package goncfiles

import (
	"fmt"
	"strings"
)

// Visit is one ExApp opening: Working Folder for this request plus the Saved Default.
type Visit struct {
	SavedDefault  string
	WorkingRel    string
	VisitRelative string
	FS            Folder
	defaults      DefaultPathStore
	root          Root
}

// Open resolves the Working Folder for this visit.
// initialFolderName is used when no Saved Default is stored yet (app-icon first launch).
// visitRelative empty means app-icon launch (Saved Default, creating the initial folder empty if missing).
// A Files-view folder is used only for this visit and does not change the Saved Default.
// Missing or forbidden visit paths fail closed (no create, no fallback).
func Open(root Root, defaults DefaultPathStore, initialFolderName, visitRelative string) (*Visit, error) {
	saved, err := defaults.GetDefault()
	if err != nil {
		return nil, err
	}
	if saved == "" {
		saved = initialFolderName
	}
	if CleanRel(saved) == "" {
		return nil, fmt.Errorf("invalid saved Working Folder path")
	}

	raw := strings.Trim(strings.ReplaceAll(visitRelative, "\\", "/"), "/")
	v := &Visit{
		SavedDefault: saved,
		defaults:     defaults,
		root:         root,
	}

	if raw == "" {
		fs, err := root.EnsureFolder(saved)
		if err != nil {
			return nil, err
		}
		v.WorkingRel = saved
		v.FS = fs
		return v, nil
	}

	rel := CleanRel(raw)
	if rel == "" {
		return nil, fmt.Errorf("invalid Working Folder path")
	}
	v.VisitRelative = rel
	fs, err := root.OpenFolder(rel)
	if err != nil {
		return nil, fmt.Errorf("Working Folder %q: %w", rel, err)
	}
	v.WorkingRel = rel
	v.FS = fs
	return v, nil
}

// OpenLocal is the local-adapter convenience: files root + settings JSON.
func OpenLocal(filesRoot, settingsPath, initialFolderName, visitRelative string) (*Visit, error) {
	return Open(Local{RootDir: filesRoot}, FileStore{Path: settingsPath}, initialFolderName, visitRelative)
}

// SetDefault persists a new Saved Default and ensures the folder exists.
func (v *Visit) SetDefault(relative string) error {
	rel := CleanRel(relative)
	if rel == "" {
		return fmt.Errorf("invalid Saved Default path")
	}
	if _, err := v.root.EnsureFolder(rel); err != nil {
		return err
	}
	if err := v.defaults.SetDefault(rel); err != nil {
		return err
	}
	v.SavedDefault = rel
	return nil
}

// WorkingDir returns a local absolute path when using the local adapter; otherwise WorkingRel.
func (v *Visit) WorkingDir() string {
	if p, ok := LocalPath(v.FS); ok {
		return p
	}
	return v.WorkingRel
}