package assetloader

import (
	"fmt"
	"os"
	"path/filepath"

	"git.warky.dev/wdevs/relspecgo/pkg/safefile"
)

func openAssetRoot(path string) (*os.Root, error) {
	if err := safefile.CheckRoot(path); err != nil {
		return nil, err
	}
	return os.OpenRoot(path)
}

func readItemAsset(item Item) ([]byte, error) {
	if item.AssetRoot == "" {
		return nil, fmt.Errorf("asset root is required for manifest execution")
	}
	root, err := openAssetRoot(item.AssetRoot)
	if err != nil {
		return nil, err
	}
	defer root.Close()
	relative, err := filepath.Rel(item.AssetRoot, item.Entry.File)
	if err != nil {
		return nil, err
	}
	limit := item.MaxFileBytes
	if limit == 0 {
		limit = DefaultMaxAssetBytes
	}
	return safefile.Read(root, relative, limit)
}