1 files changed, 270 insertions, 0 deletions
diff --git a/audiotrond.go b/audiotrond.go
new file mode 100644
index 0000000..f59a4db
--- /dev/null
+++ b/audiotrond.go
@@ -0,0 +1,270 @@
+// Copyright 2022 Benjamin Barenblat
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"time"
+
+	"benjamin.barenblat.name/audiotrond/cfa635"
+	"github.com/fhs/gompd/v2/mpd"
+	"github.com/tarm/serial"
+)
+
+func putWrapped(lcd *cfa635.Module, col, row int, data []byte) error {
+	for row < 4 && len(data) > 0 {
+		if err := lcd.Put(col, row, data); err != nil {
+			return err
+		}
+		if len(data) <= 20-col {
+			data = nil
+		} else {
+			data = data[20-col:]
+		}
+		col = 0
+		row++
+	}
+	return nil
+}
+
+func update[T comparable](dst *T, src T, mtime *time.Time, now time.Time) {
+	if *dst == src {
+		return
+	}
+	*dst = src
+	*mtime = now
+}
+
+type playbackState byte
+
+const (
+	_ playbackState = 1 + iota
+	stopped
+	playing
+	paused
+)
+
+type foreground byte
+
+const (
+	_ foreground = iota
+	mpdForeground
+	clockForeground
+)
+
+type model struct {
+	State           playbackState
+	LastStateChange time.Time
+
+	Duration time.Duration
+	Elapsed  time.Duration
+
+	Track               string
+	Artist              string
+	Album               string
+	LastTrackInfoUpdate time.Time
+
+	Foreground foreground
+}
+
+func connectToCFA635() *cfa635.Module {
+	s, err := serial.OpenPort(&serial.Config{Name: "/dev/lcd", Baud: 115200})
+	if err != nil {
+		panic(err)
+	}
+	m := cfa635.Connect(s)
+
+	go func() {
+		for r := m.ReadReport(); r != nil; r = m.ReadReport() {
+			log.Println("report:", r)
+		}
+	}()
+
+	return m
+}
+
+func reportPanicOrClear(lcd *cfa635.Module) {
+	if v := recover(); v != nil {
+		putWrapped(lcd, 0, 0, encode(fmt.Sprint("panic: ", v)))
+		panic(v)
+	}
+	lcd.Clear()
+}
+
+func poll(mpd *mpd.Client, now time.Time, model *model) error {
+	cmds := mpd.BeginCommandList()
+	statusP := cmds.Status()
+	currentP := cmds.CurrentSong()
+	if err := cmds.End(); err != nil {
+		return err
+	}
+
+	status, err := statusP.Value()
+	if err != nil {
+		return err
+	}
+
+	switch status["state"] {
+	case "stop":
+		update(&model.State, stopped, &model.LastStateChange, now)
+	case "play":
+		update(&model.State, playing, &model.LastStateChange, now)
+	case "pause":
+		update(&model.State, paused, &model.LastStateChange, now)
+	}
+
+	if status["duration"] == "" {
+		model.Duration = 0
+		model.Elapsed = 0
+	} else {
+		if model.Duration, err = time.ParseDuration(status["duration"] + "s"); err != nil {
+			panic(err)
+		}
+		if model.Elapsed, err = time.ParseDuration(status["elapsed"] + "s"); err != nil {
+			panic(err)
+		}
+	}
+
+	current, err := currentP.Value()
+	if err != nil {
+		return err
+	}
+
+	update(&model.Track, current["Title"], &model.LastTrackInfoUpdate, now)
+	update(&model.Artist, current["Artist"], &model.LastTrackInfoUpdate, now)
+	update(&model.Album, current["Album"], &model.LastTrackInfoUpdate, now)
+	return nil
+}
+
+func ellipsize(src []byte, ellipsis byte, dst []byte) {
+	if len(src) <= len(dst) {
+		copy(dst, src)
+	} else {
+		dots := len(dst) - 1
+		copy(dst, src[:dots])
+		dst[dots] = ellipsis
+	}
+}
+
+func fmtTime(t, max time.Duration) string {
+	f := func(neg string, h, m, s int) string {
+		_ = h
+		return fmt.Sprintf("%s%d:%02d", neg, m, s)
+	}
+	if max/time.Hour > 0 {
+		f = func(neg string, h, m, s int) string {
+			return fmt.Sprintf("%s%d:%02d:%02d", neg, h, m, s)
+		}
+	} else if int(max/time.Minute)%60 >= 10 {
+		f = func(neg string, h, m, s int) string {
+			_ = h
+			return fmt.Sprintf("%s%02d:%02d", neg, m, s)
+		}
+	}
+
+	var neg string
+	if t < 0 {
+		t *= -1
+		neg = "-"
+	}
+	return f(neg, int(t/time.Hour), int(t/time.Minute)%60, int(t/time.Second)%60)
+}
+
+func main() {
+	lcd := connectToCFA635()
+	defer reportPanicOrClear(lcd)
+	defer lcd.SetBacklight(0, 0)
+	if err := lcd.SetLED(0, false, 0); err != nil {
+		panic(err)
+	}
+	if err := lcd.SetLED(0, true, 0); err != nil {
+		panic(err)
+	}
+
+	if err := lcd.Clear(); err != nil {
+		panic(err)
+	}
+
+	mpd, err := mpd.Dial("unix", "/run/mpd/socket")
+	if err != nil {
+		panic(err)
+	}
+
+	var model model
+
+	view1 := new(view)
+	view1.LCD = cfa635.ClearedLCDState()
+	view1.Mtime = time.Now()
+
+	// Create an idle timer and put it in a drained state so the event loop
+	// can set it.
+	idle := time.NewTimer(0)
+	<-idle.C
+
+	sigterm := make(chan os.Signal, 1)
+	signal.Notify(sigterm, os.Interrupt)
+
+EventLoop:
+	for {
+		now := time.Now()
+
+		if err := poll(mpd, now, &model); err != nil {
+			panic(err)
+		}
+
+		var foreground2 foreground
+		if model.State == playing || now.Sub(model.LastStateChange).Seconds() < 17 {
+			foreground2 = mpdForeground
+		} else {
+			foreground2 = clockForeground
+		}
+
+		if foreground2 != model.Foreground {
+			switch foreground2 {
+			case mpdForeground:
+				if err := initializeMPDDisplay(lcd); err != nil {
+					panic(err)
+				}
+			case clockForeground:
+				if err := initializeClockDisplay(lcd); err != nil {
+					panic(err)
+				}
+			}
+		}
+		model.Foreground = foreground2
+
+		var view2 *view
+		switch model.Foreground {
+		case mpdForeground:
+			view2 = mpdView(&model, now, view1)
+		case clockForeground:
+			view2 = clockView(now)
+		}
+		if err := updateView(lcd, view1, view2); err != nil {
+			panic(err)
+		}
+		view1 = view2
+
+		idle.Reset(10 * time.Millisecond)
+		select {
+		case <-sigterm:
+			break EventLoop
+		case <-idle.C:
+		}
+	}
+}