// context constructs the context object for the application. This only be
// called once per request.
func (app *App) context(w http.ResponseWriter, r *http.Request) *Context {
	ctx := defaultContextManager.context(app, w, r)
	ctx = ctxu.WithVars(ctx, r)
	ctx = ctxu.WithLogger(ctx, ctxu.GetLogger(ctx,
		"vars.name",
		"vars.reference",
		"vars.digest",
		"vars.uuid"))

	context := &Context{
		App:     app,
		Context: ctx,
	}

	if app.httpHost.Scheme != "" && app.httpHost.Host != "" {
		// A "host" item in the configuration takes precedence over
		// X-Forwarded-Proto and X-Forwarded-Host headers, and the
		// hostname in the request.
		context.urlBuilder = v2.NewURLBuilder(&app.httpHost)
	} else {
		context.urlBuilder = v2.NewURLBuilderFromRequest(r)
	}

	return context
}

func (r *Session) V2RegistryEndpoint(index *IndexInfo) (ep *Endpoint, err error) {
	// TODO check if should use Mirror
	if index.Official {
		ep, err = newEndpoint(REGISTRYSERVER, true, nil)
		if err != nil {
			return
		}
		err = validateEndpoint(ep)
		if err != nil {
			return
		}
	} else if r.indexEndpoint.String() == index.GetAuthConfigKey() {
		ep = r.indexEndpoint
	} else {
		ep, err = NewEndpoint(index, nil)
		if err != nil {
			return
		}
	}

	ep.URLBuilder = v2.NewURLBuilder(ep.URL)
	return
}

func getV2Builder(e *Endpoint) *v2.URLBuilder {
	if e.URLBuilder == nil {
		e.URLBuilder = v2.NewURLBuilder(e.URL)
	}
	return e.URLBuilder
}