// SplitQuery is the stub for TabletServer.SplitQuery RPC
// TODO(erez): Remove this method and rename SplitQueryV2 to SplitQuery once
// the migration to SplitQuery V2 is done.
func (conn *gRPCQueryClient) SplitQuery(ctx context.Context, target *querypb.Target, query querytypes.BoundQuery, splitColumn string, splitCount int64) (queries []querytypes.QuerySplit, err error) {
	conn.mu.RLock()
	defer conn.mu.RUnlock()
	if conn.cc == nil {
		err = tabletconn.ConnClosed
		return
	}

	q, err := querytypes.BoundQueryToProto3(query.Sql, query.BindVariables)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	req := &querypb.SplitQueryRequest{
		Target:              target,
		EffectiveCallerId:   callerid.EffectiveCallerIDFromContext(ctx),
		ImmediateCallerId:   callerid.ImmediateCallerIDFromContext(ctx),
		Query:               q,
		SplitColumn:         []string{splitColumn},
		SplitCount:          splitCount,
		NumRowsPerQueryPart: 0,
		Algorithm:           querypb.SplitQueryRequest_EQUAL_SPLITS,
		UseSplitQueryV2:     false,
	}
	sqr, err := conn.c.SplitQuery(ctx, req)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	split, err := querytypes.Proto3ToQuerySplits(sqr.Queries)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	return split, nil
}

// SplitQuery is the stub for TabletServer.SplitQuery RPC
func (conn *gRPCQueryClient) SplitQuery(ctx context.Context, query tproto.BoundQuery, splitColumn string, splitCount int) (queries []tproto.QuerySplit, err error) {
	conn.mu.RLock()
	defer conn.mu.RUnlock()
	if conn.cc == nil {
		err = tabletconn.ConnClosed
		return
	}

	q, err := tproto.BoundQueryToProto3(query.Sql, query.BindVariables)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	req := &pb.SplitQueryRequest{
		Target:            conn.target,
		EffectiveCallerId: callerid.EffectiveCallerIDFromContext(ctx),
		ImmediateCallerId: callerid.ImmediateCallerIDFromContext(ctx),
		Query:             q,
		SplitColumn:       splitColumn,
		SplitCount:        int64(splitCount),
		SessionId:         conn.sessionID,
	}
	sqr, err := conn.c.SplitQuery(ctx, req)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	split, err := tproto.Proto3ToQuerySplits(sqr.Queries)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	return split, nil
}

// BeginExecute starts a transaction and runs an Execute.
func (conn *gRPCQueryClient) BeginExecute(ctx context.Context, target *querypb.Target, query string, bindVars map[string]interface{}, options *querypb.ExecuteOptions) (result *sqltypes.Result, transactionID int64, err error) {
	conn.mu.RLock()
	defer conn.mu.RUnlock()
	if conn.cc == nil {
		return nil, 0, tabletconn.ConnClosed
	}

	q, err := querytypes.BoundQueryToProto3(query, bindVars)
	if err != nil {
		return nil, 0, err
	}

	if *combo {
		// If combo is enabled, we combine both calls
		req := &querypb.BeginExecuteRequest{
			Target:            target,
			EffectiveCallerId: callerid.EffectiveCallerIDFromContext(ctx),
			ImmediateCallerId: callerid.ImmediateCallerIDFromContext(ctx),
			Query:             q,
			Options:           options,
		}
		reply, err := conn.c.BeginExecute(ctx, req)
		if err != nil {
			return nil, 0, tabletconn.TabletErrorFromGRPC(err)
		}
		if reply.Error != nil {
			return nil, reply.TransactionId, tabletconn.TabletErrorFromRPCError(reply.Error)
		}
		return sqltypes.Proto3ToResult(reply.Result), reply.TransactionId, nil
	}

