package monitor

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

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

// newDeadlineStore creates an isolated store with one active customer + a host row.
func newDeadlineStore(t *testing.T) *store.Store {
	t.Helper()
	st, err := store.New(filepath.Join(t.TempDir(), "test.db"), log.New(io.Discard, "", 0))
	if err != nil {
		t.Fatalf("store.New: %v", err)
	}
	t.Cleanup(func() { st.Close() })
	if err := st.SaveCustomerConfig(&store.CustomerConfig{CustomerID: "c1", APIKey: "ck", RetrievalPassword: "p"}); err != nil {
		t.Fatalf("SaveCustomerConfig: %v", err)
	}
	if err := st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "k1"}); err != nil {
		t.Fatalf("UpsertHost: %v", err)
	}
	return st
}

// hostReportJSON builds a host-report payload with the given PBS snapshots and vzdump
// backups. Each snapshot is {backup_time, verify_state}; each backup is {started_at, success}.
func hostReportJSON(t *testing.T, pbs [][2]string, backups []struct {
	at string
	ok bool
}) string {
	t.Helper()
	type snap struct {
		BackupTime  string `json:"backup_time"`
		VerifyState string `json:"verify_state"`
	}
	type bk struct {
		StartedAt string `json:"started_at"`
		Success   bool   `json:"success"`
	}
	payload := struct {
		HostID       string `json:"host_id"`
		PBSSnapshots []snap `json:"pbs_snapshots"`
		Backups      []bk   `json:"backups"`
	}{HostID: "h1"}
	for _, p := range pbs {
		payload.PBSSnapshots = append(payload.PBSSnapshots, snap{BackupTime: p[0], VerifyState: p[1]})
	}
	for _, b := range backups {
		payload.Backups = append(payload.Backups, bk{StartedAt: b.at, Success: b.ok})
	}
	out, err := json.Marshal(payload)
	if err != nil {
		t.Fatalf("marshal report: %v", err)
	}
	return string(out)
}

// runDeadline runs CheckBackupDeadlines and returns the list of emitted event types for c1.
func runDeadline(t *testing.T, st *store.Store) []string {
	t.Helper()
	var got []string
	onEvent := func(customerID, eventType, severity, message, detailsJSON, source string) {
		if customerID == "c1" {
			got = append(got, eventType)
		}
	}
	// nil staleness → no "down" skip; the check evaluates c1.
	CheckBackupDeadlines(st, nil, onEvent, log.New(io.Discard, "", 0))
	return got
}

func has(events []string, t string) bool {
	for _, e := range events {
		if e == t {
			return true
		}
	}
	return false
}

func rfc(d time.Duration) string {
	return time.Now().UTC().Add(d).Format(time.RFC3339)
}

// TestCheckBackupDeadlines_FreshVerifiedPBS_NoBackupAlarm is the COMPANION test.
// It FAILS against the pre-fix (event-based) check: with a fresh, verified PBS snapshot
// but no backup_completed event, the old code emitted expected_backup_missed anyway.
// The repoint reads the host-report instead, so a healthy customer raises no alarm.
func TestCheckBackupDeadlines_FreshVerifiedPBS_NoBackupAlarm(t *testing.T) {
	st := newDeadlineStore(t)
	// Make the db-dump half pass too, so the only thing under test is the backup half.
	if _, err := st.SaveEvent("c1", "db_dump_completed", "info", "", "{}", "controller"); err != nil {
		t.Fatal(err)
	}
	report := hostReportJSON(t, [][2]string{{rfc(-3 * time.Hour), "ok"}}, nil)
	if err := st.SaveHostReport("h1", "c1", []byte(report), store.HostReportDenorm{}); err != nil {
		t.Fatal(err)
	}

	got := runDeadline(t, st)
	if has(got, "expected_backup_missed") {
		t.Fatalf("fresh+verified PBS must NOT raise expected_backup_missed; got %v", got)
	}
	if has(got, "expected_dbdump_missed") {
		t.Fatalf("db_dump_completed present → no dbdump alarm expected; got %v", got)
	}
}

// TestCheckBackupDeadlines_StalePBS_Alarms: an offsite snapshot past the OFFSITE limit → alarm.
//
// R-82 Slice C changed the threshold this fixture must cross, NOT the behaviour it asserts. 30h was
// "stale" while one 26h limit covered every tier; under a weekly offsite tier a 30h snapshot is
// healthy, and alarming on it is exactly the cry-wolf `backupStaleAfter`'s comment predicted. The
// test still proves a stale offsite tier alarms — now at 9 days, past the 8-day offsite limit.
func TestCheckBackupDeadlines_StalePBS_Alarms(t *testing.T) {
	st := newDeadlineStore(t)
	st.SaveEvent("c1", "db_dump_completed", "info", "", "{}", "controller")
	report := hostReportJSON(t, [][2]string{{rfc(-9 * 24 * time.Hour), "ok"}}, nil)
	if err := st.SaveHostReport("h1", "c1", []byte(report), store.HostReportDenorm{}); err != nil {
		t.Fatal(err)
	}
	got := runDeadline(t, st)
	if !has(got, "expected_backup_missed") {
		t.Fatalf("stale (>26h) PBS snapshot must raise expected_backup_missed; got %v", got)
	}
}

// TestCheckBackupDeadlines_FailedVerify_Alarms: fresh snapshot but verify failed → alarm.
func TestCheckBackupDeadlines_FailedVerify_Alarms(t *testing.T) {
	st := newDeadlineStore(t)
	st.SaveEvent("c1", "db_dump_completed", "info", "", "{}", "controller")
	report := hostReportJSON(t, [][2]string{{rfc(-2 * time.Hour), "failed"}}, nil)
	if err := st.SaveHostReport("h1", "c1", []byte(report), store.HostReportDenorm{}); err != nil {
		t.Fatal(err)
	}
	got := runDeadline(t, st)
	if !has(got, "expected_backup_missed") {
		t.Fatalf("failed PBS verify must raise expected_backup_missed; got %v", got)
	}
}

