slideshow/internal/slideshow.go

package internal

import (
	"os/exec"
	"strconv"
	"sync"
	"time"

	"git.velvettear.de/velvettear/loggo"
	"git.velvettear.de/velvettear/slideshow/internal/config"
)

var loop int64

// start the loop for the slideshow
func StartSlideshow() {
	for {
		timestamp := time.Now().UnixMilli()
		loop++
		imageLoop()
		loggo.InfoTimed("slideshow loop #"+strconv.FormatInt(loop, 10)+" finished", timestamp)
		loggo.Debug("sleeping for " + strconv.FormatFloat(config.Interval.Seconds(), 'f', 0, 64) + " seconds...")
		time.Sleep(config.Interval)
	}
}

// the image loop of the slideshoow
func imageLoop() {
	name, error := requestImageName()
	if error != nil {
		loggo.Error("encountered an error requesting the name of an image", error.Error())
		return
	}
	var waitgroup sync.WaitGroup
	waitgroup.Add(2)
	go setBackground(name, &waitgroup)
	go exportColorPalette(name, &waitgroup)
	waitgroup.Wait()
	if !config.IsScriptStageSet() {
		runScript(false)
	}
}

// encapsulated method to set the background image in a goroutine
func setBackground(name string, waitgroup *sync.WaitGroup) {
	timestamp := time.Now().UnixMilli()
	defer waitgroup.Done()
	if config.IsScriptStagePreImage() {
		runScript(false)
	}
	stream, error := requestImageData(name)
	if error != nil {
		loggo.Error("encountered an error requesting the data stream for image '"+name+"'", error.Error())
		return
	}
	error = streamToFeh(stream)
	if error != nil {
		loggo.Error("encountered an error piping the data stream for image '"+name+"' to 'feh'", error.Error())
	}
	loggo.InfoTimed("set new background image '"+name+"' via 'feh'", timestamp)
	if config.IsScriptStagePostImage() {
		runScript(false)
	}
}

// encapsulated method to set the background image in a goroutine
func exportColorPalette(name string, waitgroup *sync.WaitGroup) {
	timestamp := time.Now().UnixMilli()
	if !config.IsPaletteSet() {
		return
	}
	defer waitgroup.Done()
	if config.IsScriptStagePrePalette() {
		runScript(false)
	}
	stream, error := requestColorPalette(name)
	if error != nil {
		loggo.Error("encountered an error requesting the data stream for the color palette of image '"+name+"'", error.Error())
		return
	}
	error = streamToFile(stream, config.PaletteFile)
	if error != nil {
		loggo.Error("encountered an error piping the data stream for the color palette of image '"+name+"' to file '"+config.PaletteFile+"'", error.Error())
	}
	loggo.InfoTimed("exported color palette of image '"+name+"' to  '"+config.PaletteFile+"'", timestamp)
	if config.IsScriptStagePostPalette() {
		runScript(false)
	}
}

// encapsulated method to run the defined script
func runScript(running bool) {
	if !running && config.ScriptAsync {
		go runScript(true)
		return
	}
	timestamp := time.Now().UnixMilli()
	if !config.IsScriptSet() {
		return
	}
	cmd := exec.Command(config.Script)
	error := cmd.Run()
	if error != nil {
		loggo.Error("encountered an error executing the script '"+config.Script+"'", error.Error())
		return
	}
	var extras []string
	if config.ScriptAsync {
		extras = append(extras, "async: "+strconv.FormatBool(config.ScriptAsync))
	}
	if config.IsScriptStageSet() {
		extras = append(extras, "stage: "+config.ScriptStage)
	}
	loggo.InfoTimed("executed script '"+config.Script+"'", timestamp, extras...)
}