package locator_test

import (
	"bytes"
	"crypto/rand"
	"strings"
	"testing"

	"g.activething.com/go/DateKeys/datekey"
	"g.activething.com/go/DateKeys/extension"
	"g.activething.com/go/DateKeys/internal/testkit"
	"g.activething.com/go/DateKeys/locator"
	"g.activething.com/go/DateKeys/profile"
)

const cid = "bafybeigdyrzt5sfp7udm7hu76uh7y26nf3efuylqabf3oclgtqy55fbzdi"

func sample(t *testing.T) (*locator.Locator, []byte, []byte) {
	t.Helper()
	dkc := make([]byte, 5000)
	rand.Read(dkc)
	loc, rest, err := locator.NewEnvelope(dkc)
	if err != nil {
		t.Fatal(err)
	}
	loc.Addresses = []locator.Address{{URI: "https://ejemplo.org/foto.jpg", Offset: 123456}, {URI: "ipfs://" + cid}}
	return loc, rest, dkc
}

// Spec v0.11 §44.1: the envelope is the .dkc in age, split in a header that
// the locator carries and a rest without a mark.
func TestEnvelope(t *testing.T) {
	loc, rest, dkc := sample(t)
	if bytes.Contains(rest, []byte("age-encryption")) || len(rest) != int(loc.RestSize) || len(loc.EnvelopeHeader) > locator.MaxHeaderLen || !bytes.HasSuffix(loc.EnvelopeHeader, []byte("\n")) {
		t.Fatalf("rest of %d bytes, header %q", len(rest), loc.EnvelopeHeader)
	}
	got, err := loc.OpenEnvelope(rest)
	if err != nil || !bytes.Equal(got, dkc) {
		t.Fatalf("the envelope: %v", err)
	}
	// Inside another file: the rest is read from its offset, and only that.
	host := bytes.Repeat([]byte("JPEG"), 1000)
	file, offset := locator.Hide(host, rest)
	trailing := append(bytes.Clone(file), []byte("more after")...)
	for _, f := range [][]byte{file, trailing} {
		r, err := loc.RestIn(f, offset)
		if err != nil {
			t.Fatal(err)
		}
		if got, err := loc.OpenEnvelope(r); err != nil || !bytes.Equal(got, dkc) {
			t.Errorf("rest in a host: %v", err)
		}
	}
	if _, err := loc.RestIn(host, uint64(len(host))); err == nil {
		t.Error("a rest beyond the end of the resource")
	}
	// Whoever recompresses the host breaks the rest, and the locator says so.
	bad := bytes.Clone(rest)
	bad[len(bad)/2] ^= 1
	if _, err := loc.OpenEnvelope(bad); err == nil || !strings.Contains(err.Error(), "SHA-256 of the rest") {
		t.Errorf("a rest changed: %v", err)
	}
	if _, err := loc.OpenEnvelope(rest[:len(rest)-1]); err == nil {
		t.Error("a short rest")
	}
	wrong := *loc
	wrong.CapsuleDigest[0] ^= 1
	if _, err := wrong.OpenEnvelope(rest); err == nil || !strings.Contains(err.Error(), "capsule_digest") {
		t.Errorf("another capsule_digest: %v", err)
	}
}

// Spec §44.1: the plaintext of the locator measures 4096 bytes, or the least
// multiple that holds it, so its length does not tell the addresses.
func TestLocatorPlaintext(t *testing.T) {
	loc, _, _ := sample(t)
	one := *loc
	one.Addresses = loc.Addresses[:1]
	for _, l := range []*locator.Locator{&one, loc} {
		b, err := l.Marshal()
		if err != nil || len(b) != locator.Block {
			t.Fatalf("%d bytes, %v", len(b), err)
		}
		back, err := locator.Unmarshal(b)
		if err != nil || len(back.Addresses) != len(l.Addresses) || back.Addresses[0] != l.Addresses[0] || back.EnvelopeKey != l.EnvelopeKey ||
			!bytes.Equal(back.EnvelopeHeader, l.EnvelopeHeader) || back.RestDigest != l.RestDigest || back.RestSize != l.RestSize || back.CapsuleDigest != l.CapsuleDigest {
			t.Fatalf("the round trip: %v", err)
		}
	}
	// Eight long addresses make it larger: the least multiple of 4096.
	big := *loc
	big.Addresses = nil
	for range locator.MaxAddresses {
		big.Addresses = append(big.Addresses, locator.Address{URI: "https://ejemplo.org/" + strings.Repeat("a", 900), Offset: 1 << 40})
	}
	b, err := big.Marshal()
	if err != nil || len(b)%locator.Block != 0 || len(b) < 2*locator.Block {
		t.Fatalf("%d bytes, %v", len(b), err)
	}
	if _, err := locator.Unmarshal(b); err != nil {
		t.Fatal(err)
	}
	// Anything other than that length is not canonical.
	b1, _ := one.Marshal()
	if _, err := locator.Unmarshal(append(bytes.Clone(b1), make([]byte, locator.Block)...)); err == nil {
		t.Error("a plaintext of two blocks for one")
	}
	if _, err := locator.Unmarshal(b1[:len(b1)-1]); err == nil {
		t.Error("a truncated plaintext")
	}
	nonzero := bytes.Clone(b1)
	nonzero[len(nonzero)-1] = 1
	if _, err := locator.Unmarshal(nonzero); err == nil {
		t.Error("padding that is not zeros")
	}
}

