package monitor

import (
	"encoding/json"
	"io"
	"log"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"gitea.dooplex.hu/admin/felhom-hub/internal/store"
)

// R-85 Part 2 — the restore-test result must be HEARD.
//
// Before this, a failed restore-test was a `[WARN]` line in the ingest handler and nothing else —
// no event, no notification, no gauge. That was true for the LOCAL tier that was already being
// tested, which means the loudest DR signal this system produces was in practice inaudible.

type capturedEvent struct {
	customerID, eventType, severity, message string
}

func rtStore(t *testing.T) *store.Store {
	t.Helper()
	st, err := store.New(filepath.Join(t.TempDir(), "rt.db"), log.New(io.Discard, "", 0))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { st.Close() })
	if err := st.SaveCustomerConfig(&store.CustomerConfig{CustomerID: "c1", APIKey: "k", RetrievalPassword: "p"}); err != nil {
		t.Fatal(err)
	}
	if err := st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "k1"}); err != nil {
		t.Fatal(err)
	}
	return st
}

// rtReport builds a host-report carrying storage targets and zero or one restore-test.
func rtReport(t *testing.T, tier string, pass bool, testedAt time.Time, errMsg string) string {
	t.Helper()
	type rt struct {
		SourceArchive string `json:"source_archive"`
		SourceTier    string `json:"source_tier"`
		Pass          bool   `json:"pass"`
		Error         string `json:"error,omitempty"`
		TestedAt      string `json:"tested_at"`
	}
	type stg struct {
		Name    string `json:"name"`
		Type    string `json:"type"`
		Content string `json:"content"`
	}
	payload := struct {
		RestoreTests   []rt  `json:"restore_tests"`
		StorageTargets []stg `json:"storage_targets"`
	}{
		StorageTargets: []stg{
			{Name: "local", Type: "local", Content: "backup,iso"},
			{Name: "felhom-pbs", Type: "pbs", Content: "backup"},
		},
	}
	if tier != "" {
		payload.RestoreTests = []rt{{
			SourceArchive: tier + ":backup/ct/9201/x", SourceTier: tier,
			Pass: pass, Error: errMsg, TestedAt: testedAt.UTC().Format(time.RFC3339),
		}}
	}
	b, err := json.Marshal(payload)
	if err != nil {
		t.Fatal(err)
	}
	return string(b)
}

func rtChecker(st *store.Store, got *[]capturedEvent, logTo io.Writer) *RestoreTestChecker {
	if logTo == nil {
		logTo = io.Discard
	}
	return NewRestoreTestChecker(st, func(cid, et, sev, msg, _, _ string) {
		*got = append(*got, capturedEvent{cid, et, sev, msg})
	}, log.New(logTo, "", 0))
}

// ── SCENARIO B — a failed restore-test is HEARD ──────────────────────────────────────────────
//
// The assertion is that a NOTIFICATION IS EMITTED, not that a handler ran. The hollow version of
// this test checks for a log line, which passes against exactly the code this task replaces.
//
// COMPANION RED-PROOF (observed): make checkFailure `return` before emit (the pre-R-85 shape — log
// and stop) and this fails with "a FAILED restore-test must EMIT an operator event; got 0 event(s)".
// Restored.
func TestRestoreTest_FailureEmitsAnOperatorEvent(t *testing.T) {
	st := rtStore(t)
	now := time.Now().UTC()
	if err := st.SaveHostReport("h1", "c1",
		[]byte(rtReport(t, "pbs", false, now, "restore task: context deadline exceeded")),
		store.HostReportDenorm{}); err != nil {
		t.Fatal(err)
	}
	var got []capturedEvent
	rtChecker(st, &got, nil).Check()

	var fail *capturedEvent
	for i := range got {
		if got[i].eventType == EventRestoreTestFailed {
			fail = &got[i]
		}
	}
	if fail == nil {
		t.Fatalf("a FAILED restore-test must EMIT an operator event; got %d event(s): %+v", len(got), got)
	}
	if fail.severity != "error" {
		t.Fatalf("a failed restore-test is an error, got severity %q", fail.severity)
	}
	if !strings.Contains(fail.message, "pbs") {
		t.Fatalf("the TIER must be named — 'a restore-test failed' without saying which tier is not actionable; got %q", fail.message)
	}
}

