feat: add working watchdog cycle

internal/database/watchdog.go

@@ -1,36 +1,73 @@
 package database
 
 import (
+	"eden-server/internal/utility"
 	"log/slog"
 	"os"
+	"path/filepath"
 
 	"gorm.io/gorm"
 )
 
-func watchdog(w string, db *gorm.DB) {
+func watchdog(env utility.Environment, db *gorm.DB) {
 	slog.Info("performing the watchdog cycle")
 
-	files, err := GetFiles(db)
+	fsFiles, err := os.ReadDir(env.ContentDirectory)
+	if err != nil {
+		slog.Error("failed to read the content directory on the filesystem", "error", err)
+		return
+	}
+
+	dbFiles, err := GetFiles(db)
 	if err != nil {
 		slog.Error("failed to retrieve the files indexed from the database", "error", err)
 		return
 	}
 
-	var purgeList []string
-	for _, f := range files {
-		i, err := os.Stat(f.Filepath)
-		if err != nil {
-			if os.IsNotExist(err) {
-				purgeList = append(purgeList, f.Filepath)
-				continue
-			}
-			slog.Warn("stat failed", "file", f.Filepath, "error", err)
-			continue
-		}
+	// generate a set of filesystem contents
+	fsSet := make(map[string]struct{}) // cool name for the files that are (now) marked for annihilation
+	for _, f := range fsFiles {
+		// absolute path creation
+		fullPath := filepath.Join(env.ContentDirectory, f.Name())
+		fsSet[fullPath] = struct{}{}
+	}
 
-		if i.IsDir() {
-			purgeList = append(purgeList, f.Filepath) // also mark it for purger if its a directory. We do not want that here
+	// generate a set of Database contents
+	dbSet := make(map[string]File) // cool name for the files that are going to be deregistered from the database
+	for _, f := range dbFiles {
+		dbSet[f.FilePath] = f
+	}
+
+	// FS -> DB
+	// check for orphaned filesystem files
+	var fsPurgeScroll []string
+	for path := range fsSet {
+		if _, exists := dbSet[path]; !exists {
+			fsPurgeScroll = append(fsPurgeScroll, path)
+		}
+	}
+
+	// DB -> FS
+	// check stale database records
+	var dbPurgeScroll []File
+	for path, f := range dbSet {
+		if _, exists := fsSet[path]; !exists {
+			dbPurgeScroll = append(dbPurgeScroll, f)
+		}
+	}
+
+	if len(fsPurgeScroll) > 0 {
+		slog.Info("filesystem purge scroll is populated, engaging purge")
+		//filepath is stored in the slice, the filename or file object, see above
+		for _, fp := range fsPurgeScroll {
+			utility.RemoveFile(fp)
+		}
+	}
+
+	if len(dbPurgeScroll) > 0 {
+		slog.Info("database purge scroll is populated, engaging purge")
+		for _, f := range dbPurgeScroll {
+			DeregisterFile(db, f)
 		}
 	}
-	slog.Info("purge list", "files", purgeList)
 }