	// Begin part.
	breq := &querypb.BeginRequest{
		Target:            target,
		EffectiveCallerId: callerid.EffectiveCallerIDFromContext(ctx),
		ImmediateCallerId: callerid.ImmediateCallerIDFromContext(ctx),
	}
	br, err := conn.c.Begin(ctx, breq)
	if err != nil {
		return nil, 0, tabletconn.TabletErrorFromGRPC(err)
	}
	transactionID = br.TransactionId

	// Execute part.
	ereq := &querypb.ExecuteRequest{
		Target:            target,
		EffectiveCallerId: breq.EffectiveCallerId,
		ImmediateCallerId: breq.ImmediateCallerId,
		Query:             q,
		TransactionId:     transactionID,
		Options:           options,
	}
	er, err := conn.c.Execute(ctx, ereq)
	if err != nil {
		return nil, transactionID, tabletconn.TabletErrorFromGRPC(err)
	}
	return sqltypes.Proto3ToResult(er.Result), transactionID, nil

}

// SplitQuery is part of tabletconn.TabletConn
func (itc *internalTabletConn) SplitQuery(ctx context.Context, target *querypb.Target, query querytypes.BoundQuery, splitColumn string, splitCount int64) ([]querytypes.QuerySplit, error) {
	splits, err := itc.tablet.qsc.QueryService().SplitQuery(ctx, target, query.Sql, query.BindVariables, splitColumn, splitCount)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(vterrors.ToGRPCError(err))
	}
	return splits, nil
}

// ExecuteBatch sends a batch query to VTTablet.
func (conn *gRPCQueryClient) ExecuteBatch(ctx context.Context, target *querypb.Target, queries []querytypes.BoundQuery, asTransaction bool, transactionID int64, options *querypb.ExecuteOptions) ([]sqltypes.Result, error) {
	conn.mu.RLock()
	defer conn.mu.RUnlock()
	if conn.cc == nil {
		return nil, tabletconn.ConnClosed
	}

	req := &querypb.ExecuteBatchRequest{
		Target:            target,
		EffectiveCallerId: callerid.EffectiveCallerIDFromContext(ctx),
		ImmediateCallerId: callerid.ImmediateCallerIDFromContext(ctx),
		Queries:           make([]*querypb.BoundQuery, len(queries)),
		AsTransaction:     asTransaction,
		TransactionId:     transactionID,
		Options:           options,
	}
	for i, q := range queries {
		qq, err := querytypes.BoundQueryToProto3(q.Sql, q.BindVariables)
		if err != nil {
			return nil, err
		}
		req.Queries[i] = qq
	}
	ebr, err := conn.c.ExecuteBatch(ctx, req)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	return sqltypes.Proto3ToResults(ebr.Results), nil
}

// SplitQueryV2 is part of tabletconn.TabletConn
// TODO(erez): Rename to SplitQuery once the migration to SplitQuery V2 is done.
func (itc *internalTabletConn) SplitQueryV2(
	ctx context.Context,
	query querytypes.BoundQuery,
	splitColumns []string,
	splitCount int64,
	numRowsPerQueryPart int64,
	algorithm querypb.SplitQueryRequest_Algorithm) ([]querytypes.QuerySplit, error) {

	splits, err := itc.tablet.qsc.QueryService().SplitQueryV2(
		ctx,
		&querypb.Target{
			Keyspace:   itc.tablet.keyspace,
			Shard:      itc.tablet.shard,
			TabletType: itc.tablet.tabletType,
		},
		query.Sql,
		query.BindVariables,
		splitColumns,
		splitCount,
		numRowsPerQueryPart,
		algorithm)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(err))
	}
	return splits, nil
}

