//go:build integration

package link

import (
	"bytes"
	"context"
	"encoding/json"
	"log"
	"strings"
	"testing"

	"github.com/nats-io/nats.go/jetstream"
	"github.com/novox/mesh-controller/internal/broker"
)

func callsBucket(t *testing.T) *BusCalls {
	t.Helper()
	js := aBus(t)
	api, err := jetstream.New(js.Conn())
	if err != nil {
		t.Fatal(err)
	}
	_ = api.DeleteKeyValue(t.Context(), broker.CallsBucket)
	if err := js.EnsureControllerBuckets(); err != nil {
		t.Fatal(err)
	}
	keeper, err := CallsOnTheBus(t.Context(), js.Conn())
	if err != nil {
		t.Fatal(err)
	}
	return keeper
}

func TestNatsACallsOutcomeOutlivesItsController(t *testing.T) {
	keeper := callsBucket(t)
	first := NewCallLog()
	if err := first.Durably(t.Context(), keeper, "controller@one", nil); err != nil {
		t.Fatal(err)
	}
	a := newAnswers(t)
	first.serveCall("mesh-controller", "push", json.RawMessage(`{"node":"anchor","values":"secret"}`),
		"_INBOX.node-tools.g14.Pe3sGzAtv8jUBYQ6sKSvKz.1",
		func(context.Context, json.RawMessage) (any, error) { return "anchor told", nil }, a.respond, nil)
	recent, _ := first.Recent()
	finished := waitKept(t, keeper, recent[0].ID, CallAnswered)
	// A second call, still running when its controller stops.
	left := first.begin("mesh-controller", "plans", json.RawMessage(`{}`), "")
	waitKept(t, keeper, left.ID, CallRunning)

	var said bytes.Buffer
	second := NewCallLog()
	if err := second.Durably(t.Context(), keeper, "controller@two", log.New(&said, "", 0)); err != nil {
		t.Fatal(err)
	}
	c, found, err := second.Get(finished.ID)
	if err != nil || !found {
		t.Fatalf("the next controller cannot read %s: %v %v", finished.ID, found, err)
	}
	if !strings.Contains(string(c.Answer), "anchor told") || c.Caller != "node-tools.g14" || c.Holder != "controller@one" {
		t.Fatalf("kept %+v", c)
	}
	if strings.Contains(string(c.Args), "secret") {
		t.Fatalf("a setting was kept: %s", c.Args)
	}
	abandoned, _, _ := second.Get(left.ID)
	if abandoned.State != CallAbandoned || !strings.Contains(said.String(), left.ID) {
		t.Fatalf("a call left running reads %q, and was said: %q", abandoned.State, said.String())
	}
	listed, err := second.Recent()
	if err != nil || len(listed) != 2 {
		t.Fatalf("the next controller lists %d calls: %v", len(listed), err)
	}
	// Its own running calls are not its predecessor's: a controller starting again under the same
	// name leaves them alone.
	mine := second.begin("mesh-controller", "status", nil, "")
	waitKept(t, keeper, mine.ID, CallRunning)
	if err := second.Durably(t.Context(), keeper, "controller@two", nil); err != nil {
		t.Fatal(err)
	}
	if c, _, _ := keeper.Kept(t.Context(), mine.ID); c.State != CallRunning {
		t.Fatalf("a controller marked its own running call %q", c.State)
	}
}

func TestNatsAFinishRacingTheSweepsSnapshotReadsFinished(t *testing.T) {
	keeper := callsBucket(t)
	running := Call{ID: "call-711-1", Seat: "mesh-controller", Verb: "push", State: CallRunning, Holder: "controller@one"}
	if err := keeper.Keep(t.Context(), running); err != nil {
		t.Fatal(err)
	}
	waitKept(t, keeper, running.ID, CallRunning)

	finished := running
	finished.State = CallAnswered
	finished.Answer = json.RawMessage(`"anchor told"`)
	wrapped := racingRecent{CallKeeper: keeper, thenLand: func() {
		if err := keeper.Keep(context.Background(), finished); err != nil {
			t.Error(err)
		}
		waitKept(t, keeper, running.ID, CallAnswered)
	}}

	var said bytes.Buffer
	second := NewCallLog()
	if err := second.Durably(t.Context(), wrapped, "controller@two", log.New(&said, "", 0)); err != nil {
		t.Fatal(err)
	}
	got, found, err := second.Get(running.ID)
	if err != nil || !found || got.State != CallAnswered || !strings.Contains(string(got.Answer), "anchor told") {
		t.Fatalf("its finish did not stand: %+v %v %v", got, found, err)
	}
	if strings.Contains(said.String(), running.ID) {
		t.Errorf("a finished call was said abandoned: %q", said.String())
	}
}

