package profile_test

import (
	"bytes"
	"encoding/hex"
	"errors"
	"testing"
	"time"

	datekeys "g.activething.com/go/DateKeys"
	"g.activething.com/go/DateKeys/codec"
	"g.activething.com/go/DateKeys/internal/testkit"
	"g.activething.com/go/DateKeys/profile"
)

func TestQuicknetMatchesGoldenVector(t *testing.T) {
	var golden testkit.ProfileVector
	if err := testkit.ReadJSON("../testdata/vectors/profile_quicknet.json", &golden); err != nil {
		t.Fatal(err)
	}
	got, err := testkit.QuicknetProfileVector()
	if err != nil {
		t.Fatal(err)
	}
	if got != golden {
		t.Fatalf("Quicknet profile vector changed:\n got %+v\nwant %+v", got, golden)
	}
	if golden.ProfileHash != profile.QuicknetProfileHash {
		t.Fatalf("pinned hash %s differs from golden %s", profile.QuicknetProfileHash, golden.ProfileHash)
	}
	// Spec §12 values, restated independently of the constants.
	p := profile.Quicknet()
	if p.ID != "datekeys:quicknet:v1" || p.Provider != "drand" || p.Network != "quicknet" ||
		p.Period != 3*time.Second || p.GenesisTime != 1692803367 || p.Scheme != "bls-unchained-g1-rfc9380" ||
		p.ChainHashHex() != "52db9ba70e0cc0f6eaf7803dd07447a1f5477735fd3f661792ba94600c84e971" ||
		hex.EncodeToString(p.GenesisSeed[:]) != "f477d5c89f21a17c863a7f937c6a6d15859414d2be09cd448d4279af331c5d3e" {
		t.Fatal("Quicknet parameters differ from spec §12")
	}
}

func TestQuicknetCBORLayout(t *testing.T) {
	b, err := profile.Quicknet().CanonicalCBOR()
	if err != nil {
		t.Fatal(err)
	}
	// Map of 11 entries whose keys 0..10 appear in order (spec §11).
	if b[0] != 0xab {
		t.Fatalf("map header %#x", b[0])
	}
	var m map[uint64]any
	if err := codec.Unmarshal(b, &m); err != nil {
		t.Fatal(err)
	}
	want := map[uint64]any{0: "datekeys-provider-profile", 1: uint64(1), 2: "datekeys:quicknet:v1", 3: "drand", 4: "quicknet", 7: uint64(3), 8: uint64(1692803367), 9: "bls-unchained-g1-rfc9380"}
	for k, v := range want {
		if m[k] != v {
			t.Errorf("key %d = %v, want %v", k, m[k], v)
		}
	}
	for _, k := range []uint64{5, 6, 10} {
		if _, ok := m[k].([]byte); !ok {
			t.Errorf("key %d is not a byte string", k)
		}
	}
}

func TestDecodeRoundTrip(t *testing.T) {
	b, _ := profile.Quicknet().CanonicalCBOR()
	p, err := profile.Decode(b)
	if err != nil {
		t.Fatal(err)
	}
	b2, _ := p.CanonicalCBOR()
	if !bytes.Equal(b, b2) {
		t.Fatal("Decode/CanonicalCBOR is not the identity")
	}
	// The same values with a different key order or integer width are rejected.
	period, genesis := []byte{0x07, 0x03}, []byte{0x08, 0x1a, 0x64, 0xe6, 0x21, 0x27}
	pair := append(append([]byte(nil), period...), genesis...)
	if !bytes.Contains(b, pair) {
		t.Fatal("unexpected layout")
	}
	swapped := bytes.Replace(b, pair, append(append([]byte(nil), genesis...), period...), 1)
	widened := bytes.Replace(b, period, []byte{0x07, 0x18, 0x03}, 1)
	for name, in := range map[string][]byte{"keys out of order": swapped, "integer not in shortest form": widened} {
		if _, err := profile.Decode(in); !errors.Is(err, datekeys.ErrNonCanonicalCBOR) {
			t.Errorf("%s accepted: %v", name, err)
		}
	}
	future, _ := codec.Marshal(map[uint64]any{0: profile.TypeTag, 1: uint64(2)})
	if _, err := profile.Decode(future); !errors.Is(err, datekeys.ErrUnsupportedVersion) {
		t.Fatalf("future schema: %v", err)
	}
}

// Spec §11, §58: period in 1..2^53-1 and genesis_time in 0..2^53-1, both
// unsigned. Out of the schema is ErrNonCanonicalCBOR, whatever Validate would
// say of the value.
func TestIntegerRanges(t *testing.T) {
	b, _ := profile.Quicknet().CanonicalCBOR()
	var m map[uint64]any
	if err := codec.Unmarshal(b, &m); err != nil {
		t.Fatal(err)
	}
	for name, v := range map[string]struct {
		key uint64
		val any
	}{
		"negative genesis_time": {8, int64(-1)},
		"genesis_time 2^53":     {8, uint64(codec.MaxSafeUint + 1)},
		"period 2^53":           {7, uint64(codec.MaxSafeUint + 1)},
		"period 0":              {7, uint64(0)},
		"period above one day":  {7, uint64(86401)},
	} {
		c := map[uint64]any{}
		for k, x := range m {
			c[k] = x
		}
		c[v.key] = v.val
		in, err := codec.Marshal(c)
		if err != nil {
			t.Fatal(err)
		}
		if _, err := profile.Decode(in); !errors.Is(err, datekeys.ErrNonCanonicalCBOR) {
			t.Errorf("%s: %v", name, err)
		}
	}
	// The encoder refuses the same values with the same code.
	for _, g := range []int64{-1, codec.MaxSafeUint + 1} {
		p := profile.Quicknet()
		p.GenesisTime = g
		if _, err := p.CanonicalCBOR(); !errors.Is(err, datekeys.ErrNonCanonicalCBOR) {
			t.Errorf("genesis time %d encoded: %v", g, err)
		}
	}
}