// StreamExecute is part of tabletconn.TabletConn
// We need to copy the bind variables as tablet server will change them.
func (itc *internalTabletConn) StreamExecute(ctx context.Context, target *querypb.Target, query string, bindVars map[string]interface{}, options *querypb.ExecuteOptions) (sqltypes.ResultStream, error) {
	bv, err := querytypes.BindVariablesToProto3(bindVars)
	if err != nil {
		return nil, err
	}
	bindVars, err = querytypes.Proto3ToBindVariables(bv)
	if err != nil {
		return nil, err
	}
	result := make(chan *sqltypes.Result, 10)
	var finalErr error

	go func() {
		finalErr = itc.tablet.qsc.QueryService().StreamExecute(ctx, target, query, bindVars, options, func(reply *sqltypes.Result) error {
			// We need to deep-copy the reply before returning,
			// because the underlying buffers are reused.
			result <- reply.Copy()
			return nil
		})
		finalErr = tabletconn.TabletErrorFromGRPC(vterrors.ToGRPCError(finalErr))

		// the client will only access finalErr after the
		// channel is closed, and then it's already set.
		close(result)
	}()

	return &streamExecuteAdapter{result, &finalErr}, nil
}

// StreamHealth is part of tabletconn.TabletConn
func (itc *internalTabletConn) StreamHealth(ctx context.Context) (tabletconn.StreamHealthReader, error) {
	result := make(chan *querypb.StreamHealthResponse, 10)

	id, err := itc.tablet.qsc.QueryService().StreamHealthRegister(result)
	if err != nil {
		return nil, err
	}

	var finalErr error
	go func() {
		select {
		case <-ctx.Done():
		}

		// We populate finalErr before closing the channel.
		// The consumer first waits on the channel closure,
		// then read finalErr
		finalErr = itc.tablet.qsc.QueryService().StreamHealthUnregister(id)
		finalErr = tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(finalErr))
		close(result)
	}()

	return &streamHealthReader{
		c:   result,
		err: &finalErr,
	}, nil
}

// Execute sends the query to VTTablet.
func (conn *gRPCQueryClient) Execute(ctx context.Context, query string, bindVars map[string]interface{}, transactionID int64) (*sqltypes.Result, error) {
	conn.mu.RLock()
	defer conn.mu.RUnlock()
	if conn.cc == nil {
		return nil, tabletconn.ConnClosed
	}

	q, err := tproto.BoundQueryToProto3(query, bindVars)
	if err != nil {
		return nil, err
	}

	req := &pb.ExecuteRequest{
		Target:            conn.target,
		EffectiveCallerId: callerid.EffectiveCallerIDFromContext(ctx),
		ImmediateCallerId: callerid.ImmediateCallerIDFromContext(ctx),
		Query:             q,
		TransactionId:     transactionID,
		SessionId:         conn.sessionID,
	}
	er, err := conn.c.Execute(ctx, req)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	return sqltypes.Proto3ToResult(er.Result), nil
}

// ExecuteBatch is part of tabletconn.TabletConn
// We need to copy the bind variables as tablet server will change them.
func (itc *internalTabletConn) ExecuteBatch(ctx context.Context, queries []tproto.BoundQuery, asTransaction bool, transactionID int64) (*tproto.QueryResultList, error) {
	q := make([]tproto.BoundQuery, len(queries))
	for i, query := range queries {
		bv, err := tproto.BindVariablesToProto3(query.BindVariables)
		if err != nil {
			return nil, err
		}
		bindVars, err := tproto.Proto3ToBindVariables(bv)
		if err != nil {
			return nil, err
		}
		q[i].Sql = query.Sql
		q[i].BindVariables = bindVars
	}
	reply := &tproto.QueryResultList{}
	if err := itc.tablet.qsc.QueryService().ExecuteBatch(ctx, &querypb.Target{
		Keyspace:   itc.tablet.keyspace,
		Shard:      itc.tablet.shard,
		TabletType: itc.tablet.tabletType,
	}, &tproto.QueryList{
		Queries:       q,
		AsTransaction: asTransaction,
		TransactionId: transactionID,
	}, reply); err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(err))
	}
	return reply, nil
}

