// Package handler implements network RPC handler
package handler

import (
	"context"

	"github.com/micro/go-micro/errors"
	"github.com/micro/go-micro/network"
	pbNet "github.com/micro/go-micro/network/proto"
	pbRtr "github.com/micro/go-micro/router/proto"
)

// Network implements network handler
type Network struct {
	Network network.Network
}

// toplogyToProto recursively traverses node topology and returns it
func peerTopology(peer network.Node, depth uint) *pbNet.Peer {
	node := &pbNet.Node{
		Id:      peer.Id(),
		Address: peer.Address(),
	}

	pbPeers := &pbNet.Peer{
		Node:  node,
		Peers: make([]*pbNet.Peer, 0),
	}

	// return if we reached the end of topology or depth
	if depth == 0 || len(peer.Peers()) == 0 {
		return pbPeers
	}

	// decrement the depth
	depth--

	// iterate through peers of peers aka pops
	for _, pop := range peer.Peers() {
		peer := peerTopology(pop, depth)
		pbPeers.Peers = append(pbPeers.Peers, peer)
	}

	return pbPeers
}

// ListPeers returns a list of all the nodes the node has a direct link with
func (n *Network) ListPeers(ctx context.Context, req *pbNet.PeerRequest, resp *pbNet.PeerResponse) error {
	depth := uint(req.Depth)
	if depth <= 0 || depth > network.MaxDepth {
		depth = network.MaxDepth
	}

	// get node peers
	nodePeers := n.Network.Peers()

	// network node aka root node
	node := &pbNet.Node{
		Id:      n.Network.Id(),
		Address: n.Network.Address(),
	}
	// we will build proto topology into this
	peers := &pbNet.Peer{
		Node:  node,
		Peers: make([]*pbNet.Peer, 0),
	}

	for _, nodePeer := range nodePeers {
		peer := peerTopology(nodePeer, depth)
		peers.Peers = append(peers.Peers, peer)
	}

	resp.Peers = peers

	return nil
}

// ListRoutes returns a list of routing table routes
func (n *Network) ListRoutes(ctx context.Context, req *pbRtr.Request, resp *pbRtr.ListResponse) error {
	routes, err := n.Network.Options().Router.Table().List()
	if err != nil {
		return errors.InternalServerError("go.micro.network", "failed to list routes: %s", err)
	}

	var respRoutes []*pbRtr.Route
	for _, route := range routes {
		respRoute := &pbRtr.Route{
			Service: route.Service,
			Address: route.Address,
			Gateway: route.Gateway,
			Network: route.Network,
			Router:  route.Router,
			Link:    route.Link,
			Metric:  int64(route.Metric),
		}
		respRoutes = append(respRoutes, respRoute)
	}

	resp.Routes = respRoutes

	return nil
}