Phase4

apps/node-agent/internal/world/world.go

@@ -0,0 +1,114 @@
+package world
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// Summary describes a discovered Minecraft world directory.
+type Summary struct {
+	Name        string `json:"name"`
+	Path        string `json:"path"`
+	SizeBytes   int64  `json:"sizeBytes"`
+	HasLevelDat bool   `json:"hasLevelDat"`
+}
+
+// ValidateWorld checks that a world directory contains level.dat.
+func ValidateWorld(dataPath, worldName string) error {
+	worldName = strings.TrimSpace(worldName)
+	if worldName == "" || strings.Contains(worldName, "..") || strings.ContainsAny(worldName, `/\`) {
+		return fmt.Errorf("invalid world name")
+	}
+
+	worldDir := filepath.Join(dataPath, worldName)
+	levelDat := filepath.Join(worldDir, "level.dat")
+
+	info, err := os.Stat(levelDat)
+	if err != nil {
+		return fmt.Errorf("level.dat not found in world directory")
+	}
+	if info.IsDir() {
+		return fmt.Errorf("level.dat is not a file")
+	}
+
+	return nil
+}
+
+// ListWorlds scans the server data directory for world folders.
+func ListWorlds(dataPath, activeWorldName string) ([]Summary, error) {
+	entries, err := os.ReadDir(dataPath)
+	if err != nil {
+		return nil, err
+	}
+
+	worlds := make([]Summary, 0)
+
+	for _, entry := range entries {
+		if !entry.IsDir() || strings.HasPrefix(entry.Name(), ".") {
+			continue
+		}
+
+		worldPath := filepath.Join(dataPath, entry.Name())
+		levelDat := filepath.Join(worldPath, "level.dat")
+		hasLevelDat := false
+		if info, err := os.Stat(levelDat); err == nil && !info.IsDir() {
+			hasLevelDat = true
+		}
+
+		size, err := dirSize(worldPath)
+		if err != nil {
+			return nil, err
+		}
+
+		worlds = append(worlds, Summary{
+			Name:        entry.Name(),
+			Path:        entry.Name(),
+			SizeBytes:   size,
+			HasLevelDat: hasLevelDat,
+		})
+	}
+
+	if activeWorldName != "" {
+		found := false
+		for _, world := range worlds {
+			if world.Name == activeWorldName {
+				found = true
+				break
+			}
+		}
+		if !found {
+			if err := ValidateWorld(dataPath, activeWorldName); err == nil {
+				size, sizeErr := dirSize(filepath.Join(dataPath, activeWorldName))
+				if sizeErr != nil {
+					return nil, sizeErr
+				}
+				worlds = append(worlds, Summary{
+					Name:        activeWorldName,
+					Path:        activeWorldName,
+					SizeBytes:   size,
+					HasLevelDat: true,
+				})
+			}
+		}
+	}
+
+	return worlds, nil
+}
+
+func dirSize(root string) (int64, error) {
+	var total int64
+
+	err := filepath.Walk(root, func(_ string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if !info.IsDir() {
+			total += info.Size()
+		}
+		return nil
+	})
+
+	return total, err
+}