// Edge-triggered: a permanently failing tier must not emit on every sweep.
func TestRestoreTest_FailureDoesNotSpam(t *testing.T) {
	st := rtStore(t)
	now := time.Now().UTC()
	st.SaveHostReport("h1", "c1", []byte(rtReport(t, "pbs", false, now, "boom")), store.HostReportDenorm{})
	var got []capturedEvent
	c := rtChecker(st, &got, nil)
	c.Check()
	c.Check()
	c.Check()
	n := 0
	for _, e := range got {
		if e.eventType == EventRestoreTestFailed {
			n++
		}
	}
	if n != 1 {
		t.Fatalf("a persistently failing tier must report ONCE per failing run, got %d", n)
	}
}

// A PASS must not emit a failure event.
func TestRestoreTest_PassEmitsNoFailure(t *testing.T) {
	st := rtStore(t)
	now := time.Now().UTC()
	st.SaveHostReport("h1", "c1", []byte(rtReport(t, "pbs", true, now, "")), store.HostReportDenorm{})
	var got []capturedEvent
	rtChecker(st, &got, nil).Check()
	for _, e := range got {
		if e.eventType == EventRestoreTestFailed {
			t.Fatalf("a PASSING restore-test must not emit a failure; got %+v", e)
		}
	}
}

// ── SCENARIO D — a newborn box does not alarm  (the R-81 lesson) ─────────────────────────────
//
// COMPANION RED-PROOF (observed): remove the anchor branch from assessRestoreProven (treat "never
// proven" as MISSED outright) and this fails with "a newborn box must NOT alarm; got
// restore_test_stale ...". That is the fourth instance of no-signal-as-bad-signal, and it would
// have been written by the same hand that just fixed the third.
func TestRestoreTest_NewbornDoesNotAlarm(t *testing.T) {
	st := rtStore(t)
	now := time.Now().UTC()
	// A report with NO restore-test at all, and first contact one hour ago.
	st.SaveHostReport("h1", "c1", []byte(rtReport(t, "", false, now, "")), store.HostReportDenorm{})

	var got []capturedEvent
	var logbuf strings.Builder
	rtChecker(st, &got, &logbuf).Check()

	for _, e := range got {
		if e.eventType == EventRestoreTestStale {
			t.Fatalf("a newborn box must NOT alarm; got %s: %s", e.eventType, e.message)
		}
	}
	// ...but the deferral must be VISIBLE, or quiet is indistinguishable from not-checked.
	if !strings.Contains(logbuf.String(), "not restore-proven yet") {
		t.Fatalf("the deferred verdict must be logged; log:\n%s", logbuf.String())
	}
}

// The boundary, pinned by name so a refactor has to delete an obviously-named contract.
func TestRestoreTest_Contract_UnprovenIsUnknownUntilTheAnchorElapses(t *testing.T) {
	now := time.Date(2026, 7, 26, 12, 0, 0, 0, time.UTC)
	cases := []struct {
		name       string
		watched    time.Duration
		wantMissed bool
	}{
		{"newborn, 1h", time.Hour, false},
		{"just inside", restoreProvenStaleAfter - time.Minute, false},
		{"exactly at the limit", restoreProvenStaleAfter, false},
		{"just outside", restoreProvenStaleAfter + time.Minute, true},
		{"long past", 30 * 24 * time.Hour, true},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			got := assessRestoreProven("pbs", time.Time{}, now.Add(-c.watched), now)
			if got.missed() != c.wantMissed {
				t.Fatalf("CONTRACT VIOLATED: unproven for %s (limit %s) → missed=%v, want %v (reason %q)",
					c.watched, restoreProvenStaleAfter, got.missed(), c.wantMissed, got.reason)
			}
			if !c.wantMissed && got.verdict != verdictUnknown {
				t.Fatalf("a deferred tier must be UNKNOWN (visible), not OK; got verdict=%d", got.verdict)
			}
		})
	}
}

