package escrow

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// R-199 links 6→8, with REAL crypto (age is present on the build/demo host; ensureAge skips
// elsewhere). These are the unit half of the session's question — "is the repository password
// actually recoverable from the sealed bundle" — and the live half is the same equality on hardware.

const testR = "correct horse battery staple sedative anaconda wobbly kingdom placard yodel"

func sealBundle(t *testing.T, b IdentityBundle, r string) []byte {
	t.Helper()
	blob, err := WrapIdentityBundle(context.Background(), b, r)
	if err != nil {
		t.Fatalf("WrapIdentityBundle: %v", err)
	}
	return blob
}

func fetcherFor(blob []byte) BlobFetcher {
	return func(context.Context) ([]byte, bool, error) { return blob, true, nil }
}

// Scenario A (unit) — the recovered repository password is BYTE-IDENTICAL to the sealed one, and it
// is the REPOSITORY password rather than some other field of a bundle that also parses.
//
// RED-PROOF: return bundle.PBSToken (or TunnelToken, or WGPrivateKey) instead of
// bundle.ResticRepoPassword → a plausible-looking bundle yields a non-matching key → this FAILS.
// That mutation is the shape of the bug that would otherwise ship silently, because every one of
// those fields is a non-empty string that looks like a secret.
func TestRecoverOffsiteRepoPassword_ReturnsTheRepositoryPassword(t *testing.T) {
	ensureAge(t)
	const repoPW = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
	blob := sealBundle(t, IdentityBundle{
		TunnelToken:        "TUNNEL-TOKEN-NOT-THE-ANSWER",
		PBSToken:           "PBS-TOKEN-NOT-THE-ANSWER",
		WGPrivateKey:       "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=",
		ResticRepoPassword: repoPW,
	}, testR)

	got, err := (OffsiteKeyRecoverer{Fetch: fetcherFor(blob)}).RecoverOffsiteRepoPassword(context.Background(), testR)
	if err != nil {
		t.Fatalf("recover: %v", err)
	}
	if got != repoPW {
		t.Fatalf("the recovered key is not the sealed repository password (len %d vs %d) — a different "+
			"field of the bundle was returned", len(got), len(repoPW))
	}
	// Belt: it must not be any of the OTHER fields, so a future refactor cannot satisfy the check
	// above by coincidence.
	for _, other := range []string{"TUNNEL-TOKEN-NOT-THE-ANSWER", "PBS-TOKEN-NOT-THE-ANSWER", "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="} {
		if got == other {
			t.Fatalf("the recoverer returned the wrong bundle field")
		}
	}
}

// Scenario B — a WRONG recovery code fails closed, the failure names no secret, and nothing is
// written. The fail-closed property is the crypto's (age's scrypt KDF), which is why there is no
// validation step here to get wrong — the test pins that it stays that way.
func TestRecoverOffsiteRepoPassword_WrongCodeFailsClosed(t *testing.T) {
	ensureAge(t)
	const repoPW = "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
	blob := sealBundle(t, IdentityBundle{TunnelToken: "t", PBSToken: "p", ResticRepoPassword: repoPW}, testR)

	got, err := (OffsiteKeyRecoverer{Fetch: fetcherFor(blob)}).RecoverOffsiteRepoPassword(context.Background(), "not the recovery code at all")
	if err == nil {
		t.Fatal("a wrong recovery code MUST fail — a plausible-but-wrong bundle is the one outcome the design forbids")
	}
	if got != "" {
		t.Fatalf("a failed unseal returned %d bytes — there must be no partial result", len(got))
	}
	// The error may name the step; it may never name a secret.
	for _, secret := range []string{repoPW, testR, "not the recovery code at all"} {
		if strings.Contains(err.Error(), secret) {
			t.Fatalf("the failure message leaked a secret: %v", err)
		}
	}
}

// A bundle with no repository password is its OWN answer, not a wrong-code error. Sealed before
// fork-4 (agent < v0.77.0) the field did not exist; sending the operator to re-check a correctly
// typed recovery code would be the wrong instruction.
func TestRecoverOffsiteRepoPassword_PreForkFourBundle(t *testing.T) {
	ensureAge(t)
	blob := sealBundle(t, IdentityBundle{TunnelToken: "t", PBSToken: "p"}, testR)

	_, err := (OffsiteKeyRecoverer{Fetch: fetcherFor(blob)}).RecoverOffsiteRepoPassword(context.Background(), testR)
	if !errors.Is(err, ErrNoResticPassword) {
		t.Fatalf("a pre-fork-4 bundle must report its own error, got %v", err)
	}
}

