package nomad

import (
	"github.com/hashicorp/go-memdb"
	"github.com/hashicorp/nomad/nomad/state"
	"github.com/hashicorp/nomad/nomad/structs"
)

type Resources struct {
	srv *Server
}

// List is used to list the jobs registered in the system
// TODO logic to determine context, to return only that context if needed
// TODO if no context, return all
// TODO refactor to prevent duplication
func (r *Resources) List(args *structs.ResourcesRequest,
	reply *structs.ResourcesResponse) error {

	matches := make(map[string][]string)

	// Setup the blocking query
	opts := blockingOptions{
		queryMeta: &reply.QueryMeta,
		queryOpts: &structs.QueryOptions{},
		run: func(ws memdb.WatchSet, state *state.StateStore) error {

			// return jobs matching given prefix
			var err error
			var iter memdb.ResultIterator
			truncations := make(map[string]bool)

			if args.Context == "job" {
				iter, err = state.JobsByIDPrefix(ws, args.Prefix)
				if err != nil {
					return err
				}

				var jobs []string
				for i := 0; i < 20; i++ {
					raw := iter.Next()
					if raw == nil {
						break
					}

					job := raw.(*structs.Job)
					jobs = append(jobs, job.ID)
				}

				if iter.Next() != nil {
					truncations["job"] = true
				}

				matches["job"] = jobs
			}

			if args.Context == "eval" {
				iter, err = state.EvalsByIDPrefix(ws, args.Prefix)
				if err != nil {
					return err
				}

				var evals []string
				for i := 0; i < 20; i++ { // TODO extract magic number
					raw := iter.Next()
					if raw == nil {
						break
					}

					eval := raw.(*structs.Evaluation)
					evals = append(evals, eval.ID)
				}

				if iter.Next() != nil {
					truncations["eval"] = true
				}

				matches["eval"] = evals
			}

			reply.Matches = matches
			reply.Truncations = truncations

			return nil
		}}
	return r.srv.blockingRPC(&opts)
}