package objectstore

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"io"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"archivdms/config"
)

func newTestStore(t *testing.T) *LocalStore {
	t.Helper()
	l, err := NewLocalStore(config.StorageConfig{BasePath: t.TempDir()}, "test-master-secret", "https://dms.example.test")
	if err != nil {
		t.Fatalf("NewLocalStore: %v", err)
	}
	return l
}

// stage writes a scratch file and returns its path plus content hash.
func stage(t *testing.T, content string) (string, string) {
	t.Helper()
	p := filepath.Join(t.TempDir(), "scratch.pdf")
	if err := os.WriteFile(p, []byte(content), 0o640); err != nil {
		t.Fatalf("write scratch: %v", err)
	}
	sum := sha256.Sum256([]byte(content))
	return p, hex.EncodeToString(sum[:])
}

// AK 1 + Prüfung 1: Round-Trip Archive -> Open, WORM path scheme and 0440.
func TestArchiveOpenRoundTrip(t *testing.T) {
	l := newTestStore(t)
	ctx := context.Background()
	src, hash := stage(t, "hello worm")
	at := time.Date(2026, 3, 7, 10, 0, 0, 0, time.UTC)

	dst, err := l.Archive(ctx, 42, src, ".pdf", hash, at)
	if err != nil {
		t.Fatalf("Archive: %v", err)
	}
	want := filepath.Join(l.cfg.StorePath(), "42", "2026", "03", hash+".pdf")
	if dst != want {
		t.Fatalf("path scheme changed: got %q want %q", dst, want)
	}
	fi, err := os.Stat(dst)
	if err != nil {
		t.Fatalf("stat archived: %v", err)
	}
	if fi.Mode().Perm() != 0o440 {
		t.Fatalf("WORM permissions: got %o want 0440", fi.Mode().Perm())
	}
	if _, err := os.Stat(src); !os.IsNotExist(err) {
		t.Fatalf("scratch file not consumed")
	}

	f, err := l.Open(ctx, 42, dst)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	defer f.Close()
	got, _ := io.ReadAll(f)
	if string(got) != "hello worm" {
		t.Fatalf("round-trip content mismatch: %q", got)
	}

	// Duplicate archival of the same content is rejected.
	src2, _ := stage(t, "hello worm")
	if _, err := l.Archive(ctx, 42, src2, ".pdf", hash, at); !errors.Is(err, ErrObjectExists) {
		t.Fatalf("duplicate: got %v want ErrObjectExists", err)
	}
}

// AK 1: cross-tenant access is refused even with a valid path.
func TestOpenForeignTenantRejected(t *testing.T) {
	l := newTestStore(t)
	ctx := context.Background()
	src, hash := stage(t, "tenant one")
	dst, err := l.Archive(ctx, 1, src, ".pdf", hash, time.Now())
	if err != nil {
		t.Fatalf("Archive: %v", err)
	}
	if _, err := l.Open(ctx, 2, dst); !errors.Is(err, ErrOutsideTenant) {
		t.Fatalf("foreign tenant: got %v want ErrOutsideTenant", err)
	}
	if _, err := l.Open(ctx, 1, filepath.Join(filepath.Dir(dst), "..", "..", "..", "2", "x.pdf")); !errors.Is(err, ErrOutsideTenant) {
		t.Fatalf("traversal: got %v want ErrOutsideTenant", err)
	}
}

// Prüfung 3: missing object yields a clear, typed error.
func TestMissingObjectErrors(t *testing.T) {
	l := newTestStore(t)
	ctx := context.Background()
	missing := filepath.Join(l.cfg.StorePath(), "7", "2026", "01", "deadbeef.pdf")

	if _, err := l.Open(ctx, 7, missing); !errors.Is(err, ErrObjectNotFound) {
		t.Fatalf("Open: got %v want ErrObjectNotFound", err)
	}
	if _, err := l.Stat(ctx, 7, missing); !errors.Is(err, ErrObjectNotFound) {
		t.Fatalf("Stat: got %v want ErrObjectNotFound", err)
	}
	if err := l.Delete(ctx, 7, missing); !errors.Is(err, ErrObjectNotFound) {
		t.Fatalf("Delete: got %v want ErrObjectNotFound", err)
	}
	if _, err := l.Open(ctx, 7, ""); !errors.Is(err, ErrObjectNotFound) {
		t.Fatalf("empty path: got %v want ErrObjectNotFound", err)
	}
}

