package bundle

import (
	"archive/tar"
	"bytes"
	"compress/gzip"
	"crypto/ed25519"
	"crypto/sha256"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"io"
	"os"
	"reflect"
	"sort"
	"testing"
)

// legacyManifestV1 mirrors the decoder fields present in the locally available
// v1.0.0 source. It deliberately has no future capability or deployment fields.
type legacyManifestV1 struct {
	RevisionID string `json:"revision_id"`
	SpeakerID  string `json:"speaker_id"`
	CreatedAt  string `json:"created_at"`
	Files      []struct {
		Path   string `json:"path"`
		SHA256 string `json:"sha256"`
	} `json:"files"`
	Algorithm       string `json:"signature_algorithm"`
	PublicKeyBase64 string `json:"public_key_base64"`
}

func TestLegacyCompatibilityFrozenSignedCurrentBaseline(t *testing.T) {
	raw, err := os.ReadFile("testdata/current_baseline_signed_bundle.tar.gz")
	if err != nil {
		t.Fatal(err)
	}
	pub := ed25519.NewKeyFromSeed(bytes.Repeat([]byte{0x42}, ed25519.SeedSize)).Public().(ed25519.PublicKey)
	verified, err := VerifyGzippedTar(raw, pub)
	if err != nil {
		t.Fatalf("frozen signed baseline rejected: %v", err)
	}
	if verified.Manifest.RevisionID != "revision-legacy" || verified.Manifest.SpeakerID != "speaker-legacy" || len(verified.Files) != 2 {
		t.Fatalf("frozen baseline contents: %+v", verified.Manifest)
	}
}

func TestLegacyCompatibilityBundleWire(t *testing.T) {
	seed := bytes.Repeat([]byte{0x42}, ed25519.SeedSize)
	priv := ed25519.NewKeyFromSeed(seed)
	pub := priv.Public().(ed25519.PublicKey)
	fragments := map[string]string{
		"bird.conf":                      "router id 192.0.2.1;\n",
		"bird.d/evobgp_prefixes_v4.conf": "# revision\n",
		"_preview":                       "must not ship",
	}
	raw, err := BuildGzippedTar("revision-legacy", "speaker-legacy", fragments, priv)
	if err != nil {
		t.Fatal(err)
	}
	gr, err := gzip.NewReader(bytes.NewReader(raw))
	if err != nil {
		t.Fatal(err)
	}
	defer func() { _ = gr.Close() }()
	tr := tar.NewReader(gr)
	entries := map[string][]byte{}
	var order []string
	for {
		h, err := tr.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			t.Fatal(err)
		}
		body, err := io.ReadAll(tr)
		if err != nil {
			t.Fatal(err)
		}
		order = append(order, h.Name)
		entries[h.Name] = body
	}
	wantOrder := []string{"manifest.json", "bundle.sig", "bird.conf", "bird.d/evobgp_prefixes_v4.conf"}
	if !reflect.DeepEqual(order, wantOrder) {
		t.Fatalf("legacy tar layout: got %v, want %v", order, wantOrder)
	}
	var top map[string]json.RawMessage
	if err := json.Unmarshal(entries["manifest.json"], &top); err != nil {
		t.Fatal(err)
	}
	wantFields := []string{"created_at", "files", "public_key_base64", "revision_id", "signature_algorithm", "speaker_id"}
	fields := make([]string, 0, len(top))
	for k := range top {
		fields = append(fields, k)
	}
	sort.Strings(fields)
	if !reflect.DeepEqual(fields, wantFields) {
		t.Fatalf("manifest fields: got %v, want %v", fields, wantFields)
	}
	var m legacyManifestV1
	if err := json.Unmarshal(entries["manifest.json"], &m); err != nil {
		t.Fatal(err)
	}
	if m.RevisionID != "revision-legacy" || m.SpeakerID != "speaker-legacy" || m.CreatedAt == "" || m.Algorithm != "ed25519" || m.PublicKeyBase64 != base64.StdEncoding.EncodeToString(pub) {
		t.Fatalf("legacy manifest fields: %+v", m)
	}
	if !ed25519.Verify(pub, entries["manifest.json"], entries["bundle.sig"]) {
		t.Fatal("legacy Ed25519 verifier rejected current signed manifest")
	}
	if len(m.Files) != 2 {
		t.Fatalf("legacy manifest file count: %d", len(m.Files))
	}
	for _, f := range m.Files {
		sum := sha256.Sum256(entries[f.Path])
		if hex.EncodeToString(sum[:]) != f.SHA256 {
			t.Fatalf("legacy SHA-256 mismatch for %q", f.Path)
		}
	}
}