// 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 manager

import (
	"net"

	"v.io/x/lib/vlog"
	"v.io/x/ref/runtime/internal/lib/upcqueue"
	"v.io/x/ref/runtime/internal/rpc/stream"
	"v.io/x/ref/runtime/internal/rpc/stream/vc"
	iversion "v.io/x/ref/runtime/internal/rpc/version"

	"v.io/v23/context"
	"v.io/v23/naming"
	"v.io/v23/security"
	"v.io/v23/verror"
)

type adapter interface {
	Accept() (stream.XConn, naming.Endpoint, error)
	Close() error
}

type xListener struct {
	m          *xmanager
	q          *upcqueue.T
	principal  security.Principal
	lBlessings security.Blessings
	ln         adapter
}

func (ln *xListener) acceptLoop(ctx *context.T) {
	for {
		conn, lep, err := ln.ln.Accept()
		if err != nil {
			vlog.Errorf("netAcceptLoop: %v", err)
			return
		}
		// TODO(suharshs): Get the versions here correctly.
		vc, err := vc.XNewAccepted(ctx, conn, ln.principal, lep, ln.lBlessings, *iversion.SupportedRange, ln.q)
		if err != nil {
			vlog.Errorf("netAcceptLoop: %v", err)
			return
		}
		if err := ln.m.vcCache.Insert(vc); err != nil {
			vlog.Errorf("m.vcCache.Insert: %v", err)
		}
	}
}

func (ln *xListener) Accept() (stream.XFlow, error) {
	item, err := ln.q.Get(nil)
	switch {
	case err == upcqueue.ErrQueueIsClosed:
		return nil, verror.New(stream.ErrNetwork, nil, verror.New(errListenerAlreadyClosed, nil))
	case err != nil:
		return nil, verror.New(stream.ErrNetwork, nil, verror.New(errAcceptFailed, nil, err))
	default:
		return item.(stream.XFlow), nil
	}
}

func (ln *xListener) Close() error {
	// TODO(suharshs): implement this for real.
	ln.q.Close()
	return nil
}

type netAdapter struct {
	net.Listener
	rid naming.RoutingID
}

func (n *netAdapter) Accept() (stream.XConn, naming.Endpoint, error) {
	if conn, err := n.Listener.Accept(); err != nil {
		return nil, nil, err
	} else {
		return xNetConn{conn}, localEndpoint(conn, n.rid), nil
	}
}

func newXNetListener(ctx *context.T, m *xmanager, netLn net.Listener, principal security.Principal, blessings security.Blessings) stream.XListener {
	ln := &xListener{
		m:          m,
		q:          upcqueue.New(),
		ln:         &netAdapter{netLn, m.rid},
		principal:  principal,
		lBlessings: blessings,
	}
	go ln.acceptLoop(ctx)
	return ln
}

type proxyAdapter struct {
	q *upcqueue.T
}

func (p *proxyAdapter) Accept() (stream.XConn, naming.Endpoint, error) {
	item, err := p.q.Get(nil)
	f := item.(stream.XFlow)
	return f, f.LocalEndpoint(), err
}

func (p *proxyAdapter) Close() error {
	p.q.Close()
	return nil
}

func newXProxyListener(proxyEP naming.Endpoint, m *xmanager, ctx *context.T, principal security.Principal) (stream.XListener, error) {
	pa := &proxyAdapter{upcqueue.New()}
	ln := &xListener{
		m:          m,
		q:          upcqueue.New(),
		ln:         pa,
		principal:  principal,
		lBlessings: principal.BlessingStore().Default(),
	}
	_, vc, err := m.internalDial(proxyEP, ln.principal)
	if err != nil {
		return nil, err
	}
	if err := vc.ListenTo(pa.q); err != nil {
		return nil, err
	}
	go ln.acceptLoop(ctx)
	return ln, nil
}