package repository

import (
	"codeword/internal/models"
	codeword_rpc "codeword/internal/proto/codeword"
	"context"
	"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"
)

type StatsRepository struct {
	mdb *mongo.Collection
}

func NewStatsRepository(deps Deps) *StatsRepository {

	return &StatsRepository{mdb: deps.Mdb}
}

func (r *StatsRepository) UpdateStatistics(ctx context.Context, req *models.ActivateReq, promoCode *models.PromoCode, userID string) error {
	var key string
	if req.FastLink != "" {
		key = req.FastLink
	} else {
		key = "-"
	}

	var promoCodeStats models.PromoCodeStats
	err := r.mdb.FindOne(ctx, bson.M{"_id": promoCode.ID}).Decode(&promoCodeStats)
	if err != nil && mongo.ErrNoDocuments == nil {
		return err
	}

	if promoCodeStats.UsageMap != nil {
		usageList := promoCodeStats.UsageMap[key]
		for _, usage := range usageList {
			if usage.UserID == userID {
				return ErrPromoCodeAlreadyActivated
			}
		}
	}

	usage := models.Usage{
		UserID: userID,
		Time:   uint64(time.Now().Unix()),
	}

	update := bson.M{
		"$push": bson.M{
			"usageMap." + key: usage,
		},
	}

	opts := options.Update().SetUpsert(true)
	_, err = r.mdb.UpdateOne(ctx, bson.M{"_id": promoCode.ID}, update, opts)
	return err
}

func (r *StatsRepository) GetStatistics(ctx context.Context, promoCodeID string) (models.PromoCodeStats, error) {
	objID, err := primitive.ObjectIDFromHex(promoCodeID)
	if err != nil {
		return models.PromoCodeStats{}, err
	}

	filter := bson.M{"_id": objID}

	var promoCodeStats models.PromoCodeStats
	err = r.mdb.FindOne(ctx, filter).Decode(&promoCodeStats)
	if err != nil {
		if err == mongo.ErrNoDocuments {
			return models.PromoCodeStats{}, nil
		}
		return models.PromoCodeStats{}, err
	}

	return promoCodeStats, nil
}

func (r *StatsRepository) GetAllPromoActivations(ctx context.Context, req *codeword_rpc.Time) (*codeword_rpc.PromoActivationResp, error) {
	pipeline := []bson.M{
		{
			"$project": bson.M{
				"_id":        1,
				"usageArray": bson.M{"$objectToArray": "$usageMap"},
			},
		},
		{
			"$unwind": "$usageArray",
		},
		{
			"$unwind": "$usageArray.v",
		},
		{
			"$group": bson.M{
				"_id": "$_id",
				"users": bson.M{"$push": bson.M{
					"UserID": "$usageArray.v.userID",
					"Time":   "$usageArray.v.time",
				}},
			},
		},
	}

	cursor, err := r.mdb.Aggregate(ctx, pipeline)
	if err != nil {
		return nil, err
	}

	result := make(map[string]*codeword_rpc.PromoActivationResp_Activations)
	for cursor.Next(ctx) {
		var data struct {
			ID    string `bson:"_id"`
			Users []struct {
				UserID string `bson:"UserID"`
				Time   int64
			} `bson:"users"`
		}
		err := cursor.Decode(&data)
		if err != nil {
			return nil, err
		}

		if _, ok := result[data.ID]; !ok {
			result[data.ID] = &codeword_rpc.PromoActivationResp_Activations{}
		}

		for _, user := range data.Users {
			result[data.ID].Values = append(result[data.ID].Values, user.UserID)
		}
	}

	return &codeword_rpc.PromoActivationResp{
		Response: result,
	}, nil
}