package service

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strings"
	"testing"

	"github.com/user-management-system/internal/auth"
	"github.com/user-management-system/internal/domain"
)

func mustHashRecoveryCode(t *testing.T, code string) string {
	t.Helper()
	hashed, err := auth.HashRecoveryCode(code)
	if err != nil {
		t.Fatalf("hash recovery code: %v", err)
	}
	return hashed
}

func mustMarshalJSON(t *testing.T, value any) string {
	t.Helper()
	payload, err := json.Marshal(value)
	if err != nil {
		t.Fatalf("marshal json: %v", err)
	}
	return string(payload)
}

type totpTestRepo struct {
	user                         *domain.User
	getErr                       error
	updateTOTPErr                error
	consumeRecoveryCodeErr       error
	consumeRecoveryCodeCalled    bool
	verifyTOTPOrRecoveryCodeErr  error
	verifyTOTPOrRecoveryCodeCalled bool
}

func (r *totpTestRepo) Create(ctx context.Context, user *domain.User) error { return nil }
func (r *totpTestRepo) Update(ctx context.Context, user *domain.User) error { return nil }
func (r *totpTestRepo) UpdateTOTP(ctx context.Context, user *domain.User) error {
	if r.updateTOTPErr != nil {
		return r.updateTOTPErr
	}
	copyUser := *user
	r.user = &copyUser
	return nil
}
func (r *totpTestRepo) Delete(ctx context.Context, id int64) error { return nil }
func (r *totpTestRepo) GetByID(ctx context.Context, id int64) (*domain.User, error) {
	if r.getErr != nil {
		return nil, r.getErr
	}
	if r.user == nil || r.user.ID != id {
		return nil, errors.New("not found")
	}
	copyUser := *r.user
	return &copyUser, nil
}
func (r *totpTestRepo) GetByUsername(ctx context.Context, username string) (*domain.User, error) {
	return nil, errors.New("not implemented")
}
func (r *totpTestRepo) GetByEmail(ctx context.Context, email string) (*domain.User, error) {
	return nil, errors.New("not implemented")
}
func (r *totpTestRepo) GetByPhone(ctx context.Context, phone string) (*domain.User, error) {
	return nil, errors.New("not implemented")
}
func (r *totpTestRepo) List(ctx context.Context, offset, limit int) ([]*domain.User, int64, error) {
	return nil, 0, errors.New("not implemented")
}
func (r *totpTestRepo) ListByStatus(ctx context.Context, status domain.UserStatus, offset, limit int) ([]*domain.User, int64, error) {
	return nil, 0, errors.New("not implemented")
}
func (r *totpTestRepo) UpdateStatus(ctx context.Context, id int64, status domain.UserStatus) error {
	return errors.New("not implemented")
}
func (r *totpTestRepo) UpdateLastLogin(ctx context.Context, id int64, ip string) error {
	return errors.New("not implemented")
}
func (r *totpTestRepo) ExistsByUsername(ctx context.Context, username string) (bool, error) {
	return false, errors.New("not implemented")
}
func (r *totpTestRepo) ExistsByEmail(ctx context.Context, email string) (bool, error) {
	return false, errors.New("not implemented")
}
func (r *totpTestRepo) ExistsByPhone(ctx context.Context, phone string) (bool, error) {
	return false, errors.New("not implemented")
}

func (r *totpTestRepo) Search(ctx context.Context, keyword string, offset, limit int) ([]*domain.User, int64, error) {
	return nil, 0, errors.New("not implemented")
}

func (r *totpTestRepo) ConsumeTOTPRecoveryCode(ctx context.Context, userID int64, code string) (*domain.User, bool, error) {
	r.consumeRecoveryCodeCalled = true
	if r.consumeRecoveryCodeErr != nil {
		return nil, false, r.consumeRecoveryCodeErr
	}
	if r.user == nil || r.user.ID != userID {
		return nil, false, errors.New("not found")
	}

