalign=0.5)
            datatable.attach(label, colbase, colbase + 1,
                             i % Base.ROWS, i % Base.ROWS + 1)
            entry = gtk.Entry()
            # The right size for the ISO8601 timestamp
            entry.set_width_chars(20)
            entry.set_text("n/a")
            datatable.attach(entry, colbase + 1, colbase + 2,
                             i % Base.ROWS, i % Base.ROWS + 1)
            gpswidgets.append(entry)
        vbox.add(self.dataframe)

        self.noisebox = gtk.HBox(False, 0)
        vbox.add(self.noisebox)
        noiseframe = gtk.Frame(label="Noise Statistics")
        self.noisebox.add(noiseframe)
        self.noiseview = NoiseView()
        noiseframe.add(self.noiseview.widget)

        self.gsbox = gtk.HBox(False, 0)
        vbox.add(self.gsbox)
        gsframe = gtk.Frame(label="Maidenhead Grid Square")
        self.gsbox.add(gsframe)
        self.gsview = MaidenheadView()
        gsframe.add(self.gsview.widget)

        self.aisbox = gtk.HBox(False, 0)
        vbox.add(self.aisbox)
        aisframe = gtk.Frame(label="AIS Data")
        self.aisbox.add(aisframe)
        self.aisview = AISView(self.deg_type)
        aisframe.add(self.aisview.widget)

        self.window.show_all()
        # Hide the Noise Statistics window until user selects it.
        self.uimanager.get_widget('/MenuBar/View/Noise').set_active(False)
        self.noisebox.hide()
        # Hide the Maidenhead window until user selects it.
        self.uimanager.get_widget('/MenuBar/View/Maidenhead').set_active(False)
        self.gsbox.hide()
        # Hide the AIS window until user selects it.
        self.uimanager.get_widget('/MenuBar/View/AIS').set_active(False)
        self.aisbox.hide()

        self.view_name_to_widget = {
            "Skyview": self.satbox,
            "Responses": self.rawdisplay,
            "GPS": self.dataframe,
            "Noise": self.noisebox,
            "Maidenhead": self.gsbox,
            "AIS": self.aisbox}

        # Discard field labels and associate data hooks with their widgets
        Base.gpsfields = map(lambda ((label, hook), widget): (hook, widget),
                             zip(Base.gpsfields, gpswidgets))

    def view_toggle(self, action):
        # print "View toggle:", action.get_active(), action.get_name()
        if hasattr(self, 'view_name_to_widget'):
            if action.get_active():
                self.view_name_to_widget[action.get_name()].show()
            else:
                self.view_name_to_widget[action.get_name()].hide()
        # The effect we're after is to make the top-level window
        # resize itself to fit when we show or hide widgets.
        # This is undocumented magic to do that.
        self.window.resize(1, 1)

    def set_satlist_field(self, row, column, value):
        "Set a specified field in the satellite list."
        try:
            self.satlist.set_value(self.row_iters[row], column, value)
        except IndexError:
            sys.stderr.write("xgps: channel = %d, MAXCHANNELS = %d\n" % (row, gps.MAXCHANNELS))

    def delete_event(self, _widget, _event, _data=None):
        gtk.main_quit()
        return False

    # State updates

    def update_time(self, data):
        if hasattr(data, "time"):
            # str() just in case we get an old-style float.
            return str(data.time)
        else:
            return "n/a"

    def update_latitude(self, data):
        if data.mode >= gps.MODE_2D and hasattr(data, "lat"):
            lat = gps.clienthelpers.deg_to_str(self.deg_type, abs(data.lat))
            if data.lat < 0:
                ns = 'S'
            else:
                ns = 'N'
            return "%s %s" % (lat, ns)
        else:
            return "n/a"

    def update_longitude(self, data):
        if data.mode >= gps.MODE_2D and hasattr(data, "lon"):
            lon = gps.clienthelpers.deg_to_str(self.deg_type, abs(data.lon))
            if data.lon < 0:
                ew = 'W'
            else:
                ew = 'E'
            return "%s %s" % (lon, ew)
        else:
            return "n/a"

    def update_altitude(self, data):
        if data.mode >= gps.MODE_3D and hasattr(data, "alt"):
            return "%.3f %s" % (
                data.alt * self.conversions.altfactor,
                self.conversions.altunits)
        else:
            return "n/a"

    def update_speed(self, data):
        if hasattr(data, "speed"):
            return "%.3f %s" % (
                data.speed * self.conversions.speedfactor,
                self.conversions.speedunits)
        else:
            return "n/a"

    def update_climb(self, data):
        if hasattr(data, "climb"):
            return "%.3f %s" % (
                data.climb * self.conversions.speedfactor,
                self.conversions.speedunits)
        else:
            return "n/a"

    def update_track(self, data):
        if hasattr(data, "track"):
            return gps.clienthelpers.deg_to_str(self.deg_type, abs(data.track))
        else:
            return "n/a"

    def update_err(self, data, errtype):
        if hasattr(data, errtype):
            return "%.3f %s" % (
                getattr(data, errtype) * self.conversions.altfactor,
                self.conversions.altunits)
        else:
            return "n/a"

    def update_err_speed(self, data, errtype):
        if hasattr(data, errtype):
            return "%.3f %s" % (
                getattr(data, errtype) * self.conversions.speedfactor,
                self.conversions.speedunits)
        else:
            return "n/a"

    def update_err_degrees(self, data, errtype):
        if hasattr(data, errtype):
            return "%.3f °" % (getattr(data, errtype))
        else:
            return "n/a"