// TestCheckBackupDeadlines_NoHostReport_NoBackupAlarm: a customer with no host-report
// (legacy/defunct controller-only) must NOT get a backup alarm from this check —
// liveness is the staleness checker's job.
func TestCheckBackupDeadlines_NoHostReport_NoBackupAlarm(t *testing.T) {
	st := newDeadlineStore(t)
	st.SaveEvent("c1", "db_dump_completed", "info", "", "{}", "controller")
	// No SaveHostReport call.
	got := runDeadline(t, st)
	if has(got, "expected_backup_missed") {
		t.Fatalf("no host-report → no backup alarm; got %v", got)
	}
}

// TestCheckBackupDeadlines_DbDumpHalfPreserved: fresh backup (no backup alarm) but a
// missing db_dump_completed event must still raise expected_dbdump_missed.
func TestCheckBackupDeadlines_DbDumpHalfPreserved(t *testing.T) {
	st := newDeadlineStore(t)
	report := hostReportJSON(t, [][2]string{{rfc(-2 * time.Hour), "ok"}}, nil)
	if err := st.SaveHostReport("h1", "c1", []byte(report), store.HostReportDenorm{}); err != nil {
		t.Fatal(err)
	}
	got := runDeadline(t, st)
	if has(got, "expected_backup_missed") {
		t.Fatalf("fresh backup → no backup alarm; got %v", got)
	}
	if !has(got, "expected_dbdump_missed") {
		t.Fatalf("missing db_dump_completed must still raise expected_dbdump_missed; got %v", got)
	}
}

// TestAssessBackupFreshness exercises the pure freshness policy directly.
//
// R-81: every case here passes a ZERO backupEvidence — no hub-history evidence and no
// first-contact anchor. That is deliberate: it pins the latest-report-only behaviour
// unchanged, and the "no snapshots and no backups" row exercises the UNANCHORED absence
// branch (zero anchor → fail toward visibility, the v0.73.0 legacy-shape precedent).
// The anchored branches have their own named tests below.
func TestAssessBackupFreshness(t *testing.T) {
	now := time.Date(2026, 6, 16, 3, 0, 0, 0, time.UTC)
	at := func(d time.Duration) string { return now.Add(d).Format(time.RFC3339) }

	cases := []struct {
		name       string
		report     string
		wantMissed bool
	}{
		{"fresh verified PBS", `{"pbs_snapshots":[{"backup_time":"` + at(-3*time.Hour) + `","verify_state":"ok"}]}`, false},
		{"fresh unverified (none) is not a failure", `{"pbs_snapshots":[{"backup_time":"` + at(-3*time.Hour) + `","verify_state":"none"}]}`, false},
		// Slice C: a 30h offsite snapshot is HEALTHY under the weekly (8d) offsite limit.
		{"offsite 30h is fresh under the weekly limit", `{"pbs_snapshots":[{"backup_time":"` + at(-30*time.Hour) + `","verify_state":"ok"}]}`, false},
		{"offsite 6d is fresh under the weekly limit", `{"pbs_snapshots":[{"backup_time":"` + at(-6*24*time.Hour) + `","verify_state":"ok"}]}`, false},
		{"offsite 9d is STALE past the weekly limit", `{"pbs_snapshots":[{"backup_time":"` + at(-9*24*time.Hour) + `","verify_state":"ok"}]}`, true},
		{"fresh but verify failed", `{"pbs_snapshots":[{"backup_time":"` + at(-2*time.Hour) + `","verify_state":"failed"}]}`, true},
		{"no snapshots and no backups", `{"pbs_snapshots":[],"backups":[]}`, true},
		{"host vzdump fresh success", `{"backups":[{"target_id":"local","started_at":"` + at(-4*time.Hour) + `","success":true}]}`, false},
		{"host vzdump only, failed → counts as none", `{"backups":[{"target_id":"local","started_at":"` + at(-4*time.Hour) + `","success":false}]}`, true},
		{"host fresh + offsite within weekly → both healthy", `{"pbs_snapshots":[{"backup_time":"` + at(-40*time.Hour) + `","verify_state":"ok"}],"backups":[{"target_id":"local","started_at":"` + at(-2*time.Hour) + `","success":true}]}`, false},
		// Slice C's core: the tiers are judged SEPARATELY. A fresh host backup must NOT rescue an
		// offsite tier that is genuinely past its own (weekly) limit — the merged threshold did.
		{"host fresh does NOT rescue a 9d offsite tier", `{"pbs_snapshots":[{"backup_time":"` + at(-9*24*time.Hour) + `","verify_state":"ok"}],"backups":[{"target_id":"local","started_at":"` + at(-2*time.Hour) + `","success":true}]}`, true},
		{"offsite fresh does NOT rescue a 30h host tier", `{"pbs_snapshots":[{"backup_time":"` + at(-2*time.Hour) + `","verify_state":"ok"}],"backups":[{"target_id":"local","started_at":"` + at(-30*time.Hour) + `","success":true}]}`, true},
		{"unparseable report", `not json`, true},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			got := assessBackupFreshness(c.report, backupEvidence{}, now)
			if got.missed() != c.wantMissed {
				t.Fatalf("missed=%v want=%v (reason=%q)", got.missed(), c.wantMissed, got.reason)
			}
		})
	}
}