package fsm

import (
	"github.com/hashicorp/consul/agent/consul/autopilot"
	"github.com/hashicorp/consul/agent/consul/state"
	"github.com/hashicorp/consul/agent/structs"
	"github.com/hashicorp/go-msgpack/codec"
	"github.com/hashicorp/raft"
)

func init() {
	registerPersister(persistOSS)

	registerRestorer(structs.RegisterRequestType, restoreRegistration)
	registerRestorer(structs.KVSRequestType, restoreKV)
	registerRestorer(structs.TombstoneRequestType, restoreTombstone)
	registerRestorer(structs.SessionRequestType, restoreSession)
	registerRestorer(structs.ACLRequestType, restoreACL)
	registerRestorer(structs.ACLBootstrapRequestType, restoreACLBootstrap)
	registerRestorer(structs.CoordinateBatchUpdateType, restoreCoordinates)
	registerRestorer(structs.PreparedQueryRequestType, restorePreparedQuery)
	registerRestorer(structs.AutopilotRequestType, restoreAutopilot)
}

func persistOSS(s *snapshot, sink raft.SnapshotSink, encoder *codec.Encoder) error {
	if err := s.persistNodes(sink, encoder); err != nil {
		return err
	}
	if err := s.persistSessions(sink, encoder); err != nil {
		return err
	}
	if err := s.persistACLs(sink, encoder); err != nil {
		return err
	}
	if err := s.persistKVs(sink, encoder); err != nil {
		return err
	}
	if err := s.persistTombstones(sink, encoder); err != nil {
		return err
	}
	if err := s.persistPreparedQueries(sink, encoder); err != nil {
		return err
	}
	if err := s.persistAutopilot(sink, encoder); err != nil {
		return err
	}
	return nil
}

func (s *snapshot) persistNodes(sink raft.SnapshotSink,
	encoder *codec.Encoder) error {

	// Get all the nodes
	nodes, err := s.state.Nodes()
	if err != nil {
		return err
	}

	// Register each node
	for node := nodes.Next(); node != nil; node = nodes.Next() {
		n := node.(*structs.Node)
		req := structs.RegisterRequest{
			Node:            n.Node,
			Address:         n.Address,
			TaggedAddresses: n.TaggedAddresses,
		}

		// Register the node itself
		if _, err := sink.Write([]byte{byte(structs.RegisterRequestType)}); err != nil {
			return err
		}
		if err := encoder.Encode(&req); err != nil {
			return err
		}

		// Register each service this node has
		services, err := s.state.Services(n.Node)
		if err != nil {
			return err
		}
		for service := services.Next(); service != nil; service = services.Next() {
			if _, err := sink.Write([]byte{byte(structs.RegisterRequestType)}); err != nil {
				return err
			}
			req.Service = service.(*structs.ServiceNode).ToNodeService()
			if err := encoder.Encode(&req); err != nil {
				return err
			}
		}

		// Register each check this node has
		req.Service = nil
		checks, err := s.state.Checks(n.Node)
		if err != nil {
			return err
		}
		for check := checks.Next(); check != nil; check = checks.Next() {
			if _, err := sink.Write([]byte{byte(structs.RegisterRequestType)}); err != nil {
				return err
			}
			req.Check = check.(*structs.HealthCheck)
			if err := encoder.Encode(&req); err != nil {
				return err
			}
		}
	}

	// Save the coordinates separately since they are not part of the
	// register request interface. To avoid copying them out, we turn
	// them into batches with a single coordinate each.
	coords, err := s.state.Coordinates()
	if err != nil {
		return err
	}
	for coord := coords.Next(); coord != nil; coord = coords.Next() {
		if _, err := sink.Write([]byte{byte(structs.CoordinateBatchUpdateType)}); err != nil {
			return err
		}
		updates := structs.Coordinates{coord.(*structs.Coordinate)}
		if err := encoder.Encode(&updates); err != nil {
			return err
		}
	}
	return nil
}

func (s *snapshot) persistSessions(sink raft.SnapshotSink,
	encoder *codec.Encoder) error {
	sessions, err := s.state.Sessions()
	if err != nil {
		return err
	}

	for session := sessions.Next(); session != nil; session = sessions.Next() {
		if _, err := sink.Write([]byte{byte(structs.SessionRequestType)}); err != nil {
			return err
		}
		if err := encoder.Encode(session.(*structs.Session)); err != nil {
			return err
		}
	}
	return nil
}

func (s *snapshot) persistACLs(sink raft.SnapshotSink,
	encoder *codec.Encoder) error {
	acls, err := s.state.ACLs()
	if err != nil {
		return err
	}

