package backup

import (
	"os"
	"path/filepath"
	"testing"

	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
)

// R-241 shape (c) — the recovery offer is driven by the comparison the box already makes.
//
// Scenarios C and D from the task, plus §7.2's two staleness cases. The point of shape (c) is that
// it asks the real question — *does the hub hold a package for a key other than the one I am
// using?* — rather than the two proxies that have each now been wrong in opposite directions.

// offerFixture builds a manager holding a repository password, with the hub's cached facts settable.
// Returns the local key's hash so a test can make the hub's hash match or differ deliberately.
func offerFixture(t *testing.T, hubHoldsPackage bool) (*Manager, *settings.Settings, string) {
	t.Helper()
	m, sett, pwPath := mintGuardManager(t, false) // mint freely first
	if err := sett.SetOffboxTarget(&settings.OffboxTarget{
		Enabled: true, Host: "nas.local", Port: 22, User: "felhom", RepoPath: "/srv/repo", Schedule: "daily",
	}); err != nil {
		t.Fatal(err)
	}
	if err := m.WriteOffboxSecrets("KEYMATERIAL", "nas.local ssh-ed25519 HOSTKEY"); err != nil {
		t.Fatal(err)
	}
	if _, err := os.Stat(pwPath); err != nil {
		t.Fatalf("fixture should hold a repository password: %v", err)
	}
	local, ok := m.OffboxRepoPasswordHash()
	if !ok {
		t.Fatal("fixture should be able to hash its own key")
	}
	if err := sett.SetHubEscrowIdentityPresent(hubHoldsPackage); err != nil {
		t.Fatal(err)
	}
	return m, sett, local
}

const otherKeyHash = "9b4a9a9dcec7898e7544f35b18470aac77c3d9064e5d3a302897617fa62edd65"

// ── SCENARIO C — a differing key offers recovery, whatever the reason for the difference ────────
//
// This is the venue's exact state on 2026-08-07: a key present, no orphan recorded, escrow stuck
// pending — and before shape (c), silence.
func TestR241_ScenarioC_DifferingKeyOffersRecovery(t *testing.T) {
	m, sett, local := offerFixture(t, true)
	if local == otherKeyHash {
		t.Fatal("fixture precondition: the local key must differ from the hub's")
	}
	if err := sett.SetHubEscrowKeySHA256(otherKeyHash, "2026-08-07T03:28:03Z"); err != nil {
		t.Fatal(err)
	}
	// Neither proxy fires: a key EXISTS (so not shape (a)) and nothing is orphaned (so not shape (b)).
	if _, ok := m.OffboxRepoPasswordHash(); !ok {
		t.Fatal("precondition: shape (a) must be false")
	}
	if m.OffboxOrphaned() {
		t.Fatal("precondition: shape (b) must be false")
	}
	if !m.OffsiteRecoveryOffer() {
		t.Fatal("R-241: the hub holds a package for a DIFFERENT key and the screen was not offered — this is the defect")
	}
}

// ── SCENARIO D — a healthy box is never offered recovery ────────────────────────────────────────
//
// RED-PROOF: drop the `hubHash != localHash` conjunct in shape (c) (make it `hubHash != ""`). A
// healthy box is then offered recovery forever, and this test fails — which is how a screen stops
// being read.
func TestR241_ScenarioD_MatchingKeyOffersNothing(t *testing.T) {
	m, sett, local := offerFixture(t, true)
	if err := sett.SetHubEscrowKeySHA256(local, "2026-08-07T09:00:00Z"); err != nil {
		t.Fatal(err)
	}
	if m.OffsiteRecoveryOffer() {
		t.Fatal("a box whose key the hub's package covers must never be offered recovery")
	}
}

// A box the hub holds nothing for is never offered, even if a stale hash lingers in settings. Fact 1
// stays required — the spike's comment block calls dropping it "the plausible wrong fix".
func TestR241_ShapeC_NeverHadOffsiteIsStillSilent(t *testing.T) {
	m, sett, _ := offerFixture(t, false) // the hub holds NOTHING
	if err := sett.SetHubEscrowKeySHA256(otherKeyHash, "2026-08-07T09:00:00Z"); err != nil {
		t.Fatal(err)
	}
	if m.OffsiteRecoveryOffer() {
		t.Fatal("a box that never had off-site backups must never be greeted by a recovery screen")
	}
}

// ── §7.2 — the staleness decision, both halves ──────────────────────────────────────────────────

// A KNOWN DIFFERENCE OFFERS, however old the reading. Age is deliberately not gated on: gating would
// make a box offline from the hub silently stop offering, which is the failure this session exists
// to remove.
func TestR241_StaleComparison_KnownDifferenceStillOffers(t *testing.T) {
	m, sett, _ := offerFixture(t, true)
	if err := sett.SetHubEscrowKeySHA256(otherKeyHash, "2020-01-01T00:00:00Z"); err != nil { // ancient
		t.Fatal(err)
	}
	if !m.OffsiteRecoveryOffer() {
		t.Fatal("a known difference must offer regardless of how old the reading is (§7.2)")
	}
}

// AN ABSENT HASH FALLS BACK TO (a)/(b) — it does not offer. "" is the hub positively saying its
// package seals no repository password (legacy hash-less escrow); there is nothing to compare, and
// offering would put a permanent screen in front of every legacy box.
func TestR241_StaleComparison_AbsentHashFallsBackAndDoesNotOffer(t *testing.T) {
	m, sett, _ := offerFixture(t, true)
	if err := sett.SetHubEscrowKeySHA256("", ""); err != nil {
		t.Fatal(err)
	}
	if m.OffsiteRecoveryOffer() {
		t.Fatal("a hash never learned must fall back to (a)/(b), not offer (§7.2)")
	}
	// ...and the fallback still works: mark the repo orphaned and shape (b) fires as before.
	if err := m.settings.UpdateOffboxStatus(func(o *settings.OffboxTarget) { o.RepoState = "orphaned" }); err != nil {
		t.Fatal(err)
	}
	if !m.OffsiteRecoveryOffer() {
		t.Fatal("shape (b) must still work when the hub's hash was never learned")
	}
}

// Shape (a) is untouched: a box with no key at all is still offered, which is the pristine rebuild.
func TestR241_ShapeAStillWorks(t *testing.T) {
	m, sett, _ := offerFixture(t, true)
	if err := os.Remove(filepath.Join(m.cfg.Paths.DataDir, "offbox", "repo_password")); err != nil {
		t.Fatal(err)
	}
	if err := sett.SetHubEscrowKeySHA256(otherKeyHash, "2026-08-07T09:00:00Z"); err != nil {
		t.Fatal(err)
	}
	if !m.OffsiteRecoveryOffer() {
		t.Fatal("shape (a) — no repository password at all — must still offer")
	}
}