// StreamExecute is part of tabletconn.TabletConn
// We need to copy the bind variables as tablet server will change them.
func (itc *internalTabletConn) StreamExecute(ctx context.Context, query string, bindVars map[string]interface{}, transactionID int64) (<-chan *mproto.QueryResult, tabletconn.ErrFunc, error) {
	bindVars = tproto.Proto3ToBindVariables(tproto.BindVariablesToProto3(bindVars))
	result := make(chan *mproto.QueryResult, 10)
	var finalErr error

	go func() {
		finalErr = itc.tablet.qsc.QueryService().StreamExecute(ctx, &pbq.Target{
			Keyspace:   itc.tablet.keyspace,
			Shard:      itc.tablet.shard,
			TabletType: itc.tablet.tabletType,
		}, &tproto.Query{
			Sql:           query,
			BindVariables: bindVars,
			TransactionId: transactionID,
		}, func(reply *mproto.QueryResult) error {
			result <- reply
			return nil
		})

		// the client will only access finalErr after the
		// channel is closed, and then it's already set.
		close(result)
	}()

	return result, func() error {
		return tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(finalErr))
	}, nil
}

// StreamExecute is part of tabletconn.TabletConn
// We need to copy the bind variables as tablet server will change them.
func (itc *internalTabletConn) StreamExecute(ctx context.Context, query string, bindVars map[string]interface{}, transactionID int64) (<-chan *sqltypes.Result, tabletconn.ErrFunc, error) {
	bv, err := querytypes.BindVariablesToProto3(bindVars)
	if err != nil {
		return nil, nil, err
	}
	bindVars, err = querytypes.Proto3ToBindVariables(bv)
	if err != nil {
		return nil, nil, err
	}
	result := make(chan *sqltypes.Result, 10)
	var finalErr error

	go func() {
		finalErr = itc.tablet.qsc.QueryService().StreamExecute(ctx, &querypb.Target{
			Keyspace:   itc.tablet.keyspace,
			Shard:      itc.tablet.shard,
			TabletType: itc.tablet.tabletType,
		}, query, bindVars, 0, func(reply *sqltypes.Result) error {
			// We need to deep-copy the reply before returning,
			// because the underlying buffers are reused.
			result <- reply.Copy()
			return nil
		})

		// the client will only access finalErr after the
		// channel is closed, and then it's already set.
		close(result)
	}()

	return result, func() error {
		return tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(finalErr))
	}, nil
}

// Begin is part of tabletconn.TabletConn
func (itc *internalTabletConn) Begin(ctx context.Context, target *querypb.Target) (int64, error) {
	transactionID, err := itc.tablet.qsc.QueryService().Begin(ctx, target)
	if err != nil {
		return 0, tabletconn.TabletErrorFromGRPC(vterrors.ToGRPCError(err))
	}
	return transactionID, nil
}

// ExecuteBatch sends a batch query to VTTablet.
func (conn *gRPCQueryClient) ExecuteBatch(ctx context.Context, queries []tproto.BoundQuery, asTransaction bool, transactionID int64) (*tproto.QueryResultList, error) {
	conn.mu.RLock()
	defer conn.mu.RUnlock()
	if conn.cc == nil {
		return nil, tabletconn.ConnClosed
	}

	req := &pb.ExecuteBatchRequest{
		Target:            conn.target,
		EffectiveCallerId: callerid.EffectiveCallerIDFromContext(ctx),
		ImmediateCallerId: callerid.ImmediateCallerIDFromContext(ctx),
		Queries:           make([]*pb.BoundQuery, len(queries)),
		AsTransaction:     asTransaction,
		TransactionId:     transactionID,
		SessionId:         conn.sessionID,
	}
	for i, q := range queries {
		req.Queries[i] = tproto.BoundQueryToProto3(q.Sql, q.BindVariables)
	}
	ebr, err := conn.c.ExecuteBatch(ctx, req)
	if err != nil {
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
	return tproto.Proto3ToQueryResultList(ebr.Results), nil
}

