package web

import "context"

// FolderOption is a flattened, indented folder choice for <select> dropdowns
// (asset create/edit, move-to pickers).
type FolderOption struct {
	ID    int64  `json:"id"`
	Path  string `json:"path"`
	Depth int    `json:"depth"`
}

// folderOptions returns every folder as a flat, depth-first ordered list
// with indentable depth, suitable for a folder-picker <select>.
func (a *App) folderOptions(ctx context.Context) ([]FolderOption, error) {
	all, err := a.Folders.All(ctx)
	if err != nil {
		return nil, err
	}
	byParent := map[int64][]struct {
		ID   int64
		Name string
	}{}
	var top []struct {
		ID   int64
		Name string
	}
	for _, f := range all {
		item := struct {
			ID   int64
			Name string
		}{f.ID, f.Name}
		if f.ParentID == nil {
			top = append(top, item)
		} else {
			byParent[*f.ParentID] = append(byParent[*f.ParentID], item)
		}
	}

	var out []FolderOption
	var walk func(id int64, name, prefix string, depth int)
	walk = func(id int64, name, prefix string, depth int) {
		path := name
		if prefix != "" {
			path = prefix + " / " + name
		}
		out = append(out, FolderOption{ID: id, Path: path, Depth: depth})
		for _, child := range byParent[id] {
			walk(child.ID, child.Name, path, depth+1)
		}
	}
	for _, t := range top {
		walk(t.ID, t.Name, "", 0)
	}
	return out, nil
}