add aroow to show direction of travel

while : ; do fennel fake-nmea.fnl foo.nmea ./fake-nmea.sock ; done

pkgs/maps/fake-nmea.fnl

@@ -0,0 +1,10 @@
+(local { : sleep } (require :posix.unistd))
+
+(let [[filename socketname]  arg
+      socket (io.popen (.. "socat - unix-listen:" socketname) :w)]
+  (with-open [handle (io.open filename :r)]
+    (each [l (handle:lines "L")]
+      (if (string.match l "GNS") (sleep 1))
+      (socket:write l)
+      (socket:flush)
+      )))

pkgs/maps/main.fnl

@@ -2,6 +2,8 @@
 (local { : fdopen } (require :posix.stdio))
 (local nmea (require :nmea))
 
+(import-macros { : define-tests : expect : expect= } :assert)
+
 (local {
         : Gtk
         : OsmGpsMap
@@ -20,6 +22,16 @@ label.readout {
 }
 ")
 
+(local utc-offset
+       (let [now (os.time)
+             localt (os.date "*t" now)
+             utct (os.date "!*t" now)]
+         (tset localt :isdst false)
+         (os.difftime (os.time localt) (os.time utct))))
+
+
+
+
 (fn styles []
   (let [style_provider (Gtk.CssProvider)]
     (Gtk.StyleContext.add_provider_for_screen
@@ -38,20 +50,73 @@ label.readout {
                            :on_destroy Gtk.main_quit
                            }))
 
-(fn osm-widget []
-  (doto (OsmGpsMap.Map {})
-    (tset :map-source  OsmGpsMap.MapSource_t.OPENSTREETMAP)
-    (: :set_center_and_zoom 52.595 -0.1 14)
-    (: :layer_add (OsmGpsMap.MapOsd {
-                                     :show_copyright true
-                                     ; :show_coordinates true
-                                     :show_scale true
-                                     }))
-    ))
+(local state-widgets { })
+
+(fn osm-widget []
+  (let [w
+        (doto (OsmGpsMap.Map {})
+          (tset :map-source  OsmGpsMap.MapSource_t.OPENSTREETMAP)
+          (: :set_center_and_zoom 52.595 -0.1 17)
+          (: :layer_add (OsmGpsMap.MapOsd {
+                                           :show_copyright true
+                                        ; :show_coordinates true
+                                           :show_scale true
+                                           }))
+          )]
+    (tset state-widgets :osm w)
+    w))
+
+
+(fn readout [name text]
+  (let [w
+        (doto (Gtk.Label {:label text : name})
+          (-> (: :get_style_context)
+              (: :add_class :readout)))]
+    (tset state-widgets name w)
+    w))
+
+(local knot-in-m-s
+       (/ 1852 ; metres in nautical mile
+          3600 ; seconds in an hour
+          ))
+
+(fn hhmmss [seconds-since-midnight]
+  (let [s (% seconds-since-midnight 60)
+        m (% (// (- seconds-since-midnight s) 60) 60)
+        h (// (- seconds-since-midnight (* m 60) s) 3600)]
+    (string.format "%d:%02d:%02d" h m s)))
+
+(expect= (hhmmss (+ 45 (* 60 12) (* 60 60 3))) "3:12:45")
+
+
+(local
+ app-state {
+            :time-of-day 0
+            :elapsed-time 0
+            :speed 14
+            :lat 49
+            :lon 0
+            :course 22
+            }
+ )
+
+
+(fn merge [table1 table2]
+  (collect [k v (pairs table2) &into table1]
+    k v))
+
+
+(fn update-app-state [new-vals]
+  (merge app-state new-vals)
+  (each [name widget (pairs state-widgets)]
+    (case name
+      :speed (widget:set_label
+              (string.format "%.1f km/h" (* app-state.speed 3.6)))
+      :osm (widget:set_center app-state.lat app-state.lon)
+      :time (widget:set_label
+             (hhmmss (+ utc-offset app-state.time-of-day)))
+      )))
 
-(fn readout [text]
-  (doto (Gtk.Label {:label text})
-    (-> (: :get_style_context) (: :add_class :readout))))
 
 (fn readouts []
   (doto (Gtk.Box
@@ -60,13 +125,37 @@ label.readout {
           :halign Gtk.Align.END
           })
     (-> (: :get_style_context) (: :add_class :readouts))
-    (: :add (readout "21:05:00"))
-    (: :add (readout "00:00"))
-    (: :add (readout "25 km/h"))))
+    (: :add (readout :time ""))
+    (: :add (readout :elapsed-time ""))
+    (: :add (readout :speed "0"))))
+
+(fn arrow []
+  (let [height 40
+        w (Gtk.Label {
+                       :halign Gtk.Align.CENTER
+                       :valign Gtk.Align.CENTER
+                       :width height :height height
+                       :on_draw
+                       (fn [self g]
+                         (g:set_source_rgb 0.4 0.0 0.1)
+                         (g:translate (// height 2) (// height 2))
+                         (g:rotate (/ (* -2  app-state.course math.pi) 360) )
+                         (g:translate (// height -2) (// height -2))
+                         (g:set_line_width 4)
+                         (g:move_to 10 height)
+                         (g:line_to (// height 2) 0)
+                         (g:line_to (- height 10) height)
+                         (g:fill)
+                         true)
+                       })]
+    w))
+
+
+(local socket-path (or (. arg 1) "/var/run/gnss-share.sock"))
 
