// Package testutil provides isolated runtime fixtures for tests that write saves.
package testutil

import (
	"io/fs"
	"os"
	"path/filepath"
	"strings"
)

// CopyRuntime copies data, never links writable saves to the source checkout.
// Local operator configuration and binaries are intentionally excluded.
func CopyRuntime(root, destination string) error {
	entries, err := os.ReadDir(root)
	if err != nil {
		return err
	}
	for _, entry := range entries {
		name := entry.Name()
		if entry.IsDir() || strings.HasSuffix(name, ".local.json") || !(strings.HasSuffix(name, ".json") || name == "persistent" || name == "go.mod") {
			continue
		}
		data, err := os.ReadFile(filepath.Join(root, name))
		if err != nil {
			return err
		}
		if err = os.WriteFile(filepath.Join(destination, name), data, 0600); err != nil {
			return err
		}
	}
	return filepath.WalkDir(filepath.Join(root, "resources"), func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		relative, err := filepath.Rel(root, path)
		if err != nil {
			return err
		}
		target := filepath.Join(destination, relative)
		if d.IsDir() {
			return os.MkdirAll(target, 0700)
		}
		data, err := os.ReadFile(path)
		if err != nil {
			return err
		}
		return os.WriteFile(target, data, 0600)
	})
}