func TestAddresses(t *testing.T) {
	for _, ok := range []string{"https://ejemplo.org/a.bin", "https://ejemplo.org:8443/x?y=1", "ipfs://" + cid, "ipfs://" + cid + "/ruta",
		"https://1.1.1.1/a", "https://[2606:4700::1111]/a", "https://ejemplo.org/a%20b", "https://ejemplo.org/~ana/(1),x;y=z",
		"https://" + strings.Repeat("a", 63) + ".org/", "https://a--b.ejemplo.org/", "https://Ejemplo.ORG:443/"} {
		if err := locator.CheckURI(ok); err != nil {
			t.Errorf("%s: %v", ok, err)
		}
	}
	for _, bad := range []string{"", "http://ejemplo.org/a", "file:///etc/passwd", "ftp://x/y", "https://user:pass@ejemplo.org/", "https://", "ipfs://notacid",
		"https://ejemplo.org/ñ", "https://ejemplo.org/a b", "ipfs://Qm" + strings.Repeat("a", 44), "https://" + strings.Repeat("a", 1100),
		// Review: addresses that are not public, and names that only a machine
		// or a local network resolves.
		"https://100.64.0.1/", "https://0.1.2.3/", "https://192.0.0.8/", "https://198.18.0.1/", "https://240.0.0.1/", "https://255.255.255.255/",
		"https://[64:ff9b::7f00:1]/", "https://[64:ff9b::a9fe:a9fe]/", "https://[::127.0.0.1]/", "https://[::ffff:127.0.0.1]/",
		"https://[2002:7f00:1::1]/", "https://[2001::1]/", "https://[2001:db8::1]/", "https://[fec0::1]/", "https://[fc00::1]/", "https://[ff02::1]/",
		"https://localhost/", "https://foo.localhost/", "https://intranet/", "https://a.local/", "https://router.home.arpa/", "https://x.internal/",
		// Characters that RFC 3986 does not allow, a broken percent sign and a
		// "." or ".." segment.
		"https://a.org/%zz", "https://a.org/%", "https://a.org/<script>", "https://a.org/{x}", "https://a.org/a|b", "https://a.org/^", "https://a.org/`",
		"ipfs://" + cid + "/../../ipns/x", "ipfs://" + cid + "/%2e%2e/x", "https://a.org/./x",
		// Base32 that is not a CID v1: no version 1, or a multihash cut.
		"ipfs://b" + strings.Repeat("a", 39), "ipfs://" + cid[:len(cid)-2],
		// Spec v0.12 writes what the reference already refused: segments of 1
		// to 63 characters that neither start nor end with a hyphen, the
		// scheme in lower case, 0x and local names in either case, an IPv4
		// without leading zeros and a canonical CID; and a port without
		// leading zeros, which it accepted up to five digits.
		"https://" + strings.Repeat("a", 64) + ".org/", "https://-a.ejemplo.org/", "https://a-.ejemplo.org/", "https://ejemplo.org./", "https://a..b.org/",
		"HTTPS://ejemplo.org/", "IPFS://" + cid, "https://ejemplo.0X10/", "https://nas.LOCAL/", "https://01.2.3.4/", "https://8.8.8.08/",
		"https://ejemplo.org:0443/", "https://ejemplo.org:00443/", "https://[2606:4700::1111]:0443/",
		"ipfs://" + cid[:len(cid)-1] + "j", "ipfs://" + cid + "==", "ipfs://b" + strings.ToUpper(cid[1:]), "ipfs://bafkqaaa"} {
		if err := locator.CheckURI(bad); err == nil {
			t.Errorf("%q accepted", bad)
		}
	}
	if h := (locator.Address{URI: "https://ejemplo.org:8443/x"}).Host(); h != "ejemplo.org" {
		t.Errorf("host %q", h)
	}
	if h := (locator.Address{URI: "ipfs://" + cid}).Host(); h != cid {
		t.Errorf("cid %q", h)
	}
	loc, _, _ := sample(t)
	loc.Addresses = nil
	if _, err := loc.Marshal(); err == nil {
		t.Error("no addresses")
	}
	loc.Addresses = make([]locator.Address, 9)
	if _, err := loc.Marshal(); err == nil {
		t.Error("nine addresses")
	}
}