 (local gnss-socket
        (let [addr (Gio.UnixSocketAddress {
-                                          :path "/var/run/gnss-share.sock"
+                                          :path socket-path
                                           })]
          (: (Gio.SocketClient) :connect addr nil)))
 
@@ -74,8 +163,22 @@ label.readout {
   (each [l #(socket:read "l")]
     ; (print "gnss" l)
     (if (not (= l ""))
-        (print (view (nmea.parse l)))))
-
+        (let [message (nmea.parse l)]
+          (case message
+            { : lat : lon : utc}
+            (update-app-state
+             {
+              : lat : lon
+              :time-of-day
+              (let [(h m s) (string.match utc "(..)(..)(..)")]
+                (+ s (* m 60) (* h 60 60)))
+              }
+             )
+            { : speed-knots }
+            (update-app-state { :speed (* speed-knots knot-in-m-s) }))
+          (if message.bearing-true
+              (update-app-state { :course message.bearing-true }))
+          )))
   true)
 
 (let [sock (gnss-socket:get_socket)
@@ -90,6 +193,7 @@ label.readout {
  (doto (Gtk.Overlay {})
    (: :add (osm-widget))
    (: :add_overlay (readouts))
+   (: :add_overlay (arrow))
    ))
 
 (window:show_all)

pkgs/maps/nmea.fnl

@@ -54,6 +54,15 @@
       nil
       (tonumber s)))
 
+(fn parse-coordinate [value sign]
+  (if (= value "")
+      nil
+      (let [(deg min) (string.match value "(..)(.+)")]
+        (*
+         (+ (tonumber deg)
+            (/ (tonumber min) 60))
+         (case sign :N 1 :E 1 :S -1 :W -1)))))
+
 (local
  msg-types
  {
@@ -66,14 +75,9 @@
            altitude _
            geoidal-separation _
            _ _ ] fields
-          latf (if (= lat "")
-                   nil
-                   (* (tonumber lat) 0.01 (case latsign :N 1 :S -1)))
-          lonf (if (= lon "")
-                   nil
-                   (* (tonumber lon) 0.01 (case lonsign :E 1 :W -1)))]
-      { :lat latf
-        :lon lonf
+          ]
+      { :lat (parse-coordinate lat latsign)
+        :lon (parse-coordinate lon lonsign)
         : fix-quality
         :total-space-vehicles (try-number total-space-vehicles)
         :hdop (try-number hdop)
@@ -86,39 +90,27 @@
         knots bearing-true date
         magn-var magn-var-sign
         mode nav-status &as fields]]
-    (let [latf (if (= lat "")
-                   nil
-                   (* (tonumber lat) 0.01 (case latsign :N 1 :S -1)))
-          lonf (if (= lon "")
-                   nil
-                   (* (tonumber lon) 0.01 (case lonsign :E 1 :W -1)))
-          magnetic-variation (if (= magn-var "")
+    (let [magnetic-variation (if (= magn-var "")
                                  nil
                                  (* (tonumber magn-var)
                                     (case magn-var-sign :E 1 :W -1)))]
       { : utc
         : valid
-        :lat latf
-        :lon lonf
+        :lat (parse-coordinate lat latsign)
+        :lon (parse-coordinate lon lonsign)
         :speed-knots (try-number knots)
         :bearing-true (try-number bearing-true)
         : date
-        : magnetic-variation
+        : magnetic-variation ;;; XXX probably wrong
         : mode
         }))
 
   :GNS
   (fn [fields]
     (let [[utc lat latsign lon lonsign mode total-space-vehicles
-           hdop altitude geoidal-separation _ _ nav-status] fields
-          latf (if (= lat "")
-                   nil
-                   (* (tonumber lat) 0.01 (case latsign :N 1 :S -1)))
-          lonf (if (= lon "")
-                   nil
-                   (* (tonumber lon) 0.01 (case lonsign :E 1 :W -1)))]
-      { :lat latf
-        :lon lonf
+           hdop altitude geoidal-separation _ _ nav-status] fields]
+      { :lat (parse-coordinate lat latsign)
+        :lon (parse-coordinate lon lonsign)
         : mode
         :total-space-vehicles (try-number total-space-vehicles)
         :hdop (try-number hdop)
@@ -150,14 +142,16 @@
           (tset :talker talker))
         split)))
 
+;; XXX this is wrong. 5131.348976 is 51 degrees 31.348976 minutes
+
 (expect=
  (parse-line
   "$GNGNS,111134.00,5131.348976,N,00005.551003,W,AAAANN,19,0.7,20.3,47.0,,,V*0C\n")
  {:altitude 20.3
   :geoidal-separation 47
   :hdop 0.7
-  :lat 51.31348976
-  :lon -0.05551003
+  :lat 51.522482933333
+  :lon -0.092516716666667
   :message-type "GNS"
   :mode "AAAANN"
   :nav-status "V"