added proton drive integration

internal/drive/drive.go

@@ -0,0 +1,88 @@
+package drive
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+const binaryName = "proton-drive"
+
+// Lookup returns the full path to the proton-drive binary in PATH.
+func Lookup() (string, error) {
+	return exec.LookPath(binaryName)
+}
+
+// CheckAuth verifies that the user is authenticated by listing /my-files.
+func CheckAuth() error {
+	binary, err := Lookup()
+	if err != nil {
+		return fmt.Errorf("proton-drive not found in PATH: %w", err)
+	}
+
+	cmd := exec.Command(binary, "filesystem", "list", "/my-files")
+	cmd.Stdout = nil
+	cmd.Stderr = nil
+
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("not authenticated with proton-drive (run 'proton-drive auth login'): %w", err)
+	}
+	return nil
+}
+
+// Upload uploads localPath to remotePath on Proton Drive.
+// remotePath is a full path including filename (e.g. /my-files/md/report.md).
+// The CLI uploads to a parent directory and preserves the local filename,
+// so if the remote filename differs from the local one, a temp copy is staged.
+// Existing remote files are overwritten (--conflict-strategy replace).
+func Upload(localPath, remotePath string) error {
+	binary, err := Lookup()
+	if err != nil {
+		return fmt.Errorf("proton-drive not found in PATH: %w", err)
+	}
+
+	remoteDir := filepath.Dir(remotePath)
+	remoteName := filepath.Base(remotePath)
+	localName := filepath.Base(localPath)
+
+	if remoteName == localName {
+		return runUpload(binary, localPath, remoteDir)
+	}
+
+	tmpDir, err := os.MkdirTemp("", "dirmd-upload-*")
+	if err != nil {
+		return fmt.Errorf("cannot create temp dir: %w", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	tmpFile := filepath.Join(tmpDir, remoteName)
+	if err := copyFile(localPath, tmpFile); err != nil {
+		return fmt.Errorf("cannot stage temp file: %w", err)
+	}
+
+	return runUpload(binary, tmpFile, remoteDir)
+}
+
+func runUpload(binary, localPath, remoteDir string) error {
+	cmd := exec.Command(binary, "filesystem", "upload", localPath, remoteDir,
+		"--conflict-strategy", "replace")
+
+	var stderr strings.Builder
+	cmd.Stderr = &stderr
+
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("upload to proton-drive failed: %w: %s",
+			err, strings.TrimSpace(stderr.String()))
+	}
+	return nil
+}
+
+func copyFile(src, dst string) error {
+	data, err := os.ReadFile(src)
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(dst, data, 0644)
+}