package declaration

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"reflect"
	"strings"
	"testing"
)

func refFile(extra string) string {
	return `{"declaration":1,"resources":[{"id":"m.f","type":"file","path":"/etc/m","digest":"sha256:` +
		strings.Repeat("a", 64) + `","size":70000` + extra + `}]}`
}

// 1694/AC1: a reference round trips, and an invalid one is refused naming the field.
func TestAFileReferenceRoundTripsAndABadOneNamesItsField(t *testing.T) {
	d, err := Parse([]byte(refFile("")))
	if err != nil {
		t.Fatal(err)
	}
	f := d.Resources[0].(*File)
	if !f.IsReference() || f.Size != 70000 || f.Digest != "sha256:"+strings.Repeat("a", 64) {
		t.Fatalf("read: %+v", f)
	}
	raw, _ := json.Marshal(d.Resources[0])
	d2, err := Parse([]byte(`{"declaration":1,"resources":[` + string(raw) + `]}`))
	if err != nil || !reflect.DeepEqual(d2.Resources[0], d.Resources[0]) {
		t.Fatalf("round trip: %v %s", err, raw)
	}
	for want, raw := range map[string]string{
		"digest":     strings.Replace(refFile(""), strings.Repeat("a", 64), "abc", 1),
		"size":       strings.Replace(refFile(""), `"size":70000`, `"size":0`, 1),
		"lower-case": strings.Replace(refFile(""), strings.Repeat("a", 64), strings.Repeat("A", 64), 1),
		"content":    refFile(`,"content":"x"`),
		"bytes":      refFile(`,"bytes":"eA=="`),
		"whole":      refFile(`,"into":"block"`),
	} {
		_, err := Parse([]byte(raw))
		if err == nil || !strings.Contains(err.Error(), want) {
			t.Errorf("want a refusal naming %q, got %v", want, err)
		}
	}
	// a size alone is not a reference
	if _, err := Parse([]byte(`{"declaration":1,"resources":[{"id":"m.f","type":"file","path":"/e","size":5}]}`)); err == nil {
		t.Error("a size without a digest was accepted")
	}
}

// 1694/AC2: a declaration as today's SDK writes it reads unchanged and its bytes carry no new key.
func TestAnInlineFileIsReadAndWrittenAsBefore(t *testing.T) {
	const in = `{"id":"m.f","type":"file","path":"/e","content":"hello"}`
	d, err := Parse([]byte(`{"declaration":1,"resources":[` + in + `]}`))
	if err != nil {
		t.Fatal(err)
	}
	out, _ := json.Marshal(d.Resources[0])
	if string(out) != in {
		t.Fatalf("signed bytes changed: %s", out)
	}
	if d.Resources[0].(*File).IsReference() {
		t.Fatal("inline read as a reference")
	}
}

// 1694/AC3: the controller's helper makes a reference of a big file and the engine's check refuses a changed byte.
func TestABigFileBecomesAReferenceAndAChangedByteFailsTheCheck(t *testing.T) {
	big := strings.Repeat("x", FileReferenceThreshold+1)
	f := &File{ID: "m.f", Type: TypeFile, Path: "/e", Content: big}
	if !f.TravelsByDigest() {
		t.Fatal("a file over the threshold stays inline")
	}
	ref, body, err := f.AsReference()
	if err != nil || ref.Content != "" || ref.Size != int64(len(big)) || string(body) != big {
		t.Fatalf("%v %+v", err, ref)
	}
	if p := ref.validate("f", false); len(p) > 0 {
		t.Fatalf("the reference is refused: %v", p)
	}
	if name, err := ObjectName(ref.Digest); err != nil || len(name) != 64 {
		t.Fatalf("object name %q %v", name, err)
	}
	if err := ref.Verify(body); err != nil {
		t.Fatal(err)
	}
	bad := bytes.Clone(body)
	bad[7] ^= 1
	if err := ref.Verify(bad); err == nil || !strings.Contains(err.Error(), "hashes to") {
		t.Fatalf("a changed byte: %v", err)
	}
	if err := ref.Verify(body[1:]); err == nil || !strings.Contains(err.Error(), "bytes") {
		t.Fatalf("a short object: %v", err)
	}
}

// 1694/AC4: what stays inline, and bytes files travel decoded.
func TestWhichFilesTravelByDigest(t *testing.T) {
	small := strings.Repeat("x", FileReferenceThreshold)
	big := strings.Repeat("x", FileReferenceThreshold+1)
	for name, f := range map[string]File{
		"at the threshold": {Content: small},
		"sealed":           {Sealed: "s"},
		"secrets":          {Content: big, Secrets: map[string]string{"a": "b"}},
		"into":             {Content: big, Into: IntoBlock},
	} {
		if f.TravelsByDigest() {
			t.Errorf("%s travels by digest", name)
		}
		if _, _, err := f.AsReference(); err == nil {
			t.Errorf("%s was made a reference", name)
		}
	}
	exact := File{ID: "m.e", Bytes: base64.StdEncoding.EncodeToString(bytes.Repeat([]byte{7}, FileReferenceThreshold))}
	if exact.TravelsByDigest() {
		t.Error("a bytes file of exactly the threshold travels by digest")
	}
	if _, _, err := exact.AsReference(); err == nil {
		t.Error("a bytes file of exactly the threshold was made a reference")
	}
	raw := bytes.Repeat([]byte{0, 1, 2}, FileReferenceThreshold)
	f := File{ID: "m.b", Bytes: base64.StdEncoding.EncodeToString(raw)}
	ref, body, err := f.AsReference()
	if err != nil || !bytes.Equal(body, raw) || ref.Size != int64(len(raw)) || ref.Digest != DigestOf(raw) {
		t.Fatalf("bytes file: %v", err)
	}
}

func TestTheSharedNames(t *testing.T) {
	if FileBucket != "declaration-files" || FileReferencesCapability != "file-references" || FileReferenceThreshold != 65536 {
		t.Fatal("a name changed")
	}
	if _, err := ObjectName("sha256:zz"); err == nil {
		t.Fatal("bad digest named an object")
	}
}