package repository

import (
	"codeword/internal/models"
	"context"
	"errors"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"time"
)

var (
	ErrDuplicateCodeword = errors.New("duplicate codeword")
	ErrPromoCodeNotFound = errors.New("promo code not found")
)

type PromoCodeRepository struct {
	mdb *mongo.Collection
}

func NewPromoCodeRepository(mdb *mongo.Collection) *PromoCodeRepository {
	indexModel := mongo.IndexModel{
		Keys: bson.D{
			{"codeword", 1},
			{"delete", 1},
		},
		Options: options.Index().SetUnique(true).SetPartialFilterExpression(bson.M{"delete": false}),
	}
	_, err := mdb.Indexes().CreateOne(context.Background(), indexModel)
	if err != nil {
		panic(err)
	}

	return &PromoCodeRepository{mdb: mdb}
}

func (r *PromoCodeRepository) CreatePromoCode(ctx context.Context, promoCode *models.PromoCode) (*models.PromoCode, error) {
	promoCode.CreatedAt = time.Now()
	promoCode.ID = primitive.NewObjectID()

	_, err := r.mdb.InsertOne(ctx, promoCode)
	if err != nil {
		if writeErr, ok := err.(mongo.WriteException); ok {
			for _, writeError := range writeErr.WriteErrors {
				if writeError.Code == 11000 {
					return nil, ErrDuplicateCodeword
				}
			}
		}

		return nil, err
	}

	return promoCode, nil
}

func (r *PromoCodeRepository) EditPromoCode(ctx context.Context, editPromoCode *models.ReqEditPromoCode) (*models.PromoCode, error) {
	promoCodeID, err := primitive.ObjectIDFromHex(editPromoCode.ID)
	if err != nil {
		return nil, err
	}

	updateFields := bson.M{}
	if editPromoCode.Description != nil {
		updateFields["description"] = *editPromoCode.Description
	}
	if editPromoCode.Greetings != nil {
		updateFields["greetings"] = *editPromoCode.Greetings
	}
	if editPromoCode.DueTo != nil {
		updateFields["dueTo"] = *editPromoCode.DueTo
	}
	if editPromoCode.ActivationCount != nil {
		updateFields["activationCount"] = *editPromoCode.ActivationCount
	}
	if editPromoCode.Delete != nil {
		updateFields["delete"] = *editPromoCode.Delete
	}

	if len(updateFields) == 0 {
		return r.GetPromoCodeByID(ctx, promoCodeID)
	}

	update := bson.M{"$set": updateFields}
	result, err := r.mdb.UpdateOne(ctx, bson.M{"_id": promoCodeID}, update)
	if err != nil {
		return nil, err
	}

	if result.MatchedCount == 0 {
		return nil, ErrPromoCodeNotFound
	}

	return r.GetPromoCodeByID(ctx, promoCodeID)
}

func (r *PromoCodeRepository) GetPromoCodeByID(ctx context.Context, promoCodeID primitive.ObjectID) (*models.PromoCode, error) {
	var promoCode models.PromoCode
	err := r.mdb.FindOne(ctx, bson.M{"_id": promoCodeID}).Decode(&promoCode)
	if err != nil {
		if err == mongo.ErrNoDocuments {
			return nil, ErrPromoCodeNotFound
		}

		return nil, err
	}

	return &promoCode, nil
}