package link

import (
	"context"
	"encoding/json"
	"testing"
	"time"

	"github.com/nats-io/nats.go"
	"github.com/nats-io/nats.go/jetstream"

	"github.com/novox/mesh-controller/internal/broker"
)

// The checks of pull requests are queued by the pull request (novox/hq ADR 0406 §3, §4, issue 974).

func aPullCheck(id string, number int, head, trunk string, ready bool) BuildRequest {
	return BuildRequest{ID: id, Repository: "https://forge.example/novox/a.git", Ref: head,
		Check: &CheckRequest{Owner: "novox", Repo: "a", Number: number, Trunk: trunk, Ready: ready}}
}

// The subject a check is asked on says its queue and its pull request: ready or other, `<owner>.<repo>.<number>` with
// a dot in a name made an underscore, `group.<name>` for a group's, the id for a try; a build is on the seat's own queue.
func TestACheckIsAskedOnItsQueueBySubject(t *testing.T) {
	for _, c := range []struct {
		r    BuildRequest
		want string
	}{
		{aPullCheck("b1", 7, "h", "t", false), "mesh.seat.node-build-agent.check.other.novox.a.7"},
		{aPullCheck("b2", 7, "h", "t", true), "mesh.seat.node-build-agent.check.ready.novox.a.7"},
		{BuildRequest{ID: "b3", Check: &CheckRequest{Owner: "no.vox", Repo: "a.b", Number: 12}}, "mesh.seat.node-build-agent.check.other.no_vox.a_b.12"},
		{BuildRequest{ID: "b4", Check: &CheckRequest{Owner: "novox", Repo: "a", Group: "g.1", Ready: true}}, "mesh.seat.node-build-agent.check.ready.group.g_1"},
		{BuildRequest{ID: "b5", Check: &CheckRequest{Owner: "novox", Repo: "a", Try: true}}, "mesh.seat.node-build-agent.check.other.try.b5"},
		{BuildRequest{ID: "b6", Repository: "/r"}, "mesh.seat.node-build-agent.accept.build"},
		{BuildRequest{ID: "b7", Repository: "/r", DryRun: true}, "mesh.seat.node-build-agent.accept.build"},
	} {
		if got := WorkSubjectOf(TheBuildMachine, c.r); got != c.want {
			t.Errorf("%s is asked on %s; want %s", c.r.ID, got, c.want)
		}
	}
	// The retired role has no check queues: its checks wait with its builds.
	if got := WorkSubjectOf(TheBuildMachineBefore, aPullCheck("b8", 7, "h", "t", true)); got != "mesh.seat.mesh-build-machine.accept.build" {
		t.Errorf("a check of the retired role is asked on %s", got)
	}
}

func queueOf(t *testing.T, js *broker.JetStream) Queue {
	t.Helper()
	q, err := ReadQueue(context.Background(), js, TheBuildMachine)
	if err != nil {
		t.Fatal(err)
	}
	return q
}

// A newer request for a pull request replaces the one still waiting, by the stream's rule, and each open pull request is
// left with one queued check (acceptance 5).

// A delivery build is taken before a check of a ready pull request, that before any other check, and the others in the
// order they were asked.

// aKeyBucket makes mesh-delivery's bucket of pull requests' keys, which the bus here has not been given by that module.
func aKeyBucket(t *testing.T, js *broker.JetStream) jetstream.KeyValue {
	t.Helper()
	api, err := jetstream.New(js.Conn())
	if err != nil {
		t.Fatal(err)
	}
	kv, err := api.CreateKeyValue(t.Context(), jetstream.KeyValueConfig{Bucket: broker.PullsBucket})
	if err != nil {
		t.Fatal(err)
	}
	return kv
}

func putKey(t *testing.T, kv jetstream.KeyValue, number int, k PullKey) {
	t.Helper()
	body, _ := json.Marshal(k)
	if _, err := kv.Put(t.Context(), PullKeyOf("novox", "a", number), body); err != nil {
		t.Fatal(err)
	}
}

// A request left on the third queue for a head and a trunk commit its key says were judged is acknowledged and dropped when a
// builder takes it; one for a head the key does not say judged is run.

