working as intended

backend/backend.go

@@ -5,11 +5,13 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"io/fs"
 	"os/exec"
 	"path/filepath"
 	"strings"
 	"time"
 	"git.noctra.dev/noctra/servtex/globals"
+	"github.com/fsnotify/fsnotify"
 )
 
 // Returns the current time in the timezone specified in the config file
@@ -111,15 +113,89 @@ func ConfigReader(configFileName string, configOptionStorage *globals.Config) er
 	return err 
 }
 
+// Contents copied from https://github.com/fsnotify/fsnotify/blob/main/cmd/fsnotify/watch.go
+func watchLoop(watcher *fsnotify.Watcher, callOnChange func() error) {
+	defer watcher.Close()
+	for {
+		select {
+			// Errors
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					LogLine(fmt.Sprintf("Watcher crashed on error, manual compile only: %s", err), 4)
+					return
+				}
+				LogLine(fmt.Sprintf("Watcher Error: %s", err), 3)
+
+			// Events
+			case event, ok := <-watcher.Events:
+				if !ok {
+					LogLine(fmt.Sprintf("Watcher crashed on event, manual compile only: %s", event), 4)
+					return
+				}
+				LogLine(fmt.Sprintf("File change noticed: %s", event.Name), 2)
+
+				err := callOnChange()
+				if err != nil {
+					LogLine(fmt.Sprintf("Latex compilation failed: %s", err), 4)
+				}
+
+				if err = watcher.Add(event.Name); err != nil {
+					LogLine(fmt.Sprintf("File could not be re-added to watcher: %s", event.Name), 4)
+				}
+			}
+	}
+}
+
+
+func texFinder(path string) []string {
+	var texFiles []string
+	err := filepath.WalkDir(path, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+		    return err
+		}
+		if !d.IsDir() && filepath.Ext(path) == ".tex" {
+		    texFiles = append(texFiles, path)
+		}
+		return nil
+	})
+	if err != nil {
+		LogLine("Some paths could not be traversed while search for .tex files", 3)
+	}
+	return texFiles
+}
+
 // Watches a specified directory and calls a function on change
 //
 // Optionally, a minimum time to wait for consecutive changes can be specified
-func ChangeWatch(path string, callOnChange func()) {
-	LogLine("File change noticed", 2)
+func ChangeWatch(path string, callOnChange func() error) {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		LogLine("File system watcher could not be initialised, manual compile only", 4)
+		return
+	}
+
+	for _, file := range texFinder(path) {
+		if err = watcher.Add(file); err != nil {
+			LogLine(fmt.Sprintf("File could not be added to watcher: %s", err), 4)
+		}
+		LogLine(fmt.Sprintf("File added to watcher: %s", file), 1)
+	}
+
+	go watchLoop(watcher, callOnChange)
+
+	LogLine("Watcher initialised", 1)
+}
+
+
+func updateExecutionTimestamp(execution *globals.LatexExecution) {
+	execution.Timestamp = GetLocalTimePretty()
+	execution.TimestampRFC = GetLocalTimeRFC()
 }
 
 // Intended to be run as goroutine
-func LatexCompile(config globals.Config, execution *globals.LatexExecution) error {
+func LatexCompile() error {
+	execution := &globals.LatexExec
+	config := globals.AppConfig
 	if execution.ExecutionLock.TryLock() {
 		defer execution.ExecutionLock.Unlock()
 	} else {
@@ -143,7 +219,8 @@ func LatexCompile(config globals.Config, execution *globals.LatexExecution) erro
 		default:
 			execution.ExecutionState = "Unknown Latex Engine"
 			execution.Output = []byte{}
-			execution.Timestamp = GetLocalTimePretty()
+			updateExecutionTimestamp(execution)
+
 			LogLine("Unsupported LaTeX Engine", 4)
 			return errors.New("Unsupported LaTeX Engine")
 	}
@@ -156,8 +233,9 @@ func LatexCompile(config globals.Config, execution *globals.LatexExecution) erro
 	}
 
 	execution.Output = stdout
-	execution.Timestamp = GetLocalTimePretty()
 	execution.ExecutionState = "Done"
+	updateExecutionTimestamp(execution)
+
 	LogLine("LaTeX execution finished", 2)
 	return nil
 }