// Scenario D at this layer — no blob is a clean, distinguishable answer.
func TestRecoverOffsiteRepoPassword_NoBlob(t *testing.T) {
	rec := OffsiteKeyRecoverer{Fetch: func(context.Context) ([]byte, bool, error) { return nil, false, nil }}
	_, err := rec.RecoverOffsiteRepoPassword(context.Background(), testR)
	if !errors.Is(err, ErrNoEscrowBlob) {
		t.Fatalf("absent blob must yield ErrNoEscrowBlob, got %v", err)
	}
}

// Scenario F — R persists NOWHERE. TMPDIR is redirected into the test's own directory, the unseal is
// run for real, and the whole tree is then walked: no file may contain R (or the recovered password),
// and the staging directory the unseal creates must be gone.
//
// RED-PROOF: write R to a temp file anywhere in the flow (e.g. add
// `os.WriteFile(filepath.Join(work,"r"), []byte(recoveryCode), 0o600)` inside UnwrapIdentity before
// its defer removes the dir — or simply drop that defer and let the plaintext staging survive) → the
// walk finds it → this FAILS.
func TestRecoverOffsiteRepoPassword_RLeavesNoTrace(t *testing.T) {
	ensureAge(t)
	const repoPW = "1111111111111111111111111111111111111111111111111111111111111111"
	tmp := t.TempDir()
	t.Setenv("TMPDIR", tmp) // os.MkdirTemp honours this — every staging dir lands under the walk

	const wrongR = "wrong code entirely"
	blob := sealBundle(t, IdentityBundle{TunnelToken: "t", PBSToken: "p", ResticRepoPassword: repoPW}, testR)
	if _, err := (OffsiteKeyRecoverer{Fetch: fetcherFor(blob)}).RecoverOffsiteRepoPassword(context.Background(), testR); err != nil {
		t.Fatalf("recover: %v", err)
	}
	// A failed unseal must leave nothing either — exercise both paths before walking.
	_, _ = (OffsiteKeyRecoverer{Fetch: fetcherFor(blob)}).RecoverOffsiteRepoPassword(context.Background(), wrongR)

	// THE PRIMARY ASSERTION IS EMPTINESS, not content. A content scan alone is defeatable by a later
	// call OVERWRITING the leaked file with a different secret — which is exactly how the first
	// version of this test passed its own red-proof while R sat on disk. Nothing in this test writes
	// under TMPDIR, so after both calls the tree must contain no files at all.
	var survivors []string
	err := filepath.Walk(tmp, func(path string, info os.FileInfo, err error) error {
		if err != nil || info == nil || info.IsDir() || path == tmp {
			return nil
		}
		survivors = append(survivors, strings.TrimPrefix(path, tmp))
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if len(survivors) > 0 {
		t.Fatalf("the unseal left %d file(s) behind under TMPDIR: %v — R, the sealed blob and the "+
			"recovered plaintext all pass through there and none of them may outlive the call", len(survivors), survivors)
	}
	// Defence in depth: any secret that DOES appear anywhere is named, for every code used.
	_ = filepath.Walk(tmp, func(path string, info os.FileInfo, err error) error {
		if err != nil || info == nil || info.IsDir() {
			return nil
		}
		body, rerr := os.ReadFile(path)
		if rerr != nil {
			return nil
		}
		for label, secret := range map[string]string{"R": testR, "a wrong R": wrongR, "the repository password": repoPW} {
			if strings.Contains(string(body), secret) {
				t.Errorf("%s survived on disk at %s", label, path)
			}
		}
		return nil
	})
	// And the staging directories are gone, not merely free of secrets.
	entries, _ := os.ReadDir(tmp)
	for _, e := range entries {
		if e.IsDir() && strings.HasPrefix(e.Name(), "felhom-idesc-") {
			t.Fatalf("an unseal staging directory survived: %s", e.Name())
		}
	}
}

