Implement JWT authentication and app passkey support

- Add JWT token generation and validation
- Implement bcrypt password hashing
- Create auth service with register/login/refresh/logout
- Add app passkey generation and management
- Implement protected routes and auth middleware
- Add comprehensive tests for new functionality

internal/auth/jwt.go

@@ -0,0 +1,61 @@
+package auth
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
+)
+
+// Claims represents the JWT claims for MyGO access tokens.
+type Claims struct {
+	jwt.RegisteredClaims
+	UserID string `json:"uid"`
+}
+
+// GenerateAccessToken creates a signed JWT access token for a user.
+func GenerateAccessToken(userID string, secret []byte, ttl time.Duration) (string, error) {
+	now := time.Now()
+	claims := Claims{
+		RegisteredClaims: jwt.RegisteredClaims{
+			ID:        uuid.NewString(),
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(ttl)),
+		},
+		UserID: userID,
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	signed, err := token.SignedString(secret)
+	if err != nil {
+		return "", fmt.Errorf("sign token: %w", err)
+	}
+
+	return signed, nil
+}
+
+// GenerateRefreshToken creates a signed JWT refresh token.
+func GenerateRefreshToken(userID string, secret []byte, ttl time.Duration) (string, error) {
+	return GenerateAccessToken(userID, secret, ttl)
+}
+
+// ParseToken validates and parses a JWT token string.
+func ParseToken(tokenString string, secret []byte) (*Claims, error) {
+	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(t *jwt.Token) (any, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
+		}
+		return secret, nil
+	})
+	if err != nil {
+		return nil, fmt.Errorf("parse token: %w", err)
+	}
+
+	claims, ok := token.Claims.(*Claims)
+	if !ok || !token.Valid {
+		return nil, fmt.Errorf("invalid token claims")
+	}
+
+	return claims, nil
+}

internal/auth/jwt_test.go

@@ -0,0 +1,93 @@
+package auth
+
+import (
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestGenerateAccessToken(t *testing.T) {
+	secret := []byte("test-secret")
+	token, err := GenerateAccessToken("user-1", secret, 15*time.Minute)
+	if err != nil {
+		t.Fatalf("GenerateAccessToken = %v", err)
+	}
+	if token == "" {
+		t.Fatal("token is empty")
+	}
+	if !strings.Contains(token, ".") {
+		t.Fatal("token does not look like a JWT")
+	}
+}
+
+func TestParseTokenValid(t *testing.T) {
+	secret := []byte("test-secret")
+	token, err := GenerateAccessToken("user-1", secret, 15*time.Minute)
+	if err != nil {
+		t.Fatalf("GenerateAccessToken = %v", err)
+	}
+
+	claims, err := ParseToken(token, secret)
+	if err != nil {
+		t.Fatalf("ParseToken = %v", err)
+	}
+	if claims.UserID != "user-1" {
+		t.Errorf("UserID = %q, want %q", claims.UserID, "user-1")
+	}
+}
+
+func TestParseTokenWrongSecret(t *testing.T) {
+	secret := []byte("test-secret")
+	token, err := GenerateAccessToken("user-1", secret, 15*time.Minute)
+	if err != nil {
+		t.Fatalf("GenerateAccessToken = %v", err)
+	}
+
+	_, err = ParseToken(token, []byte("wrong-secret"))
+	if err == nil {
+		t.Fatal("expected error for wrong secret, got nil")
+	}
+}
+
+func TestParseTokenExpired(t *testing.T) {
+	secret := []byte("test-secret")
+	token, err := GenerateAccessToken("user-1", secret, -1*time.Minute)
+	if err != nil {
+		t.Fatalf("GenerateAccessToken = %v", err)
+	}
+
+	_, err = ParseToken(token, secret)
+	if err == nil {
+		t.Fatal("expected error for expired token, got nil")
+	}
+}
+
+func TestParseTokenInvalidFormat(t *testing.T) {
+	_, err := ParseToken("not-a-jwt", []byte("secret"))
+	if err == nil {
+		t.Fatal("expected error for invalid format, got nil")
+	}
+}
+
+func TestGenerateRefreshToken(t *testing.T) {
+	secret := []byte("test-secret")
+	token, err := GenerateRefreshToken("user-1", secret, 7*24*time.Hour)
+	if err != nil {
+		t.Fatalf("GenerateRefreshToken = %v", err)
+	}
+	if token == "" {
+		t.Fatal("token is empty")
+	}
+}
+
+func TestTokenUserIDCarried(t *testing.T) {
+	secret := []byte("test-secret")
+	token, _ := GenerateAccessToken("alice-42", secret, 15*time.Minute)
+	claims, err := ParseToken(token, secret)
+	if err != nil {
+		t.Fatalf("ParseToken = %v", err)
+	}
+	if claims.UserID != "alice-42" {
+		t.Errorf("UserID = %q, want %q", claims.UserID, "alice-42")
+	}
+}