	var hashedCodes []string
	if strings.TrimSpace(r.user.TOTPRecoveryCodes) != "" {
		if err := json.Unmarshal([]byte(r.user.TOTPRecoveryCodes), &hashedCodes); err != nil {
			return nil, false, fmt.Errorf("解析恢复码失败: %w", err)
		}
	}
	idx, matched := auth.VerifyRecoveryCode(code, hashedCodes)
	if !matched {
		return nil, false, nil
	}

	copyUser := *r.user
	hashedCodes = append(hashedCodes[:idx], hashedCodes[idx+1:]...)
	copyUser.TOTPRecoveryCodes = mustMarshalJSONFromHelper(hashedCodes)
	r.user = &copyUser
	return &copyUser, true, nil
}

func (r *totpTestRepo) VerifyTOTPOrRecoveryCode(ctx context.Context, userID int64, code string) (bool, error) {
	r.verifyTOTPOrRecoveryCodeCalled = true
	if r.verifyTOTPOrRecoveryCodeErr != nil {
		return false, r.verifyTOTPOrRecoveryCodeErr
	}
	if r.user == nil || r.user.ID != userID {
		return false, errors.New("not found")
	}
	if !r.user.TOTPEnabled {
		return false, errors.New("TOTP not enabled")
	}

	// 尝试验证 TOTP 码（简化：只检查是否为特定测试码）
	if code == "123456" || code == "654321" {
		return true, nil
	}

	// 尝试验证恢复码
	var hashedCodes []string
	if strings.TrimSpace(r.user.TOTPRecoveryCodes) != "" {
		if err := json.Unmarshal([]byte(r.user.TOTPRecoveryCodes), &hashedCodes); err != nil {
			return false, fmt.Errorf("解析恢复码失败: %w", err)
		}
	}
	_, matched := auth.VerifyRecoveryCode(code, hashedCodes)
	return matched, nil
}

func mustMarshalJSONFromHelper(value any) string {
	payload, err := json.Marshal(value)
	if err != nil {
		panic(err)
	}
	return string(payload)
}

func TestTOTPService_ReturnsDecodeErrorForCorruptedRecoveryCodes(t *testing.T) {
	repo := &totpTestRepo{user: &domain.User{
		ID:                42,
		Username:          "totp-user",
		TOTPEnabled:       true,
		TOTPSecret:        "invalid-secret",
		TOTPRecoveryCodes: "not-json",
	}}
	svc := NewTOTPService(repo)

	err := svc.VerifyTOTP(context.Background(), 42, "recovery-code")
	if err == nil {
		t.Fatal("expected corrupted recovery-code payload to fail")
	}
	if !strings.Contains(err.Error(), "解析恢复码失败") {
		t.Fatalf("expected decode error, got: %v", err)
	}
}

func TestTOTPService_ReturnsAtomicConsumptionErrorAfterRecoveryCodeConsumption(t *testing.T) {
	repo := &totpTestRepo{
		user: &domain.User{
			ID:                7,
			Username:          "totp-user",
			TOTPEnabled:       true,
			TOTPSecret:        "invalid-secret",
			TOTPRecoveryCodes: mustMarshalJSON(t, []string{mustHashRecoveryCode(t, "RECOVERY-1")}),
		},
		consumeRecoveryCodeErr: errors.New("write failed"),
	}
	svc := NewTOTPService(repo)

	err := svc.VerifyTOTP(context.Background(), 7, "RECOVERY-1")
	if err == nil {
		t.Fatal("expected update failure to be returned")
	}
	if !repo.consumeRecoveryCodeCalled {
		t.Fatal("expected atomic consumption path to be invoked")
	}
	if !strings.Contains(err.Error(), "消费恢复码失败") {
		t.Fatalf("expected atomic consume error, got: %v", err)
	}
}

func TestTOTPService_ConsumesHashedRecoveryCodeOnVerify(t *testing.T) {
	repo := &totpTestRepo{
		user: &domain.User{
			ID:                8,
			Username:          "totp-user",
			TOTPEnabled:       true,
			TOTPSecret:        "invalid-secret",
			TOTPRecoveryCodes: mustMarshalJSON(t, []string{mustHashRecoveryCode(t, "RECOVERY-1"), mustHashRecoveryCode(t, "RECOVERY-2")}),
		},
	}
	svc := NewTOTPService(repo)

