// 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"
	"time"

	inaming "v.io/x/ref/runtime/internal/naming"
	"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/rpc"
	"v.io/v23/security"
	"v.io/v23/verror"
)

type xmanager struct {
	ctx     *context.T // TODO(mattr): This should be pushed into the managers interfaces.
	rid     naming.RoutingID
	vcCache *vc.XVCCache
}

func XInternalNew(ctx *context.T, rid naming.RoutingID) stream.XManager {
	return &xmanager{
		ctx:     ctx,
		rid:     rid,
		vcCache: vc.NewXVCCache(),
	}
}

func xdial(network, address string, timeout time.Duration) (net.Conn, error) {
	d, _, _, _ := rpc.RegisteredProtocol(network)
	if d != nil {
		conn, err := d(network, address, timeout)
		if err != nil {
			return nil, verror.New(stream.ErrDialFailed, nil, err)
		}
		return conn, nil
	}
	return nil, verror.New(stream.ErrDialFailed, nil, verror.New(errUnknownNetwork, nil, network))
}

func (m *xmanager) Listen(protocol, address string, principal security.Principal, blessings security.Blessings, opts ...stream.ListenerOpt) (stream.XListener, naming.Endpoint, error) {
	bNames, err := extractBlessingNames(principal, blessings)
	if err != nil {
		return nil, nil, err
	}
	ln, ep, err := m.internalListen(protocol, address, principal, blessings, opts...)
	if err != nil {
		return nil, nil, err
	}
	ep.Blessings = bNames
	return ln, ep, nil
}

func (m *xmanager) internalListen(protocol, address string, principal security.Principal, blessings security.Blessings, opts ...stream.ListenerOpt) (stream.XListener, *inaming.Endpoint, error) {
	if protocol == inaming.Network {
		// Act as if listening on the address of a remote proxy.
		ep, err := inaming.NewEndpoint(address)
		if err != nil {
			return nil, nil, verror.New(stream.ErrBadArg, nil, verror.New(errEndpointParseError, nil, address, err))
		}
		return m.remoteListen(ep, principal)
	}

	netln, err := listen(protocol, address)
	if err != nil {
		return nil, nil, err
	}

	ln := newXNetListener(m.ctx, m, netln, principal, blessings)
	ep := &inaming.Endpoint{
		Protocol: protocol,
		Address:  netln.Addr().String(),
		RID:      m.rid,
	}
	return ln, ep, nil
}

func (m *xmanager) remoteListen(proxy naming.Endpoint, principal security.Principal) (stream.XListener, *inaming.Endpoint, error) {
	ln, err := newXProxyListener(proxy, m, m.ctx, principal)
	if err != nil {
		return nil, nil, err
	}
	ep := &inaming.Endpoint{
		Protocol: proxy.Addr().Network(),
		Address:  proxy.Addr().String(),
		RID:      m.rid,
	}
	return ln, ep, nil
}

func (m *xmanager) Dial(remote naming.Endpoint, principal security.Principal, opts ...stream.VCOpt) (stream.XFlow, error) {
	f, _, err := m.internalDial(remote, principal, opts...)
	return f, err
}

func (m *xmanager) internalDial(remote naming.Endpoint, principal security.Principal, opts ...stream.VCOpt) (stream.XFlow, stream.XVC, error) {
	var timeout time.Duration
	for _, o := range opts {
		switch v := o.(type) {
		case DialTimeout:
			timeout = time.Duration(v)
		}
	}
	var v stream.XVC
	var err error
	if v, err = m.vcCache.ReservedFind(remote); err != nil {
		return nil, nil, err
	}
	defer m.vcCache.Unreserve(remote)
	if v == nil {
		conn, err := xdial(remote.Addr().Network(), remote.Addr().String(), timeout)
		if err != nil {
			return nil, nil, err
		}
		local := localEndpoint(conn, m.rid)
		if v, err = vc.XNewDialed(m.ctx, xNetConn{conn}, principal, local, remote, *iversion.SupportedRange); err != nil {
			return nil, nil, err
		}
		if err := m.vcCache.Insert(v); err != nil {
			return nil, nil, err
		}
	}

	if remote.RoutingID() != v.(backingVC).RemoteEndpoint().RoutingID() {
		flow, err := v.Connect()
		if err != nil {
			return nil, nil, err
		}
		if v, err = vc.XNewDialed(m.ctx, flow, principal, flow.LocalEndpoint(), remote, *iversion.SupportedRange); err != nil {
			return nil, nil, err
		}
	}
	f, err := v.Connect()
	return f, v, err
}

func (m *xmanager) Shutdown() {
	// TODO(suharshs): Implement this.
}

func (m *xmanager) RoutingID() naming.RoutingID {
	return m.rid
}

type backingVC interface {
	LocalEndpoint() naming.Endpoint
	RemoteEndpoint() naming.Endpoint
	LocalPrincipal() security.Principal
	LocalBlessings() security.Blessings
	RemoteBlessings() security.Blessings
	LocalDischarges() map[string]security.Discharge
	RemoteDischarges() map[string]security.Discharge
	VCDataCache() stream.VCDataCache
}

func localEndpoint(conn net.Conn, rid naming.RoutingID) naming.Endpoint {
	localAddr := conn.LocalAddr()
	ep := &inaming.Endpoint{
		Protocol: localAddr.Network(),
		Address:  localAddr.String(),
		RID:      rid,
	}
	return ep
}

type xNetConn struct {
	net.Conn
}

func (xNetConn) DisableEncryption() {}