func TestDeleteRemovesObject(t *testing.T) {
	l := newTestStore(t)
	ctx := context.Background()
	src, hash := stage(t, "to be deleted")
	dst, err := l.Archive(ctx, 5, src, ".pdf", hash, time.Now())
	if err != nil {
		t.Fatalf("Archive: %v", err)
	}
	if err := l.Delete(ctx, 5, dst); err != nil {
		t.Fatalf("Delete: %v", err)
	}
	if _, err := os.Stat(dst); !os.IsNotExist(err) {
		t.Fatalf("object still present after delete")
	}
}

// AK 2 + Prüfung 2: signed URLs verify while valid and are refused afterwards.
func TestSignedURLLifecycle(t *testing.T) {
	l := newTestStore(t)
	link, err := l.SignedURL(3, 99, time.Minute)
	if err != nil {
		t.Fatalf("SignedURL: %v", err)
	}
	if !strings.HasPrefix(link, "https://dms.example.test"+SignedPath+"?") {
		t.Fatalf("unexpected link: %s", link)
	}
	u, err := url.Parse(link)
	if err != nil {
		t.Fatalf("parse link: %v", err)
	}
	ref, err := l.VerifySignedURL(u.Query(), time.Now())
	if err != nil {
		t.Fatalf("verify: %v", err)
	}
	if ref.TenantID != 3 || ref.DocumentID != 99 {
		t.Fatalf("payload mismatch: %+v", ref)
	}

	// Expired.
	if _, err := l.VerifySignedURL(u.Query(), time.Now().Add(2*time.Minute)); !errors.Is(err, ErrSignatureExpired) {
		t.Fatalf("expired: got %v want ErrSignatureExpired", err)
	}

	// Tampered document id.
	q := u.Query()
	q.Set("d", "100")
	if _, err := l.VerifySignedURL(q, time.Now()); !errors.Is(err, ErrSignatureInvalid) {
		t.Fatalf("tampered: got %v want ErrSignatureInvalid", err)
	}

	// Foreign key material.
	other, err := NewLocalStore(config.StorageConfig{BasePath: t.TempDir()}, "different-secret", "")
	if err != nil {
		t.Fatalf("NewLocalStore: %v", err)
	}
	if _, err := other.VerifySignedURL(u.Query(), time.Now()); !errors.Is(err, ErrSignatureInvalid) {
		t.Fatalf("foreign key: got %v want ErrSignatureInvalid", err)
	}

	// Missing parameters.
	if _, err := l.VerifySignedURL(url.Values{}, time.Now()); !errors.Is(err, ErrSignatureInvalid) {
		t.Fatalf("empty query: got %v want ErrSignatureInvalid", err)
	}
}

// AK 2: ttl <= 0 falls back to the configured default validity.
func TestSignedURLDefaultTTL(t *testing.T) {
	l, err := NewLocalStore(config.StorageConfig{BasePath: t.TempDir(), SignedURLTTLMinutes: 5}, "s", "")
	if err != nil {
		t.Fatalf("NewLocalStore: %v", err)
	}
	link, err := l.SignedURL(1, 1, 0)
	if err != nil {
		t.Fatalf("SignedURL: %v", err)
	}
	u, _ := url.Parse(link)
	if strings.HasPrefix(link, "http") {
		t.Fatalf("empty baseURL must yield a relative link: %s", link)
	}
	if _, err := l.VerifySignedURL(u.Query(), time.Now().Add(4*time.Minute)); err != nil {
		t.Fatalf("within default ttl: %v", err)
	}
	if _, err := l.VerifySignedURL(u.Query(), time.Now().Add(6*time.Minute)); !errors.Is(err, ErrSignatureExpired) {
		t.Fatalf("past default ttl: got %v want ErrSignatureExpired", err)
	}
}