// Rollback is part of tabletconn.TabletConn
func (itc *internalTabletConn) Rollback(ctx context.Context, transactionID int64) error {
	err := itc.tablet.qsc.QueryService().Rollback(ctx, &querypb.Target{
		Keyspace:   itc.tablet.keyspace,
		Shard:      itc.tablet.shard,
		TabletType: itc.tablet.tabletType,
	}, 0, transactionID)
	return tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(err))
}

// StreamExecute starts a streaming query to VTTablet.
func (conn *gRPCQueryClient) StreamExecute(ctx context.Context, query string, bindVars map[string]interface{}, transactionID int64) (<-chan *sqltypes.Result, tabletconn.ErrFunc, error) {
	conn.mu.RLock()
	defer conn.mu.RUnlock()
	if conn.cc == nil {
		return nil, nil, tabletconn.ConnClosed
	}

	q, err := querytypes.BoundQueryToProto3(query, bindVars)
	if err != nil {
		return nil, nil, err
	}
	req := &querypb.StreamExecuteRequest{
		Target:            conn.target,
		EffectiveCallerId: callerid.EffectiveCallerIDFromContext(ctx),
		ImmediateCallerId: callerid.ImmediateCallerIDFromContext(ctx),
		Query:             q,
		SessionId:         conn.sessionID,
	}
	stream, err := conn.c.StreamExecute(ctx, req)
	if err != nil {
		return nil, nil, tabletconn.TabletErrorFromGRPC(err)
	}
	sr := make(chan *sqltypes.Result, 10)
	var finalError error
	go func() {
		var fields []*querypb.Field
		for {
			ser, err := stream.Recv()
			if err != nil {
				if err != io.EOF {
					finalError = tabletconn.TabletErrorFromGRPC(err)
				}
				close(sr)
				return
			}
			if fields == nil {
				fields = ser.Result.Fields
			}
			sr <- sqltypes.CustomProto3ToResult(fields, ser.Result)
		}
	}()
	return sr, func() error {
		return finalError
	}, nil
}

// Commit is part of tabletconn.TabletConn
func (itc *internalTabletConn) Commit(ctx context.Context, transactionID int64) error {
	err := itc.tablet.qsc.QueryService().Commit(ctx, &pbq.Target{
		Keyspace:   itc.tablet.keyspace,
		Shard:      itc.tablet.shard,
		TabletType: itc.tablet.tabletType,
	}, &tproto.Session{
		TransactionId: transactionID,
	})
	return tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(err))
}

// Begin is part of tabletconn.TabletConn
func (itc *internalTabletConn) Begin(ctx context.Context) (int64, error) {
	transactionID, err := itc.tablet.qsc.QueryService().Begin(ctx, &querypb.Target{
		Keyspace:   itc.tablet.keyspace,
		Shard:      itc.tablet.shard,
		TabletType: itc.tablet.tabletType,
	}, 0)
	if err != nil {
		return 0, tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(err))
	}
	return transactionID, nil
}

// Begin is part of tabletconn.TabletConn
func (itc *internalTabletConn) Begin(ctx context.Context) (transactionID int64, err error) {
	result := &tproto.TransactionInfo{}
	if err := itc.tablet.qsc.QueryService().Begin(ctx, &pbq.Target{
		Keyspace:   itc.tablet.keyspace,
		Shard:      itc.tablet.shard,
		TabletType: itc.tablet.tabletType,
	}, &tproto.Session{}, result); err != nil {
		return 0, tabletconn.TabletErrorFromGRPC(tabletserver.ToGRPCError(err))
	}
	return result.TransactionId, nil
}

func (a *updateStreamAdapter) Recv() (*querypb.StreamEvent, error) {
	r, err := a.stream.Recv()
	switch err {
	case nil:
		return r.Event, nil
	case io.EOF:
		return nil, err
	default:
		return nil, tabletconn.TabletErrorFromGRPC(err)
	}
}