refactor: major project restructure

internal/fileutil/file.go

@@ -0,0 +1,52 @@
+package fileutil
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"io"
+	"os"
+)
+
+func EnsureDir(path string) error {
+	info, err := os.Stat(path)
+	if os.IsNotExist(err) {
+		return os.MkdirAll(path, 0755)
+	}
+	if err != nil {
+		return err
+	}
+	if !info.IsDir() {
+		return fmt.Errorf("file already exists at %s", path)
+	}
+
+	return nil
+}
+
+func FileExists(path string) bool {
+	info, err := os.Stat(path)
+
+	return err == nil && !info.IsDir()
+}
+
+func DeleteFile(path string) error {
+	if !FileExists(path) {
+		return nil
+	}
+
+	return os.Remove(path)
+}
+
+func GetFileHash(path string) (string, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	hash := sha256.New()
+	if _, err := io.Copy(hash, file); err != nil {
+		return "", err
+	}
+
+	return fmt.Sprintf("%x", hash.Sum(nil)), nil
+}

internal/fileutil/hashindex.go

@@ -0,0 +1,56 @@
+package fileutil
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+type HashIndex struct {
+	files map[string]string
+}
+
+func NewHashIndex(ctx context.Context, root string) (*HashIndex, error) {
+	index := &HashIndex{files: make(map[string]string)}
+
+	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+
+		if err != nil || info.IsDir() {
+			return nil
+		}
+
+		file, err := os.Open(path)
+		if err != nil {
+			return nil
+		}
+		defer file.Close()
+
+		h := sha256.New()
+		if _, err := io.Copy(h, file); err != nil {
+			return nil
+		}
+
+		sum := hex.EncodeToString(h.Sum(nil))
+		index.files[sum] = path
+
+		return nil
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	return index, nil
+}
+
+func (h *HashIndex) Find(hash string) (string, bool) {
+	path, ok := h.files[hash]
+
+	return path, ok
+}