	if err := svc.VerifyTOTP(context.Background(), 8, "RECOVERY-1"); err != nil {
		t.Fatalf("expected hashed recovery code to verify, got: %v", err)
	}
	if !repo.consumeRecoveryCodeCalled {
		t.Fatal("expected atomic recovery-code consumption path to be used")
	}
	if repo.user == nil {
		t.Fatal("expected updated user to be persisted")
	}

	var remaining []string
	if err := json.Unmarshal([]byte(repo.user.TOTPRecoveryCodes), &remaining); err != nil {
		t.Fatalf("unmarshal remaining codes: %v", err)
	}
	if len(remaining) != 1 {
		t.Fatalf("expected 1 remaining recovery code, got %d", len(remaining))
	}
	if remaining[0] != mustHashRecoveryCode(t, "RECOVERY-2") {
		t.Fatalf("expected RECOVERY-2 hash to remain, got %q", remaining[0])
	}
}

func TestTOTPService_DisableTOTP_UsesAtomicVerificationPath(t *testing.T) {
	repo := &totpTestRepo{
		user: &domain.User{
			ID:                10,
			Username:          "totp-user",
			TOTPEnabled:       true,
			TOTPSecret:        "test-secret",
			TOTPRecoveryCodes: mustMarshalJSON(t, []string{mustHashRecoveryCode(t, "RECOVERY-1")}),
		},
	}
	svc := NewTOTPService(repo)

	// 使用测试恢复码禁用 TOTP
	if err := svc.DisableTOTP(context.Background(), 10, "RECOVERY-1"); err != nil {
		t.Fatalf("expected disable to succeed with recovery code, got: %v", err)
	}

	if !repo.verifyTOTPOrRecoveryCodeCalled {
		t.Fatal("expected atomic verification path to be used")
	}

	if repo.user.TOTPEnabled {
		t.Fatal("expected TOTP to be disabled")
	}
}

func TestTOTPService_DisableTOTP_AtomicVerificationFailsOnWrongCode(t *testing.T) {
	repo := &totpTestRepo{
		user: &domain.User{
			ID:                11,
			Username:          "totp-user",
			TOTPEnabled:       true,
			TOTPSecret:        "test-secret",
			TOTPRecoveryCodes: mustMarshalJSON(t, []string{mustHashRecoveryCode(t, "RECOVERY-1")}),
		},
	}
	svc := NewTOTPService(repo)

	// 使用错误的恢复码
	err := svc.DisableTOTP(context.Background(), 11, "WRONG-CODE")
	if err == nil {
		t.Fatal("expected disable to fail with wrong code")
	}

	if !repo.verifyTOTPOrRecoveryCodeCalled {
		t.Fatal("expected atomic verification path to be used")
	}

	if !repo.user.TOTPEnabled {
		t.Fatal("expected TOTP to remain enabled after failed verification")
	}
}

func TestTOTPService_DisableAcceptsHashedRecoveryCode(t *testing.T) {
	repo := &totpTestRepo{
		user: &domain.User{
			ID:                9,
			Username:          "totp-user",
			TOTPEnabled:       true,
			TOTPSecret:        "invalid-secret",
			TOTPRecoveryCodes: mustMarshalJSON(t, []string{mustHashRecoveryCode(t, "RECOVERY-1")}),
		},
	}
	svc := NewTOTPService(repo)

	if err := svc.DisableTOTP(context.Background(), 9, "RECOVERY-1"); err != nil {
		t.Fatalf("expected hashed recovery code to disable TOTP, got: %v", err)
	}
	if repo.user == nil {
		t.Fatal("expected updated user to be persisted")
	}
	if repo.user.TOTPEnabled {
		t.Fatal("expected TOTP to be disabled")
	}
	if repo.user.TOTPSecret != "" || repo.user.TOTPRecoveryCodes != "" {
		t.Fatalf("expected TOTP secret and recovery codes to be cleared, got secret=%q codes=%q", repo.user.TOTPSecret, repo.user.TOTPRecoveryCodes)
	}
}