package api

import (
	"context"
	"database/sql"
	"log"

	codequestpb "github.com/hhhapz/codequest/api/v1"
	"github.com/hhhapz/codequest/models"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/types/known/timestamppb"
)

type UserService struct {
	codequestpb.UnimplementedUserServiceServer

	userStore UserStore
}

func (us *UserService) User(ctx context.Context, req *codequestpb.UserRequest) (*codequestpb.User, error) {
	u := UserCtx(ctx)
	return convertUser(u), nil
}

func (us *UserService) UserByEmail(ctx context.Context, req *codequestpb.UserByEmailRequest) (*codequestpb.User, error) {
	u := UserCtx(ctx)
	if u.Email == req.Email {
		return convertUser(u), nil
	}

	var err error
	if ctx, err = AdminOnly(ctx); err != nil {
		return nil, err
	}

	user, err := us.userStore.User(ctx, req.Email)
	if err != nil {
		log.Printf("Could not fetch user(%q): %v", req.Email, err)
		return nil, status.Errorf(codes.NotFound, "email not found: %q", req.Email)
	}

	return convertUser(user), nil
}

func (us *UserService) AllUsers(ctx context.Context, req *codequestpb.AllUsersRequest) (*codequestpb.AllUsersResponse, error) {
	var err error
	if ctx, err = AdminOnly(ctx); err != nil {
		return nil, err
	}

	users, err := us.userStore.Users(ctx)
	if err != nil {
		log.Printf("Could not fetch all users: %v", err)
		return nil, status.Errorf(codes.Internal, "unable to fetch users")
	}

	var userList []*codequestpb.User
	for _, u := range users {
		userList = append(userList, convertUser(u))
	}
	return &codequestpb.AllUsersResponse{Users: userList}, nil
}

func (us *UserService) UpdateUser(ctx context.Context, req *codequestpb.UpdateUserRequest) (*codequestpb.User, error) {
	u := UserCtx(ctx)

	u.Name = req.Body.Name
	if len(u.Name) < 3 || len(u.Name) > 20 {
		return nil, status.Errorf(codes.InvalidArgument, "name must be between 3 and 20 characters")
	}

	gl := req.Body.GradeLevel
	u.GradeLevel = sql.NullInt64{Int64: int64(gl), Valid: true}
	if gl < 9 || gl > 12 {
		return nil, status.Errorf(codes.InvalidArgument, "grade level must be between 9 and 12")
	}

	if err := us.userStore.UpdateUser(ctx, u); err != nil {
		log.Printf("could not update user: %v", err)
		return nil, status.Errorf(codes.Internal, "unable to update user")
	}

	return convertUser(u), nil
}

func (us *UserService) AdminUpdateUser(ctx context.Context, req *codequestpb.UpdateUserRequest) (*codequestpb.User, error) {
	var err error
	if ctx, err = AdminOnly(ctx); err != nil {
		return nil, err
	}

	user, err := us.userStore.User(ctx, req.Email)
	if err != nil {
		log.Printf("Could not fetch user(%q): %v", req.Email, err)
		return nil, status.Errorf(codes.NotFound, "email not found: %q", req.Email)
	}

	user.Name = req.Body.Name
	if len(user.Name) < 3 || len(user.Name) > 20 {
		return nil, status.Errorf(codes.InvalidArgument, "name must be between 3 and 20 characters")
	}

	gl := req.Body.GradeLevel
	user.GradeLevel = sql.NullInt64{Int64: int64(gl), Valid: true}
	if gl < 9 || gl > 12 {
		return nil, status.Errorf(codes.InvalidArgument, "grade level must be between 9 and 12")
	}

	user.Admin = req.Body.Admin

	if err := us.userStore.UpdateUser(ctx, user); err != nil {
		log.Printf("could not update user: %v", err)
		return nil, status.Errorf(codes.Internal, "unable to update user")
	}

	return convertUser(user), nil
}

func (us *UserService) DeleteUser(ctx context.Context, req *codequestpb.DeleteUserRequest) (*codequestpb.User, error) {
	var err error
	if ctx, err = AdminOnly(ctx); err != nil {
		return nil, err
	}

	user, err := us.userStore.User(ctx, req.Email)
	if err != nil {
		log.Printf("Could not fetch user(%q): %v", req.Email, err)
		return nil, status.Errorf(codes.NotFound, "email not found: %q", req.Email)
	}

	if err := us.userStore.DeleteUser(ctx, user); err != nil {
		log.Printf("could not delete user: %v", err)
		return nil, status.Errorf(codes.Internal, "unable to delete user")
	}

	return convertUser(user), nil
}

func convertUser(u *models.User) *codequestpb.User {
	return &codequestpb.User{
		Admin:      u.Admin,
		Email:      u.Email,
		GradeLevel: int32(u.GradeLevel.Int64),
		ID:         u.ID,
		Name:       u.Name,
		Picture:    u.Picture,
		CreatedAt:  timestamppb.New(u.CreatedAt.Time()),
	}
}