package objstore

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/carlosframework/platform/internal/release"
)

func resultFixture(key, verdict, version string) *ScanResult {
	return &ScanResult{
		Key: key, Verdict: verdict, Version: version,
		Engine: "clamav", Signature: "ClamAV 1.4.1/27500/x", At: time.Now().UTC(),
	}
}

// THE test for this file, and the third appearance of this bug class in the
// design's reviews.
//
// Without the version binding: v1 scanned, the tag not written because the
// ten-tag cap fired, the result says clean; the tenant overwrites with v2; the
// tag is still absent, so the door falls through to the result object and
// answers clean for bytes nobody has read. That is the laundering the verdict
// tag's own binding exists to stop, reintroduced by the mechanism meant to
// close a gap in it.
func TestResultObjectIsVersionBound(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())

	if err := WriteScanResult(ctx, s, "bab", "titogo", resultFixture("uploads/x", "clean", "v1")); err != nil {
		t.Fatal(err)
	}

	got, err := ReadScanResult(ctx, s, "bab", "titogo", "uploads/x", "v1")
	if err != nil || got == nil || got.Verdict != "clean" {
		t.Fatalf("read at v1 = %+v, %v", got, err)
	}

	// The object is overwritten. The result must not answer for the new bytes.
	got, err = ReadScanResult(ctx, s, "bab", "titogo", "uploads/x", "v2")
	if err != nil {
		t.Fatal(err)
	}
	if got != nil {
		t.Fatalf("a result written for v1 answered for v2: %+v", got)
	}
}

// The second write for a key is a REPLACE. release.Store.Put has only
// create-only and replace, so a create-only second write returns
// ErrCASConflict and silently drops the newer verdict — leaving the door on
// "pending" until some sweep happens to tag the object.
func TestResultObjectReplacesOnSecondWrite(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())

	if err := WriteScanResult(ctx, s, "bab", "titogo", resultFixture("uploads/x", "clean", "v1")); err != nil {
		t.Fatal(err)
	}
	if err := WriteScanResult(ctx, s, "bab", "titogo", resultFixture("uploads/x", "infected", "v2")); err != nil {
		t.Fatalf("second write: %v", err)
	}

	got, err := ReadScanResult(ctx, s, "bab", "titogo", "uploads/x", "v2")
	if err != nil || got == nil {
		t.Fatalf("read at v2 = %+v, %v", got, err)
	}
	if got.Verdict != "infected" {
		t.Fatalf("verdict = %q, want the v2 verdict — the newer one was dropped", got.Verdict)
	}
}

// Absent is a state, not an error.
func TestReadScanResultAbsent(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())

	got, err := ReadScanResult(ctx, s, "bab", "titogo", "uploads/never", "v1")
	if err != nil || got != nil {
		t.Fatalf("= %+v, %v", got, err)
	}
}

// An unknown schema refuses rather than being read as a verdict. Same rule as
// the record and the sidecar, and for the same reason: this one can be the
// only thing standing between an app and a payload.
func TestScanResultSchemaRefusesUnknown(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())

	if _, err := s.Put(ctx, ScanResultKey("bab", "titogo", "uploads/x"),
		[]byte(`{"schema":99,"key":"uploads/x","verdict":"clean","version":"v1"}`), ""); err != nil {
		t.Fatal(err)
	}
	if _, err := ReadScanResult(ctx, s, "bab", "titogo", "uploads/x", "v1"); err == nil {
		t.Fatal("an unknown schema was read as a verdict")
	}
}

// The result lives under the APP's prefix, so PurgeApp removes it and the
// name-claim gate can see it. A top-level results prefix would survive app
// deletion invisibly — and, because materialize counts any key under an app
// prefix and fails toward keeping the row, would resurrect the deleted app.
func TestScanResultKeyIsUnderTheAppPrefix(t *testing.T) {
	got := ScanResultKey("bab", "titogo", "uploads/x")
	if want := release.AppPrefix("bab", "titogo"); len(got) <= len(want) || got[:len(want)] != want {
		t.Fatalf("key %q is not under %q", got, want)
	}
	// Distinct object keys must not collide.
	if ScanResultKey("bab", "titogo", "a") == ScanResultKey("bab", "titogo", "b") {
		t.Fatal("two object keys share a result object")
	}
	// PINNED, not merely "deterministic". A key that is stable within one
	// build is stable enough to pass a self-comparison and still be a
	// different key from the one the last build wrote — and every result
	// written before the change becomes an object nothing will ever read or
	// delete, under the prefix that decides whether the app's name can be
	// claimed again.
	if want := release.AppPrefix("bab", "titogo") +
		"scan-results/c681b33175d57d52dc74238a2e327f0982614eeab6142d8e893dd83cb617488b.json"; got != want {
		t.Fatalf("key = %q, want %q — the key format moved and the old results are now unreachable", got, want)
	}
}