// ── SCENARIO C — an unproven tier becomes visible, and is DISTINCT from a failure ────────────

func TestRestoreTest_StaleIsSeparateFromFailure(t *testing.T) {
	now := time.Date(2026, 7, 26, 12, 0, 0, 0, time.UTC)

	stale := assessRestoreProven("pbs", now.Add(-9*24*time.Hour), now.Add(-60*24*time.Hour), now)
	if !stale.missed() {
		t.Fatalf("a tier last proven 9 days ago (limit %s) must be stale; got %q", restoreProvenStaleAfter, stale.reason)
	}
	// The wording must not read as "broken" — that is the other signal.
	if !strings.Contains(stale.reason, "unverified, not known-broken") {
		t.Fatalf("staleness must say UNVERIFIED, not broken — merging the two is the thing this avoids; got %q", stale.reason)
	}
	fresh := assessRestoreProven("pbs", now.Add(-2*24*time.Hour), now.Add(-60*24*time.Hour), now)
	if fresh.verdict != verdictOK {
		t.Fatalf("a tier proven 2 days ago is fine; got verdict=%d reason=%q", fresh.verdict, fresh.reason)
	}
}

// The two signals must be DIFFERENT event types — merging them would collapse "your DR is broken"
// into "your DR is unverified", and the second is the one that quietly becomes the first.
func TestRestoreTest_EventTypesAreDistinct(t *testing.T) {
	if EventRestoreTestFailed == EventRestoreTestStale {
		t.Fatal("failure and staleness must be distinct event types")
	}
}

// A tier the box does not HAVE is never reported stale — the Slice-C gate, for the same reason:
// without it, absence-is-not-failure would be re-introduced one level down.
func TestRestoreTest_TierNotPresentIsNeverStale(t *testing.T) {
	var hr hostReportRestoreTests
	if err := json.Unmarshal([]byte(`{"storage_targets":[{"name":"local","type":"local","content":"backup"}]}`), &hr); err != nil {
		t.Fatal(err)
	}
	tiers := expectedRestoreTiers(hr)
	for _, tr := range tiers {
		if tr == "pbs" {
			t.Fatalf("a box with no PBS storage must not expect a pbs tier; got %v", tiers)
		}
	}
	if len(tiers) != 1 || tiers[0] != "local" {
		t.Fatalf("want just the local tier; got %v", tiers)
	}
}

// The window scan recovers per-tier proof even though each report carries only the LATEST run.
func TestRestoreTest_LastProvenPerTierAcrossTheWindow(t *testing.T) {
	now := time.Now().UTC()
	rows := []store.HostReportRow{
		{ReceivedAt: now.Add(-1 * time.Hour), ReportJSON: rtReportRaw("pbs", true, now.Add(-2*time.Hour))},
		{ReceivedAt: now.Add(-3 * time.Hour), ReportJSON: rtReportRaw("local", true, now.Add(-4*time.Hour))},
		{ReceivedAt: now.Add(-5 * time.Hour), ReportJSON: `{{{malformed`},
	}
	got := lastProvenPerTier(rows)
	if _, ok := got["pbs"]; !ok {
		t.Fatalf("the pbs tier's proof must be recovered from the window; got %v", got)
	}
	if _, ok := got["local"]; !ok {
		t.Fatalf("the local tier's proof must be recovered even though a LATER report shows only pbs; got %v", got)
	}
}

func rtReportRaw(tier string, pass bool, at time.Time) string {
	return `{"restore_tests":[{"source_archive":"` + tier + `:x","source_tier":"` + tier +
		`","pass":` + boolStr(pass) + `,"tested_at":"` + at.UTC().Format(time.RFC3339) + `"}]}`
}

func boolStr(b bool) string {
	if b {
		return "true"
	}
	return "false"
}