config file reading logic implemented, project structure refined

backend/backend.go

@@ -0,0 +1,81 @@
+package backend
+
+import (
+	"os"
+	"path/filepath"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"git.noctra.dev/noctra/servtex/globals"
+)
+
+// Helper for configReader() that does the actual reading
+func configReaderParse(filePath string, configOptionStorage *globals.Config) error {
+	jsonData, err := os.ReadFile(filePath)
+	if err == nil {
+		err = json.Unmarshal(jsonData, &configOptionStorage)
+		if err != nil { 
+			// log error unmarshal failure
+			return errors.New("Config file could not be read")
+		}
+	} else {
+		return errors.New("Config file does not exist")
+	}
+
+	return nil
+}
+
+// Reads config file and stores the options in configOptionStorage
+// Tries executable/path/configFileName
+//	 %LOCALAPPDATA%\servtex\configFileName
+//	 ~/.config/servtex/configFileName
+func ConfigReader(configFileName string, configOptionStorage *globals.Config) error {
+	exePath, err := os.Executable()
+	if err == nil {
+		path := filepath.Join(filepath.Dir(exePath), configFileName)
+		err = configReaderParse(path, configOptionStorage)
+		if err == nil { return nil }
+	}
+
+	localappdata := os.Getenv("LOCALAPPDATA")
+	if localappdata != "" {
+		path := filepath.Join(localappdata, "servtex", configFileName)
+		err = configReaderParse(path, configOptionStorage)
+		if err == nil { return nil }
+	}
+
+	path := filepath.Join("~", ".config", "servtex", configFileName)
+	err = configReaderParse(path, configOptionStorage)
+	if err == nil { return nil }
+
+	// log error no config file found
+	return errors.New("Configuration file not found or json parsing error")
+}
+
+// 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()) {
+}
+
+// Intended to be run as goroutine
+func LatexCompile(config *globals.Config) error {
+	if !config.ExecutionLock.TryLock() {
+		return errors.New("Execution already in progress")
+	}
+
+	var latexCommand string
+	switch config.LatexEngine {
+		case "lualatex":
+		latexCommand = fmt.Sprintf(
+			"lualatex -output-directory=%s -jobname=servtex %s",
+			config.LatexOutputPath,
+			config.LatexSourceFilePath,
+		)
+
+	}
+	
+	fmt.Sprintf(latexCommand) // placeholder for compilation
+	config.ExecutionLock.Unlock()
+	return nil
+}
+