// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package xproxyd

import (
	"fmt"

	"v.io/v23"
	"v.io/v23/context"
	"v.io/v23/flow"
	"v.io/v23/flow/message"
	"v.io/v23/naming"
	"v.io/v23/security"
)

// setEndpointRoutingID returns a copy of ep with RoutingId changed to rid.
func setEndpointRoutingID(ep naming.Endpoint, rid naming.RoutingID) (naming.Endpoint, error) {
	network, address, routes, _, bnames, mountable := getEndpointParts(ep)
	opts := routes
	opts = append(opts, bnames...)
	opts = append(opts, rid)
	opts = append(opts, mountable)
	epString := naming.FormatEndpoint(network, address, opts...)
	return v23.NewEndpoint(epString)
}

// setEndpointRoutes returns a copy of ep with Routes changed to routes.
func setEndpointRoutes(ep naming.Endpoint, routes []string) (naming.Endpoint, error) {
	network, address, _, rid, bnames, mountable := getEndpointParts(ep)
	opts := routeOpts(routes)
	opts = append(opts, bnames...)
	opts = append(opts, rid)
	opts = append(opts, mountable)
	epString := naming.FormatEndpoint(network, address, opts...)
	return v23.NewEndpoint(epString)
}

// getEndpointParts returns all the fields of ep.
func getEndpointParts(ep naming.Endpoint) (network string, address string,
	routes []naming.EndpointOpt, rid naming.RoutingID,
	blessingNames []naming.EndpointOpt, mountable naming.EndpointOpt) {
	network, address = ep.Addr().Network(), ep.Addr().String()
	routes = routeOpts(ep.Routes())
	rid = ep.RoutingID()
	blessingNames = blessingOpts(ep.BlessingNames())
	mountable = naming.ServesMountTable(ep.ServesMountTable())
	return
}

func routeOpts(routes []string) []naming.EndpointOpt {
	var routeOpts []naming.EndpointOpt
	for _, route := range routes {
		routeOpts = append(routeOpts, naming.RouteOpt(route))
	}
	return routeOpts
}

func blessingOpts(blessingNames []string) []naming.EndpointOpt {
	var blessingOpts []naming.EndpointOpt
	for _, b := range blessingNames {
		blessingOpts = append(blessingOpts, naming.BlessingOpt(b))
	}
	return blessingOpts
}

type proxyBlessingsForPeer struct{}

// TODO(suharshs): Figure out what blessings to present here. And present discharges.
func (proxyBlessingsForPeer) run(ctx *context.T, lep, rep naming.Endpoint, rb security.Blessings,
	rd map[string]security.Discharge) (security.Blessings, map[string]security.Discharge, error) {
	return v23.GetPrincipal(ctx).BlessingStore().Default(), nil, nil
}

func readSetupMessage(ctx *context.T, f flow.Flow) (*message.Setup, error) {
	b, err := f.ReadMsg()
	if err != nil {
		return nil, err
	}
	m, err := message.Read(ctx, b)
	if err != nil {
		return nil, err
	}
	if m, isSetup := m.(*message.Setup); isSetup {
		return m, nil
	}
	return nil, NewErrUnexpectedMessage(ctx, fmt.Sprintf("%t", m))
}

func writeSetupMessage(ctx *context.T, m message.Message, f flow.Flow) error {
	w, err := message.Append(ctx, m, []byte{})
	if err != nil {
		return err
	}
	_, err = f.WriteMsg(w)
	return err
}