package console

import (
	"context"
	"encoding/json"
	"net/http"
	"net/url"
	"testing"
	"time"

	"github.com/carlosframework/platform/internal/hostclaim"
	"github.com/carlosframework/platform/internal/hostops"
	"github.com/carlosframework/platform/internal/moves"
)

// Plan 6 Task 3 fix round 5, ruling 2: an instance incarnation's move log
// outbox rows go when the incarnation is retired or purged, in that step,
// not when the drainer next finds the claim gone (its drop stays a
// backstop). Another incarnation's rows stay.

// queueTestMoveLog queues one confirmed row for host, op and incarnation.
func queueTestMoveLog(t *testing.T, st *Store, host, op, name, inc string) {
	t.Helper()
	body, err := json.Marshal(moves.LogEvent{V: 1, Op: op, Host: host, Event: "x", Identity: name, Actor: "console", At: time.Now().UTC()})
	if err != nil {
		t.Fatal(err)
	}
	if err := st.QueueMoveLog(host, op, name, inc, body, true, time.Now()); err != nil {
		t.Fatal(err)
	}
}

func moveLogRows(t *testing.T, st *Store, host, op string) int {
	t.Helper()
	got, err := st.MoveLogPending(host, op)
	if err != nil {
		t.Fatal(err)
	}
	return len(got)
}

func holderIncarnation(t *testing.T, cx *claimCase, host string) string {
	t.Helper()
	o, err := hostclaim.Read(context.Background(), cx.rel, host)
	if err != nil || o.Absent || o.Claim.Holder == nil {
		t.Fatalf("the claim of %s: %+v %v", host, o, err)
	}
	return o.Claim.Holder.Incarnation
}

func TestRetiringAnInstancePurgesItsMoveLogRows(t *testing.T) {
	cx := newClaimCaseWith(t)
	cx.instanceWorld(t)
	cx.instance(t, `{"host":"acme.go.tito.io","region":"ie"}`)
	cx.quiesce()
	inc := holderIncarnation(t, cx, "acme.go.tito.io")
	queueTestMoveLog(t, cx.st, "acme.go.tito.io", "mv_retired", "done", inc)
	queueTestMoveLog(t, cx.st, "acme.go.tito.io", "mv_earlier", "done", "an-earlier-incarnation")
	// A row the writer refuses (the record never named its move) is held,
	// not deleted (final fix, ruling 1): the drainer runs once, as the moves
	// switch would wire it, and the row stays, held, for the retire's purge.
	r := *cx.srv.cfg.HostClaimRecovery
	r.MoveLogs = cx.srv.drainMoveLog
	if err := cx.srv.cfg.ClaimAuthority.Control.RecoveryPass(context.Background(), r); err != nil {
		t.Logf("the recovery pass: %v", err)
	}
	if got, err := cx.st.MoveLogPending("acme.go.tito.io", "mv_retired"); err != nil || len(got) != 1 || !got[0].Held {
		t.Fatalf("the refused row is not held: %+v %v", got, err)
	}
	if status := claimRetireDoor("/api/cli/apps/bab/titogo/instances/acme.go.tito.io", "acme.go.tito.io")(t, cx); status != http.StatusAccepted {
		t.Fatalf("delete answered %d", status)
	}
	if n := moveLogRows(t, cx.st, "acme.go.tito.io", "mv_retired"); n != 1 {
		t.Fatalf("the rows went before the incarnation was retired: %d", n)
	}
	// The boxes park the instance (world staging: its obligations are
	// discharged), and the delete's retry frees the claim and retires the
	// incarnation.
	for i := 0; i < 3; i++ {
		obs, err := hostclaim.Read(context.Background(), cx.rel, "acme.go.tito.io")
		if err != nil {
			t.Fatal(err)
		}
		if obs.Absent || obs.Claim.Free() {
			break
		}
		if obs.Claim.Op.Kind == hostclaim.KindParking && len(obs.Claim.Obligations) != 0 {
			if _, err := hostclaim.Update(context.Background(), cx.rel, obs, func(c *hostclaim.Claim) error { c.Obligations = nil; return nil }); err != nil {
				t.Fatal(err)
			}
		}
		rawReq(t, http.MethodDelete, cx.ts.URL+"/api/cli/apps/bab/titogo/instances/acme.go.tito.io", cx.bearer, "")
	}
	if o, err := hostclaim.Read(context.Background(), cx.rel, "acme.go.tito.io"); err != nil || !(o.Absent || o.Claim.Free()) {
		t.Fatalf("the instance was not retired: op %+v holder %+v obligations %+v %v", o.Claim.Op, o.Claim.Holder, o.Claim.Obligations, err)
	}
	if n := moveLogRows(t, cx.st, "acme.go.tito.io", "mv_retired"); n != 0 {
		t.Fatalf("%d rows of the retired incarnation remain", n)
	}
	if n := moveLogRows(t, cx.st, "acme.go.tito.io", "mv_earlier"); n != 1 {
		t.Fatalf("another incarnation's rows: %d, want 1", n)
	}
}