// A running check stops when its key's head moves or its trunk commit does, not when the key only gains its verdict, and a
// group's check, which a member's merge in the group's order writes nothing to the key of, is not stopped at all.

func TestAPullKeyIsMovedByHeadOrTrunkAndJudgedByVerdict(t *testing.T) {
	k := PullKey{Head: "aaaaaaaaaaaa1111", Trunk: "tttttttttttt1111", Verdict: "pass"}
	if k.Moved("aaaaaaaaaaaa", "tttttttttttt") || !k.Moved("bbbbbbbbbbbbbbbb", "tttttttttttt") || !k.Moved("aaaaaaaaaaaa", "uuuuuuuuuuuuuu") {
		t.Error("moved is wrong")
	}
	if !k.Judged("aaaaaaaaaaaa1111", "tttttttttttt1111") || k.Judged("aaaaaaaaaaaa1111", "") || (PullKey{Head: "a", Trunk: "t"}).Judged("a", "t") {
		t.Error("judged is wrong")
	}
}

// The queue is read across the three streams in the order they are handed out, each ask says the stream it waits in, and an
// ask is removed from that stream.

// aRunningBucket makes the bucket the builders say the checks they run in, with an age of its own short enough for a test
// (the mesh's is two minutes): a key not renewed within it is gone.
func aRunningBucket(t *testing.T, js *broker.JetStream, age time.Duration) jetstream.KeyValue {
	t.Helper()
	api, err := jetstream.New(js.Conn())
	if err != nil {
		t.Fatal(err)
	}
	kv, err := api.CreateKeyValue(t.Context(), jetstream.KeyValueConfig{Bucket: broker.CheckRunningBucket, History: 1, TTL: age})
	if err != nil {
		t.Fatal(err)
	}
	return kv
}

// A builder taking a request for a pull request's head and trunk commit that another builder is running a check of drops it:
// the bucket of running checks names the head and the trunk, the builder and the build (issue 974).

// A key that is not renewed ages out, and the request for its head and trunk commit is then taken: a builder that died
// running a check leaves nothing that holds the next one back for longer than the bucket's age.

// A builder running a check renews its key on each heartbeat, so it outlives the bucket's age, and deletes it when the check
// ends, whatever the outcome.

// A key whose verdict is "error" — a check that could not run, or was stopped — judged nothing: a request for that head and
// trunk commit must run (issue 974, review 2).
func TestAnErrorVerdictJudgesNothing(t *testing.T) {
	for verdict, judged := range map[string]bool{"pass": true, "warning": true, "fail": true, "error": false, "": false, "pending": false} {
		k := PullKey{Head: "aaaaaaaaaaaa1111", Trunk: "tttttttttttt1111", Verdict: verdict}
		if got := k.Judged("aaaaaaaaaaaa1111", "tttttttttttt1111"); got != judged {
			t.Errorf("a key with verdict %q judged = %v; want %v", verdict, got, judged)
		}
	}
}

// A check stopped because the trunk moved leaves the newer request, for the head against the new trunk commit, taken and
// run: the stop is the stopped one's failure, not the key's verdict, and the newer request is not dropped by it.

// An unacknowledged check goes to a second builder: taken from a check worker and not acknowledged, it is handed out again
// when the worker's wait is up.

// fetchOne takes the next message of a worker and leaves it unacknowledged, as a builder that died would.
func fetchOne(js *broker.JetStream, worker string) (*nats.Msg, error) {
	for _, w := range broker.CheckWorkers() {
		if w.Name != worker {
			continue
		}
		sub, err := js.Context().PullSubscribe(w.Filters[0], w.Name, nats.Bind(w.Stream, w.Name), nats.ManualAck())
		if err != nil {
			return nil, err
		}
		got, err := sub.Fetch(1, nats.MaxWait(5*time.Second))
		if err != nil {
			return nil, err
		}
		return got[0], nil
	}
	return nil, nil
}