// Update is used to perform an update of an Eval if it is outstanding.
func (e *Eval) Update(args *structs.EvalUpdateRequest,
	reply *structs.GenericResponse) error {
	if done, err := e.srv.forward("Eval.Update", args, args, reply); done {
		return err
	}
	defer metrics.MeasureSince([]string{"nomad", "eval", "update"}, time.Now())

	// Ensure there is only a single update with token
	if len(args.Evals) != 1 {
		return fmt.Errorf("only a single eval can be updated")
	}
	eval := args.Evals[0]

	// Verify the evaluation is outstanding, and that the tokens match.
	if err := e.srv.evalBroker.OutstandingReset(eval.ID, args.EvalToken); err != nil {
		return err
	}

	// Update via Raft
	_, index, err := e.srv.raftApply(structs.EvalUpdateRequestType, args)
	if err != nil {
		return err
	}

	// Update the index
	reply.Index = index
	return nil
}

// ReconcileSummaries reconciles the summaries of all the jobs in the state
// store
func (s *System) ReconcileJobSummaries(args *structs.GenericRequest, reply *structs.GenericResponse) error {
	if done, err := s.srv.forward("System.ReconcileJobSummaries", args, args, reply); done {
		return err
	}

	_, index, err := s.srv.raftApply(structs.ReconcileJobSummariesRequestType, args)
	if err != nil {
		return fmt.Errorf("reconciliation of job summaries failed: %v", err)
	}
	reply.Index = index
	return nil
}

// Reap is used to cleanup dead evaluations and allocations
func (e *Eval) Reap(args *structs.EvalDeleteRequest,
	reply *structs.GenericResponse) error {
	if done, err := e.srv.forward("Eval.Reap", args, args, reply); done {
		return err
	}
	defer metrics.MeasureSince([]string{"nomad", "eval", "reap"}, time.Now())

	// Update via Raft
	_, index, err := e.srv.raftApply(structs.EvalDeleteRequestType, args)
	if err != nil {
		return err
	}

	// Update the index
	reply.Index = index
	return nil
}

// UpdateAlloc is used to update the client status of an allocation
func (n *Node) UpdateAlloc(args *structs.AllocUpdateRequest, reply *structs.GenericResponse) error {
	if done, err := n.srv.forward("Node.UpdateAlloc", args, args, reply); done {
		return err
	}
	defer metrics.MeasureSince([]string{"nomad", "client", "update_alloc"}, time.Now())

	// Ensure at least a single alloc
	if len(args.Alloc) == 0 {
		return fmt.Errorf("must update at least one allocation")
	}

	// Add this to the batch
	n.updatesLock.Lock()
	n.updates = append(n.updates, args.Alloc...)

	// Start a new batch if none
	future := n.updateFuture
	if future == nil {
		future = NewBatchFuture()
		n.updateFuture = future
		n.updateTimer = time.AfterFunc(batchUpdateInterval, func() {
			// Get the pending updates
			n.updatesLock.Lock()
			updates := n.updates
			future := n.updateFuture
			n.updates = nil
			n.updateFuture = nil
			n.updateTimer = nil
			n.updatesLock.Unlock()

			// Perform the batch update
			n.batchUpdate(future, updates)
		})
	}
	n.updatesLock.Unlock()

	// Wait for the future
	if err := future.Wait(); err != nil {
		return err
	}

	// Setup the response
	reply.Index = future.Index()
	return nil
}

// Create is used to make a new evaluation
func (e *Eval) Create(args *structs.EvalUpdateRequest,
	reply *structs.GenericResponse) error {
	if done, err := e.srv.forward("Eval.Create", args, args, reply); done {
		return err
	}
	defer metrics.MeasureSince([]string{"nomad", "eval", "create"}, time.Now())

	// Ensure there is only a single update with token
	if len(args.Evals) != 1 {
		return fmt.Errorf("only a single eval can be created")
	}
	eval := args.Evals[0]

	// Verify the parent evaluation is outstanding, and that the tokens match.
	token, ok := e.srv.evalBroker.Outstanding(eval.PreviousEval)
	if !ok {
		return fmt.Errorf("previous evaluation is not outstanding")
	}
	if args.EvalToken != token {
		return fmt.Errorf("previous evaluation token does not match")
	}

	// Look for the eval
	snap, err := e.srv.fsm.State().Snapshot()
	if err != nil {
		return err
	}
	out, err := snap.EvalByID(eval.ID)
	if err != nil {
		return err
	}
	if out != nil {
		return fmt.Errorf("evaluation already exists")
	}

	// Update via Raft
	_, index, err := e.srv.raftApply(structs.EvalUpdateRequestType, args)
	if err != nil {
		return err
	}

	// Update the index
	reply.Index = index
	return nil
}

// UpdateAlloc is used to update the client status of an allocation
func (n *Node) UpdateAlloc(args *structs.AllocUpdateRequest, reply *structs.GenericResponse) error {
	if done, err := n.srv.forward("Node.UpdateAlloc", args, args, reply); done {
		return err
	}
	defer metrics.MeasureSince([]string{"nomad", "client", "update_alloc"}, time.Now())

	// Ensure only a single alloc
	if len(args.Alloc) != 1 {
		return fmt.Errorf("must update a single allocation")
	}

	// Commit this update via Raft
	_, index, err := n.srv.raftApply(structs.AllocClientUpdateRequestType, args)
	if err != nil {
		n.srv.logger.Printf("[ERR] nomad.client: alloc update failed: %v", err)
		return err
	}

	// Setup the response
	reply.Index = index
	return nil
}