package model

import (
	"context"
	"fmt"
	"net"
	"strconv"
)

func (m *sqlModel) GetCheckablePeers(ctx context.Context) ([]*Peer, error) {

	data := []struct {
		sqlPeer       `db:"peers"`
		sqlPeerRouter `db:"peer_routers"`
	}{}
	q := `
		SELECT
			peers.id "peers.id",
			peers.asn "peers.asn",
			peers.name "peers.name",

			peer_routers.peer_id "peer_routers.peer_id",
			peer_routers.v6 "peer_routers.v6",
			peer_routers.v4 "peer_routers.v4"
		FROM peers
		LEFT JOIN peer_routers
		ON peer_routers.peer_id = peers.id
	`
	if err := m.db.SelectContext(ctx, &data, q); err != nil {
		return nil, fmt.Errorf("SELECT peers/peerRouters: %v", err)
	}

	// Collapse peers into map
	// ID -> Peer
	peers := make(map[string]*Peer)

	for _, row := range data {
		peer, ok := peers[row.sqlPeer.ID]
		if !ok {
			asn, err := strconv.ParseInt(row.sqlPeer.ASN, 10, 64)
			if err != nil {
				return nil, fmt.Errorf("data corruption: invalid ASN %q", row.sqlPeer.ASN)
			}
			peer = &Peer{
				ASN:     asn,
				Name:    row.sqlPeer.Name,
				Routers: []*Router{},
			}
			peers[row.sqlPeer.ID] = peer
		}

		var v6 net.IP
		var v4 net.IP

		if row.sqlPeerRouter.V6.Valid {
			v6 = net.ParseIP(row.sqlPeerRouter.V6.String)
		}
		if row.sqlPeerRouter.V4.Valid {
			v4 = net.ParseIP(row.sqlPeerRouter.V4.String)
		}

		peer.Routers = append(peer.Routers, &Router{
			V6: v6,
			V4: v4,
		})
	}

	res := make([]*Peer, len(peers))
	i := 0
	for _, peer := range peers {
		res[i] = peer
		i += 1
	}

	return res, nil
}