package auth

import (
	"context"
	"fmt"

	"github.com/food-ai/backend/internal/user"
)

type Service struct {
	tokenVerifier TokenVerifier
	userRepo      user.UserRepository
	jwtManager    *JWTManager
}

func NewService(tokenVerifier TokenVerifier, userRepo user.UserRepository, jwtManager *JWTManager) *Service {
	return &Service{
		tokenVerifier: tokenVerifier,
		userRepo:      userRepo,
		jwtManager:    jwtManager,
	}
}

type LoginResponse struct {
	AccessToken  string     `json:"access_token"`
	RefreshToken string     `json:"refresh_token"`
	ExpiresIn    int        `json:"expires_in"`
	User         *user.User `json:"user"`
}

type RefreshResponse struct {
	AccessToken  string `json:"access_token"`
	RefreshToken string `json:"refresh_token"`
	ExpiresIn    int    `json:"expires_in"`
}

func (s *Service) Login(ctx context.Context, firebaseToken string) (*LoginResponse, error) {
	uid, email, name, avatarURL, err := s.tokenVerifier.VerifyToken(ctx, firebaseToken)
	if err != nil {
		return nil, fmt.Errorf("verify firebase token: %w", err)
	}

	u, err := s.userRepo.UpsertByFirebaseUID(ctx, uid, email, name, avatarURL)
	if err != nil {
		return nil, fmt.Errorf("upsert user: %w", err)
	}

	accessToken, err := s.jwtManager.GenerateAccessToken(u.ID, u.Plan)
	if err != nil {
		return nil, fmt.Errorf("generate access token: %w", err)
	}

	refreshToken, expiresAt := s.jwtManager.GenerateRefreshToken()
	if err := s.userRepo.SetRefreshToken(ctx, u.ID, refreshToken, expiresAt); err != nil {
		return nil, fmt.Errorf("set refresh token: %w", err)
	}

	return &LoginResponse{
		AccessToken:  accessToken,
		RefreshToken: refreshToken,
		ExpiresIn:    int(s.jwtManager.AccessDuration().Seconds()),
		User:         u,
	}, nil
}

func (s *Service) Refresh(ctx context.Context, refreshToken string) (*RefreshResponse, error) {
	u, err := s.userRepo.FindByRefreshToken(ctx, refreshToken)
	if err != nil {
		return nil, fmt.Errorf("invalid refresh token: %w", err)
	}

	accessToken, err := s.jwtManager.GenerateAccessToken(u.ID, u.Plan)
	if err != nil {
		return nil, fmt.Errorf("generate access token: %w", err)
	}

	newRefreshToken, expiresAt := s.jwtManager.GenerateRefreshToken()
	if err := s.userRepo.SetRefreshToken(ctx, u.ID, newRefreshToken, expiresAt); err != nil {
		return nil, fmt.Errorf("set refresh token: %w", err)
	}

	return &RefreshResponse{
		AccessToken:  accessToken,
		RefreshToken: newRefreshToken,
		ExpiresIn:    int(s.jwtManager.AccessDuration().Seconds()),
	}, nil
}

func (s *Service) Logout(ctx context.Context, userID string) error {
	return s.userRepo.ClearRefreshToken(ctx, userID)
}