internal/auth/password.go

@@ -0,0 +1,26 @@
+package auth
+
+import (
+	"fmt"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+const bcryptCost = 12
+
+// HashPassword returns a bcrypt hash of the plaintext password.
+func HashPassword(password string) (string, error) {
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcryptCost)
+	if err != nil {
+		return "", fmt.Errorf("hash password: %w", err)
+	}
+	return string(hash), nil
+}
+
+// VerifyPassword compares a bcrypt hash with a plaintext password.
+func VerifyPassword(hash, password string) error {
+	if err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password)); err != nil {
+		return fmt.Errorf("invalid password")
+	}
+	return nil
+}

internal/auth/password_test.go

@@ -0,0 +1,48 @@
+package auth
+
+import (
+	"testing"
+)
+
+func TestHashPassword(t *testing.T) {
+	hash, err := HashPassword("mypassword")
+	if err != nil {
+		t.Fatalf("HashPassword = %v", err)
+	}
+	if hash == "" {
+		t.Fatal("hash is empty")
+	}
+	if hash == "mypassword" {
+		t.Fatal("hash should not equal the plaintext password")
+	}
+}
+
+func TestVerifyPasswordCorrect(t *testing.T) {
+	hash, err := HashPassword("mypassword")
+	if err != nil {
+		t.Fatalf("HashPassword = %v", err)
+	}
+
+	if err := VerifyPassword(hash, "mypassword"); err != nil {
+		t.Fatalf("VerifyPassword = %v", err)
+	}
+}
+
+func TestVerifyPasswordWrong(t *testing.T) {
+	hash, err := HashPassword("mypassword")
+	if err != nil {
+		t.Fatalf("HashPassword = %v", err)
+	}
+
+	if err := VerifyPassword(hash, "wrongpassword"); err == nil {
+		t.Fatal("expected error for wrong password, got nil")
+	}
+}
+
+func TestHashPasswordUnique(t *testing.T) {
+	hash1, _ := HashPassword("mypassword")
+	hash2, _ := HashPassword("mypassword")
+	if hash1 == hash2 {
+		t.Fatal("bcrypt should produce different hashes for the same password")
+	}
+}

internal/auth/token.go

@@ -0,0 +1,30 @@
+package auth
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+)
+
+const tokenPrefix = "mygo_"
+const tokenByteLen = 24
+
+// GenerateToken creates a random token with the "mygo_" prefix.
+// Returns the raw token (shown to the user) and its SHA-256 hash (stored in DB).
+func GenerateToken() (raw, hash string, err error) {
+	bytes := make([]byte, tokenByteLen)
+	if _, err := rand.Read(bytes); err != nil {
+		return "", "", fmt.Errorf("generate random bytes: %w", err)
+	}
+
+	raw = tokenPrefix + hex.EncodeToString(bytes)
+	hash = HashToken(raw)
+	return raw, hash, nil
+}
+
+// HashToken returns the SHA-256 hex digest of a token.
+func HashToken(token string) string {
+	sum := sha256.Sum256([]byte(token))
+	return hex.EncodeToString(sum[:])
+}

internal/auth/token_test.go

@@ -0,0 +1,59 @@
+package auth
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestGenerateToken(t *testing.T) {
+	raw, hash, err := GenerateToken()
+	if err != nil {
+		t.Fatalf("GenerateToken = %v", err)
+	}
+
+	if !strings.HasPrefix(raw, tokenPrefix) {
+		t.Errorf("raw token %q does not start with %q", raw, tokenPrefix)
+	}
+
+	expectedHash := HashToken(raw)
+	if hash != expectedHash {
+		t.Errorf("hash = %q, want %q", hash, expectedHash)
+	}
+}
+
+func TestGenerateTokenUniqueness(t *testing.T) {
+	raw1, _, _ := GenerateToken()
+	raw2, _, _ := GenerateToken()
+
+	if raw1 == raw2 {
+		t.Fatal("two generated tokens should not be equal")
+	}
+}
+
+func TestGenerateTokenLength(t *testing.T) {
+	raw, _, err := GenerateToken()
+	if err != nil {
+		t.Fatalf("GenerateToken = %v", err)
+	}
+
+	expectedLen := len(tokenPrefix) + tokenByteLen*2 // hex encodes each byte as 2 chars
+	if len(raw) != expectedLen {
+		t.Errorf("token length = %d, want %d", len(raw), expectedLen)
+	}
+}
+
+func TestHashTokenDeterministic(t *testing.T) {
+	hash1 := HashToken("mygo_test_token")
+	hash2 := HashToken("mygo_test_token")
+	if hash1 != hash2 {
+		t.Fatal("HashToken should be deterministic")
+	}
+}
+
+func TestHashTokenDifferent(t *testing.T) {
+	hash1 := HashToken("mygo_aaa")
+	hash2 := HashToken("mygo_bbb")
+	if hash1 == hash2 {
+		t.Fatal("different inputs should produce different hashes")
+	}
+}