package monitor

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

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

// R-195 — a customer with NO machine EVER bound must not alarm; a customer WITH one must.
//
// Origin, measured on the live hub 2026-08-04: `david` is a prospective customer whose record was
// created 2026-08-01 16:51:49 with no host ever bound (hosts=0, host_deletions=0, host_reports=0,
// reports=0). It e-mailed an `expected_dbdump_missed` ERROR at 03:00 UTC on 08-02, 08-03 and 08-04.
//
// The mechanism, established at source: the down-skip in CheckBackupDeadlines reads
// StalenessChecker.GetState(), whose map is seeded from store.GetCustomers() — a query over the
// `reports` table. A customer with zero reports is in no row, so it has no state, and GetState()
// returns "" rather than "down". The skip that protects every other silent customer misses the one
// that never reported at all.
//
// These tests pin BOTH halves. A suite that only proved the silence would pass against an
// implementation that never alarms, which is strictly worse than the defect it replaces.

// newUnboundStore creates a store holding ONE active customer and NO host row at all.
func newUnboundStore(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)
	}
	return st
}

// ── Half 1: the silence ────────────────────────────────────────────────────────────────────────

// TestCheckBackupDeadlines_NeverBoundHost_Silent is the david case.
//
// COMPANION RED-PROOF (observed): deleting the HasEverBoundHost guard from CheckBackupDeadlines
// makes this test fail with
//
//	deadline_unbound_test.go: a customer with NO host ever bound must raise NOTHING;
//	got [expected_dbdump_missed]
//
// which is verbatim the event `david` e-mailed three mornings running. Restored after.
func TestCheckBackupDeadlines_NeverBoundHost_Silent(t *testing.T) {
	st := newUnboundStore(t)
	// No UpsertHost, no host-report, no db_dump_completed event — nothing has ever been expected.
	got := runDeadline(t, st)
	if len(got) != 0 {
		t.Fatalf("a customer with NO host ever bound must raise NOTHING; got %v", got)
	}
}

// TestHasEverBoundHost pins the predicate itself across its three inputs, because the whole
// behaviour above turns on it and a predicate that answered `false` for everything would make the
// test above pass while silencing the entire fleet.
func TestHasEverBoundHost(t *testing.T) {
	st := newUnboundStore(t)

	if bound, err := st.HasEverBoundHost("c1"); err != nil || bound {
		t.Fatalf("no host rows → want (false,nil); got (%v,%v)", bound, err)
	}

	if err := st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "k1"}); err != nil {
		t.Fatalf("UpsertHost: %v", err)
	}
	if bound, err := st.HasEverBoundHost("c1"); err != nil || !bound {
		t.Fatalf("live host row → want (true,nil); got (%v,%v)", bound, err)
	}

	// An unknown customer is never bound — the predicate must not answer from another customer's rows.
	if bound, err := st.HasEverBoundHost("nobody"); err != nil || bound {
		t.Fatalf("unknown customer → want (false,nil); got (%v,%v)", bound, err)
	}
}

// ── Half 2: THE RED-PROOF THAT MATTERS — a bound machine must still alarm ───────────────────────

// TestCheckBackupDeadlines_BoundButNeverReported_StillAlarms is the case the change could break,
// and it is a real shape: a machine that was installed and bound and never phoned home. It has a
// `hosts` row and zero reports — indistinguishable from `david` on every signal EXCEPT the one the
// guard discriminates on. If the guard is ever "simplified" to key off report presence, customer
// age or a name pattern, this test goes red.
func TestCheckBackupDeadlines_BoundButNeverReported_StillAlarms(t *testing.T) {
	st := newUnboundStore(t)
	if err := st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "k1"}); err != nil {
		t.Fatalf("UpsertHost: %v", err)
	}
	// No host-report and no db_dump_completed — the box was bound and never said anything.
	got := runDeadline(t, st)
	if !has(got, "expected_dbdump_missed") {
		t.Fatalf("a BOUND machine that never reported is a real fault and must still alarm; got %v", got)
	}
}

// TestCheckBackupDeadlines_BoundThenWentQuiet_StillAlarms: the machine reported once, days ago,
// and stopped. Nothing about the guard may suppress that.
//
// The staleness checker's down-skip is nil here (runDeadline passes nil), which is deliberate: it
// isolates THIS guard. In production a genuinely down node is skipped by staleness and gets its own
// node_down event — that path is unchanged and is not what this test is about.
func TestCheckBackupDeadlines_BoundThenWentQuiet_StillAlarms(t *testing.T) {
	st := newUnboundStore(t)
	if err := st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "k1"}); err != nil {
		t.Fatalf("UpsertHost: %v", err)
	}
	// One host-report whose newest backup evidence is 9 days old, and a db dump that last
	// completed 5 days ago (i.e. not since midnight).
	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.Fatalf("SaveHostReport: %v", err)
	}
	got := runDeadline(t, st)
	if !has(got, "expected_backup_missed") {
		t.Fatalf("a bound machine that went quiet with stale backups must still raise expected_backup_missed; got %v", got)
	}
	if !has(got, "expected_dbdump_missed") {
		t.Fatalf("a bound machine that went quiet must still raise expected_dbdump_missed; got %v", got)
	}
}

// TestCheckBackupDeadlines_DeletedHost_StillJudged: the host row is gone but a tombstone remains
// (peti-felhom's live shape). The customer HAD a machine, so this check must not take over the
// judgement — it hands off to the staleness down-skip exactly as before the change.
func TestCheckBackupDeadlines_DeletedHost_StillJudged(t *testing.T) {
	st := newUnboundStore(t)
	if err := st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "k1"}); err != nil {
		t.Fatalf("UpsertHost: %v", err)
	}
	if err := st.DeleteHost("h1", false); err != nil {
		t.Fatalf("DeleteHost: %v", err)
	}
	if bound, err := st.HasEverBoundHost("c1"); err != nil || !bound {
		t.Fatalf("a DELETED host is still a machine that was once bound → want (true,nil); got (%v,%v)", bound, err)
	}
	got := runDeadline(t, st)
	if !has(got, "expected_dbdump_missed") {
		t.Fatalf("a customer whose host was deleted was still bound and stays judged here; got %v", got)
	}
}