func TestNatsARunningCallWithNoFinishIsStillAbandoned(t *testing.T) {
	keeper := callsBucket(t)
	running := Call{ID: "call-711-2", Seat: "mesh-controller", Verb: "plans", State: CallRunning, Holder: "controller@one"}
	if err := keeper.Keep(t.Context(), running); err != nil {
		t.Fatal(err)
	}
	waitKept(t, keeper, running.ID, CallRunning)

	var said bytes.Buffer
	second := NewCallLog()
	if err := second.Durably(t.Context(), keeper, "controller@two", log.New(&said, "", 0)); err != nil {
		t.Fatal(err)
	}
	got, found, err := second.Get(running.ID)
	if err != nil || !found || got.State != CallAbandoned || !strings.Contains(said.String(), running.ID) {
		t.Fatalf("got %+v %v %v; said %q", got, found, err, said.String())
	}
}

func TestNatsAFinishRacingTheSweepsWriteWins(t *testing.T) {
	keeper := callsBucket(t)
	running := Call{ID: "call-711-3", Seat: "mesh-controller", Verb: "push", State: CallRunning, Holder: "controller@one"}
	if err := keeper.Keep(t.Context(), running); err != nil {
		t.Fatal(err)
	}
	waitKept(t, keeper, running.ID, CallRunning)

	finished := running
	finished.State = CallFinishedAfter
	finished.Answer = json.RawMessage(`"anchor told"`)
	landed := false
	racey := &BusCalls{kv: delayedKV{KeyValue: keeper.kv, before: func() {
		if landed {
			return
		}
		landed = true
		if err := keeper.Keep(context.Background(), finished); err != nil {
			t.Error(err)
		}
		waitKept(t, keeper, running.ID, CallFinishedAfter)
	}}}

	var said bytes.Buffer
	second := NewCallLog()
	if err := second.Durably(t.Context(), racey, "controller@two", log.New(&said, "", 0)); err != nil {
		t.Fatal(err)
	}
	got, found, err := second.Get(running.ID)
	if err != nil || !found || got.State != CallFinishedAfter || !strings.Contains(string(got.Answer), "anchor told") {
		t.Fatalf("the finish did not win the race: %+v %v %v", got, found, err)
	}
	if strings.Contains(said.String(), running.ID) {
		t.Errorf("a finished call was said abandoned: %q", said.String())
	}
}

func TestNatsAMarkAbandonedGivesUpAfterTenTries(t *testing.T) {
	keeper := callsBucket(t)
	running := Call{ID: "call-711-4", Seat: "mesh-controller", Verb: "push", State: CallRunning, Holder: "controller@one"}
	if err := keeper.Keep(t.Context(), running); err != nil {
		t.Fatal(err)
	}
	waitKept(t, keeper, running.ID, CallRunning)

	tries := 0
	stuck := &BusCalls{kv: alwaysMismatchKV{KeyValue: keeper.kv, tries: &tries}}
	_, err := stuck.MarkAbandoned(t.Context(), running.ID)
	if err == nil || !strings.Contains(err.Error(), running.ID) {
		t.Fatalf("expected an error naming %s, got %v", running.ID, err)
	}
	if tries != markAbandonedTries {
		t.Fatalf("tried %d times, want %d", tries, markAbandonedTries)
	}
}

func TestNatsTheCallsBucketIsBounded(t *testing.T) {
	callsBucket(t)
	js := aBus(t)
	if err := js.EnsureControllerBuckets(); err != nil {
		t.Fatal(err)
	}
	info, err := js.Context().StreamInfo("KV_" + broker.CallsBucket)
	if err != nil {
		t.Fatal(err)
	}
	if info.Config.MaxMsgs != 2*broker.KeptCallsDurably || info.Config.MaxAge != broker.CallsKeptFor {
		t.Fatalf("kept %d messages for %s", info.Config.MaxMsgs, info.Config.MaxAge)
	}
}

func TestNatsAnAnswerLargerThanTheBoundIsCut(t *testing.T) {
	keeper := callsBucket(t)
	big, _ := json.Marshal(map[string]string{"result": strings.Repeat("x", broker.CallAnswerBytes+10)})
	c := Call{ID: "call-1-1", Seat: "mesh-controller", Verb: "plan", State: CallAnswered, Answer: big}
	if err := keeper.Keep(t.Context(), c); err != nil {
		t.Fatal(err)
	}
	got, found, err := keeper.Kept(t.Context(), "call-1-1")
	if err != nil || !found || !strings.Contains(string(got.Answer), "the first") {
		t.Fatalf("%v %v %.200s", found, err, got.Answer)
	}
}