; (local { : view } (require :fennel))
(local { : fdopen } (require :posix.stdio))
(local nmea (require :nmea))

(import-macros { : define-tests : expect : expect= } :assert)

(local {
        : Gtk
        : OsmGpsMap
        : Gdk
        : Gio
        : GLib
        }
       (require :lgi))

(local CSS "
label.readout {
    font: 48px \"Noto Sans\";
    margin: 10px;
    padding: 5px;
    background-color: rgba(0, 0, 0, 0.2);
}
")

(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
     (Gdk.Screen.get_default)
     style_provider
     Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION
     )
    (style_provider:load_from_data CSS)))

(local window (Gtk.Window {
                           :title "Map"
                           :name "toplevel"
                           :default_width 720
                           :default_height 800

                           :on_destroy Gtk.main_quit
                           }))

(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 readouts []
  (doto (Gtk.Box
         {
          :orientation Gtk.Orientation.VERTICAL
          :halign Gtk.Align.END
          })
    (-> (: :get_style_context) (: :add_class :readouts))
    (: :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 socket-path
                                          })]
         (: (Gio.SocketClient) :connect addr nil)))

(fn read-gnss [socket]
  (each [l #(socket:read "l")]
    ; (print "gnss" l)
    (if (not (= 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)
      fd (sock:get_fd)
      events [ GLib.IOCondition.IN GLib.IOCondition.HUP]
      channel (GLib.IOChannel.unix_new fd)
      handle (fdopen fd :r)]
  (GLib.io_add_watch channel 0 events #(read-gnss handle)))


(window:add
 (doto (Gtk.Overlay {})
   (: :add (osm-widget))
   (: :add_overlay (readouts))
   (: :add_overlay (arrow))
   ))

(window:show_all)
(styles)
(Gtk:main)