Add click event handling

Signed-off-by: AKP <tom@tdpain.net>

README.md

@@ -4,12 +4,13 @@
 
 ---
 
-This is a i3wm status bar that's built as a toy project. It's pretty basic, doesn't have many features and isn't very configurable unless you want to edit the source and recompile it.
+This is a i3wm status bar that's built as a toy project. ~~It's~~ **It was** pretty basic (I've since added click event support), doesn't have many features and isn't very configurable unless you want to edit the source and recompile it.
 
 This interacts with i3 using the [i3bar input protocol](https://i3wm.org/docs/i3bar-protocol.html). i3 versions earlier than v4.3 are not supported.
 
 ### Features
 
+* Supports click events
 * SIGUSR1 forces a refresh
 * It has colours
 * Sometimes it breaks

cmd/bar/main.go

@@ -25,7 +25,7 @@ func main() {
 		Filename: logFileName,
 		MaxSize:  1,  // MB
 		MaxAge:   14, // days
-	})).Level(zerolog.ErrorLevel)
+	})).Level(zerolog.DebugLevel)
 
 	if err := run(); err != nil {
 		log.Fatal().Err(err).Msg("unhandled error")
@@ -33,7 +33,7 @@ func main() {
 }
 
 func run() error {
-	b := i3bar.New(os.Stdout, time.Second*5, syscall.SIGUSR1)
+	b := i3bar.New(os.Stdout, os.Stdin, time.Second*5, syscall.SIGUSR1)
 	if err := b.Initialise(); err != nil {
 		return err
 	}

internal/i3bar/i3bar.go

@@ -1,6 +1,8 @@
 package i3bar
 
 import (
+	"bufio"
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -14,17 +16,20 @@ import (
 
 type I3bar struct {
 	writer               io.Writer
+	reader               io.Reader
 	updateInterval       time.Duration
 	updateSignal         syscall.Signal
 	registeredGenerators []BlockGenerator
+	registeredConsumers  []ClickEventConsumer
 
 	hasInitialised   bool
 	hasSentFirstLine bool
 }
 
-func New(writer io.Writer, updateInterval time.Duration, updateSignal syscall.Signal) *I3bar {
+func New(writer io.Writer, reader io.Reader, updateInterval time.Duration, updateSignal syscall.Signal) *I3bar {
 	return &I3bar{
 		writer:         writer,
+		reader:         reader,
 		updateInterval: updateInterval,
 		updateSignal:   updateSignal,
 	}
@@ -32,13 +37,13 @@ func New(writer io.Writer, updateInterval time.Duration, updateSignal syscall.Si
 
 func (b *I3bar) Initialise() error {
 	capabilities, err := json.Marshal(map[string]any{
-		"version": 1,
+		"version":      1,
 		"click_events": true,
 	})
 	if err != nil {
 		return err
 	}
-	
+
 	if _, err := b.writer.Write(append(capabilities, '\n')); err != nil {
 		return err
 	}
@@ -95,8 +100,15 @@ func (b *I3bar) Emit(generators []BlockGenerator) error {
 	return nil
 }
 
+// RegisterBlockGenerator registers a block generator with the status bar. This
+// function should not be called after StartLoop is called.
 func (b *I3bar) RegisterBlockGenerator(bg ...BlockGenerator) {
 	b.registeredGenerators = append(b.registeredGenerators, bg...)
+	for _, generator := range bg {
+		if g, ok := generator.(ClickEventConsumer); ok {
+			b.registeredConsumers = append(b.registeredConsumers, g)
+		}
+	}
 }
 
 func (b *I3bar) StartLoop() error {
@@ -110,15 +122,50 @@ func (b *I3bar) StartLoop() error {
 	sigUpdate := make(chan os.Signal, 1)
 	signal.Notify(sigUpdate, os.Signal(b.updateSignal))
 
+	go b.consumerLoop(func() {
+		sigUpdate <- b.updateSignal
+	})
+
 	for {
 		select {
 		case <-sigUpdate:
 			if err := b.Emit(b.registeredGenerators); err != nil {
-				return err
+				log.Error().Err(err).Msg("could not emit registered generators")
 			}
 		case <-ticker.C:
 			if err := b.Emit(b.registeredGenerators); err != nil {
-				return err
+				log.Error().Err(err).Msg("could not emit registered generators")
+			}
+		}
+	}
+}
+
+func (b *I3bar) consumerLoop(requestBarRefresh func()) {
+	r := bufio.NewReader(b.reader)
+	for {
+		inputBytes, err := r.ReadBytes('\n')
+		if err != nil {
+			log.Error().Err(err).Msg("could not read from input reader")
+			continue
+		}
+
+		// "ReadBytes reads until the first occurrence of delim in the input,
+		// returning a slice containing the data up to and including the
+		// delimiter."
+		inputBytes = inputBytes[:len(inputBytes)-1]
+
+		// try and parse inputted JSON
+		event := new(ClickEvent)
+		if err := json.Unmarshal(bytes.Trim(inputBytes, ","), event); err != nil {
+			continue // idk what this could be but it's not relevant so BYE!
+		}
+
+		for _, consumer := range b.registeredConsumers {
+			consumerName, consumerInstance := consumer.GetNameAndInstance()
+			if consumerName == event.Name && (consumerName == "" || consumerInstance == event.Instance) {
+				if consumer.OnClick(event) {
+					requestBarRefresh()
+				}
 			}
 		}
 	}
@@ -144,7 +191,36 @@ type Block struct {
 	Markup              string `json:"markup,omitempty"`
 }
 
-type BlockGenerator interface {
-	Block(*ColorSet) (*Block, error)
+type ProvidesNameAndInstance interface {
 	GetNameAndInstance() (name, instance string)
 }
+
+type BlockGenerator interface {
+	ProvidesNameAndInstance
+	Block(*ColorSet) (*Block, error)
+}
+
+type ClickEvent struct {
+	Name      string   `json:"name"`
+	Instance  string   `json:"instance"`
+	Button    int      `json:"button"`
+	Modifiers []string `json:"modifiers"`
+	X         int      `json:"x"`
+	Y         int      `json:"y"`
+	RelativeX int      `json:"relative_x"`
+	RelativeY int      `json:"relative_y"`
+	OutputX   int      `json:"output_x"`
+	OutputY   int      `json:"output_y"`
+	Width     int      `json:"width"`
+	Height    int      `json:"height"`
+}
+
+type ClickEventConsumer interface {
+	ProvidesNameAndInstance
+	// OnClick is called when a new ClickEvent is recieved with the
+	// corresponding name and instance is recieved. If OnClick returns true, a
+	// refresh of the entire statusbar will be performed.
+	//
+	// OnClick must not modify the ClickEvent as it may be reused elsewhere.
+	OnClick(*ClickEvent) (shouldRefresh bool)
+}