package main

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

type path string
type PlatformDirs interface {
    UserCacheDir() string
    UserCachePath() path
    isPlatformDirs()
}
type PlatformDirsImpl struct {
    X__this PlatformDirs // topmost impl to dyn dispatch to
    appname string
    appauthor string
}

func NewPlatformDirs(appname string, appauthor string) *PlatformDirsImpl {
    p := &PlatformDirsImpl{
        appname: appname,
        appauthor: appauthor,
    }
    p.X__this = p
    return p
}
func (p *PlatformDirsImpl) UserCacheDir() string {
    panic("abstract")
}
func (p *PlatformDirsImpl) UserCachePath() path {
    return path(p.X__this.(PlatformDirs).UserCacheDir())
}
func (p *PlatformDirsImpl) isPlatformDirs() {}

type Windows interface {
    PlatformDirs
    isWindows()
}
type WindowsImpl struct {
    PlatformDirsImpl
}

func NewWindows(appname string, appauthor string) *WindowsImpl {
    w := &WindowsImpl{*NewPlatformDirs(appname, appauthor)}
    w.X__this = w
    return w
}
func (p *WindowsImpl) UserCacheDir() string {
    d, err := os.UserHomeDir()
    if err != nil {
        panic(err)
    }
    return filepath.Join(d, "the-cache-folder", p.appauthor, p.appname)
}
func (p *WindowsImpl) isWindows() {}

func main() {
    w := NewWindows("MyApp", "MyCompany")
    fmt.Println(w.UserCachePath())
    // Output: /root/the-cache-folder/MyCompany/MyApp
}