Feat/update migrate (#910)

* * update migrate

* * rename handlers to sources

* * delete dead code

* * fix go test error

pkg/migrate/internal/common.go

@@ -0,0 +1,162 @@
+package internal
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+func ResolveTargetHome(override string) (string, error) {
+	if override != "" {
+		return ExpandHome(override), nil
+	}
+	if envHome := os.Getenv("PICOCLAW_HOME"); envHome != "" {
+		return ExpandHome(envHome), nil
+	}
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("resolving home directory: %w", err)
+	}
+	return filepath.Join(home, ".picoclaw"), nil
+}
+
+func ExpandHome(path string) string {
+	if path == "" {
+		return path
+	}
+	if path[0] == '~' {
+		home, _ := os.UserHomeDir()
+		if len(path) > 1 && path[1] == '/' {
+			return home + path[1:]
+		}
+		return home
+	}
+	return path
+}
+
+func ResolveWorkspace(homeDir string) string {
+	return filepath.Join(homeDir, "workspace")
+}
+
+func PlanWorkspaceMigration(
+	srcWorkspace, dstWorkspace string,
+	migrateableFiles []string,
+	migrateableDirs []string,
+	force bool,
+) ([]Action, error) {
+	var actions []Action
+
+	for _, filename := range migrateableFiles {
+		src := filepath.Join(srcWorkspace, filename)
+		dst := filepath.Join(dstWorkspace, filename)
+		action := planFileCopy(src, dst, force)
+		if action.Type != ActionSkip || action.Description != "" {
+			actions = append(actions, action)
+		}
+	}
+
+	for _, dirname := range migrateableDirs {
+		srcDir := filepath.Join(srcWorkspace, dirname)
+		if _, err := os.Stat(srcDir); os.IsNotExist(err) {
+			continue
+		}
+		dirActions, err := planDirCopy(srcDir, filepath.Join(dstWorkspace, dirname), force)
+		if err != nil {
+			return nil, err
+		}
+		actions = append(actions, dirActions...)
+	}
+
+	return actions, nil
+}
+
+func planFileCopy(src, dst string, force bool) Action {
+	if _, err := os.Stat(src); os.IsNotExist(err) {
+		return Action{
+			Type:        ActionSkip,
+			Source:      src,
+			Target:      dst,
+			Description: "source file not found",
+		}
+	}
+
+	_, dstExists := os.Stat(dst)
+	if dstExists == nil && !force {
+		return Action{
+			Type:        ActionBackup,
+			Source:      src,
+			Target:      dst,
+			Description: "destination exists, will backup and overwrite",
+		}
+	}
+
+	return Action{
+		Type:        ActionCopy,
+		Source:      src,
+		Target:      dst,
+		Description: "copy file",
+	}
+}
+
+func planDirCopy(srcDir, dstDir string, force bool) ([]Action, error) {
+	var actions []Action
+
+	err := filepath.Walk(srcDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		relPath, err := filepath.Rel(srcDir, path)
+		if err != nil {
+			return err
+		}
+
+		dst := filepath.Join(dstDir, relPath)
+
+		if info.IsDir() {
+			actions = append(actions, Action{
+				Type:        ActionCreateDir,
+				Target:      dst,
+				Description: "create directory",
+			})
+			return nil
+		}
+
+		action := planFileCopy(path, dst, force)
+		actions = append(actions, action)
+		return nil
+	})
+
+	return actions, err
+}
+
+func RelPath(path, base string) string {
+	rel, err := filepath.Rel(base, path)
+	if err != nil {
+		return filepath.Base(path)
+	}
+	return rel
+}
+
+func CopyFile(src, dst string) error {
+	srcFile, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer srcFile.Close()
+
+	info, err := srcFile.Stat()
+	if err != nil {
+		return err
+	}
+
+	dstFile, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, info.Mode())
+	if err != nil {
+		return err
+	}
+	defer dstFile.Close()
+
+	_, err = io.Copy(dstFile, srcFile)
+	return err
+}