package inject

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

// Injector writes node config into a mounted image (boot/root paths supplied by caller).
type Injector struct {
    BootPath string
    RootPath string
}

// FileSpec describes a file to write.
type FileSpec struct {
    Path    string
    Content []byte
    Mode    os.FileMode
    RootFS  bool // if true, write under root path; else boot path
}

func (i *Injector) Write(files []FileSpec) error {
    for _, f := range files {
        base := i.BootPath
        if f.RootFS {
            base = i.RootPath
        }
        target := filepath.Join(base, f.Path)
        if err := os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
            return fmt.Errorf("mkdir %s: %w", filepath.Dir(target), err)
        }
        if err := os.WriteFile(target, f.Content, f.Mode); err != nil {
            return fmt.Errorf("write %s: %w", target, err)
        }
    }
    return nil
}