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//
// dolmetschctl
//
//
// Copyright (C) 2019 Christian Pointner <equinox@spreadspace.org>
//
// This file is part of dolmetschctl.
//
// dolmetschctl is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// any later version.
//
// dolmetschctl is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
//
package main
import (
"fmt"
"log"
"time"
"spreadspace.org/dolmetschctl/pkg/mixer"
)
type State int
const (
StateNew = iota
StateSettling
StateSettled
)
func (s State) String() string {
switch s {
case StateNew:
return "new"
case StateSettling:
return "settling"
case StateSettled:
return "settled"
default:
return "unknown"
}
}
type Language string
func (l Language) String() string {
if l == "" {
return "none"
}
return string(l)
}
type MixerChannelState struct {
level mixer.FaderLevel
mute mixer.Mute
}
type MixerChannel struct {
num mixer.Channel
target MixerChannelState
current MixerChannelState
}
type MixerChannels struct {
main MixerChannel
voice MixerChannel
}
type selectLangRequest struct {
l Language
resultCh chan error
}
type StateMachine struct {
mixer *mixer.Mixer
selectLangCh chan selectLangRequest
quitCh chan bool
exitedCh chan struct{}
mixerEventCh chan mixer.Event
languages map[Language]*MixerChannels
channel2lang map[mixer.Channel]Language
currentState State
currentLang Language
targetLang Language
}
func (sm *StateMachine) handleMixerEvent(ev mixer.Event) {
lang, exists := sm.channel2lang[ev.Channel]
if !exists {
// TODO: make this panic?
log.Printf("got mixer-event for unknown channel: %s", ev)
return
}
mcs, exists := sm.languages[lang]
if !exists {
panic(fmt.Sprintf("channel2lang map contains unknown language entries!"))
return
}
var mc *MixerChannel
switch ev.Channel {
case mcs.main.num:
mc = &mcs.main
case mcs.voice.num:
mc = &mcs.voice
default:
panic(fmt.Sprintf("channel2lang points to language that does not use the channel!"))
return
}
switch ev.Type {
case mixer.EventFaderChange:
mc.current.level = ev.Level
case mixer.EventMute:
mc.current.mute = ev.Mute
}
}
// make sure that our state and the mixer are in sync
func (sm *StateMachine) initMixer() {
for _, mcs := range sm.languages {
sm.mixer.SetLevel(mcs.main.num, mixer.FaderLevel0db-1)
sm.mixer.SetLevel(mcs.main.num, mixer.FaderLevel0db)
mcs.main.target.level = mixer.FaderLevel0db
sm.mixer.SetLevel(mcs.voice.num, mixer.FaderLevelOff+1)
sm.mixer.SetLevel(mcs.voice.num, mixer.FaderLevelOff)
mcs.voice.target.level = mixer.FaderLevelOff
}
sm.currentLang = ""
sm.targetLang = ""
sm.currentState = StateSettled
}
// the "current language" is what is currently spoken on stage
func (sm *StateMachine) selectLang(l Language) error {
if l != "" {
if _, exists := sm.languages[l]; !exists {
return fmt.Errorf("language '%s' does not exist", l)
}
}
sm.targetLang = l
log.Printf("new target language: '%s'", sm.targetLang)
return nil
}
func calcNextLevel(target, current mixer.FaderLevel) mixer.FaderLevel {
next := target
if current != mixer.FaderLevelUnknown {
if next > current {
next = current + 1
} else {
next = current - 1
}
}
return next
}
func (sm *StateMachine) reconcile(ticker bool) {
for lang, mcs := range sm.languages {
if sm.targetLang == "" || lang == sm.targetLang || mcs.voice.current.mute == mixer.MuteMuted {
mcs.main.target.level = mixer.FaderLevel0db
mcs.voice.target.level = mixer.FaderLevelOff
} else {
mcs.main.target.level = mixer.FaderLevel(float32(mixer.FaderLevel0db) * 0.5) // TODO: hardcoded Value!!
mcs.voice.target.level = mixer.FaderLevel0db
}
}
if sm.currentState != StateSettled && !ticker {
return
}
sm.currentState = StateSettled
for _, mcs := range sm.languages {
if mcs.main.target.level != mcs.main.current.level {
sm.mixer.SetLevel(mcs.main.num, calcNextLevel(mcs.main.target.level, mcs.main.current.level))
sm.currentState = StateSettling
}
if mcs.voice.target.level != mcs.voice.current.level {
sm.mixer.SetLevel(mcs.voice.num, calcNextLevel(mcs.voice.target.level, mcs.voice.current.level))
sm.currentState = StateSettling
}
}
}
func (sm *StateMachine) run() {
defer close(sm.exitedCh)
sm.initMixer()
t := time.NewTicker(10 * time.Millisecond)
for {
select {
case <-t.C:
if sm.currentState == StateSettling {
sm.reconcile(true)
}
case req := <-sm.selectLangCh:
req.resultCh <- sm.selectLang(req.l)
sm.reconcile(false)
case ev := <-sm.mixerEventCh:
sm.handleMixerEvent(ev)
sm.reconcile(false)
case <-sm.quitCh:
return
}
}
}
func NewStateMachine(m *mixer.Mixer) (*StateMachine, error) {
sm := &StateMachine{mixer: m}
sm.selectLangCh = make(chan selectLangRequest, 10)
sm.quitCh = make(chan bool, 1)
sm.exitedCh = make(chan struct{})
sm.mixerEventCh = make(chan mixer.Event, 1000)
sm.languages = make(map[Language]*MixerChannels)
sm.channel2lang = make(map[mixer.Channel]Language)
sm.currentState = StateNew
sm.currentLang = ""
sm.targetLang = ""
return sm, nil
}
// TODO: currently we can only deal with 2 languages...
func (sm *StateMachine) AddLanguage(name Language, main, voice mixer.Channel) error {
if sm.currentState != StateNew {
return fmt.Errorf("adding languages is only allowed during startup")
}
if name == "none" {
return fmt.Errorf("language 'none' is reserved")
}
if _, exists := sm.languages[name]; exists {
return fmt.Errorf("language '%s' already exists", name)
}
for ch := range []mixer.Channel{main, voice} {
if _, exists := sm.languages[name]; exists {
return fmt.Errorf("mixer channel %v is already in use by language '%s'", ch, name)
}
}
unknown := MixerChannelState{level: mixer.FaderLevelUnknown, mute: mixer.MuteUnknown}
chMain := MixerChannel{num: main, current: unknown, target: unknown}
chVoice := MixerChannel{num: voice, current: unknown, target: unknown}
sm.languages[name] = &MixerChannels{chMain, chVoice}
sm.channel2lang[main] = name
sm.channel2lang[voice] = name
sm.mixer.Subscribe(main, sm.mixerEventCh)
sm.mixer.Subscribe(voice, sm.mixerEventCh)
return nil
}
func (sm *StateMachine) Start() {
go sm.run()
}
func (sm *StateMachine) SelectLanguage(l Language) error {
resultCh := make(chan error)
sm.selectLangCh <- selectLangRequest{l, resultCh}
return <-resultCh
}
func (sm *StateMachine) Shutdown() {
select {
case sm.quitCh <- true:
default:
}
<-sm.exitedCh
}
|
