Application settings

internal/app/settings.go

@@ -1,18 +1,37 @@
 package app
 
 import (
+	"encoding/json"
 	"errors"
+	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
-	"runtime"
+	goRuntime "runtime"
+
+	"github.com/wailsapp/wails/v2/pkg/runtime"
 )
 
+type Settings struct {
+	DefaultLimit    int64  `json:"defaultLimit"`
+	DefaultSort     string `json:"defaultSort"`
+	AutosubmitQuery bool   `json:"autosubmitQuery"`
+}
+
+func NewSettings() Settings {
+	return Settings{
+		DefaultLimit:    20,
+		DefaultSort:     `{ "_id": 1 }`,
+		AutosubmitQuery: true,
+	}
+}
+
 func appDataDirectory() (string, error) {
 	var err error
 	homeDir, err := os.UserHomeDir()
 	prefDir := ""
 
-	switch runtime.GOOS {
+	switch goRuntime.GOOS {
 	case "windows":
 		prefDir = filepath.Join(homeDir, "/AppData/Local/Mongodup")
 	case "darwin":
@@ -35,3 +54,85 @@ func appDataFilePath(filename string) (string, error) {
 	path := filepath.Join(dir, filename)
 	return path, nil
 }
+
+func (a *App) Settings() Settings {
+	s := NewSettings()
+	filePath, err := appDataFilePath("settings.json")
+	if err != nil {
+		fmt.Println(err.Error())
+		runtime.MessageDialog(a.ctx, runtime.MessageDialogOptions{
+			Type:    runtime.ErrorDialog,
+			Title:   "Could not retrieve application settings, using defaults!",
+			Message: err.Error(),
+		})
+		return s
+	}
+
+	jsonData, err := ioutil.ReadFile(filePath)
+	if err != nil {
+		// It's ok if the file cannot be opened, for example if it is not accessible.
+		// Therefore no error is returned.
+		fmt.Println(err.Error())
+		return s
+	}
+
+	if len(jsonData) == 0 {
+		return s
+	} else {
+		err = json.Unmarshal(jsonData, &s)
+
+		if err != nil {
+			fmt.Println(err.Error())
+			runtime.MessageDialog(a.ctx, runtime.MessageDialogOptions{
+				Type:    runtime.ErrorDialog,
+				Title:   "Could not retrieve application settings, using defaults!",
+				Message: err.Error(),
+			})
+		}
+		return s
+	}
+}
+
+func (a *App) UpdateSettings(jsonData string) Settings {
+	s := a.Settings()
+	err := json.Unmarshal([]byte(jsonData), &s)
+	if err != nil {
+		runtime.MessageDialog(a.ctx, runtime.MessageDialogOptions{
+			Type:    runtime.InfoDialog,
+			Title:   "Malformed JSON",
+			Message: err.Error(),
+		})
+		return s
+	}
+
+	filePath, err := appDataFilePath("settings.json")
+	if err != nil {
+		runtime.MessageDialog(a.ctx, runtime.MessageDialogOptions{
+			Type:    runtime.InfoDialog,
+			Title:   "Could not update settings.json",
+			Message: err.Error(),
+		})
+		return s
+	}
+
+	newJson, err := json.MarshalIndent(s, "", "\t")
+	if err != nil {
+		runtime.MessageDialog(a.ctx, runtime.MessageDialogOptions{
+			Type:    runtime.InfoDialog,
+			Title:   "Could not marshal settings into JSON",
+			Message: err.Error(),
+		})
+		return s
+	}
+
+	err = ioutil.WriteFile(filePath, newJson, os.ModePerm)
+	if err != nil {
+		runtime.MessageDialog(a.ctx, runtime.MessageDialogOptions{
+			Type:    runtime.InfoDialog,
+			Title:   "Could not update host list",
+			Message: err.Error(),
+		})
+	}
+
+	return s
+}