	for acl := acls.Next(); acl != nil; acl = acls.Next() {
		if _, err := sink.Write([]byte{byte(structs.ACLRequestType)}); err != nil {
			return err
		}
		if err := encoder.Encode(acl.(*structs.ACL)); err != nil {
			return err
		}
	}

	bs, err := s.state.ACLBootstrap()
	if err != nil {
		return err
	}
	if bs != nil {
		if _, err := sink.Write([]byte{byte(structs.ACLBootstrapRequestType)}); err != nil {
			return err
		}
		if err := encoder.Encode(bs); err != nil {
			return err
		}
	}

	return nil
}

func (s *snapshot) persistKVs(sink raft.SnapshotSink,
	encoder *codec.Encoder) error {
	entries, err := s.state.KVs()
	if err != nil {
		return err
	}

	for entry := entries.Next(); entry != nil; entry = entries.Next() {
		if _, err := sink.Write([]byte{byte(structs.KVSRequestType)}); err != nil {
			return err
		}
		if err := encoder.Encode(entry.(*structs.DirEntry)); err != nil {
			return err
		}
	}
	return nil
}

func (s *snapshot) persistTombstones(sink raft.SnapshotSink,
	encoder *codec.Encoder) error {
	stones, err := s.state.Tombstones()
	if err != nil {
		return err
	}

	for stone := stones.Next(); stone != nil; stone = stones.Next() {
		if _, err := sink.Write([]byte{byte(structs.TombstoneRequestType)}); err != nil {
			return err
		}

		// For historical reasons, these are serialized in the snapshots
		// as KV entries. We want to keep the snapshot format compatible
		// with pre-0.6 versions for now.
		s := stone.(*state.Tombstone)
		fake := &structs.DirEntry{
			Key: s.Key,
			RaftIndex: structs.RaftIndex{
				ModifyIndex: s.Index,
			},
		}
		if err := encoder.Encode(fake); err != nil {
			return err
		}
	}
	return nil
}

func (s *snapshot) persistPreparedQueries(sink raft.SnapshotSink,
	encoder *codec.Encoder) error {
	queries, err := s.state.PreparedQueries()
	if err != nil {
		return err
	}

	for _, query := range queries {
		if _, err := sink.Write([]byte{byte(structs.PreparedQueryRequestType)}); err != nil {
			return err
		}
		if err := encoder.Encode(query); err != nil {
			return err
		}
	}
	return nil
}

func (s *snapshot) persistAutopilot(sink raft.SnapshotSink,
	encoder *codec.Encoder) error {
	autopilot, err := s.state.Autopilot()
	if err != nil {
		return err
	}
	if autopilot == nil {
		return nil
	}

	if _, err := sink.Write([]byte{byte(structs.AutopilotRequestType)}); err != nil {
		return err
	}
	if err := encoder.Encode(autopilot); err != nil {
		return err
	}
	return nil
}

func restoreRegistration(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.RegisterRequest
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.Registration(header.LastIndex, &req); err != nil {
		return err
	}
	return nil
}

func restoreKV(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.DirEntry
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.KVS(&req); err != nil {
		return err
	}
	return nil
}

func restoreTombstone(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.DirEntry
	if err := decoder.Decode(&req); err != nil {
		return err
	}

	// For historical reasons, these are serialized in the
	// snapshots as KV entries. We want to keep the snapshot
	// format compatible with pre-0.6 versions for now.
	stone := &state.Tombstone{
		Key:   req.Key,
		Index: req.ModifyIndex,
	}
	if err := restore.Tombstone(stone); err != nil {
		return err
	}
	return nil
}

func restoreSession(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.Session
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.Session(&req); err != nil {
		return err
	}
	return nil
}

func restoreACL(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.ACL
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.ACL(&req); err != nil {
		return err
	}
	return nil
}

func restoreACLBootstrap(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.ACLBootstrap
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.ACLBootstrap(&req); err != nil {
		return err
	}
	return nil
}

func restoreCoordinates(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.Coordinates
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.Coordinates(header.LastIndex, req); err != nil {
		return err
	}
	return nil
}

func restorePreparedQuery(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req structs.PreparedQuery
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.PreparedQuery(&req); err != nil {
		return err
	}
	return nil
}

func restoreAutopilot(header *snapshotHeader, restore *state.Restore, decoder *codec.Decoder) error {
	var req autopilot.Config
	if err := decoder.Decode(&req); err != nil {
		return err
	}
	if err := restore.Autopilot(&req); err != nil {
		return err
	}
	return nil
}