package server

import (
	"context"
	"fmt"
	"strconv"
	"time"

	pb "go-microservices/proto/auth"
	"go-microservices/services/auth-service/internal/models"
	"go-microservices/services/auth-service/internal/repository"
	"go-microservices/services/auth-service/internal/utils"

	"golang.org/x/crypto/bcrypt"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type AuthServer struct {
	pb.UnimplementedAuthServiceServer
	repo *repository.Repository
}

func NewAuthServer(repo *repository.Repository) *AuthServer {
	return &AuthServer{repo: repo}
}

func (s *AuthServer) SignUp(ctx context.Context, req *pb.SignUpRequest) (*pb.SignUpResponse, error) {
	hashed, err := bcrypt.GenerateFromPassword([]byte(req.Password), bcrypt.DefaultCost)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "failed to hash password: %v", err)
	}

	auth := &models.Auth{
		Username: req.Username,
		Email:    req.Email,
		Password: string(hashed),
		Role:     "user", // default role (proto SignUpRequest doesn't include role)
	}

	if err := s.repo.CreateAuth(auth); err != nil {
		return nil, status.Errorf(codes.Internal, "failed to create user: %v", err)
	}

	userID := fmt.Sprintf("%d", auth.ID)
	return &pb.SignUpResponse{UserId: userID, Message: "registered"}, nil
}

func (s *AuthServer) SignIn(ctx context.Context, req *pb.SignInRequest) (*pb.SignInResponse, error) {
	auth, err := s.repo.GetAuthByEmail(req.Email)
	if err != nil || auth == nil {
		return nil, status.Errorf(codes.Unauthenticated, "invalid credentials")
	}

	if err := bcrypt.CompareHashAndPassword([]byte(auth.Password), []byte(req.Password)); err != nil {
		return nil, status.Errorf(codes.Unauthenticated, "invalid credentials")
	}

	accessToken, refreshToken, err := utils.GenerateJWT(*auth)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "failed to generate tokens: %v", err)
	}

	userID := fmt.Sprintf("%d", auth.ID)
	return &pb.SignInResponse{
		AccessToken:  accessToken,
		RefreshToken: refreshToken,
		UserId:       userID,
		Message:      "logged in",
	}, nil
}

func (s *AuthServer) ValidateToken(ctx context.Context, req *pb.ValidateTokenRequest) (*pb.ValidateTokenResponse, error) {
	claims, err := utils.ValidateJWT(req.Token, false)
	if err != nil {
		return &pb.ValidateTokenResponse{Valid: false, UserId: "", Message: "invalid token"}, nil
	}

	var userID string
	if sub, ok := claims["sub"]; ok {
		switch v := sub.(type) {
		case string:
			userID = v
		case float64:
			userID = strconv.FormatFloat(v, 'f', 0, 64)
		default:
			userID = fmt.Sprintf("%v", v)
		}
	}

	if userID == "" {
		return &pb.ValidateTokenResponse{Valid: false, UserId: "", Message: "invalid token"}, nil
	}

	return &pb.ValidateTokenResponse{Valid: true, UserId: userID, Message: "valid"}, nil
}

func (s *AuthServer) GetUserInfo(ctx context.Context, req *pb.GetUserInfoRequest) (*pb.GetUserInfoResponse, error) {
	// expect req.UserId (proto field user_id)
	if req.UserId == "" {
		return nil, status.Errorf(codes.InvalidArgument, "user id required")
	}
	u64, err := strconv.ParseUint(req.UserId, 10, 64)
	if err != nil {
		return nil, status.Errorf(codes.InvalidArgument, "invalid user id: %v", err)
	}
	user, err := s.repo.GetAuthByID(uint(u64))
	if err != nil || user == nil {
		return nil, status.Errorf(codes.NotFound, "user not found")
	}

	return &pb.GetUserInfoResponse{
		UserId:   fmt.Sprintf("%d", user.ID),
		Username: user.Username,
		Email:    user.Email,
		Roles:    []string{user.Role},
	}, nil
}

// CreateTest creates a simple Test record in the database
func (s *AuthServer) CreateTest(ctx context.Context, req *pb.CreateTestRequest) (*pb.CreateTestResponse, error) {
	if req.Content == "" {
		return nil, status.Errorf(codes.InvalidArgument, "content required")
	}
	t := &models.Test{Content: req.Content}
	if err := s.repo.CreateTest(t); err != nil {
		return nil, status.Errorf(codes.Internal, "failed to create test: %v", err)
	}
	return &pb.CreateTestResponse{
		Test: &pb.Test{
			Id:        uint64(t.ID),
			Content:   t.Content,
			CreatedAt: t.CreatedAt.Format(time.RFC3339),
		},
	}, nil
}

// ListTests returns recent test records
func (s *AuthServer) ListTests(ctx context.Context, req *pb.ListTestsRequest) (*pb.ListTestsResponse, error) {
	tests, err := s.repo.ListTests()
	if err != nil {
		return nil, status.Errorf(codes.Internal, "failed to list tests: %v", err)
	}
	resp := &pb.ListTestsResponse{Tests: make([]*pb.Test, 0, len(tests))}
	for _, t := range tests {
		resp.Tests = append(resp.Tests, &pb.Test{
			Id:        uint64(t.ID),
			Content:   t.Content,
			CreatedAt: t.CreatedAt.Format(time.RFC3339),
		})
	}
	return resp, nil
}

// GetTest retrieves a single test by ID
func (s *AuthServer) GetTest(ctx context.Context, req *pb.GetTestRequest) (*pb.GetTestResponse, error) {
	if req.Id == 0 {
		return nil, status.Errorf(codes.InvalidArgument, "test id required")
	}
	t, err := s.repo.GetTestByID(uint(req.Id))
	if err != nil || t == nil {
		return nil, status.Errorf(codes.NotFound, "test not found")
	}
	return &pb.GetTestResponse{
		Test: &pb.Test{
			Id:        uint64(t.ID),
			Content:   t.Content,
			CreatedAt: t.CreatedAt.Format(time.RFC3339),
		},
	}, nil
}

// UpdateTest updates an existing test
func (s *AuthServer) UpdateTest(ctx context.Context, req *pb.UpdateTestRequest) (*pb.UpdateTestResponse, error) {
	if req.Id == 0 {
		return nil, status.Errorf(codes.InvalidArgument, "test id required")
	}
	if req.Content == "" {
		return nil, status.Errorf(codes.InvalidArgument, "content required")
	}
	t, err := s.repo.GetTestByID(uint(req.Id))
	if err != nil || t == nil {
		return nil, status.Errorf(codes.NotFound, "test not found")
	}
	t.Content = req.Content
	if err := s.repo.UpdateTest(t); err != nil {
		return nil, status.Errorf(codes.Internal, "failed to update test: %v", err)
	}
	return &pb.UpdateTestResponse{
		Test: &pb.Test{
			Id:        uint64(t.ID),
			Content:   t.Content,
			CreatedAt: t.CreatedAt.Format(time.RFC3339),
		},
	}, nil
}

// DeleteTest deletes a test by ID
func (s *AuthServer) DeleteTest(ctx context.Context, req *pb.DeleteTestRequest) (*pb.DeleteTestResponse, error) {
	if req.Id == 0 {
		return nil, status.Errorf(codes.InvalidArgument, "test id required")
	}
	if err := s.repo.DeleteTest(uint(req.Id)); err != nil {
		return nil, status.Errorf(codes.Internal, "failed to delete test: %v", err)
	}
	return &pb.DeleteTestResponse{
		Success: true,
		Message: "test deleted",
	}, nil
}