func TestValidateRejectsTamperedProfiles(t *testing.T) {
	for _, tc := range []struct {
		name   string
		mutate func(p *profile.Profile)
		want   error
	}{
		{"chain hash changed", func(p *profile.Profile) { p.ChainHash[0] ^= 1 }, datekeys.ErrProfileMismatch},
		{"genesis seed changed", func(p *profile.Profile) { p.GenesisSeed[0] ^= 1 }, datekeys.ErrProfileMismatch},
		{"genesis time changed", func(p *profile.Profile) { p.GenesisTime++ }, datekeys.ErrProfileMismatch},
		{"period changed", func(p *profile.Profile) { p.Period = 30 * time.Second }, datekeys.ErrProfileMismatch},
		{"network id changed", func(p *profile.Profile) { p.Network = "default" }, datekeys.ErrProfileMismatch},
		{"public key not a point", func(p *profile.Profile) { p.PublicKey = bytes.Repeat([]byte{0xff}, 96) }, datekeys.ErrUnknownProfile},
		{"public key truncated", func(p *profile.Profile) { p.PublicKey = p.PublicKey[:95] }, datekeys.ErrUnknownProfile},
		{"unknown scheme", func(p *profile.Profile) { p.Scheme = "bls-unchained-g9" }, datekeys.ErrUnknownProfile},
		{"scheme without tlock support", func(p *profile.Profile) { p.Scheme = "pedersen-bls-chained" }, datekeys.ErrUnknownProfile},
		{"unknown provider", func(p *profile.Profile) { p.Provider = "roughtime" }, datekeys.ErrUnknownProfile},
		{"sub-second period", func(p *profile.Profile) { p.Period = 1500 * time.Millisecond }, datekeys.ErrUnknownProfile},
		{"uppercase profile id", func(p *profile.Profile) { p.ID = "DateKeys:quicknet:v1" }, datekeys.ErrUnknownProfile},
		{"profile id with quote", func(p *profile.Profile) { p.ID = `datekeys:"quicknet` }, datekeys.ErrUnknownProfile},
		// Spec §57: the Provider Profile names and public key outside their
		// CDDL rules are ERR_UNKNOWN_PROFILE.
		{"uppercase provider", func(p *profile.Profile) { p.Provider = "Drand" }, datekeys.ErrUnknownProfile},
		{"empty public key", func(p *profile.Profile) { p.PublicKey = []byte{} }, datekeys.ErrUnknownProfile},
		{"public key above 1024 bytes", func(p *profile.Profile) { p.PublicKey = make([]byte, 1025) }, datekeys.ErrUnknownProfile},
	} {
		t.Run(tc.name, func(t *testing.T) {
			p := profile.Quicknet()
			tc.mutate(p)
			if err := p.Validate(); !errors.Is(err, tc.want) {
				t.Fatalf("got %v, want %v", err, tc.want)
			}
		})
	}
}

func TestRegistry(t *testing.T) {
	reg, err := profile.Default()
	if err != nil {
		t.Fatal(err)
	}
	p, ok := reg.Lookup(profile.QuicknetID)
	if !ok {
		t.Fatal("Quicknet not pinned")
	}
	// Lookup hands out copies: mutating one does not alter the registry.
	p.PublicKey[0] ^= 0xff
	p.ChainHash[0] ^= 0xff
	again, _ := reg.Lookup(profile.QuicknetID)
	if err := again.Validate(); err != nil {
		t.Fatalf("registry state was mutated through a lookup: %v", err)
	}
	if _, ok := reg.Lookup("datekeys:evmnet:v1"); ok {
		t.Fatal("unknown profile found")
	}

	var wrong [32]byte
	if _, err := profile.NewRegistry(profile.Pin{Profile: profile.Quicknet(), Hash: wrong}); !errors.Is(err, datekeys.ErrProfileMismatch) {
		t.Fatalf("wrong pinned hash accepted: %v", err)
	}
	h, _ := profile.Quicknet().Hash()
	if _, err := profile.NewRegistry(profile.Pin{Profile: profile.Quicknet(), Hash: h}, profile.Pin{Profile: profile.Quicknet(), Hash: h}); err == nil {
		t.Fatal("duplicate profile accepted")
	}
	bad := profile.Quicknet()
	bad.ChainHash[31] ^= 1
	bh, _ := bad.Hash()
	if _, err := profile.NewRegistry(profile.Pin{Profile: bad, Hash: bh}); !errors.Is(err, datekeys.ErrProfileMismatch) {
		t.Fatalf("self-inconsistent profile pinned: %v", err)
	}
}

func TestMaxRound(t *testing.T) {
	p := profile.Quicknet()
	if got := p.MaxRound(); got != 83903165811 {
		t.Fatalf("MaxRound = %d", got)
	}
}

func FuzzDecode(f *testing.F) {
	b, _ := profile.Quicknet().CanonicalCBOR()
	f.Add(b)
	f.Add(b[:100])
	f.Fuzz(func(t *testing.T, in []byte) {
		p, err := profile.Decode(in)
		if err != nil {
			if datekeys.Code(err) == "" {
				t.Fatalf("error without a normative code: %v", err)
			}
			return
		}
		out, err := p.CanonicalCBOR()
		if err != nil || !bytes.Equal(out, in) {
			t.Fatal("accepted a profile that does not re-encode to its input")
		}
	})
}