    def update_status(self, data):
        if data.mode == gps.MODE_2D:
            status = "2D FIX"
        elif data.mode == gps.MODE_3D:
            status = "3D FIX"
        else:
            status = "NO FIX"
        if data.mode != self.saved_mode:
            self.last_transition = time.time()
            self.saved_mode = data.mode
        return status + " (%d secs)" % (time.time() - self.last_transition)

    def update_gpsdata(self, tpv):
        "Update the GPS data fields."
        # the first 14 fields are updated using TPV data
        for (hook, widget) in Base.gpsfields[:14]:
            if hook:  # Remove this guard when we have all hooks
                widget.set_text(hook(self, tpv))
        self.gsview.update(tpv)

    def update_skyview(self, data):
        "Update the satellite list and skyview."
        if hasattr(data, 'satellites'):
            satellites = data.satellites
            for fld in reversed(SKY_VIEW_SORT_FIELDS):
                rev = (fld[0] == '-')
                if rev:
                    fld = fld[1:]
                satellites = sorted(
                    satellites[:],
                    cmp=lambda x, y: cmp(x[fld], y[fld]), reverse=rev)

            for (i, satellite) in enumerate(satellites):
                self.set_satlist_field(i, 0, satellite.PRN)
                self.set_satlist_field(i, 1, satellite.el)
                self.set_satlist_field(i, 2, satellite.az)
                self.set_satlist_field(i, 3, satellite.ss)
                yesno = 'N'
                if satellite.used:
                    yesno = 'Y'
                self.set_satlist_field(i, 4, yesno)
            for i in range(len(satellites), gps.MAXCHANNELS):
                for j in range(0, 5):
                    self.set_satlist_field(i, j, "")
            self.skyview.redraw(satellites)

    # Preferences

    def set_units(self, system):
        "Change the display units."
        self.conversions = unit_adjustments(system)

    def set_step_of_grid(self, system):
        "Change the step of grid."
        self.skyview.step_of_grid = system

    # I/O monitoring and gtk housekeeping

    def watch(self, daemon, device):
        "Set up monitoring of a daemon instance."
        self.daemon = daemon
        self.device = device
        gobject.io_add_watch(daemon.sock, gobject.IO_IN, self.handle_response)
        gobject.io_add_watch(daemon.sock, gobject.IO_ERR, self.handle_hangup)
        gobject.io_add_watch(daemon.sock, gobject.IO_HUP, self.handle_hangup)

    def handle_response(self, source, condition):
        "Handle ordinary I/O ready condition from the daemon."
        if self.daemon.read() == -1:
            self.handle_hangup(source, condition)
        if self.daemon.valid & gps.PACKET_SET:
            if self.device and "device" in self.daemon.data and self.device != self.daemon.data["device"]:
                return True
            self.rawdisplay.set_text(self.daemon.response.strip())
            if self.daemon.data["class"] == "SKY":
                self.update_skyview(self.daemon.data)
            elif self.daemon.data["class"] == "TPV":
                self.update_gpsdata(self.daemon.data)
            elif self.daemon.data["class"] == "GST":
                self.noiseview.update(self.daemon.data)
                if not self.noise_latch:
                    self.noise_latch = True
                    self.uimanager.get_widget('/MenuBar/View/Noise').set_active(True)
                    self.noisebox.show()
            elif self.daemon.data["class"] == "AIS":
                self.aisview.update(self.daemon.data)
                if not self.ais_latch:
                    self.ais_latch = True
                    self.uimanager.get_widget('/MenuBar/View/AIS').set_active(True)
                    self.aisbox.show()

        return True

    def handle_hangup(self, _source, _condition):
        "Handle hangup condition from the daemon."
        w = gtk.MessageDialog(type=gtk.MESSAGE_ERROR,
                              flags=gtk.DIALOG_DESTROY_WITH_PARENT,
                              buttons=gtk.BUTTONS_CANCEL)
        w.connect("destroy", lambda _unused: gtk.main_quit())
        w.set_markup("gpsd has stopped sending data.")
        w.run()
        gtk.main_quit()
        return True

    def main(self):
        gtk.main()

if __name__ == "__main__":
    try:
        import getopt
        (options, arguments) = getopt.getopt(sys.argv[1:], "D:hl:u:V?",
                                             ['verbose'])
        debug = 0
        degreefmt = 'd'
        unit_system = None
        for (opt, val) in options:
            if opt in '-D':
                debug = int(val)
            elif opt == '-l':
                degreeformat = val
            elif opt == '-u':
                unit_system = val
            elif opt in ('-?', '-h', '--help'):
                print __doc__
                sys.exit(0)
            elif opt == 'V':
                sys.stderr.write("xgps 1.0\n")
                sys.exit(0)

        degreefmt = {'d': gps.clienthelpers.deg_dd,
                     'm': gps.clienthelpers.deg_ddmm,
                     's': gps.clienthelpers.deg_ddmmss}[degreefmt]

        (host, port, device) = ("localhost", "2947", None)
        if len(arguments):
            args = arguments[0].split(":")
            if len(args) >= 1:
                host = args[0]
            if len(args) >= 2:
                port = args[1]
            if len(args) >= 3:
                device = args[2]

        base = Base(deg_type=degreefmt)
        base.set_units(unit_system)
        try:
            daemon = gps.gps(host=host,
                             port=port,
                             mode=gps.WATCH_ENABLE | gps.WATCH_JSON | gps.WATCH_SCALED,
                             verbose=debug)
            base.watch(daemon, device)
            base.main()
        except socket.error:
            w = gtk.MessageDialog(type=gtk.MESSAGE_ERROR,
                                  flags=gtk.DIALOG_DESTROY_WITH_PARENT,
                                  buttons=gtk.BUTTONS_CANCEL)
            w.set_markup("gpsd is not running.")
            w.run()
            w.destroy()
    except KeyboardInterrupt:
        pass