// The app purge retires its instances' incarnations itself (RetirePurgeHosts,
// not this door), and records each in its journal; its last stage drops their
// rows. The fixture world cannot drive a purge of an app with instances to
// completion (its hosts' purge needs the boxes), so the stage is tested on a
// journal.
func TestPurgingAnAppPurgesItsInstancesMoveLogRows(t *testing.T) {
	fx := newConsoleFixture(t)
	j := hostops.PurgeJournal{Hosts: map[string]hostops.PurgeHost{
		"a.example.com": {Holder: &hostclaim.Holder{Incarnation: "inc-a"}},
		"b.example.com": {Holder: &hostclaim.Holder{Incarnation: "inc-b"}},
		"c.example.com": {},
	}}
	queueTestMoveLog(t, fx.st, "a.example.com", "mv_1", "done", "inc-a")
	queueTestMoveLog(t, fx.st, "b.example.com", "mv_2", "done", "inc-b")
	queueTestMoveLog(t, fx.st, "b.example.com", "mv_3", "done", "inc-b-earlier")
	queueTestMoveLog(t, fx.st, "d.example.com", "mv_4", "done", "inc-d")
	if err := fx.srv.purgeMoveLogOfPurgedHosts(j); err != nil {
		t.Fatal(err)
	}
	for _, c := range []struct {
		host, op string
		want     int
	}{{"a.example.com", "mv_1", 0}, {"b.example.com", "mv_2", 0}, {"b.example.com", "mv_3", 1}, {"d.example.com", "mv_4", 1}} {
		if n := moveLogRows(t, fx.st, c.host, c.op); n != c.want {
			t.Errorf("%s %s: %d rows, want %d", c.host, c.op, n, c.want)
		}
	}
}

// Final fix, ruling 2: the purge's own run (Resume) drops the rows of the
// incarnations its journal records, from a retired journal on. The world's
// app has no instance the fixture can purge (an instance's host purge needs
// the boxes), so the journal gains one, already retired, the moment it is
// "retired"; Resume then runs from there to done.
func TestPurgeResumeDropsItsHostsMoveLogRows(t *testing.T) {
	cx := newClaimCaseWith(t)
	cx.purgeWorld(t)
	cx.quiesce()
	queueTestMoveLog(t, cx.st, "gone.example.com", "mv_1", "done", "inc-gone")
	queueTestMoveLog(t, cx.st, "gone.example.com", "mv_2", "done", "inc-earlier")
	v := url.Values{"csrf": {cx.csrf}, "app": {"titogo"}, "confirm": {"titogo"}}
	if status, _, out := postGated(t, cx.consoleFixture, cx.browser, cx.ts.URL+"/a/bab/trash/delete", v); status != http.StatusAccepted {
		t.Fatalf("purge answered %d: %s", status, out)
	}
	a, err := hostops.ReadCanonicalAdmission(context.Background(), cx.rel, "bab", "titogo")
	if err != nil || a.Value.Op == nil {
		t.Fatalf("no accepted purge: %v", err)
	}
	op, appID := a.Value.Op.ID, a.Value.AppID
	cx.publishPurgeCensus(t, op)
	injected := false
	for i := 0; i < 12 && cx.ownsPurge(t, "bab", "titogo", op); i++ {
		if j, tag, err := hostops.ReadPurgeJournal(context.Background(), cx.rel, "bab", "titogo", op, appID); err == nil && j.Phase == "retired" && !injected {
			if j.Hosts == nil {
				j.Hosts = map[string]hostops.PurgeHost{}
			}
			j.Hosts["gone.example.com"] = hostops.PurgeHost{Holder: &hostclaim.Holder{Incarnation: "inc-gone"}, Retired: true}
			if _, err := cx.srv.cfg.ClaimAuthority.Control.SavePurgeJournal(context.Background(), j, tag); err != nil {
				t.Fatalf("record the retired host in the journal: %v", err)
			}
			injected = true
		}
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		if err := cx.srv.RunClaimRecoveryPass(ctx); err != nil {
			t.Logf("purge %s recovery pass %d: %v", op, i, err)
		}
		cancel()
	}
	if !injected {
		t.Fatal("the purge never stood at retired")
	}
	if cx.ownsPurge(t, "bab", "titogo", op) {
		t.Fatalf("purge %s did not finish", op)
	}
	if n := moveLogRows(t, cx.st, "gone.example.com", "mv_1"); n != 0 {
		t.Fatalf("%d rows of the purged incarnation remain", n)
	}
	if n := moveLogRows(t, cx.st, "gone.example.com", "mv_2"); n != 1 {
		t.Fatalf("another incarnation's rows: %d, want 1", n)
	}
}