settings: Save future changes in a dedicated file

admin/api/settings.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path"
 	"reflect"
+	"strconv"
 	"time"
 
 	"srs.epita.fr/fic-server/admin/sync"
@@ -38,9 +39,34 @@ func declareSettingsRoutes(router *gin.RouterGroup) {
 		c.JSON(http.StatusOK, true)
 	})
 
+	router.GET("/settings-next", listNextSettings)
+
+	apiNextSettingsRoutes := router.Group("/settings-next/:ts")
+	apiNextSettingsRoutes.Use(NextSettingsHandler)
+	apiNextSettingsRoutes.GET("", getNextSettings)
+	apiNextSettingsRoutes.DELETE("", deleteNextSettings)
+
 	router.POST("/reset", reset)
 }
 
+func NextSettingsHandler(c *gin.Context) {
+	ts, err := strconv.ParseInt(string(c.Params.ByName("ts")), 10, 64)
+	if err != nil {
+		c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": "Invalid next settings identifier"})
+		return
+	}
+
+	nsf, err := settings.ReadNextSettingsFile(path.Join(settings.SettingsDir, fmt.Sprintf("%d.json", ts)), ts)
+	if err != nil {
+		c.AbortWithStatusJSON(http.StatusNotFound, gin.H{"errmsg": "Next settings not found"})
+		return
+	}
+
+	c.Set("next-settings", nsf)
+
+	c.Next()
+}
+
 func getROSettings(c *gin.Context) {
 	syncMtd := "Disabled"
 	if sync.GlobalImporter != nil {
@@ -142,14 +168,102 @@ func saveSettings(c *gin.Context) {
 		return
 	}
 
-	if err := settings.SaveSettings(path.Join(settings.SettingsDir, settings.SettingsFile), config); err != nil {
-		log.Println("Unable to SaveSettings:", err.Error())
-		c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": fmt.Sprintf("Unable to save settings: %s", err.Error())})
+	// Is this a future setting?
+	if c.Request.URL.Query().Has("t") {
+		t, err := time.Parse(time.RFC3339, c.Request.URL.Query().Get("t"))
+		if err != nil {
+			c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": err.Error()})
+			return
+		}
+
+		// Load current settings to perform diff later
+		init_settings, err := settings.ReadSettings(path.Join(settings.SettingsDir, settings.SettingsFile))
+		if err != nil {
+			log.Println("Unable to ReadSettings:", err.Error())
+			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": fmt.Sprintf("Unable to read settings: %s", err.Error())})
+			return
+		}
+
+		current_settings := init_settings
+		// Apply already registered settings
+		nsu, err := settings.MergeNextSettingsUntil(&t)
+		if err == nil {
+			current_settings = settings.MergeSettings(*init_settings, nsu)
+		} else {
+			log.Println("Unable to MergeNextSettingsUntil:", err.Error())
+			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": fmt.Sprintf("Unable to merge next settings: %s", err.Error())})
+			return
+		}
+
+		// Keep only diff
+		diff := settings.DiffSettings(current_settings, config)
+
+		hasItems := false
+		for _, _ = range diff {
+			hasItems = true
+			break
+		}
+
+		if !hasItems {
+			c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": "No difference to apply."})
+			return
+		}
+
+		if !c.Request.URL.Query().Has("erase") {
+			// Check if there is already diff to apply at the given time
+			if nsf, err := settings.ReadNextSettingsFile(path.Join(settings.SettingsDir, fmt.Sprintf("%d.json", t.Unix())), t.Unix()); err == nil {
+				for k, v := range nsf.Values {
+					if _, ok := diff[k]; !ok {
+						diff[k] = v
+					}
+				}
+			}
+		}
+
+		// Save the diff
+		settings.SaveSettings(path.Join(settings.SettingsDir, fmt.Sprintf("%d.json", t.Unix())), diff)
+
+		// Return current settings
+		c.JSON(http.StatusOK, current_settings)
+	} else {
+		// Just apply settings right now!
+		if err := settings.SaveSettings(path.Join(settings.SettingsDir, settings.SettingsFile), config); err != nil {
+			log.Println("Unable to SaveSettings:", err.Error())
+			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": fmt.Sprintf("Unable to save settings: %s", err.Error())})
+			return
+		}
+
+		ApplySettings(config)
+		c.JSON(http.StatusOK, config)
+	}
+}
+
+func listNextSettings(c *gin.Context) {
+	nsf, err := settings.ListNextSettingsFiles()
+	if err != nil {
+		log.Println("Unable to ListNextSettingsFiles:", err.Error())
+		c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": fmt.Sprintf("Unable to list next settings files: %s", err.Error())})
 		return
 	}
 
-	ApplySettings(config)
-	c.JSON(http.StatusOK, config)
+	c.JSON(http.StatusOK, nsf)
+}
+
+func getNextSettings(c *gin.Context) {
+	c.JSON(http.StatusOK, c.MustGet("next-settings").(*settings.NextSettingsFile))
+}
+
+func deleteNextSettings(c *gin.Context) {
+	nsf := c.MustGet("next-settings").(*settings.NextSettingsFile)
+
+	err := os.Remove(path.Join(settings.SettingsDir, fmt.Sprintf("%d.json", nsf.Id)))
+	if err != nil {
+		log.Println("Unable to remove the file:", err.Error())
+		c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": fmt.Sprintf("Unable to remove the file: %s", err.Error())})
+		return
+	}
+
+	c.JSON(http.StatusOK, true)
 }
 
 func ApplySettings(config *settings.Settings) {