// The fallback set is deleted with the app's consent, and swept by age
// otherwise. Nothing else removes one: the drain drops a result only when a
// LATER scan records a real verdict on the same key, which for a permanently
// untaggable object never happens.
func TestResultObjectCollectedByAge(t *testing.T) {
	ctx := context.Background()
	dir := t.TempDir()
	s := release.NewDirStore(dir)

	for _, k := range []string{"uploads/old", "uploads/new"} {
		if err := WriteScanResult(ctx, s, "bab", "titogo", resultFixture(k, "clean", "v1")); err != nil {
			t.Fatal(err)
		}
	}
	old := time.Now().Add(-48 * time.Hour)
	aged := filepath.Join(dir, filepath.FromSlash(ScanResultKey("bab", "titogo", "uploads/old")))
	if err := os.Chtimes(aged, old, old); err != nil {
		t.Fatal(err)
	}

	n, err := CollectScanResults(ctx, s, "bab", "titogo", time.Now().Add(-QueueTTL))
	if err != nil {
		t.Fatal(err)
	}
	if n != 1 {
		t.Fatalf("collected %d, want the one past its TTL", n)
	}
	if _, _, err := s.Get(ctx, ScanResultKey("bab", "titogo", "uploads/old")); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("the aged result survived: %v", err)
	}
	if _, _, err := s.Get(ctx, ScanResultKey("bab", "titogo", "uploads/new")); err != nil {
		t.Fatalf("the age sweep took a result still inside its TTL: %v", err)
	}
}

// A store that cannot rank by modification time is SKIPPED, not an error —
// the same degradation storagePass accepts for SizeLister. A tick that failed
// over a capability a fake lacks would be a tick that stopped draining.
func TestCollectScanResultsWithoutModLister(t *testing.T) {
	if _, err := CollectScanResults(context.Background(), plainStore{}, "bab", "titogo", time.Now()); !errors.Is(err, ErrNoModLister) {
		t.Fatalf("err = %v, want ErrNoModLister", err)
	}
}

// plainStore implements release.Store and nothing optional.
type plainStore struct{ release.Store }

// A whole app's results go when the app's consent does.
func TestDeleteScanResults(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())
	for _, k := range []string{"uploads/a", "uploads/b"} {
		if err := WriteScanResult(ctx, s, "bab", "titogo", resultFixture(k, "clean", "v1")); err != nil {
			t.Fatal(err)
		}
	}
	if err := DeleteScanResults(ctx, s, "bab", "titogo"); err != nil {
		t.Fatal(err)
	}
	left, err := s.List(ctx, ScanResultsPrefix("bab", "titogo"))
	if err != nil || len(left) != 0 {
		t.Fatalf("results survived: %v, %v", left, err)
	}
	// Deleting an empty set is not an error.
	if err := DeleteScanResults(ctx, s, "bab", "titogo"); err != nil {
		t.Fatal(err)
	}
}

// Deleted when a later scan DOES persist a verdict, so the fallback cannot
// outlive the real answer. Deleting an absent one is not an error.
func TestDeleteScanResult(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())

	if err := WriteScanResult(ctx, s, "bab", "titogo", resultFixture("uploads/x", "clean", "v1")); err != nil {
		t.Fatal(err)
	}
	if err := DeleteScanResult(ctx, s, "bab", "titogo", "uploads/x"); err != nil {
		t.Fatal(err)
	}
	if _, _, err := s.Get(ctx, ScanResultKey("bab", "titogo", "uploads/x")); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("result survived deletion: %v", err)
	}
	if err := DeleteScanResult(ctx, s, "bab", "titogo", "uploads/x"); err != nil {
		t.Fatalf("deleting an absent result: %v", err)
	}
}