refactor vfs into its own package

3 files changed, 85 insertions, 0 deletions

diff --git a/internal/vfs/memoryfs.go b/internal/vfs/memoryfs.go
new file mode 100644
index 0000000..22b1611
--- /dev/null
+++ b/internal/vfs/memoryfs.go
@@ -0,0 +1,33 @@
+package vfs
+
+import (
+	"fmt"
+	"strings"
+)
+
+type MemoryFS map[string][]byte
+
+func (fs MemoryFS) ReadFile(filePath string) ([]byte, error) {
+	if bytes, ok := fs[filePath]; ok {
+		return bytes, nil
+	}
+	return []byte{}, fmt.Errorf("no such file path: %s", filePath)
+}
+
+func (fs MemoryFS) SaveFile(filePath string, bytes []byte) error {
+	fs[filePath] = bytes
+	return nil
+}
+
+func (fs MemoryFS) FindFiles(dataDir, suffix string) ([]string, error) {
+	var filePaths []string
+
+	for filePath := range fs {
+		if !strings.HasSuffix(filePath, suffix) {
+			continue
+		}
+		filePaths = append(filePaths, filePath)
+	}
+
+	return filePaths, nil
+}
diff --git a/internal/vfs/realfs.go b/internal/vfs/realfs.go
new file mode 100644
index 0000000..8b9c9de
--- /dev/null
+++ b/internal/vfs/realfs.go
@@ -0,0 +1,44 @@
+package vfs
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type RealFS struct{}
+
+func (RealFS) ReadFile(filePath string) ([]byte, error) {
+	return os.ReadFile(filePath)
+}
+
+func (RealFS) SaveFile(filePath string, bytes []byte) error {
+	dir := filepath.Dir(filePath)
+	if _, err := os.Stat(dir); os.IsNotExist(err) {
+		if err := os.MkdirAll(dir, 0755); err != nil {
+			return err
+		}
+	}
+	return os.WriteFile(filePath, bytes, 0644)
+}
+
+func (RealFS) FindFiles(dataDir, suffix string) ([]string, error) {
+	var filePaths []string
+
+	visit := func() filepath.WalkFunc {
+		return func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				log.Println(err)
+				return nil
+			}
+			if info.IsDir() || !strings.HasSuffix(path, suffix) {
+				return nil
+			}
+			filePaths = append(filePaths, path)
+			return nil
+		}
+	}
+
+	return filePaths, filepath.Walk(dataDir, visit())
+}
diff --git a/internal/vfs/vfs.go b/internal/vfs/vfs.go
new file mode 100644
index 0000000..0297ff9
--- /dev/null
+++ b/internal/vfs/vfs.go
@@ -0,0 +1,8 @@
+package vfs
+
+// virtual file system - useful for testing as well
+type VFS interface {
+	ReadFile(name string) ([]byte, error)
+	SaveFile(filePath string, bytes []byte) error
+	FindFiles(dataPath, suffix string) ([]string, error)
+}