// A fetch failure surfaces as a fetch failure, not as a wrong-code error — the operator must not be
// sent to re-read their recovery code because the hub was unreachable.
//
// ⚠ THIS TEST WAS GREEN THROUGHOUT THE DEFECT IT DESCRIBES (R-224, 2026-08-06). Its sentence is
// exactly right and it did not prevent anything, for two reasons worth keeping:
//
//  1. **It asserted the MECHANISM, one layer below the consequence.** It checked this package's error
//     STRING. The merge happened one layer up, in the local-api handler's `default` branch, which
//     answered a fetch failure with "the recovery code did not open the sealed bundle". The customer
//     never sees this string; they see that one. The project's own rule — prefer the test that asserts
//     the CONSEQUENCE (does the customer get blamed?) over the one that asserts the MECHANISM (is the
//     error distinct here?) — names this case precisely.
//  2. **It asserted on TEXT.** `strings.Contains(err.Error(), …)` cannot be consumed by a caller, so
//     it pinned something no production code could branch on. The distinction it checked was real and
//     unusable.
//
// It now asserts the SENTINEL, which is what the handler branches on, and its consequence-level twin
// lives in `internal/localapi/escrow_recover_class_test.go` where the status is asserted.
func TestRecoverOffsiteRepoPassword_FetchErrorIsDistinct(t *testing.T) {
	rec := OffsiteKeyRecoverer{Fetch: func(context.Context) ([]byte, bool, error) {
		return nil, false, errors.New("hub: connection refused")
	}}
	_, err := rec.RecoverOffsiteRepoPassword(context.Background(), testR)
	if err == nil || !errors.Is(err, ErrBundleFetch) {
		t.Fatalf("a fetch failure must classify as ErrBundleFetch, got %v", err)
	}
	if errors.Is(err, ErrNoEscrowBlob) || errors.Is(err, ErrNoResticPassword) {
		t.Fatal("a transport failure must not masquerade as a content verdict")
	}
}

// ── R-224 — A FAILED FETCH IS NOT A WRONG CODE ──────────────────────────────────────────────────
//
// CAMPAIGN-11 F3 measured the consequence of these two being indistinguishable: with the hub
// firewalled off and a CORRECT current recovery code, the customer was told the code did not open
// their package, in 0.0556 s — no unseal was attempted at all.
//
// The pair below is the whole point. Asserting only the first would pass with a `return ErrBundleFetch`
// stuck on every error path, which is the same defect pointing the other way.
func TestRecoverOffsiteRepoPassword_FetchFailureIsClassifiedAsFetch(t *testing.T) {
	boom := errors.New("hub: transport error: dial tcp 37.191.56.193:443: connect: no route to host")
	r := OffsiteKeyRecoverer{Fetch: func(context.Context) ([]byte, bool, error) { return nil, false, boom }}

	_, err := r.RecoverOffsiteRepoPassword(context.Background(), testR)
	if err == nil {
		t.Fatal("a failing fetch must return an error")
	}
	// RED-PROOF: drop the `%w: %w` join in RecoverOffsiteRepoPassword (return the bare wrapped cause,
	// as it was before R-224) → this FAILS, and the local-api handler falls back to the wrong-code
	// message exactly as it did on 2026-08-05.
	if !errors.Is(err, ErrBundleFetch) {
		t.Fatalf("a failed fetch must classify as ErrBundleFetch, got %v", err)
	}
	// The underlying cause survives for the operator log.
	if !errors.Is(err, boom) {
		t.Fatalf("the fetch cause must stay wrapped for the operator, got %v", err)
	}
	// And it must NOT be mistaken for either of the bundle-content situations.
	if errors.Is(err, ErrNoEscrowBlob) || errors.Is(err, ErrNoResticPassword) {
		t.Fatalf("a transport failure is neither of the bundle-content errors: %v", err)
	}
}

// The other half: a genuinely wrong code must NOT classify as a fetch failure, or the fix trades one
// misattribution for its mirror image and the customer is told the hub is down when they mistyped.
func TestRecoverOffsiteRepoPassword_WrongCodeIsNotAFetchFailure(t *testing.T) {
	ensureAge(t)
	blob := sealBundle(t, IdentityBundle{ResticRepoPassword: "0123456789abcdef"}, testR)
	r := OffsiteKeyRecoverer{Fetch: fetcherFor(blob)}

	_, err := r.RecoverOffsiteRepoPassword(context.Background(),
		"wrong horse battery staple sedative anaconda wobbly kingdom placard yodel")
	if err == nil {
		t.Fatal("a wrong recovery code must fail closed")
	}
	if errors.Is(err, ErrBundleFetch) {
		t.Fatalf("a wrong code must NOT classify as a fetch failure, got %v", err)
	}
}

// A clean "the hub holds nothing" keeps its own identity too — it is not a fetch failure, and the
// customer must not be told the hub was unreachable when it answered perfectly well.
func TestRecoverOffsiteRepoPassword_AbsentBlobIsNotAFetchFailure(t *testing.T) {
	r := OffsiteKeyRecoverer{Fetch: func(context.Context) ([]byte, bool, error) { return nil, false, nil }}
	_, err := r.RecoverOffsiteRepoPassword(context.Background(), testR)
	if !errors.Is(err, ErrNoEscrowBlob) {
		t.Fatalf("an absent blob must stay ErrNoEscrowBlob, got %v", err)
	}
	if errors.Is(err, ErrBundleFetch) {
		t.Fatalf("an absent blob is not a fetch FAILURE, got %v", err)
	}
}