// Spec §44.1: the locator is an age file with one tlock stanza for the round
// of the DateKey: it opens with that release and with no other.
func TestSealedLocator(t *testing.T) {
	p := profile.Quicknet()
	loc, _, _ := sample(t)
	sealed, err := locator.Seal(p, 1000, loc)
	if err != nil {
		t.Fatal(err)
	}
	if bytes.Contains(sealed, []byte(cid)) || bytes.Contains(sealed, loc.EnvelopeKey[:]) {
		t.Error("the locator is not hidden")
	}
	back, err := locator.Open(p, 1000, testkit.Release(1000), sealed)
	if err != nil || back.EnvelopeKey != loc.EnvelopeKey || back.Addresses[1].URI != loc.Addresses[1].URI {
		t.Fatalf("Open: %v", err)
	}
	// Another round: unusable.
	if _, err := locator.Open(p, 1001, testkit.Release(1001), sealed); err == nil {
		t.Error("a locator for round 1000 opened with round 1001")
	}
	if _, err := locator.Open(p, 1000, testkit.Release(1001), sealed); err == nil {
		t.Error("a locator opened with another release")
	}
}

func TestInfo(t *testing.T) {
	p := profile.Quicknet()
	dk, err := datekey.Resolve(p, testkit.Genesis().AddDate(0, 0, 400))
	if err != nil {
		t.Fatal(err)
	}
	loc, _, _ := sample(t)
	sealed, err := locator.Seal(p, dk.Round, loc)
	if err != nil {
		t.Fatal(err)
	}
	other, err := locator.Seal(p, dk.Round+1, loc)
	if err != nil {
		t.Fatal(err)
	}
	// Review: the locator is an age file with one tlock stanza for the round
	// of the DateKey; anything else is refused by the writer, and unusable.
	for name, s := range map[string][]byte{"not an age file": []byte("an age file"), "another round": other} {
		if _, err := (&locator.Info{DateKey: dk, Sealed: s}).Extension(); err == nil {
			t.Errorf("%s: written", name)
		}
	}
	for _, in := range []*locator.Info{
		{DateKey: dk},
		{Note: "Cartas del viaje a Lisboa", DateKey: dk},
		{Note: "Con localizador", DateKey: dk, Sealed: sealed},
	} {
		x, err := in.Extension()
		if err != nil {
			t.Fatal(err)
		}
		out, err := locator.ParseInfo(x)
		if err != nil || out.Note != in.Note || out.DateKey != in.DateKey || !bytes.Equal(out.Sealed, in.Sealed) {
			t.Errorf("%+v: %v", in, err)
		}
	}
	// What makes the extension unusable.
	good, _ := (&locator.Info{Note: "n", DateKey: dk}).Extension()
	for name, x := range map[string]extension.Extension{
		"another id":      {ID: extension.NoteID, Version: 1, Data: good.Data},
		"version 2":       {ID: extension.CapsuleID, Version: 2, Data: good.Data},
		"no data":         {ID: extension.CapsuleID, Version: 1},
		"not CBOR":        {ID: extension.CapsuleID, Version: 1, Data: []byte("nope")},
		"a bad DateKey":   {ID: extension.CapsuleID, Version: 1, Data: []byte{0xa1, 0x01, 0x61, 0x6e}},
		"a note with tab": {ID: extension.CapsuleID, Version: 1, Data: []byte{0xa2, 0x00, 0x63, 'a', '\t', 'b', 0x01, 0x60}},
	} {
		if _, err := locator.ParseInfo(x); err == nil {
			t.Errorf("%s: accepted", name)
		}
	}
	if _, err := (&locator.Info{Note: "a\nb", DateKey: dk}).Extension(); err == nil {
		t.Error("a note with a line feed")
	}
}