package models

import (
	"time"
)

// User Graph datamodel
type User struct {
	ID     string `json:"id"`
	Email  string `json:"email"`

	FirstName   string `json:"firstName"`
	LastName    string `json:"lastName"`

	CreatedAt     time.Time `json:"createdAt"`
	UpdatedAt     time.Time `json:"updatedAt"`
}

// Create the loader that resembles other loaders in the dataloaders package
// This is merely an example

func User(db *pg.DB, w http.ResponseWriter, r *http.Request, next http.Handler) {
	loader := generated.NewUserLoader(generated.UserLoaderConfig{
		MaxBatch: 100,
		Wait:     1 * time.Millisecond,
		Fetch: func(keys []int) ([]*models.User, []error) {

			var dbUsers []*models.User
			// This query does NOT return an array that matches the order of the IN
			// clause.  Meaning: SELECT * FROM Users where id IN (1,8,3)
			// will not return users 1, 8, 3 in that order.  This order is VERY important
			// as that is how the dataloaden library resolves and matches objects.  Note the ids here are collected via
			// goroutines and the order is not going to be nicely ordered to match your DB
			// result query.  Try adding a breakpoint here and looking at the arg(keys) and the
			// resulting array from the following where query.
			err := db.Model(&dbUsers).WhereIn("id IN (?)", keys).Select()

			if err != nil {
				return []*models.User{}, []error{err}
			}

			// All we're doing here on out is just ordering our
			// collection to match the argument keys []int collection
			userKeys := make(map[int]*models.User)
			users := make([]*models.User, len(keys))

			for _, user := range dbUsers {
				userKeys[user.ID] = user

			}

			for i, k := range keys {
				if user, ok := userKeys[k]; ok {
					users[i] = user
				}
			}

			return users, []error{err}
		},
	})

	ctx := context.WithValue(r.Context(), UserLoader, loader)
	next.ServeHTTP(w, r.WithContext(ctx))
}


// Add a new entry in the NewMiddleware function

func NewMiddleware(session *mgo.Session) []func(handler http.Handler) http.Handler {
	return []func(handler http.Handler) http.Handler{
		setLoader(session, User),
    // setLoader(session, YourLoader)
	}
}