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// 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:
}
}
}
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